Cassini Information Management System in Distributed Operations Collaboration and Cassini Science Planning

Science.gov (United States)

Equils, Douglas J.

2008-01-01

Launched on October 15, 1997, the Cassini-Huygens spacecraft began its ambitious journey to the Saturnian system with a complex suite of 12 scientific instruments, and another 6 instruments aboard the European Space Agencies Huygens Probe. Over the next 6 1/2 years, Cassini would continue its relatively simplistic cruise phase operations, flying past Venus, Earth, and Jupiter. However, following Saturn Orbit Insertion (SOI), Cassini would become involved in a complex series of tasks that required detailed resource management, distributed operations collaboration, and a data base for capturing science objectives. Collectively, these needs were met through a web-based software tool designed to help with the Cassini uplink process and ultimately used to generate more robust sequences for spacecraft operations. In 2001, in conjunction with the Southwest Research Institute (SwRI) and later Venustar Software and Engineering Inc., the Cassini Information Management System (CIMS) was released which enabled the Cassini spacecraft and science planning teams to perform complex information management and team collaboration between scientists and engineers in 17 countries. Originally tailored to help manage the science planning uplink process, CIMS has been actively evolving since its inception to meet the changing and growing needs of the Cassini uplink team and effectively reduce mission risk through a series of resource management validation algorithms. These algorithms have been implemented in the web-based software tool to identify potential sequence conflicts early in the science planning process. CIMS mitigates these sequence conflicts through identification of timing incongruities, pointing inconsistencies, flight rule violations, data volume issues, and by assisting in Deep Space Network (DSN) coverage analysis. In preparation for extended mission operations, CIMS has also evolved further to assist in the planning and coordination of the dual playback redundancy of

Modernization of the Cassini Ground System

Science.gov (United States)

Razo, Gus; Fujii, Tammy

2014-01-01

The Cassini Spacecraft and its ground system have been operational for over 16 years. Modernization presents several challenges due to the personnel, processes, and tools already invested and embedded into the current ground system structure. Every mission's ground system has its own unique complexities and challenges, involving various organizational units. As any mission from its inception to its execution, schedules are always tight. This forces GDS engineers to implement a working ground system that is not necessarily fully optimized. Ground system challenges increase as technology evolves and cyber threats become more sophisticated. Cassini's main challenges were due to its ground system existing before many security requirements were levied on the multi-mission tools and networks. This caused a domino effect on Cassini GDS tools that relied on outdated technological features. In the aerospace industry reliable and established technology is preferred over innovative yet less proven technology. Loss of data for a spacecraft mission can be catastrophic; therefore, there is a reluctance to make changes and updates to the ground system. Nevertheless, all missions and associated teams face the need to modernize their processes and tools. Systems development methods from well-known system analysis and design principles can be applied to many missions' ground systems. Modernization should always be considered, but should be done in such a way that it does not affect flexibility nor interfere with established practices. Cassini has accomplished a secure and efficient ground data system through periodic updates. The obstacles faced while performing the modernization of the Cassini ground system will be outlined, as well as the advantages and challenges that were encountered.

Cassini: The Journey and the Legacy

KAUST Repository

Porco, Carolyn

2018-01-15

An international mission to explore, in depth, the Saturnian system ﾖthe planet Saturn and its magnetosphere, glorious rings, and many moons- begun over 27 years ago. After seven years of development, the Cassini spacecraft was launched in 1997, spent seven years trekking to Saturn, and finally entered Saturn orbit in the summer of 2004. In the course of its 13 years orbiting this ring world, Cassini returned over 450 thousand images, 635GB of data, and invaluable insights on the solar systemﾒs most splendid and scientifically rich planetary system. In this lecture, Carolyn Porco, the leader of the imaging science team on NASA\\'s Cassini mission, will delight her audience with a retrospective look at what has been learned from this profoundly successful mission and what its final legacy is likely to be.

Cassini radar: Instrument description and performance status

Science.gov (United States)

Johnson, W. T. K.; Im, E.; Borgarelli, L.; ZampoliniFaustini, E.

1995-01-01

The spacecraft of the Cassini mission is planned to be launched towards Saturn in October 1997. The mission is designed to study the physical structure and chemical composition of Titan. The results of the tests performed on the Cassini radar engineering qualification model (EQM) are summarized. The approach followed in the verification and evaluation of the performance of the radio frequency subsystem EQM is presented. The results show that the instrument satisfies the most relevant mission requirements.

Titan's Topography and Shape at the End of the Cassini Mission

Science.gov (United States)

Corlies, P.; Hayes, A. G.; Birch, S. P. D.; Lorenz, R.; Stiles, B. W.; Kirk, R.; Poggiali, V.; Zebker, H.; Iess, L.

2017-12-01

With the conclusion of the Cassini mission, we present an updated topographic map of Titan, including all the available altimetry, SARtopo, and stereophotogrammetry topographic data sets available from the mission. We use radial basis functions to interpolate the sparse data set, which covers only ˜9% of Titan's global area. The most notable updates to the topography include higher coverage of the poles of Titan, improved fits to the global shape, and a finer resolution of the global interpolation. We also present a statistical analysis of the error in the derived products and perform a global minimization on a profile-by-profile basis to account for observed biases in the input data set. We find a greater flattening of Titan than measured, additional topographic rises in Titan's southern hemisphere and better constrain the possible locations of past and present liquids on Titan's surface.

Light weight radioisotope heater unit (LWRHU) production for the Cassini mission

International Nuclear Information System (INIS)

Rinehart, G.H.

1997-01-01

The Light-Weight Radioisotope Heater Unit (LWRHU) is a [sup 238]PuO[sub 2] fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. The heat sources are required to maintain the temperature of specific components within normal operating ranges. The heat source consists of a hot- pressed [sup 238]PuO[sub 2] fuel pellet, a Pt-3ORh vented capsule, a pyrolytic graphite insulator, and a woven graphite aeroshell assembly. Los Alamos National Laboratory has fabricated 180 heat sources, 157 of which will be used on the Cassini mission

Cassini-Huygens Nears Saturn Orbit Insertion

Science.gov (United States)

Showstack, Randy

2004-06-01

After nearly 7 years and a 3.5-billion-km, circuitous journey from Earth, the $3-billion Cassini-Huygens mission to Saturn and Titan-an international effort by NASA, the European Space Agency, and the Italian Space Agency-now is just days away from its critical Saturn orbit insertion. Scheduled for 30 June, this will begin the 4-years part of the mission to study the Saturnian system. At a 3 June briefing at NASA headquarters in Washington, D.C., Robert Mitchell, the Cassini program manager with the Jet Propulsion Laboratory in Pasadena, California, said that scientists involved with the program are feeling excited, relieved, and also a bit anxious as the Cassini-Huygens spacecraft draws near to the ringed planet and its system.

GPHS-RTGs in support of the Cassini Mission. Semi annual technical progress report, 1 April 1996--29 September 1996

International Nuclear Information System (INIS)

1996-01-01

This technical progress report discusses work on the Radioisotope Generators and Ancillary Activities for the Cassini spacecraft. The Cassini spacecraft is expected to launch in October 1997, and will explore Saturn and its moons. This progress report discusses issues in: spacecraft integration and liason, engineering support, safety, qualified unicouple fabrication, ETG fabrication and testing, ground support equipment, RTG shipping and launch support, designs, reviews and mission application. Safety analysis of the RTGs during reentry and launch accidents are covered. This report covers the period of April 1 to September 29, 1996

Cassini Radar EQM Model: Instrument Description and Performance Status

Science.gov (United States)

Borgarelli, L.; Faustini, E. Zampolini; Im, E.; Johnson, W. T. K.

1996-01-01

The spaeccraft of the Cassini Mission is planned to be launched towards Saturn in October 1997. The mission is designed to study the physical structure and chemical composition of Titan. The results of the tests performed on the Cassini radar engineering qualification model (EQM) are summarized. The approach followed in the verification and evaluation of the performance of the radio frequency subsystem EQM is presented. The results show that the instrument satisfies the relevant mission requirements.

JUPITER’S PHASE VARIATIONS FROM CASSINI : A TESTBED FOR FUTURE DIRECT-IMAGING MISSIONS

International Nuclear Information System (INIS)

Mayorga, L. C.; Jackiewicz, J.; Rages, K.; West, R. A.; Knowles, B.; Lewis, N.; Marley, M. S.

2016-01-01

We present empirical phase curves of Jupiter from ∼0° to 140° as measured in multiple optical bandpasses by Cassini /Imaging Science Subsystem (ISS) during the Millennium flyby of Jupiter in late 2000 to early 2001. Phase curves are of interest for studying the energy balance of Jupiter and understanding the scattering behavior of the planet as an exoplanet analog. We find that Jupiter is significantly darker at partial phases than an idealized Lambertian planet by roughly 25% and is not well fit by Jupiter-like exoplanet atmospheric models across all wavelengths. We provide analytic fits to Jupiter’s phase function in several Cassini /ISS imaging filter bandpasses. In addition, these observations show that Jupiter’s color is more variable with phase angle than predicted by models. Therefore, the color of even a near Jupiter-twin planet observed at a partial phase cannot be assumed to be comparable to that of Jupiter at full phase. We discuss how the Wide-Field Infrared Survey Telescope and other future direct-imaging missions can enhance the study of cool giants.

Distributed Operations for the Cassini/Huygens Mission

Science.gov (United States)

Lock, P.; Sarrel, M.

1998-01-01

The cassini project employs a concept known as distributed operations which allows independent instrument operations from diverse locations, provides full empowerment of all participants and maximizes use of limited resources.

Outreach for Cassini Huyghens mission and future Saturn and Titan exploration: From the Antikythera Mechanism to the TSSM mission

Science.gov (United States)

Moussas, Xenophon; Bampasidis, Georgios; Coustenis, Athena; Solomonidou, Anezina

2010-05-01

These days Outreach is an activity tightly related to success in science. The public with its great interest to space and astronomy in general, the solar system exploration and Saturn and Titan in particular, loves the scientific outcome of Cassini and Huygens. This love of the public gives a lot, as its known interest to space, persuades politicians and policy makers to support space and future Saturn and Titan explorations. We use the scientific results from Cassini and Huyghens together with a mosaic from ancient science concerning the history of solar system exploration, such as the oldest known complex astronomical device, the Antikyhtera Mechanism, in outreach activities to ensure future missions and continuous support to present ones. A future mission to the Saturnian System focusing on exotic Titan will broaden people's interest not only to Physics and Astronomy, but to Mechanics, Technology and even Philosophy as well, since, obviously, the roots of the vast contribution of Space Science and Astronomy to the contemporary society can be traced back to the first astronomers of Antiquity. As an example we use the Antikythera Mechanism, a favourite astronomical device for the public, which is the first geared astronomical device ever, constructed that combines the spirit of the ancient Astronomy and scientific accuracy. It is common belief that Astronomy and Astrophysics is a perfect tool to easily involve people in Science, as the public is always interested in space subjects, captivated by the beauty and the mystery of the Universe. Years after the successful entry, descent and landing of the Huygens probe on Titan's surface, the outstanding achievements of the Cassini-Huygens mission enhance the outreach potential of Space Science. Titan is an earth-like world, embedded in a dense nitrogen atmospheric envelop and a surface carved by rivers, mountains, dunes and lakes, its exploration will certainly empower the perspective of the society for space activities

RTG performance on Galileo and Ulysses and Cassini test results

International Nuclear Information System (INIS)

Kelly, C. Edward; Klee, Paul M.

1997-01-01

Power output from telemetry for the two Galileo RTGs are shown from the 1989 launch to the recent Jupiter encounter. Comparisons of predicted, measured and required performance are shown. Similar comparisons are made for the RTG on the Ulysses spacecraft which completed its planned mission in 1995. Also presented are test results from small scale thermoelectric modules and full scale converters performed for the Cassini program. The Cassini mission to Saturn is scheduled for an October 1997 launch. Small scale module test results on thermoelectric couples from the qualification and flight production runs are shown. These tests have exceeded 19,000 hours are continuing to provide increased confidence in the predicted long term performance of the Cassini RTGs. Test results are presented for full scale units both ETGs (E-6, E-7) and RTGs (F-2, F-5) along with mission power predictions. F-5, fueled in 1985, served as a spare for the Galileo and Ulysses missions and plays the same role in the Cassini program. It has successfully completed all acceptance testing. The ten years storage between thermal vacuum tests is the longest ever experienced by an RTG. The data from this test are unique in providing the effects of long term low temperature storage on power output. All ETG and RTG test results to date indicate that the power requirements of the Cassini spacecraft will be met. BOM and EOM power margins of at least five percent are predicted

Cassini's Grand Finale Overview

Science.gov (United States)

Spilker, L. J.

2017-12-01

After 13 years in orbit, the Cassini-Huygens Mission to Saturn ended in a science-rich blaze of glory. Cassini sent back its final bits of unique science data on September 15, 2017, as it plunged into Saturn's atmosphere, vaporizing and satisfying planetary protection requirements. Cassini's final phase covered roughly ten months and ended with the first time exploration of the region between the rings and planet. In late 2016 Cassini transitioned to a series of 20 Ring Grazing orbits with peripases just outside Saturn's F ring, providing close flybys of tiny ring moons, including Pan, Daphnis and Atlas, and high-resolution views of Saturn's A and F rings. A final Titan flyby in late April 2017 propelled Cassini across Saturn's main rings and into its Grand Finale orbits. Comprised of 22 orbits, Cassini repeatedly dove between Saturn's innermost rings and upper atmosphere to answer fundamental questions unattainable earlier in the mission. The last orbit turned the spacecraft into the first Saturn atmosphere probe. The Grand Finale orbits provided highest resolution observations of both the rings and Saturn, and in-situ sampling of the ring particle composition, Saturn's atmosphere, plasma, and innermost radiation belts. The gravitational field was measured to unprecedented accuracy, providing information on the interior structure of the planet, winds in the deeper atmosphere, and mass of the rings. The magnetic field provided insight into the physical nature of the magnetic dynamo and structure of the internal magnetic field. The ion and neutral mass spectrometer sampled the upper atmosphere for molecules that escape the atmosphere in addition to molecules originating from the rings. The cosmic dust analyzer directly sampled the composition from different parts of the main rings for the first time. Fields and particles instruments directly measured the plasma environment between the rings and planet. Science highlights and new mysteries collected in the Grand

RTG performance on Galileo and Ulysses and Cassini test results

International Nuclear Information System (INIS)

Kelly, C.E.; Klee, P.M.

1997-01-01

Power output from telemetry for the two Galileo RTGs are shown from the 1989 launch to the recent Jupiter encounter. Comparisons of predicted, measured and required performance are shown. Similar comparisons are made for the RTG on the Ulysses spacecraft which completed its planned mission in 1995. Also presented are test results from small scale thermoelectric modules and full scale converters performed for the Cassini program. The Cassini mission to Saturn is scheduled for an October 1997 launch. Small scale module test results on thermoelectric couples from the qualification and flight production runs are shown. These tests have exceeded 19,000 hours are continuing to provide increased confidence in the predicted long term performance of the Cassini RTGs. Test results are presented for full scale units both ETGs (E-6, E-7) and RTGs (F-2, F-5) along with mission power predictions. F-5, fueled in 1985, served as a spare for the Galileo and Ulysses missions and plays the same role in the Cassini program. It has successfully completed all acceptance testing. The ten years storage between thermal vacuum tests is the longest ever experienced by an RTG. The data from this test are unique in providing the effects of long term low temperature storage on power output. All ETG and RTG test results to date indicate that the power requirements of the Cassini spacecraft will be met. BOM and EOM power margins of at least five percent are predicted. copyright 1997 American Institute of Physics

GPHS-RTGs in support of the Cassini Mission. Semi-annual technical progress report, April 3, 1995--October 1, 1995

International Nuclear Information System (INIS)

1995-01-01

This document is the April-October 1995 Progress Report on the Cassini RTG Program. Nine tasks are summarized; (1) Spacecraft integration and liason, (2) Engineering support, (3) Safety, (4) Unicouple fabrication, (5) ETG fabrication, assembly, and test, (6) Ground support equipment, (7) RTG shipping and launch support, (8) Design, reviews, and mission applications, and (9) Project management, QA, contract changes, and material acquisitions

Health Physics Innovations Developed During Cassini for Future Space Applications

Science.gov (United States)

Nickell, Rodney E.; Rutherford, Theresa M.; Marmaro, George M.

1999-01-01

The long history of space flight includes missions that used Space Nuclear Auxiliary Power devices, starting with the Transit 4A Spacecraft (1961), continuing through the Apollo, Pioneer, Viking, Voyager, Galileo, Ulysses, Mars Pathfinder, and most recently, Cassini (1997). All Major Radiological Source (MRS) missions were processed at Kennedy Space Center/Cape Canaveral Air Station (KSC/CCAS) Launch Site in full compliance with program and regulatory requirements. The cumulative experience gained supporting these past missions has led to significant innovations which will be useful for benchmarking future MRS mission ground processing. Innovations developed during ground support for the Cassini mission include official declaration of sealed-source classifications, utilization of a mobile analytical laboratory, employment of a computerized dosimetry record management system, and cross-utilization of personnel from related disciplines.

Cassini: The Journey and the Legacy

KAUST Repository

Porco, Carolyn

2018-01-01

An international mission to explore, in depth, the Saturnian system ﾖthe planet Saturn and its magnetosphere, glorious rings, and many moons- begun over 27 years ago. After seven years of development, the Cassini spacecraft was launched in 1997

Cassini Attitude and Articulation Control Subsystem Fault Protection Challenges During Saturn Proximal Orbits

Science.gov (United States)

Bates, David M.

2015-01-01

NASA's Cassini Spacecraft, launched on October 15th, 1997 arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004-08), and has since been approved for a first and second extended mission through 2017. As part of the final extended mission, Cassini will begin an aggressive and exciting campaign of high inclination low altitude flybys within the inner most rings of Saturn, skimming Saturn's outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, presents unique fault protection related challenges, the details of which are discussed in this paper.

CASSINI V/E/J/S/SS RPWS EDITED WAVEFORM FULL RES V1.0

Data.gov (United States)

National Aeronautics and Space Administration — The Cassini Radio and Plasma Wave Science (RPWS) edited full resolution data set includes all waveform data for the entire Cassini mission. This data set includes...

CASSINI MAGNETOMETER RAW DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains magnetic-field data acquired during the cruise and tour phases of the Cassini mission to Saturn. The data set begins with data collected on 16...

THERMAL AND CHEMICAL STRUCTURE VARIATIONS IN TITAN'S STRATOSPHERE DURING THE CASSINI MISSION

Energy Technology Data Exchange (ETDEWEB)

Bampasidis, Georgios; Coustenis, A.; Vinatier, S. [Laboratoire d' Etudes Spatiales et d' Instrumentation en Astrophysique (LESIA), Observatoire de Paris, CNRS, UPMC Univ. Paris 06, Univ. Paris-Diderot, 5, place Jules Janssen, F-92195 Meudon Cedex (France); Achterberg, R. K. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Lavvas, P. [GSMA, Universite Reims Champagne-Ardenne, F-51687 Reims Cedex 2 (France); Nixon, C. A.; Jennings, D. E.; Flasar, F. M.; Carlson, R. C.; Romani, P. N.; Guandique, E. A. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Teanby, N. A. [School of Earth Sciences, University of Bristol, Bristol BS8 1RJ (United Kingdom); Moussas, X.; Preka-Papadema, P.; Stamogiorgos, S., E-mail: gbabasid@phys.uoa.gr [Faculty of Physics, National and Kapodistrian University of Athens, Panepistimioupolis, GR 15783 Zographos, Athens (Greece)

2012-12-01

We have developed a line-by-line Atmospheric Radiative Transfer for Titan code that includes the most recent laboratory spectroscopic data and haze descriptions relative to Titan's stratosphere. We use this code to model Cassini Composite Infrared Spectrometer data taken during the numerous Titan flybys from 2006 to 2012 at surface-intercepting geometry in the 600-1500 cm{sup -1} range for latitudes from 50 Degree-Sign S to 50 Degree-Sign N. We report variations in temperature and chemical composition in the stratosphere during the Cassini mission, before and after the Northern Spring Equinox (NSE). We find indication for a weakening of the temperature gradient with warming of the stratosphere and cooling of the lower mesosphere. In addition, we infer precise concentrations for the trace gases and their main isotopologues and find that the chemical composition in Titan's stratosphere varies significantly with latitude during the 6 years investigated here, with increased mixing ratios toward the northern latitudes. In particular, we monitor and quantify the amplitude of a maximum enhancement of several gases observed at northern latitudes up to 50 Degree-Sign N around mid-2009, at the time of the NSE. We find that this rise is followed by a rapid decrease in chemical inventory in 2010 probably due to a weakening north polar vortex with reduced lateral mixing across the vortex boundary.

Cassini Operational Sun Sensor Risk Management During Proximal Orbit Saturn Ring Plane Crossings

Science.gov (United States)

Bates, David M.

2016-01-01

NASA's Cassini Spacecraft, launched on October 15th, 1997 which arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004–08), and has since been approved for a first and second extended mission through 2017. As part of the final extended missions, Cassini will begin an aggressive and exciting campaign of high inclination, low altitude flybys within the inner most rings of Saturn, skimming Saturn’s outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, requires a strategy for managing the Sun Sensor Assembly (SSA) health, the details of which are presented in this paper.

Enhancing Cassini Operations & Science Planning Tools

Science.gov (United States)

Castello, Jonathan

2012-01-01

The Cassini team uses a variety of software utilities as they manage and coordinate their mission to Saturn. Most of these tools have been unchanged for many years, and although stability is a virtue for long-lived space missions, there are some less-fragile tools that could greatly benefit from modern improvements. This report shall describe three such upgrades, including their architectural differences and their overall impact. Emphasis is placed on the motivation and rationale behind architectural choices rather than the final product, so as to illuminate the lessons learned and discoveries made.These three enhancements included developing a strategy for migrating Science Planning utilities to a new execution model, rewriting the team's internal portal for ease of use and maintenance, and developing a web-based agenda application for tracking the sequence of files being transmitted to the Cassini spacecraft. Of this set, the first two have been fully completed, while the agenda application is currently in the early prototype stage.

SORCE SOLSTICE FUV Level 3 Solar Spectral Irradiance Daily Means V012

Data.gov (United States)

National Aeronautics and Space Administration — The SORCE SOLSTICE Far-UV Solar Spectral Irradiance (SSI) data product SOR3SOLFUVD is constructed using measurements from the SOLSTICE FUV instrument, which are...

CASSINI SCALAR MAGNETOMETER CALIB DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains magnetic-field data acquired during the cruise and tour phases of the Cassini mission to Saturn. Data collection began on 16 August (day 228),...

Cassini UVIS Auroral Observations in 2016 and 2017

Science.gov (United States)

Pryor, Wayne R.; Esposito, Larry W.; Jouchoux, Alain; Radioti, Aikaterini; Grodent, Denis; Gustin, Jacques; Gerard, Jean-Claude; Lamy, Laurent; Badman, Sarah; Dyudina, Ulyana A.; Cassini UVIS Team, Cassini VIMS Team, Cassini ISS Team, HST Saturn Auroral Team

2017-10-01

In 2016 and 2017, the Cassini Saturn orbiter executed a final series of high-inclination, low-periapsis orbits ideal for studies of Saturn's polar regions. The Cassini Ultraviolet Imaging Spectrograph (UVIS) obtained an extensive set of auroral images, some at the highest spatial resolution obtained during Cassini's long orbital mission (2004-2017). In some cases, two or three spacecraft slews at right angles to the long slit of the spectrograph were required to cover the entire auroral region to form auroral images. We will present selected images from this set showing narrow arcs of emission, more diffuse auroral emissions, multiple auroral arcs in a single image, discrete spots of emission, small scale vortices, large-scale spiral forms, and parallel linear features that appear to cross in places like twisted wires. Some shorter features are transverse to the main auroral arcs, like barbs on a wire. UVIS observations were in some cases simultaneous with auroral observations from the Cassini Imaging Science Subsystem (ISS) the Cassini Visual and Infrared Mapping Spectrometer (VIMS), and the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) that will also be presented.

What Does Titan's Atmosphere Look Like Near The Poles At The End Of The Cassini Mission ?

Science.gov (United States)

Nixon, C. A.; Coustenis, A.; Jennings, D. E.; Achterberg, R. K.; Bampasidis, G.; Cottini, V.; Flasar, F. M.; Lavvas, P.

2017-12-01

The Cassini mission ends on Sept. 15, 2017, after - among other - 127 targeted Titan flybys. We have monitored the seasonal evolution near Titan's poles during the mission. Titan's North pole had been enhanced in chemical species since the beginning of the observations, but since 2010, we observe at Titan's south pole a strong temperature decrease and the onset of a dramatic enhancement of several trace species such as complex hydrocarbons and nitriles (HC3N and C6H6 in particular) previously observed only at high northern latitudes (Coustenis et al. 2016 and references therein). This is due to the transition of Titan's seasons from northern winter in 2002 to northern summer in 2017 and, at the same time, the advent of winter in the south pole, during which time species with longer chemical lifetimes remain in the north for a little longer undergoing slow photochemical destruction, while those with shorter lifetimes disappear, reappearing in the south. An opposite effect has been expected in the North, but not observed with any significant certainty until 2016. We present here an analysis of nadir spectra acquired by Cassini/CIRS (Jennings et al., 2017) at high resolution in the past years and describe the newly observed decrease in chemical abundances of the components in the North. From 2013 until 2016, the Northern polar region has shown a temperature increase of 10 K, while the South had shown a more significant decrease in a similar period of time. The chemical content in the North is finally showing a clear depletion for most molecules since 2015 (Coustenis et al., 2017). References: Coustenis et al., 2016, Icarus 270, 409-420 ; Coustenis et al., 2017, submitted; Jennings et al., 2017, Applied Optics 56, no 18, 5274-5294.

Titan after Cassini Huygens

Science.gov (United States)

Beauchamp, P. M.; Lunine, J.; Lebreton, J.; Coustenis, A.; Matson, D.; Reh, K.; Erd, C.

2008-12-01

In 2005, the Huygens Probe gave us a snapshot of a world tantalizingly like our own, yet frozen in its evolution on the threshold of life. The descent under parachute, like that of Huygens in 2005, is happening again, but this time in the Saturn-cast twilight of winter in Titan's northern reaches. With a pop, the parachute is released, and then a muffled splash signals the beginning of the first floating exploration of an extraterrestrial sea-this one not of water but of liquid hydrocarbons. Meanwhile, thousands of miles away, a hot air balloon, a "montgolfiere," cruises 6 miles above sunnier terrain, imaging vistas of dunes, river channels, mountains and valleys carved in water ice, and probing the subsurface for vast quantities of "missing" methane and ethane that might be hidden within a porous icy crust. Balloon and floater return their data to a Titan Orbiter equipped to strip away Titan's mysteries with imaging, radar profiling, and atmospheric sampling, much more powerful and more complete than Cassini was capable of. This spacecraft, preparing to enter a circular orbit around Saturn's cloud-shrouded giant moon, has just completed a series of flybys of Enceladus, a tiny but active world with plumes that blow water and organics from the interior into space. Specialized instruments on the orbiter were able to analyze these plumes directly during the flybys. Titan and Enceladus could hardly seem more different, and yet they are linked by their origin in the Saturn system, by a magnetosphere that sweeps up mass and delivers energy, and by the possibility that one or both worlds harbor life. It is the goal of the NASA/ESA Titan Saturn System Mission (TSSM) to explore and investigate these exotic and inviting worlds, to understand their natures and assess the possibilities of habitability in this system so distant from our home world. Orbiting, landing, and ballooning at Titan represent a new and exciting approach to planetary exploration. The TSSM mission

Automation of Cassini Support Imaging Uplink Command Development

Science.gov (United States)

Ly-Hollins, Lisa; Breneman, Herbert H.; Brooks, Robert

2010-01-01

"Support imaging" is imagery requested by other Cassini science teams to aid in the interpretation of their data. The generation of the spacecraft command sequences for these images is performed by the Cassini Instrument Operations Team. The process initially established for doing this was very labor-intensive, tedious and prone to human error. Team management recognized this process as one that could easily benefit from automation. Team members were tasked to document the existing manual process, develop a plan and strategy to automate the process, implement the plan and strategy, test and validate the new automated process, and deliver the new software tools and documentation to Flight Operations for use during the Cassini extended mission. In addition to the goals of higher efficiency and lower risk in the processing of support imaging requests, an effort was made to maximize adaptability of the process to accommodate uplink procedure changes and the potential addition of new capabilities outside the scope of the initial effort.

Cassini's Grand Finale Science Highlights

Science.gov (United States)

Spilker, Linda

2017-10-01

After 13 years in orbit, the Cassini-Huygens Mission to Saturn ended in a science-rich blaze of glory. Cassini returned its final bits of unique science data on September 15, 2017, as it plunged into Saturn's atmosphere satisfying planetary protection requirements. Cassini's Grand Finale covered a period of roughly five months and ended with the first time exploration of the region between the rings and planet.The final close flyby of Titan in late April 2017 propelled Cassini across Saturn’s main rings and into its Grand Finale orbits; 22 orbits that repeatedly dove between Saturn’s innermost rings and upper atmosphere making Cassini the first spacecraft to explore this region. The last orbit turned the spacecraft into the first Saturn upper atmospheric probe.The Grand Finale orbits provided highest resolution observations of both the rings and Saturn, and in-situ sampling of the ring particle composition, Saturn's atmosphere, plasma, and innermost radiation belts. The gravitational field was measured to unprecedented accuracy, providing information on the interior structure of the planet, winds in the deeper atmosphere, and mass of the rings. The magnetic field provided insight into the physical nature of the magnetic dynamo and structure of the internal magnetic field. The ion and neutral mass spectrometer sampled the upper atmosphere for molecules that escape the atmosphere in addition to molecules originating from the rings. The cosmic dust analyzer directly sampled the composition from different parts of the main rings for the first time. Fields and particles instruments directly measured the plasma environment between the rings and planet.Science highlights and new mysteries gleaned to date from the Grand Finale orbits will be discussed.The research described in this paper was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2017

Cassini RTG acceptance test results and RTG performance on Galileo and Ulysses

International Nuclear Information System (INIS)

Kelly, C.E.; Klee, P.M.

1997-01-01

Flight acceptance testing has been completed for the RTGs to be used on the Cassini spacecraft which is scheduled for an October 6, 1997 launch to Saturn. The acceptance test program includes vibration tests, magnetic field measurements, properties (weight and c.g.) and thermal vacuum test. This paper presents The thermal vacuum test results. Three RTGs are to be used, F-2, F-6, and F-7. F-5 is tile back-up RTG, as it was for the Galileo and Ulysses missions launched in 1989 and 1990, respectively. RTG performance measured during the thermal vacuum tests carried out at die Mound Laboratory facility met all specification requirements. Beginning of mission (BOM) and end of mission (EOM) power predictions have been made based on than tests results. BOM power is predicted to be 888 watts compared to the minimum requirement of 826 watts. Degradation models predict the EOM power after 16 years is to be 640 watts compared to a minimum requirement of 596 watts. Results of small scale module tests are also showing. The modules contain couples from the qualification and flight production runs. The tests have exceeded 28,000 hours (3.2 years) and are continuing to provide increased confidence in the predicted long term performance of the Cassini RTGs. All test results indicate that the power requirements of the Cassini spacecraft will be met. BOM and EOM power margins of over five percent are predicted. Power output from telemetry for the two Galileo RTGs are shown from the 1989 launch to the recent Jupiter encounter. Comparisons of predicted, measured and required performance are shown. Telemetry data are also shown for the RTG on the Ulysses spacecraft which completed its planned mission in 1995 and is now in the extended mission

Cassini RTG acceptance test results and RTG performance on Galileo and Ulysses

International Nuclear Information System (INIS)

Kelly, C.E.; Klee, P.M.

1997-01-01

Flight acceptance testing has been completed for the RTGs to be used on the Cassini spacecraft which is scheduled for an October 6, 1997 launch to Saturn. The acceptance test program includes vibration tests, magnetic field measurements, mass properties (weight and c.g.) and thermal vacuum test. This paper presents the thermal vacuum test results. Three RTGs are to be used, F-2, F-6, and F-7. F-5 is the backup RTG, as it was for the Galileo and Ulysses missions launched in 1989 and 1990, respectively. RTG performance measured during the thermal vacuum tests carried out at the Mound Laboratory facility met all specification requirements. Beginning of mission (BOM) and end of mission (EOM) power predictions have been made based on these tests results. BOM power is predicted to be 888 watts compared to the minimum requirement of 826 watts. Degradation models predict the EOM power after 16 years is to be 640 watts compared to a minimum requirement of 596 watts. Results of small scale module tests are also shown. The modules contain couples from the qualification and flight production runs. The tests have exceeded 28,000 hours (3.2 years) and are continuing to provide increased confidence in the predicted long term performance of the Cassini RTGs. All test results indicate that the power requirements of the Cassini spacecraft will be met. BOM and EOM power margins of over 5% are predicted. Power output from telemetry for the two Galileo RTGs are shown from the 1989 launch to the recent Jupiter encounter. Comparisons of predicted, measured and required performance are shown. Telemetry data are also shown for the RTG on the Ulysses spacecraft which completed its planned mission in 1995 and is now in the extended mission

Riddles of the Sphinx: Titan Science Questions at the End of Cassini-Huygens

Science.gov (United States)

Nixon, C. A.; Achterberg, R. K.; Buch, A.; Clark, R. N.; Coll, P.; Flasar, F. M.; Hayes, A. G.; Iess, L.; Lorenz, R. D.; Lopes, R.; Mastroguiseppe, M.; Raulin, F.; Smith, T.; Solomidou, A.; Sotin, C.; Strobel, D. F.; Turtle, E. P.; Vuitton, V.; West, R. A.; Yelle, R.

2017-02-01

The paper will describe the outstanding high-level questions for Titan science that are remaining at the end of the Cassini-Huygens mission, compiled by a cross-section of scientists from multiple instrument teams.

Continuing Improvement in the Planetary Ephemeris with VLBA Observations of Cassini

Science.gov (United States)

Jones, Dayton L.; Folkner, William M.; Jacobson, Robert A.; Jacobs, Christopher S.; Romney, Jonathan D.; Dhawan, Vivek; Fomalont, Edward B.

2016-06-01

During the past decade a continuing series of measurements of the barycentric position of the Saturn system in the inertial International Celestial Reference Frame (ICRF) has led to a significant improvement in our knowledge of Saturn's orbit. This in turn has improved the current accuracy and time range of the solar system ephemeris produced and maintained by the Jet Propulsion Laboratory. Our observing technique involves high-precision astrometry of the radio signal from Cassini with the NRAO Very Long Baseline Array, combined with solutions for the orbital motion of Cassini about the Saturn barycenter from Doppler tracking by the Deep Space Network. Our VLBA astrometry is done in a phase-referencing mode, providing nrad-level relative positions between Cassini and angularly nearby extragalactic radio sources. The positions of those reference radio sources are tied to the ICRF through dedicated VLBI observations by several groups around the world. We will present recent results from our astrometric observations of Cassini through early 2016. This program will continue until the end of the Cassini mission in 2017, although future improvement in Saturn's orbit will be more incremental because we have already covered more that a quarter of Saturn's orbital period. The Juno mission to Jupiter, which will orbit Jupiter for about 1.5 years starting in July 2016, will provide an excellent opportunity for us to apply the same VLBA astrometry technique to improve the orbit of Jupiter by a factor of several. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This work made use of the Swinburne University of Technology software correlator, developed as part of the Australian Major National Research Facilities Program and operated under license. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract

Implementing Distributed Operations: A Comparison of Two Deep Space Missions

Science.gov (United States)

Mishkin, Andrew; Larsen, Barbara

2006-01-01

Two very different deep space exploration missions--Mars Exploration Rover and Cassini--have made use of distributed operations for their science teams. In the case of MER, the distributed operations capability was implemented only after the prime mission was completed, as the rovers continued to operate well in excess of their expected mission lifetimes; Cassini, designed for a mission of more than ten years, had planned for distributed operations from its inception. The rapid command turnaround timeline of MER, as well as many of the operations features implemented to support it, have proven to be conducive to distributed operations. These features include: a single science team leader during the tactical operations timeline, highly integrated science and engineering teams, processes and file structures designed to permit multiple team members to work in parallel to deliver sequencing products, web-based spacecraft status and planning reports for team-wide access, and near-elimination of paper products from the operations process. Additionally, MER has benefited from the initial co-location of its entire operations team, and from having a single Principal Investigator, while Cassini operations have had to reconcile multiple science teams distributed from before launch. Cassini has faced greater challenges in implementing effective distributed operations. Because extensive early planning is required to capture science opportunities on its tour and because sequence development takes significantly longer than sequence execution, multiple teams are contributing to multiple sequences concurrently. The complexity of integrating inputs from multiple teams is exacerbated by spacecraft operability issues and resource contention among the teams, each of which has their own Principal Investigator. Finally, much of the technology that MER has exploited to facilitate distributed operations was not available when the Cassini ground system was designed, although later adoption

Cassini RTG's -- Small scale module tests

International Nuclear Information System (INIS)

Kelly, C.E.; Klee, P.M.

1994-01-01

The Cassini spacecraft, scheduled for a 1997 launch to Saturn, will be powered by three GPHS RTGs (General Purpose Heat Source Radioisotope thermoelectric Generators). The RTGs are the same type as those powering the Galileo and Ulysses spacecraft. Three new converters (F-6, F-7, and F-8) are to be built and one converter (F-2) remaining from the GPHS program will be used. F-6 and F-7 are to be fueled and F-8 serves as a spare converter. In addition, the back-up RTG (F-5) from the Ulysses launch, which is still fueled, will serve as the Cassini back-up RTG. The new RTGs will have a lower fuel loading than in the past and will provide a minimum of 276 watts each at B.O.M. (beginning of mission). The mission length is 10.75 years, at which time these RTGs will provide a minimum of 216 watts and a possible extension to 16 years when the power will be 199 watts. This paper discusses tests performed to date to confirm the successful re-establishment of the unicouple production at Martin Marietta. This production line, shut down 10 years ago, has been restarted and over 1,500 unicouples have been produced to date. Confirmation will be primarily obtained by the performance of three small scale converters in comparison with previously tested modules from the Multi Hundred Watt (MHW) (Voyager) and GPHS (Galileo, Ulysses) programs. Test results to date have shown excellent agreement with the data base

The architecture of the Cassini division

Science.gov (United States)

Hedman, M.M.; Nicholson, P.D.; Baines, K.H.; Buratti, B.J.; Sotin, Christophe; Clark, R.N.; Brown, R.H.; French, R.G.; Marouf, E.A.

2010-01-01

The Cassini Division in Saturn's rings contains a series of eight named gaps, three of which contain dense ringlets. Observations of stellar occultations by the Visual and Infrared Mapping Spectrometer onboard the Cassini spacecraft have yielded 40 accurate and precise measurements of the radial position of the edges of all of these gaps and ringlets. These data reveal suggestive patterns in the shapes of many of the gap edges: the outer edges of the five gaps without ringlets are circular to within 1 km, while the inner edges of six of the gaps are eccentric, with apsidal precession rates consistent with those expected for eccentric orbits near each edge. Intriguingly, the pattern speeds of these eccentric inner gap edges, together with that of the eccentric Huygens Ringlet, form a series with a characteristic spacing of 006 day-1. The two gaps with non-eccentric inner edges lie near first-order inner Lindblad resonances (ILRs) with moons. One such edge is close to the 5:4 ILR with Prometheus, and the radial excursions of this edge do appear to have an m = 5 component aligned with that moon. The other resonantly confined edge is the outer edge of the B ring, which lies near the 2:1 Mimas ILR. Detailed investigation of the B-ring-edge data confirm the presence of an m = 2 perturbation on the B-ring edge, but also show that during the course of the Cassini Mission, this pattern has drifted backward relative to Mimas. Comparisons with earlier occultation measurements going back to Voyager suggest the possibility that the m = 2 pattern is actually librating relative to Mimas with a libration frequency L 006 day-1 (or possibly 012 day -1). In addition to the m = 2 pattern, the B-ring edge also has an m = 1 component that rotates around the planet at a rate close to the expected apsidal precession rate (?? ?? ?? B ??? 5.??06 day -1). Thus, the pattern speeds of the eccentric edges in the Cassini Division can be generated from various combinations of the pattern speeds

UARS Solar-Stellar Irradiance Comparison Experiment (SOLSTICE) Level 3BS V001

Data.gov (United States)

National Aeronautics and Space Administration — The Solar-Stellar Irradiance Comparison Experiment (SOLSTICE) Level 3BS data product consists of daily, 1 nm resolution, solar spectral irradiances and selected...

Cassini/VIMS hyperspectral observations of the HUYGENS landing site on Titan

Science.gov (United States)

Rodriguez, S.; Le, Mouelic S.; Sotin, Christophe; Clenet, H.; Clark, R.N.; Buratti, B.; Brown, R.H.; McCord, T.B.; Nicholson, P.D.; Baines, K.H.

2006-01-01

Titan is one of the primary scientific objectives of the NASA-ESA-ASI Cassini-Huygens mission. Scattering by haze particles in Titan's atmosphere and numerous methane absorptions dramatically veil Titan's surface in the visible range, though it can be studied more easily in some narrow infrared windows. The Visual and Infrared Mapping Spectrometer (VIMS) instrument onboard the Cassini spacecraft successfully imaged its surface in the atmospheric windows, taking hyperspectral images in the range 0.4-5.2 ??m. On 26 October (TA flyby) and 13 December 2004 (TB flyby), the Cassini-Huygens mission flew over Titan at an altitude lower than 1200 km at closest approach. We report here on the analysis of VIMS images of the Huygens landing site acquired at TA and TB, with a spatial resolution ranging from 16 to14.4 km/pixel. The pure atmospheric backscattering component is corrected by using both an empirical method and a first-order theoretical model. Both approaches provide consistent results. After the removal of scattering, ratio images reveal subtle surface heterogeneities. A particularly contrasted structure appears in ratio images involving the 1.59 and 2.03 ??m images north of the Huygens landing site. Although pure water ice cannot be the only component exposed at Titan's surface, this area is consistent with a local enrichment in exposed water ice and seems to be consistent with DISR/Huygens images and spectra interpretations. The images show also a morphological structure that can be interpreted as a 150 km diameter impact crater with a central peak. ?? 2006 Elsevier Ltd. All rights reserved.

Cassini-Huygens makes first close approach to Titan

Science.gov (United States)

2004-10-01

environments ever attempted by a man-made object. On this pass, the Huygens touchdown site will be visible at around 167 degrees East and 10.7 degrees South on the sunlit face of Titan before reaching the point of closest approach. Data from the imaging and radar instrumentation on board Cassini-Huygens should provide a tantalising idea of what the surface of Titan could be like. A second view of the Huygens touchdown site will be possible on the second close fly-by in December. Jean-Pierre Lebreton, ESA’s Huygens Mission Manager and Project Scientist, said: “This first close-up look at Titan should enable us to find out just how precisely our atmospheric models fit with the real situation and of course we are excited about the prospect of discovering just what type of surface the Huygens probe could impact on early next year.” Today’s fly-by will also be looking at other aspects of Titan which, although it is the second largest moon in the Solar System after Jupiter’s Ganymede, we know relatively little about. The instruments on board the Cassini orbiter will be looking at the surface characteristics, atmospheric properties and interactions with Saturn’s magnetosphere. Huygens is dormant during the fly-by. The first images are expected at 03:30 CEST on 28 October. However, at the point of closest approach, Titan will have an apparent size far exceeding the field of view of the Cassini orbiter’s narrow-angle camera. Details below a 100-metre resolution may be seen if the camera can pierce the haze and fog. Spectacular multicolour images at 1-2 kilometre resolution are also anticipated from the Visual Infrared and Mapping Spectrometer and may reveal details about Titan surface structure and composition. However, the excitement does not stop after 26 October. On 28 October, at about 12:30 CEST, there is a close encounter with Tethys, another of the significant moons of Saturn. Tethys is a ball of solid ice about 1060 kilometres in diameter which orbits Saturn at a

Cassini's Test Methodology for Flight Software Verification and Operations

Science.gov (United States)

Wang, Eric; Brown, Jay

2007-01-01

The Cassini spacecraft was launched on 15 October 1997 on a Titan IV-B launch vehicle. The spacecraft is comprised of various subsystems, including the Attitude and Articulation Control Subsystem (AACS). The AACS Flight Software (FSW) and its development has been an ongoing effort, from the design, development and finally operations. As planned, major modifications to certain FSW functions were designed, tested, verified and uploaded during the cruise phase of the mission. Each flight software upload involved extensive verification testing. A standardized FSW testing methodology was used to verify the integrity of the flight software. This paper summarizes the flight software testing methodology used for verifying FSW from pre-launch through the prime mission, with an emphasis on flight experience testing during the first 2.5 years of the prime mission (July 2004 through January 2007).

Improved Atlases of Mimas and Enceladus derived from Cassini-ISS images

Science.gov (United States)

Roatsch, T.; Kersten, E.; Matz, K. D.; Bland, M. T.; Becker, T. L.; Patterson, G. W.

2017-12-01

The Cassini Imaging Science Subsystem (ISS) took a couple of high-resolution images of the Icy satellites Mimas and Enceladus during the last few years of the Cassini mission. Both satellites were captured over a period of non-targeted flybys: Mimas in 2016 and 2017 in orbits 230, 249, and 259 and Enceladus in 2015 and 2016 in orbits 224, 228, and 250. We used the new Mimas images to improve the existing semi-controlled mosaic of Mimas. A new controlled Enceladus mosaic was published recently [1] and was now updated using the latest Enceladus images. Both new mosaics are the baseline for improved atlases of Mimas in 3 tiles with a scale of 1:1,000,000 and Enceladus in 15 tiles with a scale of 1:500,000. The nomenclature for both satellites was proposed by the Cassini-ISS team and approved by the IAU and was not changed here. Examples of the improved atlases will be shown in this presentation. Reference: [1] Bland, M.T. et. al., A new Enceladus base map and global control network in support of geological mapping, 46th Lunar and Planetary Science Conference (2015) , abstract 2303.

Cassini at Saturn Proximal Orbits - Attitude Control Challenges

Science.gov (United States)

Burk, Thomas A.

2013-01-01

The Cassini mission at Saturn will come to an end in the spring and summer of 2017 with a series of 22 orbits that will dip inside the rings of Saturn. These are called proximal orbits and will conclude with spacecraft disposal into the atmosphere of the ringed world on September 15, 2017. These unique orbits that cross the ring plane only a few thousand kilometers above the cloud tops of the planet present new attitude control challenges for the Cassini operations team. Crossing the ring plane so close to the inner edge of the rings means that the Cassini orientation during the crossing will be tailored to protect the sensitive electronics bus of the spacecraft. This orientation will put the sun sensors at some extra risk so this paper discusses how the team prepares for dust hazards. Periapsis is so close to the planet that spacecraft controllability with RCS thrusters needs to be evaluated because of the predicted atmospheric torque near closest approach to Saturn. Radiation during the ring plane crossings will likely trigger single event transients in some attitude control sensors. This paper discusses how the attitude control team deals with radiation hazards. The angular size and unique geometry of the rings and Saturn near periapsis means that star identification will be interrupted and this paper discusses how the safe mode attitude is selected to best deal with these large bright bodies during the proximal orbits.

Risk Assessment of Cassini Sun Sensor Integrity Due to Hypervelocity Impact of Saturn Dust Particles

Science.gov (United States)

Lee, Allan Y.

2016-01-01

A sophisticated interplanetary spacecraft, Cassini is one of the heaviest and most sophisticated interplanetary spacecraft humans have ever built and launched. Since achieving orbit at Saturn in 2004, Cassini has collected science data throughout its four-year prime mission (2004-08), and has since been approved for first and second extended missions through September 2017. In late 2016, the Cassini spacecraft will begin a daring set of ballistic orbits that will hop the rings and dive between the upper atmosphere of Saturn and its innermost D-ring twenty-two times. The "dusty" environment of the inner D-ring region the spacecraft must fly through is hazardous because of the possible damage that dust particles, travelling at speeds as high as 31.4 km/s, can do to spacecraft hardware. During hazardous proximal ring-plane crossings, the Cassini mission operation team plans to point the high-gain antenna to the RAM vector in order to protect most of spacecraft instruments from the incoming energetic ring dust particles. However, this particular spacecraft attitude will expose two Sun sensors (that are mounted on the antenna dish) to the incoming dust particles. High-velocity impacts on the Sun sensor cover glass might penetrate the 2.54-mm glass cover of the Sun sensor. Even without penetration damage, craters created by these impacts on the surface of the cover glass will degrade the transmissibility of light through it. Apart from being directly impacted by the dust particles, the Sun sensors are also threatened by some fraction of ricochet ejecta that are produced by dust particle impacts on the large antenna dish (made of graphite fiber epoxy composite material). Finally, the spacecraft attitude control system must cope with disturbances due to both the translational and angular impulses imparted on the large antenna dish and the long magnetometer boom by the incoming high-velocity projectiles. Analyses performed to quantify the risks the Sun sensors must contend

Cassini UVIS Observations of Saturn during the Grand Finale Orbits

Science.gov (United States)

Pryor, W. R.; Esposito, L. W.; West, R. A.; Jouchoux, A.; Radioti, A.; Grodent, D. C.; Gerard, J. C. M. C.; Gustin, J.; Lamy, L.; Badman, S. V.

2017-12-01

In 2016 and 2017, the Cassini Saturn orbiter executed a final series of high inclination, low-periapsis orbits ideal for studies of Saturn's polar regions. The Cassini Ultraviolet Imaging Spectrograph (UVIS) obtained an extensive set of auroral images, some at the highest spatial resolution obtained during Cassini's long orbital mission (2004-2017). In some cases, two or three spacecraft slews at right angles to the long slit of the spectrograph were required to cover the entire auroral region to form auroral images. We will present selected images from this set showing narrow arcs of emission, more diffuse auroral emissions, multiple auroral arcs in a single image, discrete spots of emission, small scale vortices, large-scale spiral forms, and parallel linear features that appear to cross in places like twisted wires. Some shorter features are transverse to the main auroral arcs, like barbs on a wire. UVIS observations were in some cases simultaneous with auroral observations from the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) that will also be presented. UVIS polar images also contain spectral information suitable for studies of the auroral electron energy distribution. The long wavelength part of the UVIS polar images contains a signal from reflected sunlight containing absorption signatures of acetylene and other Saturn hydrocarbons. The hydrocarbon spatial distribution will also be examined.

CIRS-lite: A Fourier Transform Spectrometer for a Future Mission to Titan

Science.gov (United States)

Brasunas, John C.; Flasar, F. Michael; Jennings, Donald E.

2009-01-01

The CIRS FTS, aboard the NASA/ESA Cassini-Huygens mission to Saturn, has been returning exciting science since 2004. CIRS-lire, a lightweight CIRS successor, is being designed for a follow-up Titan mission.

Cassini-VIMS at Jupiter: Solar occultation measurements using Io

Science.gov (United States)

Formisano, V.; D'Aversa, E.; Bellucci, G.; Baines, K.H.; Bibring, J.-P.; Brown, R.H.; Buratti, B.J.; Capaccioni, F.; Cerroni, P.; Clark, R.N.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Jaumann, R.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe; Chamberlain, M.C.; Hansen, G.; Hibbits, K.; Showalter, M.; Filacchione, G.

2003-01-01

We report unusual and somewhat unexpected observations of the jovian satellite Io, showing strong methane absorption bands. These observations were made by the Cassini VIMS experiment during the Jupiter flyby of December/January 2000/2001. The explanation is straightforward: Entering or exiting from Jupiter's shadow during an eclipse, Io is illuminated by solar light which has transited the atmosphere of Jupiter. This light, therefore becomes imprinted with the spectral signature of Jupiter's upper atmosphere, which includes strong atmospheric methane absorption bands. Intercepting solar light refracted by the jovian atmosphere, Io essentially becomes a "miffor" for solar occultation events of Jupiter. The thickness of the layer where refracted solar light is observed is so large (more than 3000 km at Io's orbit), that we can foresee a nearly continuous multi-year period of similar events at Saturn, utilizing the large and bright ring system. During Cassini's 4-year nominal mission, this probing tecnique should reveal information of Saturn's atmosphere over a large range of southern latitudes and times. ?? 2003 Elsevier Inc. All rights reserved.

Cassini ISS Observation of Saturn from Grand Finale Orbits

Science.gov (United States)

Blalock, J. J.; Sayanagi, K. M.; Ingersoll, A. P.; Dyudina, U.; Ewald, S. P.; McCabe, R. M.; Garland, J.; Gunnarson, J.; Gallego, A.

2017-12-01

We present images captured during Cassini's Grand Finale orbits, and their preliminary analyses. During the final 22 orbits of the mission, the spacecraft is in orbits that have 6.5 day period at an inclination of 62 degrees, apoapsis altitude of about 1,272,000 km, and periapsis altitudes of about 2,500 km. Images captured during periapsis passes show Saturn's atmosphere at unprecedented spatial resolution. We present preliminary analyses of these images, including the final images captured before the end of the mission when the spacecraft enters Saturn's atmosphere on September 15th, 2017. Prominent features captured during the final orbits include the north polar vortex and other vortices as well as very detailed views of the "popcorn clouds" that reside between the Hexagon and the north pole. In the cloud field between zonal jets, clouds either resemble linear streaks suggestive of cirrus-like clouds or round shapes suggestive of vortices or cumulus anvil. The presence of linear streaks that follow lines of constant latitudes suggests that meridional mixing is inhibited at those latitudes. The size of vortices may reflect latitudinal variation in the atmospheric deformation radius. We also compare the new images to those captured earlier in the Cassini mission to characterize the temporal evolution such as changes in the zonal jet speeds, and prevalence and colors of vortices. A particular focus of our interest is the long-term change in the color of the hexagon, the evolution of the wind speeds in the jetstream that blows eastward at the boundary of the hexagon, and the morphology of the north polar vortex. Our work has been supported by NASA PATM NNX14AK07G, NSF AAG 1212216, and NASA NESSF NNX15AQ70H.

Estimation of Gravitation Parameters of Saturnian Moons Using Cassini Attitude Control Flight Data

Science.gov (United States)

Krening, Samantha C.

2013-01-01

A major science objective of the Cassini mission is to study Saturnian satellites. The gravitational properties of each Saturnian moon is of interest not only to scientists but also to attitude control engineers. When the Cassini spacecraft flies close to a moon, a gravity gradient torque is exerted on the spacecraft due to the mass of the moon. The gravity gradient torque will alter the spin rates of the reaction wheels (RWA). The change of each reaction wheel's spin rate might lead to overspeed issues or operating the wheel bearings in an undesirable boundary lubrication condition. Hence, it is imperative to understand how the gravity gradient torque caused by a moon will affect the reaction wheels in order to protect the health of the hardware. The attitude control telemetry from low-altitude flybys of Saturn's moons can be used to estimate the gravitational parameter of the moon or the distance between the centers of mass of Cassini and the moon. Flight data from several low altitude flybys of three Saturnian moons, Dione, Rhea, and Enceladus, were used to estimate the gravitational parameters of these moons. Results are compared with values given in the literature.

A post-Cassini view of Titan's methane-based hydrologic cycle

Science.gov (United States)

Hayes, Alexander G.; Lorenz, Ralph D.; Lunine, Jonathan I.

2018-05-01

The methane-based hydrologic cycle on Saturn's largest moon, Titan, is an extreme analogue to Earth's water cycle. Titan is the only planetary body in the Solar System, other than Earth, that is known to have an active hydrologic cycle. With a surface pressure of 1.5 bar and temperatures of 90 to 95 K, methane and ethane condense out of a nitrogen-based atmosphere and flow as liquids on the moon's surface. Exchange processes between atmospheric, surface and subsurface reservoirs produce methane and ethane cloud systems, as well as erosional and depositional landscapes that have strikingly similar forms to their terrestrial counterparts. Over its 13-year exploration of the Saturn system, the Cassini-Huygens mission revealed that Titan's hydrocarbon-based hydrology is driven by nested methane cycles that operate over a range of timescales, including geologic, orbital (for example, Croll-Milankovitch cycles), seasonal and that of a single convective storm. In this Review Article, we describe the dominant exchange processes that operate over these timescales and present a post-Cassini view of Titan's methane-based hydrologic system.

Cassini RADAR Observations at Titan : Results at the End of the Nominal Mission

Science.gov (United States)

Lorenz, Ralph

This talk will review some recent results of the Cassini RADAR investigations at Titan. In particular, the first half of 2008 includes three low-latitude flybys with SAR observations of Xanadu, the Huygens Landing site, and in particular three areas that may be associated with cryovolcanic features - Tortola Facula, Hotei Arcus, and Tui Regio. In addition to providing SAR coverage (which will include further mapping of dunes in the Shangri-La dark areas as well as the features above), these new flybys will permit refinement of the apparently dynamic Titan rotational state, as well as expanding our topographic knowledge.

High-Resolution Mid-IR Imaging of Jupiter's Great Red Spot: Comparing Cassini, VLT and Subaru Observations

Science.gov (United States)

Fletcher, Leigh N.; Orton, G. S.; Yanamandra-Fisher, P.; Irwin, P. G. J.; Baines, K. H.; Edkins, E.; Line, M. R.; Mousis, O.; Parrish, P. D.; Vanzi, L.; Fuse, T.; Fujoyoshi, T.

2008-09-01

In the eight years since the Cassini fly-by of Jupiter, the spatial resolution of ground-based observations of Jupiter's giant anticyclonic storm systems (the Great Red Spot, Oval BA and others) using 8m-class telescopes has surpassed the resolution of the Cassini/CIRS maps. We present a time-series of mid-IR imaging of the Great Red Spot (GRS) and its environs from the VISIR instrument on the Very Large Telescope (UT3/Melipal) and the COMICS instrument on the Subaru telescope (Hawaii). The NEMESIS optimal-estimation retrieval algorithm (Irwin et al., 2008) is used to analyse both the 7-25 micron filtered imaging from 2005-2008 and Cassini/CIRS 7-16 micron data from 2000. We demonstrate the ability to map temperatures in the 100-400 mbar range, NH3, aerosol opacity and the para-H2 fraction from the filtered imaging. Furthermore, the Cassini/CIRS spectra are used to map the PH3 mole fraction around the GRS. The thermal field, gaseous composition and aerosol distribution are used as diagnostics for the atmospheric motion associated with the GRS. Changes in the atmospheric state in response to close encounters with Oval BA and other vortices will be assessed. These results will be discussed in light of their implications for the planning of the Europa-Jupiter System Mission.

Cassini-Huygens maneuver automation for navigation

Science.gov (United States)

Goodson, Troy; Attiyah, Amy; Buffington, Brent; Hahn, Yungsun; Pojman, Joan; Stavert, Bob; Strange, Nathan; Stumpf, Paul; Wagner, Sean; Wolff, Peter;

Managing Cassini Safe Mode Attitude at Saturn

Science.gov (United States)

Burk, Thomas A.

2010-01-01

The Cassini spacecraft was launched on October 15, 1997 and arrived at Saturn on June 30, 2004. It has performed detailed observations and remote sensing of Saturn, its rings, and its satellites since that time. In the event safe mode interrupts normal orbital operations, Cassini has flight software fault protection algorithms to detect, isolate, and recover to a thermally safe and commandable attitude and then wait for further instructions from the ground. But the Saturn environment is complex, and safety hazards change depending on where Cassini is in its orbital trajectory around Saturn. Selecting an appropriate safe mode attitude that insures safe operation in the Saturn environment, including keeping the star tracker field of view clear of bright bodies, while maintaining a quiescent, commandable attitude, is a significant challenge. This paper discusses the Cassini safe table management strategy and the key criteria that must be considered, especially during low altitude flybys of Titan, in deciding what spacecraft attitude should be used in the event of safe mode.

Island of the Sun: Elite and Non-Elite Observations of the June Solstice

Science.gov (United States)

Dearborn, David S. P.; Bauer, Brian S.

In Inca times (AD 1400-1532), two small islands in Lake Titicaca had temples dedicated to the sun and the moon. Colonial documents indicate that the islands were the focus of large-scale pilgrimages. Recent archaeoastronomical work suggests that rituals, attended by both elites and commoners, were held on the Island of the Sun to observe the setting sun on the June solstice.

Saturn's Ring: Pre-Cassini Status and Mission Goals

Science.gov (United States)

Cuzzi, Jeff N.; DeVincenzi, Donald L. (Technical Monitor)

1999-01-01

of the Cassini Science Objectives.

Cost Comparison in 2015 Dollars for Radioisotope Power Systems -- Cassini and Mars Science Laboratory

International Nuclear Information System (INIS)

Werner, James Elmer; Johnson, Stephen Guy; Dwight, Carla Chelan; Lively, Kelly Lynn

2016-01-01

Radioisotope power systems (RPSs) have enabled missions requiring reliable, long-lasting power in remote, harsh environments such as space since the early 1960s. Costs for RPSs are high, but are often misrepresented due to the complexity of space missions and inconsistent charging practices among the many and changing participant organizations over the years. This paper examines historical documentation associated with two past successful flight missions, each with a different RPS design, to provide a realistic cost basis for RPS production and deployment. The missions and their respective RPSs are Cassini, launched in 1997, that uses the general purpose heat source (GPHS) radioisotope thermoelectric generator (RTG), and Mars Science Laboratory (MSL), launched in 2011, that uses the multi-mission RTG (MMRTG). Actual costs in their respective years are discussed for each of the two RTG designs and the missions they enabled, and then present day values to 2015 are computed to compare the costs. Costs for this analysis were categorized into two areas: development of the specific RTG technology, and production and deployment of an RTG. This latter category includes material costs for the flight components (including Pu-238 and fine weave pierced fabric (FWPF)); manufacturing of flight components; assembly, testing, and transport of the flight RTG(s); ground operations involving the RTG(s) through launch; nuclear safety analyses for the launch and for the facilities housing the RTG(s) during all phases of ground operations; DOE's support for NEPA analyses; and radiological contingency planning. This analysis results in a fairly similar 2015 normalized cost for the production and deployment of an RTG-approximately $118M for the GPHS-RTG and $109M for the MMRTG. In addition to these two successful flight missions, the costs for development of the MMRTG are included to serve as a future reference. Note that development costs included herein for the MMRTG do not include

Cost Comparison in 2015 Dollars for Radioisotope Power Systems -- Cassini and Mars Science Laboratory

Energy Technology Data Exchange (ETDEWEB)

Werner, James Elmer [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johnson, Stephen Guy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dwight, Carla Chelan [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lively, Kelly Lynn [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-07-01

Radioisotope power systems (RPSs) have enabled missions requiring reliable, long-lasting power in remote, harsh environments such as space since the early 1960s. Costs for RPSs are high, but are often misrepresented due to the complexity of space missions and inconsistent charging practices among the many and changing participant organizations over the years. This paper examines historical documentation associated with two past successful flight missions, each with a different RPS design, to provide a realistic cost basis for RPS production and deployment. The missions and their respective RPSs are Cassini, launched in 1997, that uses the general purpose heat source (GPHS) radioisotope thermoelectric generator (RTG), and Mars Science Laboratory (MSL), launched in 2011, that uses the multi-mission RTG (MMRTG). Actual costs in their respective years are discussed for each of the two RTG designs and the missions they enabled, and then present day values to 2015 are computed to compare the costs. Costs for this analysis were categorized into two areas: development of the specific RTG technology, and production and deployment of an RTG. This latter category includes material costs for the flight components (including Pu-238 and fine weave pierced fabric (FWPF)); manufacturing of flight components; assembly, testing, and transport of the flight RTG(s); ground operations involving the RTG(s) through launch; nuclear safety analyses for the launch and for the facilities housing the RTG(s) during all phases of ground operations; DOE’s support for NEPA analyses; and radiological contingency planning. This analysis results in a fairly similar 2015 normalized cost for the production and deployment of an RTG—approximately $118M for the GPHS-RTG and $109M for the MMRTG. In addition to these two successful flight missions, the costs for development of the MMRTG are included to serve as a future reference. Note that development costs included herein for the MMRTG do not include

Small space reactor power systems for unmanned solar system exploration missions

International Nuclear Information System (INIS)

Bloomfield, H.S.

1987-12-01

A preliminary feasibility study of the application of small nuclear reactor space power systems to the Mariner Mark II Cassini spacecraft/mission was conducted. The purpose of the study was to identify and assess the technology and performance issues associated with the reactor power system/spacecraft/mission integration. The Cassini mission was selected because study of the Saturn system was identified as a high priority outer planet exploration objective. Reactor power systems applied to this mission were evaluated for two different uses. First, a very small 1 kWe reactor power system was used as an RTG replacement for the nominal spacecraft mission science payload power requirements while still retaining the spacecraft's usual bipropellant chemical propulsion system. The second use of reactor power involved the additional replacement of the chemical propulsion system with a small reactor power system and an electric propulsion system. The study also provides an examination of potential applications for the additional power available for scientific data collection. The reactor power system characteristics utilized in the study were based on a parametric mass model that was developed specifically for these low power applications. The model was generated following a neutronic safety and operational feasibility assessment of six small reactor concepts solicited from U.S. industry. This assessment provided the validation of reactor safety for all mission phases and generatad the reactor mass and dimensional data needed for the system mass model

SAR Ambiguity Study for the Cassini Radar

Science.gov (United States)

Hensley, Scott; Im, Eastwood; Johnson, William T. K.

1993-01-01

The Cassini Radar's synthetic aperture radar (SAR) ambiguity analysis is unique with respect to other spaceborne SAR ambiguity analyses owing to the non-orbiting spacecraft trajectory, asymmetric antenna pattern, and burst mode of data collection. By properly varying the pointing, burst mode timing, and radar parameters along the trajectory this study shows that the signal-to-ambiguity ratio of better than 15 dB can be achieved for all images obtained by the Cassini Radar.

GPHS-RTGs in support of the Cassini Mission

International Nuclear Information System (INIS)

1994-01-01

This report is organized by the program task structure as follows: (1) spacecraft integration and liaison; (2) engineering support; (3) safety; (4) qualified unicouple fabrication; (5) ETG fabrication, assembly, and test; (6) ground support equipment (GSE); (7) RTG shipping and launch support; (8) designs, reviews, and mission applications; (9) project management, quality assurance and reliability, contract changes, non-capital CAGO acquisition, and CAGO maintenance; and (H) contractor acquired government owned property (CAGO) acquisition

Flyby Error Analysis Based on Contour Plots for the Cassini Tour

Science.gov (United States)

Stumpf, P. W.; Gist, E. M.; Goodson, T. D.; Hahn, Y.; Wagner, S. V.; Williams, P. N.

2008-01-01

The maneuver cancellation analysis consists of cost contour plots employed by the Cassini maneuver team. The plots are two-dimensional linear representations of a larger six-dimensional solution to a multi-maneuver, multi-encounter mission at Saturn. By using contours plotted with the dot product of vectors B and R and the dot product of vectors B and T components, it is possible to view the effects delta V on for various encounter positions in the B-plane. The plot is used in operations to help determine if the Approach Maneuver (ensuing encounter minus three days) and/or the Cleanup Maneuver (ensuing encounter plus three days) can be cancelled and also is a linear check of an integrated solution.

Cassini MIMI Close-Up of Saturn Energetic Particles: Low Altitude Trapped Radiation, Auroral Ion Acceleration, and Interchange Flow Channels

Science.gov (United States)

Mitchell, D. G.; Krimigis, S. M.; Krupp, N.; Paranicas, C.; Roussos, E.; Kollmann, P.

2017-12-01

We present observations from the final orbits of the Cassini Mission at Saturn by the Magnetospheric Imaging Instrument (MIMI). Crossing inside the D-Ring at the equator and just above Saturn's atmosphere, these orbits covered regions never visited previously in the mission. Highlights include the confirmation of an inner radiation belt analogous to the inner radiation belt at Earth by the Low Energy Magnetospheric Measurement System (LEMMS), with surprising twists—Saturn's D-ring material appears to be a source for these particles. Details will be presented in another session. The Grand Finale orbits also afforded a close-up view of the auroral ion acceleration regions by the Ion and Neutral Camera (INCA). Ionospheric ions at the base of auroral field lines are accelerated perpendicular to the magnetic field to 10's and 100's of keV, and charge exchange with exospheric neutrals to be emitted as energetic neutral atoms and images by INCA. We show that this acceleration region lies at about 0.1 Rs. Another feature seen previously in the mission but imaged with greater resolution is a flow channel associated with interchange motion in the middle magnetosphere. We show this feature to extend over several Saturn radii in the radial direction, and over about 2 Saturn radii azimuthally. Additional data have been received since the writing of this abstract and before Cassini's plunge into the atmosphere on September 15, so additional features may be presented.

NASA 3D Models: Cassini

Data.gov (United States)

National Aeronautics and Space Administration — Cassini spacecraft from SPACE rendering package, built by Michael Oberle under NASA contract at JPL. Includes orbiter only, Huygens probe detached. Accurate except...

Cassini Ion Mass Spectrometer Peak Calibrations from Statistical Analysis of Flight Data

Science.gov (United States)

Woodson, A. K.; Johnson, R. E.

2017-12-01

The Cassini Ion Mass Spectrometer (IMS) is an actuating time-of-flight (TOF) instrument capable of resolving ion mass, energy, and trajectory over a field of view that captures nearly the entire sky. One of three instruments composing the Cassini Plasma Spectrometer, IMS sampled plasma throughout the Kronian magnetosphere from 2004 through 2012 when it was permanently disabled due to an electrical malfunction. Initial calibration of the flight instrument at Southwest Research Institute (SwRI) was limited to a handful of ions and energies due to time constraints, with only about 30% of planned measurements carried out prior to launch. Further calibration measurements were subsequently carried out after launch at SwRI and Goddard Space Flight Center using the instrument prototype and engineering model, respectively. However, logistical differences among the three calibration efforts raise doubts as to how accurately the post-launch calibrations describe the behavior of the flight instrument. Indeed, derived peak parameters for some ion species differ significantly from one calibration to the next. In this study we instead perform a statistical analysis on 8 years of flight data in order to extract ion peak parameters that depend only on the response of the flight instrument itself. This is accomplished by first sorting the TOF spectra based on their apparent compositional similarities (e.g. primarily water group ions, primarily hydrocarbon ions, etc.) and normalizing each spectrum. The sorted, normalized data are then binned according to TOF, energy, and counts in order to generate energy-dependent probability density maps of each ion peak contour. Finally, by using these density maps to constrain a stochastic peak fitting algorithm we extract confidence intervals for the model parameters associated with various measured ion peaks, establishing a logistics-independent calibration of the body of IMS data gathered over the course of the Cassini mission.

Dynamics Of Saturn'S Mid-scale Storms In The Cassini Era.

Science.gov (United States)

Del Rio Gaztelurrutia, Teresa; Hueso, R.; Sánchez-Lavega, A.

2010-10-01

Convective storms, similar to those in Earth, but of much larger scale, develop often in Saturn's atmosphere. During the Voyagers’ flybys of Saturn in 1981 mid-scale storms, with an horizontal extension of the order of 1000-3000 km were observed to occur mainly in a narrow tropical-latitude band in the Northern hemisphere at latitudes 38-40 deg North. Contrasting with the Voyagers’ era, since the starting of the Cassini mission in 2004, a similar mid-scale convective activity has concentrated in the so-called "storm alley", a narrow band at a symmetric Southern latitude of 38 deg.. In this work, we characterize this storm activity using available visual information provided by Cassini ISS cameras and the continuous survey from the Earth by the International Outer Planets Watch (IOPW) and its online database PVOL (Hueso et al., Planetary and Space Science, 2010). We study the frequency of appearance of storms with sizes above 2000 km, their characteristic size and life-time, as well as their interaction with surrounding dynamical features. In particular we examine the possibility that storms might provide a mechanism of injection of energy into Saturn's jets, the influence of storms in the generation of atmospheric vortices, and the analogies and differences of Voyagers’ and present day jet structure at the relevant latitudes. Acknowledgments: This work has been funded by the Spanish MICIIN AYA2009-10701 with FEDER support and Grupos Gobierno Vasco IT-464

Charged Particle In-Situ Measurements in the Inner Saturnian Magnetosphere during the "grand Finale" of Cassini in 2016/2017

Science.gov (United States)

Krupp, N.; Roussos, E.; Mitchell, D. G.; Kollmann, P.; Paranicas, C.; Krimigis, S. M.; Hedman, M. M.; Dougherty, M. K.

2017-12-01

After 13 years in orbit around Saturn Cassini came to an end on 15 September 2017. The last phase of the mission was called the "Grand Finale" and consisted of high latitude orbits crossing the F-Ring 22 times between Nov 2016 and April 2017 followed by the so called proximal orbits passing the ring plane inside the D-ring. The roughly 7-day long F-ring orbits with periapsis at nearly the same local time allowed to study temporal variations of the particle distributions in the inner part of Saturn's magnetosphere while during the proximal orbits Cassini measured for the first time the charged particle environment in-situ inside the D-ring up to 2500 km above the 1-bar cloud level of the planet. In this presentation first results of the Low Energy Magnetospheric Measurement System LEMMS, part of the Magnetosphere Imaging Instrument MIMI during the "Grand Finale" will be summarized in detail, including the discovery of MeV particles close to Saturn, higher intensities of charged particles when Cassini was magnetically connected to the D-Ring, sharp dropouts at the inner edge of the D-ring as well as unexpected features and asymmetries in the particle measurements related to newly discovered ring arcs in the inner magnetosphere.

Simulations of the response function of a plasma ion beam spectrometer for the Cassini mission to Saturn

International Nuclear Information System (INIS)

Vilppola, J.H.; Tanskanen, P.J.; Huomo, H.; Barraclough, B.L.

1996-01-01

To obtain very high (∼1%) energy resolution with spherical-section electrostatic analyzers requires high precision in both fabrication and in the alignment process. In order to aid in the calibration of the instrument and to help minimize fabrication costs, we have applied simulation models to the ion beam spectrometer for the NASA/ESA Cassini mission to Saturn. Previously we studied the effects of misalignment and simple irregularities of the hemispherical surfaces on the performance of an electrostatic analyzer. We have considered a hemispherical electrostatic analyzer equipped with an aperture plate to collimate the stray electric field at the entrance apertures. The influence of a curved entrance aperture has also been added to the simulation model, and its effects have been studied in detail. A cylindrical three-dimensional simultaneous overrelaxation algorithm has been introduced to solve for the stray electric field. The maximum loss of transmitted particles with respect to the transmission of an ideal instrument has been set at 10%. We demonstrate that the deviation in the distributions of the energies is less than 0.2% and that the deviation in the distributions of entrance angles of transmitted particles is less than 0.1 degree. It has been found that the energy resolution of an electrostatic analyzer can be improved from ΔE/E=(1.6±0.2)% to ΔE/E=(1.3±0.2)% by the introduction of front aperture plates. Through the introduction of curved entrance slits, the azimuthal angle resolution has changed from β=(1.4±0.1)degree for the simplified geometry simulation results of our previous article to β=(2.3±0.1)degree. We have confirmed that an accuracy of 25 μm in the alignment of the two hemispherical surfaces is sufficient to give the instrument the desired resolutions. copyright 1996 American Institute of Physics

Cassini Scientist for a Day: a tactile experience

Science.gov (United States)

Canas, L.; Altobelli, N.

2012-09-01

In September 2011, the Cassini spacecraft took images of three targets and a challenge was launched to all students: to choose the one target they thought would provide the best science and to write an essay explaining their reasons (more information on the "Cassini Scientist for a Day" essay contest official webpage in: http://saturn.jpl.nasa.gov/education/scientistforaday10thedition/, run by NASA/JPL) The three targets presented were: Hyperion, Rhea and Titan, and Saturn. The idea behind "Cassini Scientist for a Day: a tactile experience" was to transform each of these images into schematic tactile images, highlighting relevant features apprehended through a tactile key, accompanied by a small text in Braille with some additional information. This initial approach would allow reach a broader community of students, more specifically those with visual impairment disabilities. Through proper implementation and careful study cases the adapted images associated with an explanatory key provide more resources in tactile astronomy. As the 2012 edition approaches a new set of targeted objet images will be once again transformed and adapted to visually impaired students and will aim to reach more students into participate in this international competition and to engage them in a quest to expand their knowledge in the amazing Cassini discoveries and the wonders of Saturn and its moons. As the winning essays will be published on the Cassini website and contest winners invited to participate in a dedicated teleconference with Cassini scientists from NASA's Jet Propulsion Laboratory, this initiative presents a great chance to all visually impaired students and teachers to participate in an exciting experience. These initiatives must be complemented with further information to strengthen the learning experience. However they stand as a good starting point to tackle further astronomical concepts in the classroom, especially this field that sometimes lacks the resources. Although

Upcoming planetary missions and the applicability of high-temperature-superconductor bolometers

International Nuclear Information System (INIS)

Brasunas, J.; Kunde, V.; Moseley, H.; Lakew, B.

1991-01-01

Planetary missions to Mars and beyond can last 11 years and longer, making impractical the use of stored cryogens. Passive radiative coolers and single-stage mechanical coolers remain possibilities. Cassini and Comet Rendezvous/Asteroid Fly-by (CRAF), both using the newly developed Mariner Mark 2 spacecraft, will be the next outer planet missions after Galileo; they are intended to provide information on the origin and evolution of the solar system. CRAF is slated for a 1994 launch. Cassini was chosen by ESA and will be launched by a Titan 4/Centaur in 1996. It will fly by Jupiter in 2000, inject an ESA-supplied probe into Titan in 2002, and take data in Saturn's orbit from 2002 to 2006. NASA/Goddard is currently developing a prototype Fourier transform spectrometer, the Composite Infrared Spectrometer (CIRS), for the Cassini mission. The baseline infrared detectors for CIRS are HgCdTe to 16 microns and Schwarz-type thermopiles from 16 to 1000 microns. The far infrared focal plane could be switched from thermopiles to high temperature superconductor (HTS) bolometers between now and 1996. An HTS bolometer could be built using the kinetic inductance effect, or the sharp resistance change at the transition. The transition-edge bolometer is more straightforward to implement, and initial efforts at NASA/Goddard are directed to that device. A working device was made and tested in early 1989. It also has somewhat elevated noise levels below 100 Hz. Upcoming efforts will center on reducing the time constant of the HTS bolometer by attempting to deposit an HTS film on a diamond substrate, and by thinning SrTiO3 substrates. Attempts will be made to improve the film quality to reduce the 1/4 noise level, and to improve the thermal isolation to increase the bolometer sensitivity

Outer Planet Missions with Electric Propulsion Systems—Part I

Directory of Open Access Journals (Sweden)

Carlos Renato Huaura Solórzano

2010-01-01

Full Text Available For interplanetary missions, efficient electric propulsion systems can be used to increase the mass delivered to the destination. Outer planet exploration has experienced new interest with the launch of the Cassini and New Horizons Missions. At the present, new technologies are studied for better use of electric propulsion systems in missions to the outer planets. This paper presents low-thrust trajectories using the method of the transporting trajectory to Uranus, Neptune, and Pluto. They use nuclear and radio isotopic electric propulsion. These direct transfers have continuous electric propulsion of low power along the entire trajectory. The main goal of the paper is to optimize the transfers, that is, to provide maximum mass to be delivered to the outer planets.

Revisit the modeling of the Saturnian ring atmosphere and ionosphere from the "Cassini Grand Finale" results

Science.gov (United States)

Tseng, W. L.; Johnson, R. E.; Tucker, O. J.; Perry, M. E.; Ip, W. H.

2017-12-01

During the Cassini Grand Finale mission, this spacecraft, for the first time, has done the in-situ measurements of Saturn's upper atmosphere and its rings and provides critical information for understanding the coupling dynamics between the main rings and the Saturnian system. The ring atmosphere is the source of neutrals (i.e., O2, H2, H; Tseng et al., 2010; 2013a), which is primarily generated by photolytic decomposition of water ice (Johnson et al., 2006), and plasma (i.e., O2+ and H2+; Tseng et al., 2011) in the Saturnian magnetosphere. In addition, the main rings have strong interaction with Saturn's atmosphere and ionosphere (i.e., a source of oxygen into Saturn's upper atmosphere and/or the "ring rain" in O'Donoghue et al., 2013). Furthermore, the near-ring plasma environment is complicated by the neutrals from both the seasonally dependent ring atmosphere and Enceladus torus (Tseng et al., 2013b), and, possibly, from small grains from the main and tenuous F and G rings (Johnson et al.2017). The data now coming from Cassini Grand Finale mission already shed light on the dominant physics and chemistry in this region of Saturn's magnetosphere, for example, the presence of carbonaceous material from meteorite impacts in the main rings and each gas species have similar distribution in the ring atmosphere. We will revisit the details in our ring atmosphere/ionosphere model to study, such as the source mechanism for the organic material and the neutral-grain-plasma interaction processes.

Playing Around in the Solar System: Mini-games for Many Missions

Science.gov (United States)

Fisher, D. K.; Leon, N.; Fitzpatrick, A. J.; Wessen, A.

2010-12-01

Several NASA solar system missions will have major milestones during 2011, the Year of the Solar System. These events include launches, encounters, and orbit insertions. Other missions will continue the explorations already underway. The “Year of the Solar System Game” on The Space Place website (http://spaceplace.nasa.gov/en/kids/solar-system) brings all these efforts together in the context of the whole solar system. The game helps to build awareness of the characteristics of our solar system and some of the missions that are continuing to advance our knowledge and understanding. It is one of many educational tools being developed and deployed for the Year of the Solar System. The game is a “super-game” that encompasses a number of mission-related “mini-games.” The mini-games can be played individually, and they all contribute toward achievements in the super-game. The enveloping interface for all the games is an animated solar system. The player clicks on a planet or a moon, sees a close-up image, and reads a short paragraph about the object. If the object has been endowed with a mission mini-game, player can click on the tiny spacecraft, read about the mission, then play the game—or, if impatient, just immediately play the game (and read about the mission later, we hope). A score “page” keeps track of the player’s achievements and scores. Players earn achievements by reading about the planets, moons, asteroids, comets, and missions and by playing the mission mini-games. The game targets upper elementary age children, as does the entire Space Place website. Each mini-game, although simple, incorporates elements of the spacecrafts’ missions and their target objects. For example, in Cassini Commander, the player must navigate the Cassini spacecraft through gaps in Saturn’s rings and around Saturn’s moons. The super-game is designed to accommodate any number of mission mini-games, so we are hoping to continue to add missions and increase

Saturn's Magnetic Field from the Cassini Grand Finale orbits

Science.gov (United States)

Dougherty, M. K.; Cao, H.; Khurana, K. K.; Hunt, G. J.; Provan, G.; Kellock, S.; Burton, M. E.; Burk, T. A.

2017-12-01

The fundamental aims of the Cassini magnetometer investigation during the Cassini Grand Finale orbits were determination of Saturn's internal planetary magnetic field and the rotation rate of the deep interior. The unique geometry of the orbits provided an unprecedented opportunity to measure the intrinsic magnetic field at close distances never before encountered. The surprising close alignment of Saturn's magnetic axis with its spin axis, known about since the days of Pioneer 11, has been a focus of the team's analysis since Cassini Saturn Orbit Insertion. However, the varying northern and southern magnetospheric planetary period oscillations, which fill the magnetosphere, has been a factor in masking the field signals from the interior. Here we describe an overview of the magnetometer results from the Grand Finale orbits, including confirmation of the extreme axisymmetric nature of the planetary magnetic field, implications for knowledge of the rotation rate and the behaviour of external magnetic fields (arising from the ring current, field aligned currents both at high and low latitudes and the modulating effect of the planetary period oscillations).

Ballistic Transport: After the Cassini Grand Finale, is there a Final Consensus on Ring Origin and Age?

Science.gov (United States)

Estrada, P. R.; Durisen, R. H.; Cuzzi, J. N.

2017-12-01

As the Cassini mission comes to its much anticipated end, somewhat befittingly to be immortalized and enshrined for all time within the gaseous confines of a planet named for the Greek god of time (Kronos), we find the time appropriate to return to the subject of ring age and origin. During Cassini's remarkable tenure, important measurements have been obtained that can help to elucidate and perhaps settle the debate once and for all on whether the rings are young or old. At the forefront lie the results of the Cassini Dust Analyzer (CDA) experiment which indicate that the range of the micrometeoroid flux at infinity for Saturn are comparable to the nominal value of the meteoroid flux value currently adopted for use in ballistic transport (BT) applications and models (Estrada et al., 2015, 2017). Moreover, the source of the micrometeoroid flux has been localized to the Edgeworth-Kuiper Belt (EKB) and is not cometary in origin as previously assumed (Altobelli et al., 2015). A major consequence of these measurements is that the EKB flux is much more gravitationally focused increasing the impact flux on the rings by a factor of ˜25 relative to cometary. This implies that the process of micrometeoroid bombardment and BT is likely even more influential in the rings' structural and compositional evolution over time. This measurement taken together with recent analysis of the bulk mass fraction of non-icy constituents (Zhang et al., 2017a,b) using Cassini radiometry data argue strongly for young rings. Another observation that will help to provide a constraint (though not absolute) is the pending measurement of the (B) ring mass. A high mass estimate as argued by some does not necessarily mean old rings, whereas a low mass ring would certainly imply as much. There are several factors that can offer insight on to the age of the rings from BT modeling, such as saturation of the ramp(s), color differences across the B-C (A-CD) boundaries, color differences across plateaus

Cassini/CIRS Observations of Water Vapor in Titan's Stratosphere

Science.gov (United States)

Bjoraker, Gordon L.; Achterberg, R. K.; Anderson, C. M.; Samuelson, R. E.; Carlson, R. C.; Jennings, D. E.

2008-01-01

The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft has obtained spectra of Titan during most of the 44 flybys of the Cassini prime mission. Water vapor on Titan was first detected using whole-disk observations from the Infrared Space Observatory (Coustenis et al 1998, Astron. Astrophys. 336, L85-L89). CIRS data permlt the retrieval of the latitudinal variation of water on Titan and some limited information on its vertical profile. Emission lines of H2O on Titan are very weak in the CIRS data. Thus, large spectral averages as well as improvements in calibration are necessary to detect water vapor. Water abundances were retrieved in nadir spectra at 55 South, the Equator, and at 19 North. Limb spectra of the Equator were also modeled to constrain the vertical distribution of water. Stratospheric temperatures in the 0.5 - 4.0 mbar range were obtained by inverting spectra of CH4 in the v4 band centered at 1304/cm. The temperature in the lower stratosphere (4 - 20 mbar) was derived from fitting pure rotation lines of CH4 between 80 and 160/cm. The origin of H2O and CO2 is believed to be from the ablation of micrometeorites containing water ice, followed by photochemistry. This external source of water originates either within the Saturn system or from the interplanetary medium. Recently, Horst et al (J. Geophys. Res. 2008, in press) developed a photochemical model of Titan in which there are two external sources of oxygen. Oxygen ions (probably from Enceladus) precipitate into Titan's atmosphere to form CO at very high altitudes (1100 km). Water ice ablation at lower altitudes (700 km) forms H2O and subsequent chemistry produces CO2. CIRS measurements of CO, CO2, and now of H2O will provide valuable constraints to these photochemical models and - improve our understanding of oxygen chemistry on Titan.

NASA-ESA Joint Mission to Explore Two Worlds of Great Astrobiological Interest - Titan and Enceladus

Science.gov (United States)

Reh, K.; Coustenis, A.; Lunine, J.; Matson, D.; Lebreton, J.-P.; Erd, C.; Beauchamp, P.

2009-04-01

Rugged shorelines, laced with canyons, leading to ethane/methane seas glimpsed through an organic haze, vast fields of dunes shaped by alien sciroccos… An icy moon festooned with plumes of water-ice and organics, whose warm watery source might be glimpsed through surface cracks that glow in the infrared… The revelations by Cassini-Huygens about Saturn's crown jewels, Titan and Enceladus, have rocked the public with glimpses of new worlds unimagined a decade before. The time is at hand to capitalize on those discoveries with a broad mission of exploration that combines the widest range of planetary science disciplines—Geology, Geophysics, Atmospheres, Astrobiology,Chemistry, Magnetospheres—in a single NASA/ESA collaboration. The Titan Saturn System Mission will explore these exciting new environments, flying through Enceladus' plumes and plunging deep into Titan's atmosphere with instruments tuned to find what Cassini could only hint at. Exploring Titan with an international fleet of vehicles; from orbit, from the surface of a great polar sea, and from the air with the first hot air balloon to ride an extraterrestrial breeze, TSSM will turn our snapshot gaze of these worlds into an epic film. This paper will describe a collaborative NASA-ESA Titan Saturn System Mission that will open a new phase of planetary exploration by projecting robotic presence on the land, on the sea, and in the air of an active, organic-rich world.

Saturn's Internal Magnetic Field Revealed by Cassini Grand Finale

Science.gov (United States)

Cao, H.; Dougherty, M. K.; Khurana, K. K.; Hunt, G. J.; Provan, G.; Kellock, S.; Burton, M. E.; Burk, T. A.

2017-12-01

Saturn's internal magnetic field has been puzzling since the first in-situ measurements during the Pioneer 11 Saturn flyby. Cassini magnetometer measurements prior to the Grand Finale phase established 1) the highly axisymmetric nature of Saturn's internal magnetic field with a dipole tilt smaller than 0.06 degrees, 2) at least an order of magnitude slower secular variation rate compared to that of the current geomagnetic field, and 3) expulsion of magnetic fluxes from the equatorial region towards high latitude. The highly axisymmetric nature of Saturn's intrinsic magnetic field not only challenges dynamo theory but also makes an accurate determination of the interior rotation rate of Saturn extremely difficult. The Cassini spacecraft entered the Grand Finale phase in April 2017, during which time the spacecraft dived through the gap between Saturn's atmosphere and the inner edge of the D-ring 22 times before descending into the deep atmosphere of Saturn. The unprecedented proximity to Saturn (reaching 2500 km above the cloud deck) and the highly inclined nature of the Grand Finale orbits provided an ideal opportunity to decode Saturn's internal magnetic field. The fluxgate magnetometer onboard Cassini made precise vector measurements during the Grand Finale phase. Magnetic signals from the interior of the planet, the magnetospheric ring current, the high-latitude field-aligned current (FAC) modulated by the 10.7 hour planetary period oscillation, and low-latitude FACs were observed during the Grand Finale phase. Here we report the magnetometer measurements during the Cassini Grand Finale phase, new features of Saturn's internal magnetic field revealed by these measurements (e.g., the high degree magnetic moments of Saturn, the level of axisymmetry beyond dipole), and implications for the deep interior of Saturn.

The Saturn Probe Interior and aTmosphere Explorer (SPRITE) Mission

Science.gov (United States)

Simon, Amy; Banfield, Donald; Atkinson, David; SPRITE Science Team

2018-01-01

A key question in planetary science is how the planets formed in our Solar System, and, by extension, in exoplanet systems. The abundances of the noble gases (He, Ne, Ar, Kr, Xe), heavy elements (C, N, O, S), and their isotopes provide important forensic clues as to location and time of formation in the early Solar System. Jupiter and Saturn contain most of the planetary mass in our solar system, and their chemical fingerprints will distinguish between competing models of the formation of all the planets. After the end of the Cassini mission, some of these elements have only ambiguous values above the cloud tops, while others (particularly the noble gases) have not been measured at all. Resolving this requires direct in situ measurements. The proposed NASA New Frontiers Saturn PRobe Interior and aTmosphere Explorer (SPRITE) mission delivers an instrumented entry probe from a carrier relay spacecraft that also provides context imaging. The powerful probe instrument suite is comprised of a Quadrupole Mass Spectrometer, a Tunable Laser Spectrometer, and an Atmospheric Structure Instrument including a Doppler Wind Experiment and a simple backscatter nephelometer. These instruments measure the elemental and isotopic abundances of helium, the heavier noble gases, and the major elements, as well as constraining cloud properties, 3-D atmospheric dynamics, and disequilibrium chemistry to at least 10 bars in Saturn's troposphere. In situ measurements of Saturn's atmosphere by SPRITE will provide a significantly improved context for interpreting the results from the Galileo probe, Juno, and Cassini missions. SPRITE will revolutionize our understanding of the formation and evolution of the gas giant planets, and ultimately the present-day structure of the Solar System.

Identifying Cassini's Magnetospheric Location Using Magnetospheric Imaging Instrument (MIMI) Data and Machine Learning

Science.gov (United States)

Vandegriff, J. D.; Smith, G. L.; Edenbaum, H.; Peachey, J. M.; Mitchell, D. G.

2017-12-01

We analyzed data from Cassini's Magnetospheric Imaging Instrument (MIMI) and Magnetometer (MAG) and attempted to identify the region of Saturn's magnetosphere that Cassini was in at a given time using machine learning. MIMI data are from the Charge-Energy-Mass Spectrometer (CHEMS) instrument and the Low-Energy Magnetospheric Measurement System (LEMMS). We trained on data where the region is known based on a previous analysis of Cassini Plasma Spectrometer (CAPS) plasma data. Three magnetospheric regions are considered: Magnetosphere, Magnetosheath, and Solar Wind. MIMI particle intensities, magnetic field values, and spacecraft position are used as input attributes, and the output is the CAPS-based region, which is available from 2004 to 2012. We then use the trained classifier to identify Cassini's magnetospheric regions for times after 2012, when CAPS data is no longer available. Training accuracy is evaluated by testing the classifier performance on a time range of known regions that the classifier has never seen. Preliminary results indicate a 68% accuracy on such test data. Other techniques are being tested that may increase this performance. We present the data and algorithms used, and will describe the latest results, including the magnetospheric regions post-2012 identified by the algorithm.

The 2015 Summer Solstice Storm: One of the Major Geomagnetic Storms of Solar Cycle 24 Observed at Ground Level

Science.gov (United States)

Augusto, C. R. A.; Navia, C. E.; de Oliveira, M. N.; Nepomuceno, A. A.; Raulin, J. P.; Tueros, E.; de Mendonça, R. R. S.; Fauth, A. C.; Vieira de Souza, H.; Kopenkin, V.; Sinzi, T.

2018-05-01

We report on the 22 - 23 June 2015 geomagnetic storm that occurred at the summer solstice. There have been fewer intense geomagnetic storms during the current solar cycle, Solar Cycle 24, than in the previous cycle. This situation changed after mid-June 2015, when one of the largest solar active regions (AR 12371) of Solar Cycle 24 that was located close to the central meridian, produced several coronal mass ejections (CMEs) associated with M-class flares. The impact of these CMEs on the Earth's magnetosphere resulted in a moderate to severe G4-class geomagnetic storm on 22 - 23 June 2015 and a G2 (moderate) geomagnetic storm on 24 June. The G4 solstice storm was the second largest (so far) geomagnetic storm of Cycle 24. We highlight the ground-level observations made with the New-Tupi, Muonca, and the CARPET El Leoncito cosmic-ray detectors that are located within the South Atlantic Anomaly (SAA) region. These observations are studied in correlation with data obtained by space-borne detectors (ACE, GOES, SDO, and SOHO) and other ground-based experiments. The CME designations are taken from the Computer Aided CME Tracking (CACTus) automated catalog. As expected, Forbush decreases (FD) associated with the passing CMEs were recorded by these detectors. We note a peculiar feature linked to a severe geomagnetic storm event. The 21 June 2015 CME 0091 (CACTus CME catalog number) was likely associated with the 22 June summer solstice FD event. The angular width of CME 0091 was very narrow and measured {˜} 56° degrees seen from Earth. In most cases, only CME halos and partial halos lead to severe geomagnetic storms. We perform a cross-check analysis of the FD events detected during the rise phase of Solar Cycle 24, the geomagnetic parameters, and the CACTus CME catalog. Our study suggests that narrow angular-width CMEs that erupt in a westward direction from the Sun-Earth line can lead to moderate and severe geomagnetic storms. We also report on the strong solar proton

Modeling Saturn's Inner Plasmasphere: Cassini's Closest Approach

Science.gov (United States)

Moore, L.; Mendillo, M.

2005-05-01

Ion densities from the three-dimensional Saturn-Thermosphere-Ionosphere-Model (STIM, Moore et al., 2004) are extended above the plasma exobase using the formalism of Pierrard and Lemaire (1996, 1998), which evaluates the balance of gravitational, centrifugal and electric forces on the plasma. The parameter space of low-energy ionospheric contributions to Saturn's plasmasphere is explored by comparing results that span the observed extremes of plasma temperature, 650 K to 1700 K, and a range of velocity distributions, Lorentzian (or Kappa) to Maxwellian. Calculations are made for plasma densities along the path of the Cassini spacecraft's orbital insertion on 1 July 2004. These calculations neglect any ring or satellite sources of plasma, which are most likely minor contributors at 1.3 Saturn radii. Modeled densities will be compared with Cassini measurements as they become available. Moore, L.E., M. Mendillo, I.C.F. Mueller-Wodarg, and D.L. Murr, Icarus, 172, 503-520, 2004. Pierrard, V. and J. Lemaire, J. Geophys. Res., 101, 7923-7934, 1996. Pierrard, V. and J. Lemaire, J. Geophys. Res., 103, 4117, 1998.

Next Generation Simulation Framework for Robotic and Human Space Missions

Science.gov (United States)

Cameron, Jonathan M.; Balaram, J.; Jain, Abhinandan; Kuo, Calvin; Lim, Christopher; Myint, Steven

2012-01-01

The Dartslab team at NASA's Jet Propulsion Laboratory (JPL) has a long history of developing physics-based simulations based on the Darts/Dshell simulation framework that have been used to simulate many planetary robotic missions, such as the Cassini spacecraft and the rovers that are currently driving on Mars. Recent collaboration efforts between the Dartslab team at JPL and the Mission Operations Directorate (MOD) at NASA Johnson Space Center (JSC) have led to significant enhancements to the Dartslab DSENDS (Dynamics Simulator for Entry, Descent and Surface landing) software framework. The new version of DSENDS is now being used for new planetary mission simulations at JPL. JSC is using DSENDS as the foundation for a suite of software known as COMPASS (Core Operations, Mission Planning, and Analysis Spacecraft Simulation) that is the basis for their new human space mission simulations and analysis. In this paper, we will describe the collaborative process with the JPL Dartslab and the JSC MOD team that resulted in the redesign and enhancement of the DSENDS software. We will outline the improvements in DSENDS that simplify creation of new high-fidelity robotic/spacecraft simulations. We will illustrate how DSENDS simulations are assembled and show results from several mission simulations.

Probing Small Lakes on Titan Using the Cassini RADAR Altimeter

Science.gov (United States)

Mastrogiuseppe, M.; Poggiali, V.; Hayes, A.; Lunine, J. I.; Seu, R.; Lorenz, R. D.; Mitri, G.; Mitchell, K. L.; Janssen, M. A.; Casarano, D.; Notarnicola, C.; Le Gall, A. A.

2017-12-01

The T126 Cassini's final flyby of Titan has offered a unique opportunity to observe an area in the Northern Polar terrain, where several small - medium size (10 - 50 km) hydrocarbon lakes are present and have been previously imaged by Cassini. The successful observation allowed the radar to operate at the closest approach over several small lakes, using its altimetry mode for the investigation of depth and liquid composition. Herein we present the result of a dedicate processing previously applied to altimetric data acquired over Ligeia Mare where the radar revealed the bathymetry and composition of the sea [1,2]. We show that, the optimal geometry condition met during the T126 fly-by allowed the radar to probe Titan's lakes revealing that such small liquid bodies can exceed one-hundred meters of depth. [1] M. Mastrogiuseppe et al. (2014, Mar.). The bathymetry of a Titan Sea. Geophysical Research Letters. [Online]. 41 (5), pp. 1432-1437. Available: http://dx.doi.org/10.1002/2013GL058618 [2] M.Mastrogiuseppe et al. (2016, Oct). Radar Sounding Using the Cassini Altimeter: Waveform Modeling and Monte Carlo Approach for Data Inversion of Observations of Titan's Seas, IEEE Transactions On Geoscience And Remote Sensing, Vol. 54, No. 10, doi: 10.1109/TGRS.2016.2563426.

Seasonal Evolution of the North and South Polar Vortex on Titan From 2004 to 2017 as Seen by Cassini/VIMS

Science.gov (United States)

Le Mouelic, S.; Robidel, R.; Rousseau, B.; Rodriguez, S.; Cornet, T.; Sotin, C.; Barnes, J. W.; Brown, R. H.; Buratti, B. J.; Baines, K. H.; Clark, R. N.; Nicholson, P. D.

2017-12-01

Cassini entered in Saturn's orbit in July 2004. In thirteen years, 127 targeted flybys of Titan have been performed. We focus our study on the analysis of the complete Visual and Infrared Mapping Spectrometer data set, with a particular emphasis on the evolving features on both poles. We have computed individual global maps of the north and south poles for each of the 127 targeted flybys, using VIMS wavelengths sensitive both to clouds and surface features. First evidences for a vast ethane cloud covering the North Pole is seen as soon as the first and second targeted flyby in October 2004 and December 2005 [1]. The first detailed imaging of this north polar feature with VIMS was obtained in December 2006, thanks to a change in inclination of the spacecraft orbit [2]. At this time, the northern lakes and seas of Titan were totally masked to the optical instruments by the haze and clouds, whereas the southern pole was well illuminated and mostly clear of haze and vast clouds. The vast north polar feature progressively vanished around the equinox in 2009 [2,3,4], in agreement with the predictions of Global Circulation Models [5]. It revealed progressively the underlying lakes to the ISS and VIMS instruments, which show up very nicely in VIMS in a series of flybys between T90 and T100. First evidences of an atmospheric vortex growing over the south pole occurred in May 2012 (T82), with a high altitude feature being detected consistently at each flyby up to the last T126 targeted flyby, and also appearing in more distant observations up to the end of the Cassini mission. Cassini has covered almost half a titanian year, corresponding to two seasons. The situation observed at the South Pole in the last images may correspond to what was observed in the north as Cassini just arrived. [1] Griffith et al., Science, 2006. [2] Le Mouélic et al., PSS, 2012. [3] Rodriguez et al., Nature, 2009. [4] Rodriguez et al., Icarus 2011. [4] Hirtzig et al., Icarus, 2013. [5] Rannou et al

Solar tides in the equatorial upper thermosphere: A comparison between AE-E data and the TIGCM for solstice, solar minimum conditions

International Nuclear Information System (INIS)

Burrage, M.D.; Storz, M.F.; Abreu, V.J.; Fesen, C.G.; Roble, R.G.

1991-01-01

Equatorial thermospheric tidal temperatures and densities inferred from Atmosphere Explorer E (AE-E) mass spectrometer data are compared with theoretical predictions from the National Center for Atmospheric Research Thermosphere/Ionisphere General Circulation Model (TIGCM) for solar minimum, solstice conditions. The thermospheric diurnal and semidiurnal tides are excited in situ by solar heating and by ion-neutral momentum coupling. Semidiurnal tides are also generated by upward propagating waves excited by heating in the lower atmosphere. The model calculations include all of these sources. The TIGCM reproduces the gross tidal features observed by the satellite, including the midnight temperature anomaly, and the diurnal phases are in good agreement for the densities of atomic oxygen and molecular nitrogen. However, for the neutral temperature, the predicted phases are 1-2 hours earlier than observed. In addition, the diurnal temperature and density amplitudes predicted by the model are considerably weaker than indicated by the AE-E measurements. The semidiurnal variations found in the observations agree well with the model for December solstice but not for June. The present results indicate that upward propagating tides from the lower atmosphere are responsible for at least half of the amplitude of the semidiurnal tide in the upper thermosphere

Detecting dust hits at Enceladus, Saturn and beyond using CAPS / ELS data from Cassini

Science.gov (United States)

Vandegriff, J. D.; Stoneberger, P. J.; Jones, G.; Waite, J. H., Jr.

2016-12-01

It has recently been shown (1) that the impact of hypervelocity dust grains on the Cassini spacecraft can be detected by the Cassini Plasma Spectrometer (CAPS) Electron Spectrometer (ELS) instrument. For multiple Enceladus flybys, fine scale features in the lower energy regime of ELS energy spectra can be explained as short-duration, isotropic plasma clouds due to dust impacts. We have developed an algorithm for detecting these hypervelocity dust impacts, and the list of such impacts during Enceladus flybys will be presented. We also present preliminary results obtained when using the algorithm to search for dust impacts in other regions of Saturn's magnetosphere as well as in the solar wind. (1) Jones, Geraint, Hypervelocity dust impact signatures detected by Cassini CAPS-ELS in the Enceladus plume, MOP Meeting, June 1-5, 2015, Atlanta, GA

Post-midnight equatorial irregularity distributions and vertical drift velocity variations during solstices

Science.gov (United States)

Su, S.-Y.; Liu, C. H.; Chao, C.-K.

2018-04-01

Longitudinal distributions of post-midnight equatorial ionospheric irregularity occurrences observed by ROCSAT-1 (1st satellite of the Republic of China) during moderate to high solar activity years in two solstices are studied with respect to the vertical drift velocity and density variations. The post-midnight irregularity distributions are found to be similar to the well-documented pre-midnight ones, but are different from some published distributions taken during solar minimum years. Even though the post-midnight ionosphere is sinking in general, longitudes of frequent positive vertical drift and high density seems to coincide with the longitudes of high irregularity occurrences. Large scatters found in the vertical drift velocity and density around the dip equator in different ROCSAT-1 orbits indicate the existence of large and frequent variations in the vertical drift velocity and density that seem to be able to provide sufficient perturbations for the Rayleigh-Taylor (RT) instability to cause the irregularity occurrences. The need of seeding agents such as gravity waves from atmospheric convective clouds to initiate the Rayleigh-Taylor instability may not be necessary.

Titan’s mid-latitude surface regions with Cassini VIMS and RADAR

Science.gov (United States)

Solomonidou, Anezina; Lopes, Rosaly M. C.; Coustenis, Athena; Malaska, Michael; Rodriguez, Sebastien; Maltagliati, Luca; Drossart, Pierre; Janssen, Michael; Lawrence, Kenneth; Jaumann, Ralf; Sohl, Frank; Stephan, Katrin; Brown, Robert H.; Bratsolis, Emmanuel; Matsoukas, Christos

2015-11-01

The Cassini-Huygens mission instruments have revealed Titan to have a complex and dynamic atmosphere and surface. Data from the remote sensing instruments have shown the presence of diverse surface terrains in terms of morphology and composition, suggesting both exogenic and endogenic processes [1]. We define both the surface and atmospheric contributions in the VIMS spectro-imaging data by use of a radiative transfer code in the near-IR range [2]. To complement this dataset, the Cassini RADAR instrument provides additional information on the surface morphology, from which valuable geological interpretations can be obtained [3]. We examine the origin of key Titan terrains, covering the mid-latitude zones extending from 50ºN to 50ºS. The different geological terrains we investigate include: mountains, plains, labyrinths, craters, dune fields, and possible cryovolcanic and/or evaporite features. We have found that the labyrinth terrains and the undifferentiated plains seem to consist of a very similar if not the same material, while the different types of plains show compositional variations [3]. The processes most likely linked to their formation are aeolian, fluvial, sedimentary, lacustrine, in addition to the deposition of atmospheric products though the process of photolysis and sedimentation of organics. We show that temporal variations of surface albedo exist for two of the candidate cryovolcanic regions. The surface albedo variations together with the presence of volcanic-like morphological features suggest that the active regions are possibly related to the deep interior, possibly via cryovolcanism processes (with important implications for the satellite’s astrobiological potential) as also indicated by new interior structure models of Titan and corresponding calculations of the spatial pattern of maximum tidal stresses [4]. However, an explanation attributed to exogenic processes is also possible [5]. We will report on results from our most recent

Ongoing Analysis of Jupiter's Equatorial Hotspots and Plumes from Cassini

Science.gov (United States)

Choi, D. S.; Showmwn, A. P.; Vasavada, A. R.; Simon-Miller, A. A.

2012-01-01

We present updated results from our ongoing analysis of Cassini observations of Jupiter's equatorial meteorology. For two months preceding the spacecraft's closest approach of the planet, the ISS instrument onboard Cassini regularly imaged the atmosphere of Jupiter. We created time-lapse movies from this period that show the complex activity and interactions of the equatorial atmosphere. During this period, hot spots exhibited significant variations in size and shape over timescales of days and weeks. Some of these changes appear to be a result of interactions with passing vortex systems in adjacent latitudes. Strong anticyclonic gyres to the southeast of the dark areas converge with flow from the west and appear to circulate into a hot spot at its southwestern corner.

Statistical Analysis of Interchange Injection Events from Over a Decade of Cassini Data

Science.gov (United States)

Azari, A.; Jia, X.; Liemohn, M. W.; Sergis, N.; Thomsen, M. F.; Mitchell, D. G.; Rymer, A. M.; Paranicas, C.; Provan, G.; Ye, S.; Cowley, S. W. H.; Hospodarsky, G. B.; Vandegriff, J. D.; Kurth, W. S.

2017-12-01

The Cassini spacecraft has routinely observed interchange injection events with multiple instruments since arriving at Saturn in 2004. Interchange injection events are thought to initiate from a Rayleigh-Taylor like plasma instability sourced from Saturn's rapid rotation (period 10.8 hours) and dense plasma population outgassing primarily from Enceladus, and are the primary source of mass transport in the inner/middle magnetosphere. This dense plasma must be transported outward, and to conserve magnetic flux, inward moving flux tubes of low density, energetic (> keV) plasma from the outer reaches of the Saturnian system also occur. These inward-bound flux tubes are referred to as interchange injections. We will present a statistical evaluation of the occurrence rates of interchange injections at Saturn demonstrating seasonal dependence of interchange over the entirety of the Cassini mission's equatorial orbits between 2005 and 2016. We identify interchange events from CHarge Energy Mass Spectrometer (CHEMS) H+ data using a trained and tested automated algorithm. Our event identification compares well with manual identification and previous surveys of injections by L-shell and local time (Chen and Hill, 2008, Lai et al., 2016, Kennelly et al., 2013). We find that peak rates of interchange events occur between 7 - 9 Saturn radii, in agreement with previous surveys. We also evaluate interchange by preferred local time sector and season, splitting our events into pre-equinox, equinox, and post - equinox time periods. We determine that over all seasons, nightside occurrence dominated as compared to dayside, but the preferred dayside sector shifts from pre-noon during equinox, to post-noon during post-equinox. We will further investigate seasonal dependence by presenting occurrence organized by the phase systems derived based on Saturn kilometric radiation (SKR) and magnetic field perturbations (PPO).

CASSINI RSS RAW DATA SET - SROC20 V1.0

Data.gov (United States)

National Aeronautics and Space Administration — The Cassini Radio Science Saturn Ring and Atmospheric Occultation experiments (SROC20) Raw Data Archive is a time-ordered collection of radio science raw data...

CASSINI S MIMI CHEMS SENSOR CALIBRATED DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — The Cassini Magnetospheric Imaging Instrument(MIMI) Charge Energy Mass Spectrometer (CHEMS) contains a deflection system and an overall field of view of 159 x 4 deg....

Cassini Spacecraft In-Flight Swap to Backup Attitude Control Thrusters

Science.gov (United States)

Bates, David M.

2010-01-01

NASA's Cassini Spacecraft, launched on October 15th, 1997 and arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. In order to meet the challenging attitude control and navigation requirements of the orbit profile at Saturn, Cassini is equipped with a monopropellant thruster based Reaction Control System (RCS), a bipropellant Main Engine Assembly (MEA) and a Reaction Wheel Assembly (RWA). In 2008, after 11 years of reliable service, several RCS thrusters began to show signs of end of life degradation, which led the operations team to successfully perform the swap to the backup RCS system, the details and challenges of which are described in this paper. With some modifications, it is hoped that similar techniques and design strategies could be used to benefit other spacecraft.

Exploring inner structure of Titan's dunes from Cassini Radar observations

Science.gov (United States)

Sharma, P.; Heggy, E.; Farr, T. G.

2013-12-01

Linear dunes discovered in the equatorial regions of Titan by the Cassini-Huygens mission are morphologically very similar to many terrestrial linear dune fields. These features have been compared with terrestrial longitudinal dune fields like the ones in Namib desert in western Africa. This comparison is based on the overall parallel orientation of Titan's dunes to the predominant wind direction on Titan, their superposition on other geomorphological features and the way they wrap around topographic obstacles. Studying the internal layering of dunes has strong implications in understanding the hypothesis for their origin and evolution. In Titan's case, although the morphology of the dunes has been studied from Cassini Synthetic Aperture Radar (SAR) images, it has not been possible to investigate their internal structure in detail as of yet. Since no radar sounding data is available for studying Titan's subsurface yet, we have developed another technique to examine the inner layering of the dunes. In this study, we utilize multiple complementary radar datasets, including radar imaging data for Titan's and Earth's dunes and Ground Penetrating Radar (GPR)/radar sounding data for terrestrial dunes. Based on dielectric mixing models, we suggest that the Cassini Ku-band microwaves should be able to penetrate up to ~ 3 m through Titan's dunes, indicating that the returned radar backscatter signal would include contributions from both surface and shallow subsurface echoes. This implies that the shallow subsurface properties can be retrieved from the observed radar backscatter (σ0). In our analysis, the variation of the radar backscatter as a function of dune height is used to provide an insight into the layering in Titan's dunes. We compare the variation of radar backscatter with elevation over individual dunes on Titan and analogous terrestrial dunes in three sites (Great Sand Sea, Siwa dunes and Qattaniya dunes) in the Egyptian Sahara. We observe a strong, positive

METER-SIZED MOONLET POPULATION IN SATURN'S C RING AND CASSINI DIVISION

International Nuclear Information System (INIS)

Baillié, Kévin; Colwell, Joshua E.; Esposito, Larry W.; Lewis, Mark C.

2013-01-01

Stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph reveal the presence of transparent holes a few meters to a few tens of meters in radial extent in otherwise optically thick regions of the C ring and the Cassini Division. We attribute the holes to gravitational disturbances generated by a population of ∼10 m boulders in the rings that is intermediate in size between the background ring particle size distribution and the previously observed ∼100 m propeller moonlets in the A ring. The size distribution of these boulders is described by a shallower power-law than the one that describes the ring particle size distribution. The number and size distribution of these boulders could be explained by limited accretion processes deep within Saturn's Roche zone.

The Saturnian satellite Rhea as seen by Cassini VIMS

Science.gov (United States)

Stephan, K.; Jaumann, R.; Wagner, R.; Clark, R.N.; Cruikshank, D.P.; Giese, B.; Hibbitts, C.A.; Roatsch, T.; Matz, K.-D.; Brown, R.H.; Filacchione, G.; Cappacioni, F.; Scholten, F.; Buratti, B.J.; Hansen, G.B.; Nicholson, P.D.; Baines, K.H.; Nelson, R.M.; Matson, D.L.

2012-01-01

Since the arrival of the Cassini spacecraft at Saturn in June 2004, the Visual and Infrared Mapping Spectrometer has obtained new spectral data of the icy satellites of Saturn in the spectral range from 0.35 to 5.2 ??m. Numerous flybys were performed at Saturn's second largest satellite Rhea, providing a nearly complete coverage with pixel-ground resolutions sufficient to analyze variations of spectral properties across Rhea's surface in detail. We present an overview of the VIMS observations obtained so far, as well as the analysis of the spectral properties identified in the VIMS spectra and their variations across its surface compared with spatially highly resolved Cassini ISS images and digital elevation models. Spectral variations measured across Rhea's surface are similar to the variations observed in the VIMS observations of its neighbor Dione, implying similar processes causing or at least inducing their occurrence. Thus, magnetospheric particles and dust impacting onto the trailing hemisphere appear to be responsible for the concentration of dark rocky/organic material and minor amounts of CO 2 in the cratered terrain on the trailing hemisphere. Despite the prominent spectral signatures of Rhea's fresh impact crater Inktomi, radiation effects were identified that also affect the H 2O ice-rich cratered terrain of the leading hemisphere. The concentration of H 2O ice in the vicinity of steep tectonic scarps near 270??W and geologically fresh impact craters implies that Rhea exhibits an icy crust at least in the upper few kilometers. Despite the evidence for past tectonic events, no indications of recent endogenically powered processes could be identified in the Cassini data. ?? 2011 Elsevier Ltd. All rights reserved.

The global distribution of thermospheric odd nitrogen for solstice conditions during solar cycle minimum

Science.gov (United States)

Gerard, J.-C.; Roble, R. G.; Rusch, D. W.; Stewart, A. I.

1984-01-01

A two-dimensional model of odd nitrogen in the thermosphere and upper mesosphere is described. The global distributions of nitric oxide and atomic nitrogen are calculated for the solstice period for quiet and moderate magnetic activity during the solar minimum period. The effect of thermospheric transport by winds is investigated along with the importance of particle-induced ionization in the auroral zones. The results are compared with rocket and satellite measurements, and the sensitivity of the model to eddy diffusion and neutral winds is investigated. Downward fluxes of NO into the mesosphere are given, and their importance for stratospheric ozone is discussed. The results show that the summer-to-winter pole meridional circulation transports both NO and N(S-4) across the solar terminator into the polar night region where there is a downward vertical transport toward the mesosphere. The model shows that odd nitrogen densities at high winter latitudes are entirely controlled by particle precipitation and transport processes.

Titan Orbiter with Aerorover Mission (TOAM)

Science.gov (United States)

Sittler, Edward C.; Cooper, J. F.; Mahaffey, P.; Esper, J.; Fairbrother, D.; Farley, R.; Pitman, J.; Kojiro, D. R.; TOAM Team

2006-12-01

We propose to develop a new mission to Titan called Titan Orbiter with Aerorover Mission (TOAM). This mission is motivated by the recent discoveries of Titan, its atmosphere and its surface by the Huygens Probe, and a combination of in situ, remote sensing and radar mapping measurements of Titan by the Cassini orbiter. Titan is a body for which Astrobiology (i.e., prebiotic chemistry) will be the primary science goal of any future missions to it. TOAM is planned to use an orbiter and balloon technology (i.e., aerorover). Aerobraking will be used to put payload into orbit around Titan. The Aerorover will probably use a hot air balloon concept using the waste heat from the MMRTG 500 watts. Orbiter support for the Aerorover is unique to our approach for Titan. Our strategy to use an orbiter is contrary to some studies using just a single probe with balloon. Autonomous operation and navigation of the Aerorover around Titan will be required, which will include descent near to the surface to collect surface samples for analysis (i.e., touch and go technique). The orbiter can provide both relay station and GPS roles for the Aerorover. The Aerorover will have all the instruments needed to sample Titan’s atmosphere, surface, possible methane lakes-rivers, use multi-spectral imagers for surface reconnaissance; to take close up surface images; take core samples and deploy seismometers during landing phase. Both active and passive broadband remote sensing techniques will be used for surface topography, winds and composition measurements.

A Three-Dimensional View of Titan's Surface Features from Cassini RADAR Stereogrammetry

Science.gov (United States)

Kirk, R. L.; Howington-Kraus, E.; Redding, B. L.; Becker, T. L.; Lee, E. M.; Stiles, B. W.; Hensley, S.; Hayes, A.; Lopes, R. M.; Lorenz, R. D.; Mitchell, K. L.; Radebaugh, J.; Paganelli, F.; Soderblom, L. A.; Stofan, E. R.; Wood, C. A.; Wall, S. D.; Cassini RADAR Team

2008-12-01

As of the end of its four-year Prime Mission, Cassini has obtained 300-1500 m resolution synthetic aperture radar images of the surface of Titan during 19 flybys. The elongated image swaths overlap extensively, and ~2% of the surface has now been imaged two or more times. The majority of image pairs have different viewing directions, and thus contain stereo parallax that encodes information about Titan's surface relief over distances of ~1 km and greater. As we have previously reported, the first step toward extracting quantitative topographic information was the development of rigorous "sensor models" that allowed the stereo systems previously used at the USGS and JPL to map Venus with Magellan images to be used for Titan mapping. The second major step toward extensive topomapping of Titan has been the reprocessing of the RADAR images based on an improved model of the satellite's rotation. Whereas the original images (except for a few pairs obtained at similar orbital phase, some of which we have mapped previously) were offset by as much as 30 km, the new versions align much better. The remaining misalignments, typically carbono)logic" cycle of precipitation, evaporation, and surface and subsurface fluid flow?

Jovian atmospheric dynamics: an update after Galileo and Cassini

International Nuclear Information System (INIS)

Vasavada, Ashwin R; Showman, Adam P

2005-01-01

The Galileo and Cassini spacecrafts have greatly enhanced the observational record of Jupiter's tropospheric dynamics, particularly through returning high spatial resolution, multi-spectral and global imaging data with episodic coverage over periods of months to years. These data, along with those from Earth-based telescopes, have revealed the stability of Jupiter's zonal jets, captured the evolution of vortices and equatorial waves, and mapped the distributions of lightning and moist convection. Because no observations of Jupiter's interior exist, a forward modelling approach has been used to relate observations at cloud level to models of shallow or deep jet structure, shallow or deep jet forcing and energy transfer between turbulence, vortices and jets. A range of observed phenomena can be reproduced in shallow models, though the Galileo probe winds and jet stability arguments hint at the presence of deep jets. Many deep models, however, fail to reproduce Jupiter-like non-zonal features (e.g. vortices). Jupiter's dynamics likely include both deep and shallow processes, requiring an integrated approach to future modelling-an important goal for the post-Galileo and Cassini era

Energy deposition and ion production from thermal oxygen ion precipitation during Cassini's T57 flyby

Science.gov (United States)

Snowden, Darci; Smith, Michael; Jimson, Theodore; Higgins, Alex

2018-05-01

Cassini's Radio Science Investigation (RSS) and Langmuir Probe observed abnormally high electron densities in Titan's ionosphere during Cassini's T57 flyby. We have developed a three-dimensional model to investigate how the precipitation of thermal magnetospheric O+ may have contributed to enhanced ion production in Titan's ionosphere. The three-dimensional model builds on previous work because it calculates both the flux of oxygen through Titan's exobase and the energy deposition and ion production rates in Titan's atmosphere. We find that energy deposition rates and ion production rates due to thermal O+ precipitation have a similar magnitude to the rates from magnetospheric electron precipitation and that the simulated ionization rates are sufficient to explain the abnormally high electron densities observed by RSS and Cassini's Langmuir Probe. Globally, thermal O+ deposits less energy in Titan's atmosphere than solar EUV, suggesting it has a smaller impact on the thermal structure of Titan's neutral atmosphere. However, our results indicate that thermal O+ precipitation can have a significant impact on Titan's ionosphere.

Cassini Scientist for a Day: an international contest in Greece

Science.gov (United States)

Solomonidou, Anezina; Moussas, Xenophon; Xystouris, Georgios; Coustenis, Athena; Lebreton, Jean-Pierre; Katsavrias, Christos; Bampasidis, Georgios; Kyriakopoulos, Konstantinos; Kouloumvakos, Athanasios; Patsou, Ioanna

2013-04-01

The Cassini Outreach Team of NASA's Jet Propulsion Laboratory is being organizing a brilliant school contest in Astronomy focusing in the Saturnian system. This essay contest provides school students all around the worlds with the opportunity to get involved in astronomy and astrophysics and planetary sciences in particular. From 2010 the 'Cassini Scientist for a Day' contest has being one of the most successful as well as important outreach activities of ESA and NASA in Greece with hundreds of participants all over Greece. The number of participants is growing rapidly every year. This type of school competition in Greece is particularly important since Astronomy and Astrophysics and Space Sciences, although very popular, are not included in the school curricula and thus students rarely have the opportunity to experience and participate actively in these subjects. For the years 2010 and 2011, the Space Physics Group of the Astronomy, Astrophysics and Mechanics section of the University of Athens in association with external colleagues has been selected as the co-ordinator of NASA for the competition in Greece. Under the guidance of Cassini Outreach team, the members of the Space Physics Group have informed, explained and spread the rules of the competition at primary, secondary and high schools all over Greece. In general, the students have the option to choose Cassini monitoring between three targets of the Saturnian system, which the participants show that will bring the best scientific result. Their arguments should be summarized in an essay of 500 words more or less. They also have the option to do team work through groups of maximum three students. The participation in the contest for 2010 was unexpectedly high and thoroughly satisfied. The winners awarded through a ceremony which was held in the largest amphitheater at the central building of the University of Athens, that was fully packed. The following year 2011 the participation increased up to 300% while

Cassini ISS Observations of Jupiter: An Exoplanet Perspective

Science.gov (United States)

West, Robert A.; Knowles, Benjamin

2017-10-01

Understanding the optical and physical properties of planets in our solar system can guide our approach to the interpretation of observations of exoplanets. Although some work has already been done along these lines, there remain low-hanging fruit. During the Cassini Jupiter encounter, the Imaging Science Subsystem (ISS) obtained an extensive set of images over a large range of phase angles (near-zero to 140 degrees) and in filters from near-UV to near-IR, including three methane bands and nearby continuum. The ISS also obtained images using polarizers. Much later in the mission we also obtained distant images while in orbit around Saturn. Some of these data have already been studied to reveal phase behavior (Dyudina et al., Astrophys. J.822, DOI: 10.3847/0004-637X/822/2/76; Mayorga et al., 2016, Astron. J. 152, DOI: 10.3847/0004-6256/152/6/209). Here we examine rotational modulation to determine wavelength and phase angle dependence, and how these may depend on cloud and haze vertical structure and optical properties. The existence of an optically thin forward-scattering and longitudinally-homogeneous haze overlying photometrically-variable cloud fields tends to suppress rotational modulation as phase angle increases, although in the strong 890-nm methane band cloud vertical structure is important. Cloud particles (non-spherical ammonia ice, mostly) have very small polarization signatures at intermediate phase angles and rotational modulation is not apparent above the noise level of our instrument. Part of this work was performed by the Jet Propulsion Lab, Cal. Inst. Of Technology.

A Ring-‘Rain’ influence for Saturn’s Cloud Albedo and Temperatures? Evidence Pro or Con from Voyager, HST, and Cassini

Science.gov (United States)

West, Robert A.; Li, Liming

2015-11-01

J. E. P. Connerney [Geophys. Res. Lett, 13, 773-776, 1986] pointed out that ‘latitudinal variations in images of Saturn’s disk, upper atmospheric temperatures, and ionospheric electron densities are found in magnetic conjugacy with features in Saturn’s ring plane’, and proposed ‘that these latitudinal variations are the result of a variable influx of water, transported along magnetic field lines from sources in Saturn’s ring plane’. Observations of H3+ support a ring-ionosphere connection [O'Donoghue et al., Nature 496, 7444, 2013]. What about cloud albedo and temperature? Connerney attributed a hemispheric asymmetry in haze and temperature to an asymmetry in water flux and predicted that ‘the presently-observed north-south asymmetry (upper tropospheric temperatures, aerosols) will persist throughout the Saturn year’. We can now test these ideas with data from the Cassini mission, from the Hubble Space Telescope, and from ground-based observations. Analyses of ground-based images and especially Hubble data established that the hemispheric asymmetry of the aerosol population does change, and seasonal effects are dominant, although non-seasonal variations are also observed [Karkoschka and Tomasko, Icarus 179, 195-221, 2005]. Upper tropospheric temperatures also vary as expected in response to seasonal forcing [Fletcher et al., Icarus 208, 337-352, 2009]. Connerney also identified dark bands in Voyager Green-filter images on magnetic conjugacy with the E ring and edges of the A and B rings. In Cassini Green-filter images there is some correspondence between dark bands and ring features in magnetic conjugacy, but collectively the correlation is not strong. Cassini 727-nm methane band images do not suggest depletion of aerosols in the upper troposphere at ring edge magnetic conjugacy latitudes as proposed by Connerney. We conclude that ring rain does not have a significant influence on upper tropospheric aerosols and temperatures on Saturn. Part of

a Search for New Physics with the Beacon Mission

Science.gov (United States)

Turyshev, Slava G.; Shao, Michael; Girerd, André; Lane, Benjamin

The primary objective of the Beyond Einstein Advanced Coherent Optical Network (BEACON) mission is a search for new physics beyond general relativity by measuring the curvature of relativistic space-time around the Earth. This curvature is characterized by the Eddington parameter γ — the most fundamental relativistic gravity parameter and a direct measure for the presence of new physical interactions. BEACON will achieve an accuracy of 1 × 10-9 in measuring the parameter γ, thereby going a factor of 30,000 beyond the present best result involving the Cassini spacecraft. Secondary mission objectives include: (i) a direct measurement of the "frame-dragging" and geodetic precessions in the Earth's rotational gravitomagnetic field, to 0.05% and 0.03% accuracy respectively, (ii) the first measurement of gravity's nonlinear effects on light and the corresponding second order spatial metric's effects to 0.01% accuracy. BEACON will lead to robust advances in tests of fundamental physics — this mission could discover a violation or extension of general relativity and/or reveal the presence of an additional long range interaction in physics. It will provide crucial information to separate modern scalar-tensor theories of gravity from general relativity, probe possible ways for gravity quantization, and test modern theories of cosmological evolution.

Travelling Ionospheric Disturbances Observed During Sudden Stratospheric Warming, Equinox and Solstice Periods with Kharkiv and Millstone Hill Incoherent Scatter Radars

Science.gov (United States)

Goncharenko, L. P.; Panasenko, S.; Aksonova, K.; Erickson, P. J.; Domnin, I. F.

2016-12-01

Travelling ionospheric disturbances (TIDs) play a key role in the coupling of different ionospheric regions through momentum an energy transfer. They are thought to be mostly associated with atmospheric gravity waves and are known to strongly affect radio propagation conditions. The incoherent scatter (IS) method enables TIDs detection in such ionospheric parameters as electron density, ion and electron temperatures, and plasma velocity along radar beam, thus providing critical information needed to examine different hypothesis about association of TIDs with their sources. In 2016, several joint measuring campaigns were conducted using Kharkiv (49.6 N, 36.4 E) and Millstone Hill (42.6 N, 288.5 E) IS radars. These campaigns covered the periods of sudden stratospheric warnings (SSW) in February, vernal equinox and summer solstice. For consistency, the data acquired by radars were processed using the same data analysis methods. The results obtained show the TIDs to be detected throughout all observation intervals in February measurements. The differences found in the behavior of TIDs over Kharkiv and Millstone Hill sites may be partially explained by variations in stratospheric wind velocity vectors during SSW period. As for March equinox and June solstice, the prevailing TIDs are observed near solar terminators. Their periods vary mostly in the range of 40 - 80 minutes, relative amplitudes are about 0.05 - 0.3 of the background electron density, and the maximum values are observed at the heights of 200 - 250 km. Systematic long-term observations of wave processes in the ionosphere with multiple IS facilities can reveal interhemispheric variability in TID parameters, give better understanding the mechanisms of TID generation and propagation, and improve regional and global ionospheric models.

CASSINI E/J/S/SW MIMI INCA SENSOR UNCALIBRATED DATA V1.1

Data.gov (United States)

National Aeronautics and Space Administration — The Cassini Magnetospheric Imaging Instrument(MIMI) Imaging Neutral Camera (INCA) uncalibrated data set includes all data collected from the MIMI Data Processing...

CASSINI E/J/S/SW MIMI INCA SENSOR UNCALIBRATED DATA V1.0

Data.gov (United States)

National Aeronautics and Space Administration — The Cassini Magnetospheric Imaging Instrument(MIMI) Imaging Neutral Camera (INCA) uncalibrated data set includes all data collected from the MIMI Data Processing...

Cassini CAPS Identification of Pickup Ion Compositions at Rhea

Science.gov (United States)

Desai, R. T.; Taylor, S. A.; Regoli, L. H.; Coates, A. J.; Nordheim, T. A.; Cordiner, M. A.; Teolis, B. D.; Thomsen, M. F.; Johnson, R. E.; Jones, G. H.; Cowee, M. M.; Waite, J. H.

2018-02-01

Saturn's largest icy moon, Rhea, hosts a tenuous surface-sputtered exosphere composed primarily of molecular oxygen and carbon dioxide. In this Letter, we examine Cassini Plasma Spectrometer velocity space distributions near Rhea and confirm that Cassini detected nongyrotropic fluxes of outflowing CO2+ during both the R1 and R1.5 encounters. Accounting for this nongyrotropy, we show that these possess comparable along-track densities of ˜2 × 10-3 cm-3. Negatively charged pickup ions, also detected during R1, are surprisingly shown as consistent with mass 26 ± 3 u which we suggest are carbon-based compounds, such as CN-, C2H-, C2-, or HCO-, sputtered from carbonaceous material on the moon's surface. The negative ions are calculated to possess along-track densities of ˜5 × 10-4 cm-3 and are suggested to derive from exogenic compounds, a finding consistent with the existence of Rhea's dynamic CO2 exosphere and surprisingly low O2 sputtering yields. These pickup ions provide important context for understanding the exospheric and surface ice composition of Rhea and of other icy moons which exhibit similar characteristics.

NASA's Planetary Science Missions and Participations

Science.gov (United States)

Daou, Doris; Green, James L.

2017-04-01

NASA's Planetary Science Division (PSD) and space agencies around the world are collaborating on an extensive array of missions exploring our solar system. Planetary science missions are conducted by some of the most sophisticated robots ever built. International collaboration is an essential part of what we do. NASA has always encouraged international participation on our missions both strategic (ie: Mars 2020) and competitive (ie: Discovery and New Frontiers) and other Space Agencies have reciprocated and invited NASA investigators to participate in their missions. NASA PSD has partnerships with virtually every major space agency. For example, NASA has had a long and very fruitful collaboration with ESA. ESA has been involved in the Cassini mission and, currently, NASA funded scientists are involved in the Rosetta mission (3 full instruments, part of another), BepiColombo mission (1 instrument in the Italian Space Agency's instrument suite), and the Jupiter Icy Moon Explorer mission (1 instrument and parts of two others). In concert with ESA's Mars missions NASA has an instrument on the Mars Express mission, the orbit-ground communications package on the Trace Gas Orbiter (launched in March 2016) and part of the DLR/Mars Organic Molecule Analyzer instruments going onboard the ExoMars Rover (to be launched in 2018). NASA's Planetary Science Division has continuously provided its U.S. planetary science community with opportunities to include international participation on NASA missions too. For example, NASA's Discovery and New Frontiers Programs provide U.S. scientists the opportunity to assemble international teams and design exciting, focused planetary science investigations that would deepen the knowledge of our Solar System. The PSD put out an international call for instruments on the Mars 2020 mission. This procurement led to the selection of Spain and Norway scientist leading two instruments and French scientists providing a significant portion of another

Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

Directory of Open Access Journals (Sweden)

B. Kazeminejad

2005-06-01

Full Text Available Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004 (Icarus, Vol. 170, 91-112 engineering model and derive extreme case (i.e. minimum and maximum profiles temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997 (ESA SP-1177 profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.

Tidal Control of Jet Eruptions Observed by Cassini ISS

Science.gov (United States)

Hurford, T. A.; Helfenstein, P.; Spitale, J. N.

2012-01-01

Observations by Cassini's Imaging Science Subsystem (ISS) of Enceladus' south polar region at high phase angles has revealed jets of material venting into space. Observations by Cassini's Composite Infrared Spectrometer (CIRS) have also shown that the south polar region is anomalously warm with hotspots associated with geological features called the Tiger Stripes. The Tiger Stripes are large rifts near the south pole of Enceladus, which are typically about 130 km in length, 2 km wide, with a trough 500 m deep, and are l1anked on each side by 100m tall ridges. Preliminary triangulation of jets as viewed at different times and with different viewing geometries in Cassini ISS images taken between 2005 and 2007 have constrained the locations of eight major eruptions of material and found all of them associated with the south polar fractures unofficially the 'Tiger Stripes', and found four of them coincident with the hotspots reported in 2006 by CIRS. While published ISS observations of jet activity suggest that individual eruption sites stay active on the timescale of years, any shorter temporal variability (on timescales of an orbital period, or 1.3 Earth days, for example) is more difficult to establish because of the spotty temporal coverage and the difficulty of visually isolating one jet from the forest of many seen in a typical image. Consequently, it is not known whether individual jets are continuously active, randomly active, or if they erupt on a predictable, periodic schedule. One mechanism that may control the timing of eruptions is diurnal tidal stress, which oscillates between compression/tension as well as right and left lateral shear at any given location throughout Enceladus' orbit and may allow the cracks to open and close regularly. We examine the stresses on the Tiger Stripe regions to see how well diurnal tidal stress caused by Enceladus' orbital eccentricity may possibly correlate with and thus control the observed eruptions. We then identify

Can the season of birth risk factor for schizophrenia be prevented by bright light treatment for the second trimester mother around the winter solstice?

Science.gov (United States)

Schwartz, Paul J

2014-12-01

The season of birth risk factor for schizophrenia exerts a pervasive effect on the global population, particularly at northerly latitudes. The winter infection hypothesis and the low vitamin D hypothesis are both compelling but lack conclusive clinical data. The present work develops a maternal-fetal chronobiological hypothesis for this season of birth risk factor and its prevention by maternal bright light treatment. Around the winter solstice, due to decreased sunlight, the chronobiological apparatus of the at-risk second trimester mother is characterized by a reduced amplitude circadian pacemaker, and a reduced maximum of her nocturnal plasma melatonin concentrations (MTmax) and an increased minimum of her nocturnal core body temperatures (Tmin)--both of which exert adverse effects on the fetal hippocampus and dorsal striatum. The consequences for the fetus include reduced volume and increased excitability of the hippocampus, ventral striatal dysfunction, increased presynaptic nigrostriatal dopamine transmission, and increased propensity for pathological nigrostriatal neuronal phasic firing. Thus, the maternal-fetal chronobiological hypothesis fully accounts for the fetal precursors of the major pathognomonic abnormalities in adults with schizophrenia. Bright light treatment for the second trimester mother around the winter solstice, by increasing maternal circadian amplitude, could possibly prevent the fetal hippocampal and striatal abnormalities and eliminate the season of birth risk factor for schizophrenia. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cassini revisited by the Cassini-Huygens probe: dynamical and photometric study of the rings with the ISS images

International Nuclear Information System (INIS)

Deau, Estelle

2007-12-01

In the Solar system, the planetary rings represent a fantastic opportunity of studying a majority of phenomena taking place in the thin discs. One can find discs at all redshifts and on all scales of the Universe. Planetary discs are very different: among the Jovian rings, one finds a halo of fine and diffuse dust; the rings of Uranus are very compact, like radially confined strings and the system of rings of Neptune consists of azimuthally stable arcs. However our interest goes on Saturn which has the most complex and widest system of rings known to date: 484 000 km and a vertical extension which increases with the distance to Saturn (typically less than 1 km to 10 000 km). The interest of such a matter organization around Saturn plus its many moons (more than one forty including 8 of a size of several hundreds kilometers) gave birth to the exploration mission CASSINI, supposed to allow the development and the refinement of models set up at the flybies of the two interplanetary probes VOYAGER. The CASSINI Mission began its nominal tour on January, 15 2005 after the orbital insertion the 1 July 2004 and the dropping of HUYGENS probe on january, 14 2005 on Titan's surface. The purpose of this thesis consists to revisit two subjects unsolved of long date in the photometric and dynamic behaviours of the Saturn's rings. In a first part, we try to solve the problem of accretion of matter within the Roche limit by studying the F ring. This ring, since its discovery in 1979 by Pioneer 11, is involved in a most various dynamic theories to explain its complex multi-radial structure and its variable azimuthal structure. We showed that the multi-radial structure of this ring can be understood by the existence of a spiral which is rolled up around a central area, bright, eccentric and inclined: the core. The lifespan of this spiral is not the same one as the core, suggesting that the processes which create the spiral are periodic. Moreover, we showed that the structure of the

Titan's interior from Cassini-Huygens

Science.gov (United States)

Tobie, G.; Baland, R.-M.; Lefevre, A.; Monteux, J.; Cadek, O.; Choblet, G.; Mitri, G.

2013-09-01

The Cassini-Huygens mission has brought many informations about Titan that can be used to infer its interior structure: the gravity field coefficients (up to degree 3, [1]), the surface shape (up to degree 6, [2]), the tidal Love number [1], the electric field [3], and the orientation of its rotation axis [4]. The measured obliquity and gravity perturbation due to tides, as well as the electric field, are lines of evidence for the presence of an internal global ocean beneath the ice surface of Titan [5,1,3]. The observed surface shape and gravity can be used to further constrain the structure of the ice shell above the internal ocean. The presence of a significant topography associated with weak gravity anomalies indicates that deflections of internal interface or lateral density variations may exist to compensate the topography. To assess the sources of compensation, we consider interior models including interface deflections and/or density variations, which reproduces simultaneously the surface gravity and long-wavelength topography data [6]. Furthermore, in order to test the long-term mechanical stability of the internal mass anomalies, we compute the relaxation rate of each internal interface in response to surface mass load. We show that the topography can be explained either by defections of the ocean/ice interface or by density variations in an upper crust [6]. For non-perfectly compensated models of the outer ice shell, the present-day structure is stable only for a conductive layer above a relatively cold ocean (for bottom viscosity > 1016 Pa.s, T residual gravity anomalies. The existence of mass anomalies in the rocky core is a most likely explanation. However, as the observed geoid and topography are mostly sensitive to the lateral structure of the outer ice shell, no information can be retrieved on the ice shell thickness, ocean density and/or size of the rocky core. Constraints on these internal parameters can be obtained from the tidal Love number and

10 Years at Saturn, and More Excitement to Come!

Science.gov (United States)

Edgington, S. G.; Spilker, L. J.; Altobelli, N.

2014-04-01

After 10 years in orbit, the Cassini-Huygens Mission to Saturn, a collaboration of NASA, ESA, and ASI, continues to wow the imagination. Every year Cassini produces answers to questions raised by the Voyager flybys, while at the same time posing new questions that can only be answered with a long duration mission using a flagship-class spacecraft. In this talk, we sample a few of Cassini's discoveries from the past decade and give an overview of what comes next.

From Data to Equations: Inferring the Laws governing Saturn's Ring Temperature

Science.gov (United States)

Altobelli, N.; Lopez-Paz, D.; Spilker, L.; Pilorz, S.

2011-10-01

Six years after Saturn Orbit Insertion (SOI), the Composite Infrared Spectrometer (CIRS) on-board the Cassini Spacecraft has been performing a thermal mapping of Saturn's main rings, by measuring the thermal radiance in the far-infrared ( [10-600] cm-1 ) for different viewing geometries. So far, more than 2.5 millions individual spectra have been recorded, from Saturn's northern winter solstice till Saturn's northern spring. We present a first attempt of treating the data set globally by applying numerical data mining techniques inherited from the field of artificial intelligence, such as neural networks and genetic programing.

Giovanni Domenico Cassini a modern astronomer in the 17th century

CERN Document Server

Bernardi, Gabriella

2017-01-01

This book offers a fascinating account of the life and scientific achievements of Giovanni Domenico Cassini, or Cassini I, the most famous astronomer of his time, who is remembered today especially for his observations of the rings and satellites of Saturn and his earlier construction of the great meridian line in the Basilica of San Petronio in Bologna. The various stages of his life are recounted in an engaging style, from his early childhood in Perinaldo and his time at the famous Jesuit College in Genoa, to his later experiences in Bologna and Paris. The emphasis, however, is on the scientific side of his life. The book explores his impressive body of work in diverse fields while also drawing attention to the international character of his endeavors, the rigor of his research, and his outstanding management skills, which combined to make him an early embodiment of the “European scientist.” It was also these abilities that gained him the attention of the most powerfu l king in Europe, Louis XIV of Fran...

Saturn's equatorial jet structure from Cassini/ISS

Science.gov (United States)

García-Melendo, Enrique; Legarreta, Jon; Sánchez-Lavega, Agustín.; Pérez-Hoyos, Santiago; Hueso, Ricardo

2010-05-01

Detailed wind observations of the equatorial regions of the gaseous giant planets, Jupiter and Saturn, are crucial for understanding the basic problem of the global circulation and obtaining new detailed information on atmospheric phenomena. In this work we present high resolution data of Saturn's equatorial region wind profile from Cassini/ISS images. To retrieve wind measurements we applied an automatic cross correlator to image pairs taken by Cassini/ISS with the MT1, MT2, MT3 filters centred at the respective three methane absorbing bands of 619nm, 727nm, and 889nm, and with the adjacent continuum CB1, CB2, and CB3 filters. We obtained a complete high resolution coverage of Saturn's wind profile in the equatorial region. The equatorial jet displays an overall symmetric structure similar to that shown the by same region in Jupiter. This result suggests that, in accordance to some of the latest compressible atmosphere computer models, probably global winds in gaseous giants are deeply rooted in the molecular hydrogen layer. Wind profiles in the methane absorbing bands show the effect of strong vertical shear, ~40m/s per scale height, confirming previous results and an important decay in the wind intensity since the Voyager era (~100 m/s in the continuum and ~200 m/s in the methane absorbing band). We also report the discovery of a new feature, a very strong and narrow jet on the equator, about only 5 degrees wide, that despite the vertical shear maintains its intensity (~420 m/s) in both, the continuum and methane absorbing band filters. Acknowledgements: Work supported by the Spanish MICIIN AYA2009-10701 with FEDER and Grupos Gobierno Vasco IT-464-07.

Temperature variations in Titan's upper atmosphere: Impact on Cassini/Huygens

Directory of Open Access Journals (Sweden)

B. Kazeminejad

2005-06-01

Full Text Available Temperature variations of Titan's upper atmosphere due to the plasma interaction of the satellite with Saturn's magnetosphere and Titan's high altitude monomer haze particles can imply an offset of up to ±30K from currently estimated model profiles. We incorporated these temperature uncertainties as an offset into the recently published Vervack et al. (2004 (Icarus, Vol. 170, 91-112 engineering model and derive extreme case (i.e. minimum and maximum profiles temperature, pressure, and density profiles. We simulated the Huygens probe hypersonic entry trajectory and obtain, as expected, deviations of the probe trajectory for the extreme atmosphere models compared to the simulation based on the nominal one. These deviations are very similar to the ones obtained with the standard Yelle et al. (1997 (ESA SP-1177 profiles. We could confirm that the difference in aerodynamic drag is of an order of magnitude that can be measured by the probe science accelerometer. They represent an important means for the reconstruction of Titan's upper atmospheric properties. Furthermore, we simulated a Cassini low Titan flyby trajectory. No major trajectory deviations were found. The atmospheric torques due to aerodynamic drag, however, are twice as high for our high temperature profile as the ones obtained with the Yelle maximum profile and more than 5 times higher than the worst case estimations from the Cassini project. We propose to use the Cassini atmospheric torque measurements during its low flybys to derive the atmospheric drag and to reconstruct Titan's upper atmosphere density, pressure, and temperature. The results could then be compared to the reconstructed profiles obtained from Huygens probe measurements. This would help to validate the probe measurements and decrease the error bars.

Characterization of Cassini GPHS fueled clad production girth welds

International Nuclear Information System (INIS)

Franco-Ferreira, E.A.; Moyer, M.W.; Reimus, M.A.H.; Placr, A.; Howard, B.D.

2000-01-01

Fueled clads for radioisotope power systems are produced by encapsulating 238 PuO 2 in iridium alloy cups, which are joined at their equators by gas tungsten arc welding. Cracking problems at the girth weld tie-in area during production of the Galileo/Ulysses GPHS capsules led to the development of a first-generation ultrasonic test for girth weld inspection at the Savannah River Plant. A second-generation test and equipment with significantly improved sensitivity and accuracy were jointly developed by the Oak Ridge Y-12 Plant and Westinghouse Savannah River Company for use during the production of Cassini GPHS capsules by the Los Alamos National Laboratory. The test consisted of Lamb wave ultrasonic scanning of the entire girth weld from each end of the capsule combined with a time-of-flight evaluation to aid in characterizing nonrelevant indications. Tangential radiography was also used as a supplementary test for further evaluation of reflector geometry. Each of the 317 fueled GP HS capsules, which were girth welded for the Cassini Program, was subjected to a series of nondestructive tests that included visual, dimensional, helium leak rate, and ultrasonic testing. Thirty-three capsules were rejected prior to ultrasonic testing. Of the 44 capsules rejected by the standard ultrasonic test, 22 were upgraded to flight quality through supplementary testing for an overall process acceptance rate of 82.6%. No confirmed instances of weld cracking were found

Five Fabulous Flybys of the Small Inner Moons of Saturn by the Cassini Spacecraft

Science.gov (United States)

Buratti, B. J.; Momary, T.; Clark, R. N.; Brown, R. H.; Filacchione, G.; Mosher, J. A.; Baines, K. H.; Nicholson, P. D.

2017-12-01

The Saturn system possesses a number of small unique moons, including the coorbitals Janus and Epimetheus; the ring moons Pan and Daphnis; and Prometheus, Pandora, and Atlas, which orbit near the edge of the main ring system. During the last phases of the Cassini mission, when the spacecraft executed close passes to the F-ring of Saturn, five "best-ever" flybys of these moons occurred. Pan, Daphnis, Atlas, Pandora, and Epimetheus were approached at distances ranging from 6000-40,000 km. The Visual Infrared Mapping Spectrometer (VIMS) captured data from the spectral range spanning 0.35-5.1 microns, as well as capturing solar phase angles not observed before. When combined with spectra from different regions of the moons obtained throughout the mission, the VIMS observations reveal substantial changes in the depth of water-ice absorption bands and color over the moons' surfaces. These measurements show the accretion of main-ring material onto the moons, with leading sides exhibiting stronger water-ice signatures in general. Atlas and Pandora have red visible spectra similar to the A-ring and unlike other icy moons, which are blue, further revealing accretion of main ring material onto the small inner moons. In general the visible spectra of the moons gets bluer with distance from Saturn until the surface of the moons is dominated by contamination from the E-ring, which is composed of fresh ice. There is a weak correlation between color and albedo, with lower-albedo moons being redder, suggesting the existence of a dark reddish contaminant from the main ring system. The solar phase curves of the moons are similar to those of larger icy moons (unfortunately no opposition surge data was gathered). 2017 California Institute of Technology. Government sponsorship acknowledged.

Iapetus: First data from the Cassini Visual Infrared Mapping Spectrometer

Science.gov (United States)

Buratti, B. J.; Cruikshank, D. P.; Clark, R.; Brown, R. H.; Bauer, J. M.; Simonelli, D. P.; Jaumann, R.; Hibbitts, K.; McCord, T. B.; Soderlund, K.; Baines, K. H.; Bellucci, G.; Bibring, J. P.; Capaccioni, F.; Cerroni, P.; Coradini, A.; Drossart, P.; Formisano, V.; Langevin, Y.; Matson, D. L.; Mennella, V.; Nelson, R.; Nicholson, P. D.; Sicardy, B.; Sotin, C.

2004-11-01

Iapetus is perhaps the most enigmatic body in the solar system: One hemisphere is as dark as lampblack, and the other is almost as bright as snow. The models that have been offered to explain this dichotomy range from endogenously placed material (Smith et al., 1982, Science 215, 504), to material exogenously placed from Phoebe (Soter, 1974, IAU Colloq. 28), or other bodies (Owen et al., 2001, Icarus 149, 160; Buratti et al., 2002, Icarus 155, 375; Buratti et al., 2003, B.A.A.S, 915). No mechanism for the darkening process or purported source for the exogenic particles is entirely satisfactory. One key question is whether the process that led to the formation of the low-albedo hemisphere of Iapetus is unique, or whether the satellite has been subjected to a satellite alteration process in a more extreme form. Both Callisto and the outer satellites of Uranus show evidence for exogenic accretion of particles onto their leading sides. A targeted flyby of Iapetus by Cassini, during which the spacecraft will approach the satellite to within 1000 km, is scheduled to occur in September 2007. An untargeted approach of 65,000 km to the satellite will occur on New Year's day 2005, and observations are planned for the period around closest approach. However, a "sneak peak" of the satellite was afforded by Cassini on July 19, 2004, during which the spacecraft approached to less than three million miles (the Voyager closest approach was 909,070 km). The first disk resolved spectra of Iapetus in the 0.4 to 5 micron region were obtained by the Cassini Visual Infrared Mapping Spectrometer (VIMS). We report the tentative identification of carbon dioxide on the low-albedo portion of the surface. A comparison of the spectrum of Iapetus to that obtained by VIMS during its flyby of Phoebe on June 11, 2004 will be made. Mixing models incorporating water ice, minerals, and organics can replicate the spectrum of the dark hemisphere. Work performed at the Jet Propulsion Laboratory

Spatially resolved near infrared observations of Enceladus' tiger stripe eruptions from Cassini VIMS

Science.gov (United States)

Dhingra, Deepak; Hedman, Matthew M.; Clark, Roger N.; Nicholson, Philip D.

2017-08-01

Particle properties of individual fissure eruptions within Enceladus' plume have been analyzed using high spatial resolution Visible and Infrared Mapping Spectrometer (VIMS) observations from the Cassini mission. To first order, the spectra of the materials emerging from Cairo, Baghdad and Damascus sulci are very similar, with a strong absorption band around 3 μm due to water-ice. The band minimum position indicates that the ice grains emerging from all the fissures are predominantly crystalline, which implies that the water-ice particles' formation temperatures are likely above 130 K. However, there is also evidence for subtle variations in the material emerging from the different source fissures. Variations in the spectral slope between 1-2.5 μm are observed and probably reflect differences in the size distributions of particles between 0.5 and 5 μm in radius. We also note variations in the shape of the 3 μm water-ice absorption band, which are consistent with differences in the relative abundance of > 5 μm particles. These differences in the particle size distribution likely reflect variations in the particle formation conditions and/or their transport within the fissures. These observations therefore provide strong motivation for detailed modeling to help place important constraints on the diversity of the sub-surface environmental conditions at the geologically active south-pole of Enceladus.

FMT (Flight Software Memory Tracker) For Cassini Spacecraft-Software Engineering Using JAVA

Science.gov (United States)

Kan, Edwin P.; Uffelman, Hal; Wax, Allan H.

1997-01-01

The software engineering design of the Flight Software Memory Tracker (FMT) Tool is discussed in this paper. FMT is a ground analysis software set, consisting of utilities and procedures, designed to track the flight software, i.e., images of memory load and updatable parameters of the computers on-board Cassini spacecraft. FMT is implemented in Java.

GPHS-RTGs in support of the Cassini RTG Program. Final technical report, January 11, 1991--April 30, 1998

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-08-01

As noted in the historical summary, this program encountered a number of changes in direction, schedule, and scope over the period 11 January 1991 to 31 December 1998. The report provides a comprehensive summary of all the varied aspects of the program over its seven and a quarter years, and highlights those aspects that provide information beneficial to future radioisotope programs. In addition to summarizing the scope of the Cassini GPHS-RTG Program provided as background, the introduction includes a discussion of the scope of the final report and offers reference sources for information on those topics not covered. Much of the design heritage of the GPHS-RTG comes from the Multi-Hundred Watt (MHW) RTGs used on the Lincoln Experimental Satellites (LES) 8/9 and Voyager spacecraft. The design utilized for the Cassini program was developed, in large part, under the GPHS-RTG program which produced the Galileo and Ulysses RTGs. Reports from those programs included detailed documentation of the design, development, and testing of converter components and full converters that were identical to, or similar to, components used in the Cassini program. Where such information is available in previous reports, it is not repeated here.

GPHS-RTGs in support of the Cassini RTG Program. Final technical report, January 11, 1991 - April 30, 1998

International Nuclear Information System (INIS)

1998-08-01

As noted in the historical summary, this program encountered a number of changes in direction, schedule, and scope over the period 11 January 1991 to 31 December 1998. The report provides a comprehensive summary of all the varied aspects of the program over its seven and a quarter years, and highlights those aspects that provide information beneficial to future radioisotope programs. In addition to summarizing the scope of the Cassini GPHS-RTG Program provided as background, the introduction includes a discussion of the scope of the final report and offers reference sources for information on those topics not covered. Much of the design heritage of the GPHS-RTG comes from the Multi-Hundred Watt (MHW) RTGs used on the Lincoln Experimental Satellites (LES) 8/9 and Voyager spacecraft. The design utilized for the Cassini program was developed, in large part, under the GPHS-RTG program which produced the Galileo and Ulysses RTGs. Reports from those programs included detailed documentation of the design, development, and testing of converter components and full converters that were identical to, or similar to, components used in the Cassini program. Where such information is available in previous reports, it is not repeated here

AN ATLAS OF BRIGHT STAR SPECTRA IN THE NEAR-INFRARED FROM CASSINI-VIMS

International Nuclear Information System (INIS)

Stewart, Paul N.; Tuthill, Peter G.; Nicholson, Philip D.; Sloan, G. C.; Hedman, Matthew M.

2015-01-01

We present the Cassini Atlas Of Stellar Spectra (CAOSS), comprised of near-infrared, low-resolution spectra of bright stars recovered from space-based observations by the Cassini spacecraft. The 65 stellar targets in the atlas are predominately M, K, and S giants. However, it also contains spectra of other bright nearby stars including carbon stars and main-sequence stars from A to F. The spectra presented are free of all spectral contamination caused by the Earth's atmosphere, including the detrimental telluric molecular bands which put parts of the near-infrared spectrum out of reach of terrestrial observations. With a single instrument, a spectro-photometric data set is recovered that spans the near-infrared from 0.8 to 5.1 μm with spectral resolution ranging from R = 53.5 to R = 325. Spectra have been calibrated into absolute flux units after careful characterization of the instrumental spectral efficiency. Spectral energy distributions for most stars match closely with literature values. All final data products have been made available online

AN ATLAS OF BRIGHT STAR SPECTRA IN THE NEAR-INFRARED FROM CASSINI-VIMS

Energy Technology Data Exchange (ETDEWEB)

Stewart, Paul N.; Tuthill, Peter G. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia); Nicholson, Philip D. [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Sloan, G. C. [Cornell Center for Astrophyics and Planetary Science, Cornell University, Ithaca, NY 14853 (United States); Hedman, Matthew M., E-mail: p.stewart@physics.usyd.edu.au [Department of Physics, University of Idaho, Moscow, ID 83844 (United States)

2015-12-15

We present the Cassini Atlas Of Stellar Spectra (CAOSS), comprised of near-infrared, low-resolution spectra of bright stars recovered from space-based observations by the Cassini spacecraft. The 65 stellar targets in the atlas are predominately M, K, and S giants. However, it also contains spectra of other bright nearby stars including carbon stars and main-sequence stars from A to F. The spectra presented are free of all spectral contamination caused by the Earth's atmosphere, including the detrimental telluric molecular bands which put parts of the near-infrared spectrum out of reach of terrestrial observations. With a single instrument, a spectro-photometric data set is recovered that spans the near-infrared from 0.8 to 5.1 μm with spectral resolution ranging from R = 53.5 to R = 325. Spectra have been calibrated into absolute flux units after careful characterization of the instrumental spectral efficiency. Spectral energy distributions for most stars match closely with literature values. All final data products have been made available online.

Titan's Surface Temperatures Maps from Cassini - CIRS Observations

Science.gov (United States)

Cottini, Valeria; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Samuelson, R. E.; Irwin, P. G. J.; Flasar, F. M.

2009-09-01

The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 μm (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the instrument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature profile by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). In future, application of our methodology over wide areas should greatly increase the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. References: Irwin, P.G.J., et al.: "The NEMESIS planetary atmosphere radiative transfer and retrieval tool" (2008). JQSRT, Vol. 109, pp. 1136-1150, 2008. Rodgers, C. D.: "Inverse Methods For Atmospheric Sounding: Theory and Practice". World Scientific, Singapore, 2000. Jennings, D.E., et al.: "Titan's Surface Brightness Temperatures." Ap. J. L., Vol. 691, pp. L103-L

GPHS-RTGs in support of the Cassini mission. Semi-annual technical report, 29 March 1993--26 September 1993

Energy Technology Data Exchange (ETDEWEB)

1993-10-24

The following tasks were reported on: Spacecraft integration and liaison, engineering support, safety, qualified unicouple fabrication, ETG fabrication/assembly/test, ground support equipment, RTG shipping and launch support, designs/reviews/mission applications, project management/quality assurance/contract changes.

Mission Techniques for Exploring Saturn's icy moons Titan and Enceladus

Science.gov (United States)

Reh, Kim; Coustenis, Athena; Lunine, Jonathan; Matson, Dennis; Lebreton, Jean-Pierre; Vargas, Andre; Beauchamp, Pat; Spilker, Tom; Strange, Nathan; Elliott, John

2010-05-01

The future exploration of Titan is of high priority for the solar system exploration community as recommended by the 2003 National Research Council (NRC) Decadal Survey [1] and ESA's Cosmic Vision Program themes. Cassini-Huygens discoveries continue to emphasize that Titan is a complex world with very many Earth-like features. Titan has a dense, nitrogen atmosphere, an active climate and meteorological cycles where conditions are such that the working fluid, methane, plays the role that water does on Earth. Titan's surface, with lakes and seas, broad river valleys, sand dunes and mountains was formed by processes like those that have shaped the Earth. Supporting this panoply of Earth-like processes is an ice crust that floats atop what might be a liquid water ocean. Furthermore, Titan is rich in very many different organic compounds—more so than any place in the solar system, except Earth. The Titan Saturn System Mission (TSSM) concept that followed the 2007 TandEM ESA CV proposal [2] and the 2007 Titan Explorer NASA Flagship study [3], was examined [4,5] and prioritized by NASA and ESA in February 2009 as a mission to follow the Europa Jupiter System Mission. The TSSM study, like others before it, again concluded that an orbiter, a montgolfiѐre hot-air balloon and a surface package (e.g. lake lander, Geosaucer (instrumented heat shield), …) are very high priority elements for any future mission to Titan. Such missions could be conceived as Flagship/Cosmic Vision L-Class or as individual smaller missions that could possibly fit within NASA's New Frontiers or ESA's Cosmic Vision M-Class budgets. As a result of a multitude of Titan mission studies, several mission concepts have been developed that potentially fit within various cost classes. Also, a clear blueprint has been laid out for early efforts critical toward reducing the risks inherent in such missions. The purpose of this paper is to provide a brief overview of potential Titan (and Enceladus) mission

Emitted Power of Jupiter Based on Cassini CIRS and VIMS Observations

Science.gov (United States)

Li, Liming; Baines, Kevin H.; Smith, Mark A.; West, Robert A.; Perez-Hoyos, Santiago; Trammel, Harold J.; Simon-Miller, Amy A.; Conrath, Barney J.; Gierasch, Peter J.; Orton, Glenn S.;

The Changing Surface of Saturn's Titan: Cassini Observations Suggest Active Cryovolcanism

Science.gov (United States)

Nelson, R. M.

2008-12-01

R. M. Nelson(1), L. Kamp(1), R. M. C. Lopes(1), D. L. Matson(1), S. D. Wall(1), R. L. Kirk(2), K. L Mitchell(1), G. Mitri(1), B. W. Hapke(3), M. D. Boryta(4), F. E. Leader(1) , W. D. Smythe(1), K. H. Baines(1), R. Jauman(5), C. Sotin(1), R. N. Clark(6), D. P. Cruikshank(7) , P. Drossart(9), B. J. Buratti(1) , J.Lunine(8), M. Combes(9), G. Bellucci(10), J.-P. Bibring(11), F. Capaccioni(10), P. Cerroni(10), A. Coradini(10), V. Formisano(10), G Filacchione(10), R. Y. Langevin(11), T. B. McCord(12), V. Mennella(13), P. D. Nicholson(14) , B. Sicardy(8) 1-JPL, 4800 Oak Grove Drive, Pasadena CA 91109, 2-USGS, Flagstaff, 3-U Pittsburgh, 4-Mt. Sac Col, 5- DLR, Berlin, 6-USGS Denver, 7-NASA AMES, 8-U Paris-Meudon, 9-Obs de Paris, 10-ISFI-CNR Rome, 11-U Paris -Sud. Orsay, 12-Bear Flt Cntr Winthrop WA, 13-Obs Capodimonte Naples, 14-Cornell U. Several Instruments on the Cassini Saturn Orbiter have been observing the surface of Saturn's moon Titan since mid 2004. The Visual and Infrared Mapping Spectrometer (VIMS) reports that regions near 26oS, 78oW (region 1) and 7oS, 138oW (region 2) exhibit photometric changes consistent with on-going surface activity. These regions are photometrically variable with time(1). Cassini Synthetic Aperture Rader (SAR) has investigated these regions and reports that both of these regions exhibit morphologies consistent with cryovolcanism (2). VIMS observed region 1 eight times and reported that on two occasions the region brightened two-fold and then decreased again on timescales of several weeks. Region 2 was observed on four occasions (Tb-Dec13/2004 ,T8-Oct27/2005, T10-Jan15/2006, T12-Mar18/2006) and exhibited a pronounced change in I/F betweenT8 and T10. Our photometric analysis finds that both regions do not exhibit photometric properties consistent with atmospheric phenomena such as tropospheric clouds. These changes must be at or very near the surface. Radar images of these regions reveal morphology that is consistent with cryovolcanoes. We

Cassini Radio Occultations of Saturn's Ionosphere: Modeling a Variable Influx of Water into Saturn's Atmosphere

Science.gov (United States)

Moore, L.; Mendillo, M.

2006-12-01

The Saturn-Thermosphere-Ionosphere-Model (STIM), a global circulation model (GCM) of Saturn's upper atmosphere, is used to investigate a range of possible parameters that could lead to the profiles measured recently by the Radio Science Subsystem (RSS) aboard Cassini. Specifically, electron density observations of Saturn's equatorial ionosphere demonstrate a dawn/dusk asymmetry, a possible double peak, and a high degree of vertical structure and variability. On average, peak electron densities are larger at dusk than dawn (5400 cm-3 vs. 1700 cm-3) and the peak altitudes are lower at dusk than dawn (1880 km vs. 2360 km). Self-consistent, time-dependent 1D water diffusion calculations have been combined with the GCM in order to examine the possibility that a topside flux of neutral water into Saturn's atmosphere may provide a loss mechanism -- via charge exchange with protons -- that is sufficient to reproduce the observed ionosphere. Our previous modeling results indicated that a constant background influx of (0.5 -- 1.0) x 107 H2O cm-2 sec-1 was adequate in reproducing Cassini measurements on average [Moore et al., 2006], however the large observed variations in the vertical electron density profiles require additional complexities in the modeling. In this study we show that one possible source of the structuring observed in the electron density profiles could be from brief surges and/or reductions in the background water flux, which ultimately may be linked to geysers near Enceladus' southern pole. Moore, L., A.F. Nagy, A.J. Kliore, I. Mueller-Wodarg, J.D. Richardson, M. Mendillo (2006), Cassini radio occultations of Saturn's ionopshere: I. model comparisons using a constant water flux, submitted to GRL.

Tidally modulated eruptions on Enceladus: Cassini ISS observations and models

International Nuclear Information System (INIS)

Nimmo, Francis; Porco, Carolyn; Mitchell, Colin

2014-01-01

We use images acquired by the Cassini Imaging Science Subsystem (ISS) to investigate the temporal variation of the brightness and height of the south polar plume of Enceladus. The plume's brightness peaks around the moon's apoapse, but with no systematic variation in scale height with either plume brightness or Enceladus' orbital position. We compare our results, both alone and supplemented with Cassini near-infrared observations, with predictions obtained from models in which tidal stresses are the principal control of the eruptive behavior. There are three main ways of explaining the observations: (1) the activity is controlled by right-lateral strike slip motion; (2) the activity is driven by eccentricity tides with an apparent time delay of about 5 hr; (3) the activity is driven by eccentricity tides plus a 1:1 physical libration with an amplitude of about 0.°8 (3.5 km). The second hypothesis might imply either a delayed eruptive response, or a dissipative, viscoelastic interior. The third hypothesis requires a libration amplitude an order of magnitude larger than predicted for a solid Enceladus. While we cannot currently exclude any of these hypotheses, the third, which is plausible for an Enceladus with a subsurface ocean, is testable by using repeat imaging of the moon's surface. A dissipative interior suggests that a regional background heat source should be detectable. The lack of a systematic variation in plume scale height, despite the large variations in plume brightness, is plausibly the result of supersonic flow; the details of the eruption process are yet to be understood.

Spatial distribution of Langmuir waves observed upstream of Saturn's bow shock by Cassini

Czech Academy of Sciences Publication Activity Database

Píša, David; Santolík, Ondřej; Hospodarsky, G. B.; Kurth, W. S.; Gurnett, D. A.; Souček, Jan

2016-01-01

Roč. 121, č. 8 (2016), s. 7771-7784 ISSN 2169-9380 R&D Projects: GA ČR GJ16-16050Y; GA ČR(CZ) GAP209/12/2394 Institutional support: RVO:68378289 Keywords : Langmuir waves * Cassini * foreshock * Saturn Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.733, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2016JA022912/abstract

Statistics of Langmuir wave amplitudes observed inside Saturn's foreshock by the Cassini spacecraft

Czech Academy of Sciences Publication Activity Database

Píša, David; Hospodarsky, G. B.; Kurth, W. S.; Santolík, Ondřej; Souček, Jan; Gurnett, D. A.; Masters, A.; Hill, M. E.

2015-01-01

Roč. 120, č. 4 (2015), s. 2531-2542 ISSN 2169-9380 R&D Projects: GA ČR GAP205/10/2279; GA ČR(CZ) GAP209/12/2394 Institutional support: RVO:68378289 Keywords : Langmuir waves * foreshock * Saturn * Cassini Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.318, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/2014JA020560/abstract

Equinoctial Activity Over Titan Dune Fields Revealed by Cassini/vims

Science.gov (United States)

Rodriguez, S.; Le Mouelic, S.; Barnes, J. W.; Hirtzig, M.; Rannou, P.; Sotin, C.; Brown, R. H.; Bow, J.; Vixie, G.; Cornet, T.; Bourgeois, O.; Narteau, C.; Courrech Du Pont, S.; Le Gall, A.; Reffet, E.; Griffith, C. A.; Jaumann, R.; Stephan, K.; Buratti, B. J.; Clark, R. N.; Baines, K. H.; Nicholson, P. D.; Coustenis, A.

2012-12-01

Titan, the largest satellite of Saturn, is the only satellite in the solar system with a dense atmosphere. The close and continuous observations of Titan by the Cassini spacecraft, in orbit around Saturn since July 2004, bring us evidences that Titan troposphere and low stratosphere experience an exotic, but complete meteorological cycle similar to the Earth hydrological cycle, with hydrocarbons evaporation, condensation in clouds, and rainfall. Cassini monitoring campaigns also demonstrate that Titan's cloud coverage and climate vary with latitude. Titan's tropics, with globally weak meteorological activity and widespread dune fields, seem to be slightly more arid than the poles, where extensive and numerous liquid reservoirs and sustained cloud activity have been discovered. Only a few tropo-spheric clouds have been observed at Titan's tropics during the southern summer. As equinox was approaching (in August 2009), they occurred more frequently and appeared to grow in strength and size. We present here the observation of intense brightening at Titan's tropics, very close to the equinox. These detections were conducted with the Visual and Infrared Mapping Spectrometer (VIMS) onboard Cassini. We will discuss the VIMS images of the three individual events detected so far, observed during the Titan's flybys T56 (22 May 2009), T65 (13 January 2010) and T70 (21 June 2010). T56, T65 and T70 observations show an intense and transient brighten-ing of large regions very close to the equator, right over the extensive dune fields of Senkyo, Belet and Shangri-La. They all appear spectrally and morphologically different from all transient surface features or atmospheric phenomena previously reported. Indeed, these events share in particular a strong brightening at wavelengths greater than 2 μm (especially at 5 μm), making them spectrally distinct from the small tropical clouds observed before the equinox and the large storms observed near the equator in September and October

Advances in Architectural Elements For Future Missions to Titan

Science.gov (United States)

Reh, Kim; Coustenis, Athena; Lunine, Jonathan; Matson, Dennis; Lebreton, Jean-Pierre; Vargas, Andre; Beauchamp, Pat; Spilker, Tom; Strange, Nathan; Elliott, John

2010-05-01

The future exploration of Titan is of high priority for the solar system exploration community as recommended by the 2003 National Research Council (NRC) Decadal Survey [1] and ESA's Cosmic Vision Program themes. Recent Cassini-Huygens discoveries continue to emphasize that Titan is a complex world with very many Earth-like features. Titan has a dense, nitrogen atmosphere, an active climate and meteorological cycles where conditions are such that the working fluid, methane, plays the role that water does on Earth. Titan's surface, with lakes and seas, broad river valleys, sand dunes and mountains was formed by processes like those that have shaped the Earth. Supporting this panoply of Earth-like processes is an ice crust that floats atop what might be a liquid water ocean. Furthermore, Titan is rich in very many different organic compounds—more so than any place in the solar system, except Earth. The Titan Saturn System Mission (TSSM) concept that followed the 2007 TandEM ESA CV proposal [2] and the 2007 Titan Explorer NASA Flagship study [3], was examined [4,5] and prioritized by NASA and ESA in February 2009 as a mission to follow the Europa Jupiter System Mission. The TSSM study, like others before it, again concluded that an orbiter, a montgolfiere hot-air balloon and a surface package (e.g. lake lander, Geosaucer (instrumented heat shield), …) are very high priority elements for any future mission to Titan. Such missions could be conceived as Flagship/Cosmic Vision L-Class or as individual smaller missions that could possibly fit into NASA New Frontiers or ESA Cosmic Vision M-Class budgets. As a result of a multitude of Titan mission studies, a clear blueprint has been laid out for the work needed to reduce the risks inherent in such missions and the areas where advances would be beneficial for elements critical to future Titan missions have been identified. The purpose of this paper is to provide a brief overview of the flagship mission architecture and

Constraints on the Mass and Location of Planet 9 set by Range and VLBI Observations of Cassini

Science.gov (United States)

Jacobson, Robert Arthur; Folkner, William; Park, Ryan; Williams, James

2018-04-01

Batygin and Brown, 2016 AJ, found that Kuiper belt objects (KBOs) with well determined orbits having periods greater than 4000 years are apsidally aligned. They attribute this orbital clustering to the existence of a distant planet, Planet 9, well beyond Neptune, with a mass roughly ten times that of Earth. If such a planet exists, it would affect the motion of the known solar system planets, in particular Saturn, which is well observed with radiometric ranging from the Cassini spacecraft and VLBI observations of Cassini. The current planetary ephemerides do not account for the postulated Planet 9, yet their fit to the observational data shows no obvious effect that could be attributed to neglecting that planet. However, it is possible that the effect could be absorbed by the estimated parameters used to determine the ephemerides. Those parameters include the planetary orbital elements, mass of the Sun, and the masses of the asteroids that perturb the Martian orbit. We recently updated the Cassini data set and extended it through the end of the mssion in 2017 September. We analyze the sensitivity of these data to the tidal perturbations caused by the postulated Planet 9 for a range of positions on the sky and tidal parameters (the ratio of the mass of Planet 9 to the cube of its distance from Saturn). We determine an upper bound on the tidal parameter and the most probable directions consistent with the observational data.

Mapping and interpretation of Sinlap crater on Titan using Cassini VIMS and RADAR data

Science.gov (United States)

Le, Mouelic S.; Paillou, P.; Janssen, M.A.; Barnes, J.W.; Rodriguez, S.; Sotin, Christophe; Brown, R.H.; Baines, K.H.; Buratti, B.J.; Clark, R.N.; Crapeau, M.; Encrenaz, P.J.; Jaumann, R.; Geudtner, D.; Paganelli, F.; Soderblom, L.; Tobie, G.; Wall, S.

2008-01-01

Only a few impact craters have been unambiguously detected on Titan by the Cassini-Huygens mission. Among these, Sinlap is the only one that has been observed both by the RADAR and VIMS instruments. This paper describes observations at centimeter and infrared wavelengths which provide complementary information about the composition, topography, and surface roughness. Several units appear in VIMS false color composites of band ratios in the Sinlap area, suggesting compositional heterogeneities. A bright pixel possibly related to a central peak does not show significant spectral variations, indicating either that the impact site was vertically homogeneous, or that this area has been recovered by homogeneous deposits. Both VIMS ratio images and dielectric constant measurements suggest the presence of an area enriched in water ice around the main ejecta blanket. Since the Ku-band SAR may see subsurface structures at the meter scale, the difference between infrared and SAR observations can be explained by the presence of a thin layer transparent to the radar. An analogy with terrestrial craters in Libya supports this interpretation. Finally, a tentative model describes the geological history of this area prior, during, and after the impact. It involves mainly the creation of ballistic ejecta and an expanding plume of vapor triggered by the impact, followed by the redeposition of icy spherules recondensed from this vapor plume blown downwind. Subsequent evolution is then driven by erosional processes and aeolian deposition. Copyright 2008 by the American Geophysical Union.

Cassini RTG program. Monthly technical progress report, September 29, 1997--October 26, 1997

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-11-24

This report describes work on the contract to provide Radioisotope Thermoelectric Generators (RTG) and Ancillary Activities in support of the Cassini Spacecraft launch. The craft was successfully launched on October 15, 1997. Early telemetry results show excellent performance from the three launched RTG modules. A major share of this report describes safety analyses for contamination radii in the event of launch failures and generator destruction, as well as launch related activities.

Titan Density Reconstruction Using Radiometric and Cassini Attitude Control Flight Data

Science.gov (United States)

Andrade, Luis G., Jr.; Burk, Thomas A.

2015-01-01

This paper compares three different methods of Titan atmospheric density reconstruction for the Titan 87 Cassini flyby. T87 was a unique flyby that provided independent Doppler radiometric measurements on the ground throughout the flyby including at Titan closest approach. At the same time, the onboard accelerometer provided an independent estimate of atmospheric drag force and density during the flyby. These results are compared with the normal method of reconstructing atmospheric density using thruster on-time and angular momentum accumulation. Differences between the estimates are analyzed and a possible explanation for the differences is evaluated.

A dusty road connecting Saturn and its rings - preliminary results from Cassini Cosmic Dust Analyser during the Grand Finale Mission

Science.gov (United States)

Hsu, S.; Burton, M. E.; Horanyi, M.; Kempf, S.; Khawaja, N.; Moragas-Klostermeyer, G.; Postberg, F.; Schirdenwahn, D.; Seiss, M.; Schmidt, J.; Spahn, F.; Srama, R.

2017-12-01

The Cosmic Dust Analyzer observations during the Cassini Grand Finale Orbits were designed for the in situ characterization of Saturn's ring composition and to study their interaction with the host planet. It is found that the gap between the inner most D ring and Saturn is almost free of larger, micron-sized dust grains but rich in nanodust particles (radius smaller than 100 nm) that only become detectable by CDA because of the high spacecraft speed of 30 km/s through this region. Regarding the grain composition, while the majority of CDA mass spectra recorded during this phase are too faint to be individually calibrated, two types of mass spectra have been identified - water ice and silicates. These two types of grains were detected at different locations with respect to the ring plane, indicating that there are compositional differences across the rings. As for the dynamics, the observations confirm the transport of charged nanodust from the main rings along magnetic field lines to the planet, as previously proposed. The agreement between the simulated density profile and the observation strongly suggests nanodust as a pathway of ring-planet interaction associated with both exogenous (e.g., impactor ejecta) and endogenous (ionospheric plasma charging) processes. CDA measurements do not indicate significant temporal variation during the the Grand Finale orbits. The measured flux corresponds to a mass transport of < 0.1 kg/sec from the main rings to Saturn in the form of nanodust, with most of the deposition occurring near the equator.

Evaluation and characterization of General Purpose Heat Source girth welds for the Cassini mission

International Nuclear Information System (INIS)

Lynch, C.M.; Moniz, P.F.; Reimus, M.A.H.

1998-01-01

General Purpose Heat Sources (GPHSs) are components of Radioisotopic thermoelectric Generators (RTGs) which provide electric power for deep space missions. Each GPHS consists of a 238 Pu oxide ceramic pellet encapsulated in a welded iridium alloy shell which forms a protective barrier against the release of plutonia in the unlikely event of a launch-pad failure or reentry incident. GPHS fueled clad girth weld flaw detection was paramount to ensuring this safety function, and was accomplished using both destructive and non-destructive evaluation techniques. The first girth weld produced from each welding campaign was metallographically examined for flaws such as incomplete weld penetration, cracks, or porosity which would render a GPHS unacceptable for flight applications. After an acceptable example weld was produced, the subsequently welded heat sources were evaluated non-destructively for flaws using ultrasonic immersion testing. Selected heat sources which failed ultrasonic testing would be radiographed, and/or, destructively evaluated to further characterize and document anomalous indications. Metallography was also performed on impacted heat sources to determine the condition of the welds

Gravimagnetic effect of the barycentric motion of the Sun and determination of the post-Newtonian parameter γ in the Cassini experiment

Science.gov (United States)

Kopeikin, S. M.; Polnarev, A. G.; Schäfer, G.; Vlasov, I. Yu.

2007-07-01

The most precise test of the post-Newtonian γ parameter in the solar system has been achieved in measurement of the frequency shift of radio waves to and from the Cassini spacecraft as they passed near the Sun. The test relies upon the JPL model of radiowave propagation that includes, but does not explicitly parametrize, the impact of the non-stationary component of the gravitational field of the Sun, generated by its barycentric orbital motion, on the Shapiro delay. This non-stationary gravitational field of the Sun is associated with the Lorentz transformation of the metric tensor and the affine connection from the heliocentric to the barycentric frame of the solar system and can be treated as gravimagnetic field. The gravimagnetic field perturbs the propagation of a radio wave and contributes to its frequency shift at the level up to 4×10-13 that may affect the precise measurement of the parameter γ in the Cassini experiment to about one part in 10 000. Our analysis suggests that the translational gravimagnetic field of the Sun can be extracted from the Cassini data, and its effect is separable from the space curvature characterized by the parameter γ.

Observations and temperatures of Io's Pele Patera from Cassini and Galileo spacecraft images

Science.gov (United States)

Radebaugh, J.; McEwen, A.S.; Milazzo, M.P.; Keszthelyi, L.P.; Davies, A.G.; Turtle, E.P.; Dawson, D.D.

2004-01-01

Pele has been the most intense high-temperature hotspot on Io to be continuously active during the Galileo monitoring from 1996-2001. A suite of characteristics suggests that Pele is an active lava lake inside a volcanic depression. In 2000-2001, Pele was observed by two spacecraft, Cassini and Galileo. The Cassini observations revealed that Pele is variable in activity over timescales of minutes, typical of active lava lakes in Hawaii and Ethiopia. These observations also revealed that the short-wavelength thermal emission from Pele decreases with rotation of Io by a factor significantly greater than the cosine of the emission angle, and that the color temperature becomes more variable and hotter at high emission angles. This behavior suggests that a significant portion of the visible thermal emission from Pele comes from lava fountains within a topographically confined lava body. High spatial resolution, nightside images from a Galileo flyby in October 2001 revealed a large, relatively cool (Pele has lavas with ultramafic compositions. The long-lived, vigorous activity of what is most likely an actively overturning lava lake in Pele Patera indicates that there is a strong connection to a large, stable magma source region. ?? 2003 Elsevier Inc. All rights reserved.

Galileo SSI and Cassini ISS Observations of Io's Pele Hotspot: Temperatures, Areas, and Variation with Time

Science.gov (United States)

Radebaugh, J.; McEwen, A. S.; Milazzo, M.; Davies, A. G.; Keszthelyi, L. P.; Geissler, P.

2002-01-01

Temperatures of Io's Pele hotspot were found using dual-filter observations from Galileo and Cassini. Temperatures average 1375 K, but vary widely over tens of minutes. Dropoff in emission with rotation consistent with lava fountaining at a lava lake. Additional information is contained in the original extended abstract.

IMF dependence of Saturn's auroras: modelling study of HST and Cassini data from 12–15 February 2008

Directory of Open Access Journals (Sweden)

E. S. Belenkaya

2010-08-01

Full Text Available To gain better understanding of auroral processes in Saturn's magnetosphere, we compare ultraviolet (UV auroral images obtained by the Hubble Space Telescope (HST with the position of the open-closed field line boundary in the ionosphere calculated using a magnetic field model that employs Cassini measurements of the interplanetary magnetic field (IMF as input. Following earlier related studies of pre-orbit insertion data from January 2004 when Cassini was located ~ 1300 Saturn radii away from the planet, here we investigate the interval 12–15 February 2008, when UV images of Saturn's southern dayside aurora were obtained by the HST while the Cassini spacecraft measured the IMF in the solar wind just upstream of the dayside bow shock. This configuration thus provides an opportunity, unique to date, to determine the IMF impinging on Saturn's magnetosphere during imaging observations, without the need to take account of extended and uncertain interplanetary propagation delays. The paraboloid model of Saturn's magnetosphere is then employed to calculate the magnetospheric magnetic field structure and ionospheric open-closed field line boundary for averaged IMF vectors that correspond, with appropriate response delays, to four HST images. We show that the IMF-dependent open field region calculated from the model agrees reasonably well with the area lying poleward of the UV emissions, thus supporting the view that the poleward boundary of Saturn's auroral oval in the dayside ionosphere lies adjacent to the open-closed field line boundary.

Diurnal Variations of Emissions of O2 singlet Delta Near Mars' Northern Summer Solstice

Science.gov (United States)

Nosowitz, Jonathon; Ziobron, Elijah; Novak, Robert E.

2017-10-01

We are presenting results of O2 singlet Delta emission, a tracer for ozone, in the Martian atmosphere for observations taken before Mars’ Northern summer solstice (Ls = 88o, February 10, 2014 ). The data were taken using CSHELL on the NASA-IRTF telescope located on Mauna Kea in Hawaii. The slit was positioned east-west on Mars and we observed diurnal variations at 20o N and 60o N. Spectral/spatial images were taken with a spectral resolution above 38,000. Mars’ relative velocity of -16 km/s enabled us to separate the Martian emission lines from the telluric absorption lines. Raw images were cleaned by removing dead and hot pixels. The images were then adjusted so that the spatial dimension was perpendicular to the spectral dimension. Extracts at 0.6 arcsec spatial resolution were taken which allowed us to measure Martian emission peaks. The Martian data were calibrated by taking similar observations from a standard star (HR4689) using the temperature, wavelength, and intensity of the star to calibrate the flux density. A Boltzmann analysis was performed on the observed emission peaks to obtain the rotational temperature of the excited O2. From this, the total emission rates were obtained. We found that at both latitudinal locations, the greatest emissions occured between 12:00- 13:00 local time on Mars. The emission intensity increases during the morning hours and then decreases towards sunset. We thank the administration and staff of the NASA-IRTF for observation time and for their assistance during operations of the telescope. We also thank Drs. M. Mumma and G. Villanueva of the NASA Goddard Space Flight Center with whom we collaborate.

[Impacts on repeated common cold for the adults with different constitutions treated by acupoint application in the dog days and the three nine-day periods after the winter solstice].

Science.gov (United States)

Lou, Bi-Dan; Yang, Li-Bai; Zhang, Wei; Li, Jin-Xiang; Li, Xiao-Ping; Li, Wu; Yang, Shu-Quan; Huang, Xiang-Hong; Liu, Xing-Ping; Cao, Yue; Pan, Jiang

2012-11-01

To observe the impacts on repeated common cold for the adults with different constitutions treated by acupoint application in the dog days (the three periods of the hottest days) and the three nine-day periods after the winter solstice (the three periods of the coldest days). One hundred and fifty-two cases of repeated common cold were divided into four zones according to the body constitution. Each zone was sub-divided into a group of the dog days + the three nine-day periods of the coldest days (group A), and a simple group of the dog periods (group B). In both groups, Dazhui (GV 14), Feishu (BL 13), Tiantu (CV 22), Danzhong (CV 17), Zhongfu (LU 1) and Shenshu (BL 23) were selected. In group A, the acupoint application was given on the 1st or 2nd day of the first, second and third periods of the hottest days in 2010, as well as the 1st or 2nd day of the first, second and third periods of the coldest days in 2010 separately. In group B, the acupoint application was only given on the 1st or 2nd day of the first, second and third periods of the hottest days in 2010. The follow-up visit was conducted before the acupoint application in the three periods of the coldest days in 2010 and before the acupoint application in the three periods of the hottest days in 2011. Additionally, the frequency of disease attack and the symptom score in sickness were taken as the observation indices for the efficacy assessment in both groups. (1) In both groups, the attack frequency was reduced obviously in half a year after the three periods of the hottest days for the patients of qi deficiency constitution, yang deficiency constitution and qi stagnation constitution and the clinical symptom score were reduced apparently (all Pcoldest days for the patients of those four constitutions as compared with those before treatment (all Pcoldest days, the efficacy for reducing the attack frequency and the improvements in the clinical symptoms were better than those in group B (all P<0.01). The

Monitor and Control of the Deep-Space network via Secure Web

Science.gov (United States)

Lamarra, N.

1997-01-01

(view graph) NASA lead center for robotic space exploration. Operating division of Caltech/Jet Propulsion Laboratory. Current missions, Voyagers, Galileo, Pathfinder, Global Surveyor. Upcoming missions, Cassini, Mars and New Millennium.

Tiger Stripes and Cassini ISS High-Resolution Imaging of Enceladus

Science.gov (United States)

Helfenstein, Paul; Denk, T.; Giese, B.; McEwen, A. S.; Neukum, G.; Perry, J.; Porco, C. C.; Thomas, P. C.; Turtle, E.; Verbiscer, A.; Veverka, J.

2008-09-01

Deciphering the mechanisms of Enceladus’ plumes is one of the most important and challenging tasks for planetary science. Cassini has provided a wealth of data by remote and in-situ data collection, but fundamental details of the vents and their context remain elusive. Three flybys of Enceladus by Cassini in 2008, on August 11 (altitude: 50km), October 9 (30km), and October 31 (200 km) are designed to further our knowledge of Enceladus’ geology and geophysics. Anticipated data include images as good as 7 m/pixel of parts of the geologically active South Polar Terrain (SPT). We targeted six different known eruption sites (Spitale and Porco 2007, Nature 449, 695-697) along Cairo Sulcus, Baghdad Suclus, and Damascus Sulcus, as well as non-active portions of the the "tiger stripes" and bright grooved terrain in between. On each of the three flybys we also plan contiguous ISS broadband multi-spectral mosaics of the entire SPT region so that we can search for volcanically and tectonically driven temporal changes and construct detailed digital terrain maps. Previous images of the tiger stripes and other rift systems on Enceladus resolve geomorphic structures on hundred meter scales or larger. Within those resolution limits, tiger stripes are morphologically distinguished most strongly from comparably sized young looking rifts elsewhere on Enceladus by their prominent upturned flanks, the muted appearance of their surface relief, and their relative absence of distinct cliff faces, probably of solid ice along scarps. The anticipated new high-resolution images will provide critical structural details needed to identify the extent to which unique attributes of tiger stripes are caused by mantling by plume fallout, tectonic deformation, seismic disruption, or perhaps thermal processes. Here, we present a first analysis of the August 11 close flyby images.

Discovery Of B Ring Propellers In Cassini UVIS, And ISS

Science.gov (United States)

Sremcevic, Miodrag; Stewart, G. R.; Albers, N.; Esposito, L. W.

2012-10-01

We present evidence for the existence of propellers in Saturn's B ring by combining data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We identify two propeller populations: (1) tens of degrees wide propellers in the dense B ring core, and (2) smaller, more A ring like, propellers populating the inner B ring. The prototype of the first population is an object observed at 18 different epochs between 2005 and 2010. The ubiquitous propeller "S" shape is seen both in UVIS occultations as an optical depth depletion and in ISS as a 40 degrees wide bright stripe in unlit geometries and dark in lit geometries. Combining the available Cassini data we infer that the object is a partial gap embedded in the high optical depth region of the B ring. The gap moves at orbital speed consistent with its radial location. From the radial separation of the propeller wings we estimate that the embedded body, which causes the propeller structure, is about 1.5km in size located at a=112,921km. The UVIS occultations indicate an asymmetric propeller "S" shape. Since the object is located at an edge between high and relatively low optical depth, this asymmetry is most likely a consequence of the strong surface mass density gradient. We estimate that there are possibly dozen up to 100 other propeller objects in Saturn's B ring. The location of the discovered body, at an edge of a dense ringlet within the B ring, suggests a novel mechanism for the up to now illusive B ring irregular large-scale structure of alternating high and low optical depth ringlets. We propose that this B ring irregular structure may have its cause in the presence of many embedded bodies that shepherd the individual B ring ringlets.

Electrical interferences observed in the Cassini CIRS spectrometer

Science.gov (United States)

Chan, Cheong; Albright, Shane; Gorius, Nicolas; Brasunas, John; Jennings, Don; Flasar, F. Michael; Carlson, Ronald; Guandique, Ever; Nixon, Conor

2015-06-01

The Composite Infrared Spectrometer (CIRS) carried onboard the Cassini spacecraft has now operated successfully for 17 years, following launch in 1997. Following insertion into Saturnian orbit in July 2004, the instrument has taken data nearly continuously, returning over 100 million interferograms (spectra) to date. Although of generally high quality, and resulting in more than 100 peer-reviewed scientific articles, the spectra are afflicted with several types of instrumental electrical (non-random) noise artifacts. These noise artifacts require either mitigation strategies (prevention), removal from the observed data, or else awareness of the affected spectral areas which must be excluded from scientific analysis. The sources and nature of these varied noise types were not readily identified until after launch. The purpose of this article is to inform users of the noise in the CIRS dataset and to serve as a `lesson-learned' guide for designers of future instruments.

Dione and Rhea seasonal exospheres revealed by Cassini CAPS and INMS

Science.gov (United States)

Teolis, B. D.; Waite, J. H.

2016-07-01

A Dione O2 and CO2 exosphere of similar composition and density to Rhea's is confirmed by Cassini spacecraft Ion Neutral Mass Spectrometer (INMS) flyby data. INMS results from three Dione and two Rhea flybys show exospheric spatial and temporal variability indicative of seasonal exospheres, modulated by winter polar gas adsorption and desorption at the equinoxes. Cassini Plasma Spectrometer (CAPS) pickup ion fluxes also show exospheric structure and evolution at Rhea consistent with INMS, after taking into consideration the anticipated charge exchange, electron impact, and photo-ionization rates. Data-model comparisons show the exospheric evolution to be consistent with polar frost diffusion into the surface regolith, which limits surface exposure and loss of the winter frost cap by sputtering. Implied O2 source rates of ∼45(7) × 1021 s-1 at Dione(Rhea) are ∼50(300) times less than expected from known O2 radiolysis yields from ion-irradiated pure water ice measured in the laboratory, ruling out secondary sputtering as a major exospheric contributor, and implying a nanometer scale surface refractory lag layer consisting of concentrated carbonaceous impurities. We estimate ∼30:1(2:1) relative O2:CO2 source rates at Dione(Rhea), consistent with a stoichiometric bulk composition below the lag layer of 0.01(0.13) C atoms per H2O molecule, deriving from endogenic constituents, implanted micrometeoritic organics, and (in particular at Dione) exogenous H2O delivery by E-ring grains. Impact deposition, gardening and vaporization may thereby control the global O2 source rates by fresh H2O ice exposure to surface radiolysis and trapped oxidant ejection.

Cassini data assessment report

International Nuclear Information System (INIS)

1998-08-01

On October 15, 1997, the Cassini spacecraft was launched from Cape Canaveral Air Station (CCAS) and is now on its way to the planet Saturn. The functional support provided to NASA by DOE included the Advance Launch Support Group (ALSG). If there had been a launch anomaly, the ALSG would have provided a level of radiological emergency response support adequate to transition into a Federal Radiological Monitoring and Assessment Center (FRMAC). Additional functional radiological emergency response support, as part of the ALSG, included the: (1) Aerial Measurement System (AMS); (2) Atmospheric Release Advisory Capability (ARAC); (3) Geographic Information System (GIS); (4) Emergency Response Data System (ERDS); (5) Radiation Emergency Assistance Center and Training Site (REAC/TS); (6) Field monitoring and sampling; (7) Radioanalysis via RASCAL; (8) Source recovery; and (9) Neutron dosimetry and communications support. This functional support provided the capability to rapidly measure and assess radiological impacts from a launch anomaly. The Radiological Control Officer (RCO) on KSC established a Radiological Control Center (RADCC) as the focal point for all on-site and off-site radiological data and information flow. Scientists and radiological response personnel located at the RADCC managed the field monitoring team on the KSC/CCAS federal properties. Off-site radiological emergency response activities for all public lands surrounding the KSC/CCAS complex were coordinated through the Off-site ALSG located at the National Guard Armory in Cocoa, Florida. All of the in situ measurement data of good quality gathered during the dry run, the first launch attempt and the launch day are listed in this document. The RASCAL analysis results of the air filters and impactor planchets are listed

Probing the Boundaries of the Heliosphere Using Observations of the Polar ENA Flux from IBEX and Cassini/INCA

Science.gov (United States)

Reisenfeld, D. B.; Janzen, P. H.; Bzowski, M.; Dialynas, K.; Funsten, H. O.; Fuselier, S. A.; Galli, A.; Kubiak, M. A.; McComas, D. J.; Schwadron, N.; Sokol, J. M.

2016-12-01

The IBEX Mission has been collecting ENAs from the outer heliosphere for nearly eight years, or three-quarters of a solar cycle. In that time, we have observed clear evidence of the imprint of the solar cycle in the time variation in the ENA flux. The most detailed of such studies has focused on the polar ENA flux observed by IBEX-Hi, as the IBEX spacecraft attitude allows for continuous coverage of the ENA flux incident from the ecliptic poles (Reisenfeld et al. 2012, 2016). By time correlating the ENA-derived heliosheath pressure to the observed 1 AU dynamic pressure, we can estimate the distance to the ENA source region. We can further derive the thickness of the ENA-producing region (presumably the inner heliosheath) by assuming pressure balance at the termination shock (TS). This requires using the 1 AU observations to derive the dynamic pressure at the TS shock by use of a mass-loaded solar wind propagation model (Schwadron et al. 2011), and by integrating ENA observations across all energies that significantly contribute to the heliosheath pressure. This means including polar ENA observations from not only IBEX-Hi, but from IBEX-Lo and Cassini/INCA, spanning an energy range of 15 eV to 40 keV. We will present our latest polar ENA observations and estimates for the distance to the TS and the thickness of the heliosheath.

AVIATR - Aerial Vehicle for In-situ and Airborne Titan Reconnaissance A Titan Airplane Mission Concept

Science.gov (United States)

Barnes, Jason W.; Lemke, Lawrence; Foch, Rick; McKay, Christopher P.; Beyer, Ross A.; Radebaugh, Jani; Atkinson, David H.; Lorenz, Ralph D.; LeMouelic, Stephane; Rodriguez, Sebastien;

Organic chemistry in Titan's upper atmosphere and its astrobiological consequences: I. Views towards Cassini plasma spectrometer (CAPS) and ion neutral mass spectrometer (INMS) experiments in space

Science.gov (United States)

Ali, A.; Sittler, E. C.; Chornay, D.; Rowe, B. R.; Puzzarini, C.

2015-05-01

radicals. These radical species subsequently might form carbanions via radiative electron attachment at low temperatures with thermal electrons. The classic example is the perinaphthenyl anion in Titan's upper atmosphere. Therefore, future astronomical observations of selected carbocations and corresponding carbanions are required to settle the key issue of molecular anion chemistry on Titan. Other than earth, Titan is the only planetary body in our solar system that is known to have reservoirs of permanent liquids on its surface. The synthesis of complex biomolecules either by organic catalysis of precipitated solutes “on hydrocarbon solvent” on Titan or through the solvation process indeed started in its upper atmosphere. The most notable examples in Titan's prebiotic atmospheric chemistry are conjugated and aromatic polycyclic molecules, N-heterocycles including the presence of imino >Cdbnd N-H functional group in the carbonium chemistry. Our major conclusion in this paper is that the synthesis of organic compounds in Titan's upper atmosphere is a direct consequence of the chemistry of carbocations involving the ion-molecule reactions. The observations of complexity in the organic chemistry on Titan from the Cassini-Huygens mission clearly indicate that Titan is so far the only planetary object in our solar system that will most likely provide an answer to the question of the synthesis of complex biomolecules on the primitive earth and the origin of life.

Cassini CAPS-ELS observations of carbon-based anions and aerosol growth in Titan's ionosphere

Science.gov (United States)

Desai, Ravindra; Coates, Andrew; Wellbrock, Anne; Kataria, Dhiren; Jones, Geraint; Lewis, Gethyn; Waite, J.

2016-06-01

Cassini observations of Titans ionosphere revealed an atmosphere rich in positively charged ions with masses up to > 350 amu and negatively charged ions and aerosols with mass over charge ratios as high as 13,800 amu/q. The detection of negatively charged molecules by the Cassini CAPS Electron Spectrometer (CAPS-ELS) was particularly surprising and showed how the synthesis of large aerosol-size particles takes place at altitudes much greater than previously thought. Here, we present further analysis into this CAPS-ELS dataset, through an enhanced understanding of the instrument's response function. In previous studies the intrinsic E/E energy resolution of the instrument did not allow specific species to be identified and the detections were classified into broad mass ranges. In this study we use an updated fitting procedure to show how the ELS mass spectrum can be resolved into specific peaks at multiples of carbon-based anions up to > 100 amu/q. The negatively charged ions and aerosols in Titans ionosphere increase in mass with decreasing altitude, the lightest species being observed close to Titan's exobase of ˜1,450km and heaviest species observed at altitudes < 950km. We identify key stages in this apparent growth process and report on key intermediaries which appear to trigger the rapid growth of the larger aerosol-size particles.

GPHS-RTGs in support of the Cassini Mission. Semi annual technical report, 30 September 1996--30 March 1997

International Nuclear Information System (INIS)

1997-01-01

The technical progress achieved during the period 27 January through 30 September 1996 through 30 March 1997 on Contract DE-AC03-91SF18852 Radioisotope Thermoelectric Generators and Ancillary Activities is described. This report is organized by program task structure: spacecraft integration and liaison; engineering support; safety; qualified unicouple production; ETG fabrication, assembly, and test; ground support equipment (GSE); RTG shipping and launch support; designs, reviews, and mission applications; project management, quality assurance, reliability, contract changes, CAGO acquisition (operating funds), and CAGO maintenance and repair; and CAGO acquisition (capital funds)

GPHS-RTGs in support of the Cassini Mission. Semi annual technical progress report, 28 March 1994--25 September 1994

International Nuclear Information System (INIS)

1994-01-01

The progress on the radioisotope generators and ancillary activities is described. This report is organized by program task as follows: spacecraft integration and liaison; engineering support; safety; qualified unicouple fabrication; ETG fabrication, assembly, and test; ground support equipment; RTG shipping and launch support; design, reviews, and mission applications; project management, quality assurance and reliability, contract changes, non-capital CAGO acquisition, and CAGO maintenance; contractor acquired government owned property (CAGO) acquisition

Nondestructive inspection of General Purpose Heat Source (GPHS) fueled clad girth welds

International Nuclear Information System (INIS)

Reimus, M. A. H.; George, T. G.; Lynch, C.; Padilla, M.; Moniz, P.; Guerrero, A.; Moyer, M. W.; Placr, A.

1998-01-01

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of 238 Pu decay to an array of thermoelectric elements. The GPHS is fabricated using an iridium-alloy to contain the 238 PuO 2 fuel pellet. GPHS capsules will be utilized in the upcoming Cassini mission to explore Saturn and its moons. The physical integrity of the girth weld is important to mission safety and performance. Because past experience had revealed a potential for initiation of small cracks in the girth weld overlap zone, a nondestructive inspection of each capsule weld is required. An ultrasonic method was used to inspect the welds of capsules fabricated for the Galileo mission. The instrument, transducer, and method used were state of the art at the time (early 1980s). The ultrasonic instrumentation and methods used to inspect the Cassini GPHSs was significantly upgraded from those used for the Galileo mission. GPHSs that had ultrasonic reflectors in excess of the reject specification level were subsequently inspected with radiography to provide additional engineering data used to accept/reject the heat source. This paper describes the Galileo-era ultrasonic instrumentation and methods and the subsequent upgrades made to support testing of Cassini GPHSs. Also discussed is the data obtained from radiographic examination and correlation to ultrasonic examination results

Nondestructive inspection of General Purpose Heat Source (GPHS) fueled clad girth welds

International Nuclear Information System (INIS)

Reimus, M.A.; George, T.G.; Lynch, C.; Padilla, M.; Moniz, P.; Guerrero, A.; Moyer, M.W.; Placr, A.

1998-01-01

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of 238 Pu decay to an array of thermoelectric elements. The GPHS is fabricated using an iridium-alloy to contain the 238 PuO 2 fuel pellet. GPHS capsules will be utilized in the upcoming Cassini mission to explore Saturn and its moons. The physical integrity of the girth weld is important to mission safety and performance. Because past experience had revealed a potential for initiation of small cracks in the girth weld overlap zone, a nondestructive inspection of each capsule weld is required. An ultrasonic method was used to inspect the welds of capsules fabricated for the Galileo mission. The instrument, transducer, and method used were state of the art at the time (early 1980s). The ultrasonic instrumentation and methods used to inspect the Cassini GPHSs was significantly upgraded from those used for the Galileo mission. GPHSs that had ultrasonic reflectors in excess of the reject specification level were subsequently inspected with radiography to provide additional engineering data used to accept/reject the heat source. This paper describes the Galileo-era ultrasonic instrumentation and methods and the subsequent upgrades made to support testing of Cassini GPHSs. Also discussed is the data obtained from radiographic examination and correlation to ultrasonic examination results. copyright 1998 American Institute of Physics

CIRS-lite, a Fourier Transform Spectrometer for Low-Cost Planetary Missions

Science.gov (United States)

Brasunas, J.; Bly, V.; Edgerton, M.; Gong, Q.; Hagopian, J.; Mamakos, W.; Morelli, A.; Pasquale, B.; Strojny, C.

2011-01-01

Passive spectroscopic remote sensing of planetary atmospheres and surfaces in the thermal infrared is a powerful tool for obtaining information about surface and atmospheric temperatures, composition, and dynamics (via the thermal wind equation). Due to its broad spectral coverage, the Fourier transform spectrometer (FTS) is particularly suited to the exploration and discovery of molecular species. NASA's Goddard Space Flight Center (GSFC) developed the CIRS (Composite Infrared Spectrometer) FTS for the NASA/ESA Cassini mission to the Saturnian system. CIRS observes Saturn, Titan, icy moons such as Enceladus, and the rings in thermal self-emission over the spectral range of 7 to 1000 ell11. CIRS has given us important new insights into stratospheric composition and jets on Jupiter and Saturn, the cryo-geyser and thermal stripes on Enceladus, and the winter polar vortex on Titan. CIRS has a mass of 43 kg, contrasted with the earlier GSFC FTS, pre-Voyager IRIS (14 kg). Future low-cost planetary missions will have very tight constraints on science payload mass, thus we must endeavor to return to IRIS-level mass while maintaining CIRS-level science capabilities ("do more with less"). CIRS-lite achieves this by pursuing: a) more sensitive infrared detectors (high Tc superconductor) to enable smaller optics. b) changed long wavelength limit from 1000 to 300 microns to reduce diffraction by smaller optics. c) CVD (chemical vapor deposition) diamond beam-splitter for broad spectral coverage. d) single FTS architecture instead of a dual FTS architecture. e) novel materials, such as single crystal silicon for the input telescope primary.

JIRAM, the image spectrometer in the near infrared on board the Juno mission to Jupiter.

Science.gov (United States)

Adriani, Alberto; Coradini, Angioletta; Filacchione, Gianrico; Lunine, Jonathan I; Bini, Alessandro; Pasqui, Claudio; Calamai, Luciano; Colosimo, Fedele; Dinelli, Bianca M; Grassi, Davide; Magni, Gianfranco; Moriconi, Maria L; Orosei, Roberto

2008-06-01

The Jovian InfraRed Auroral Mapper (JIRAM) has been accepted by NASA for inclusion in the New Frontiers mission "Juno," which will launch in August 2011. JIRAM will explore the dynamics and the chemistry of Jupiter's auroral regions by high-contrast imaging and spectroscopy. It will also analyze jovian hot spots to determine their vertical structure and infer possible mechanisms for their formation. JIRAM will sound the jovian meteorological layer to map moist convection and determine water abundance and other constituents at depths that correspond to several bars pressure. JIRAM is equipped with a single telescope that accommodates both an infrared camera and a spectrometer to facilitate a large observational flexibility in obtaining simultaneous images in the L and M bands with the spectral radiance over the central zone of the images. Moreover, JIRAM will be able to perform spectral imaging of the planet in the 2.0-5.0 microm interval of wavelengths with a spectral resolution better than 10 nm. Instrument design, modes, and observation strategy will be optimized for operations onboard a spinning satellite in polar orbit around Jupiter. The JIRAM heritage comes from Italian-made, visual-infrared imaging spectrometers dedicated to planetary exploration, such as VIMS-V on Cassini, VIRTIS on Rosetta and Venus Express, and VIR-MS on the Dawn mission.

From the Icy Satellites to Small Moons and Rings: Spectral Indicators by Cassini-VIMS Unveil Compositional Trends in the Saturnian System

Science.gov (United States)

Filacchione, G.; Capaccioni, F.; Ciarniello, M.; Nicholson, P. D.; Clark, R. N.; Cuzzi, J. N.; Buratti, B. B.; Cruikshank, D. P.; Brown, R. H.

2017-01-01

Despite water ice being the most abundant species on Saturn satellites' surfaces and ring particles, remarkable spectral differences in the 0.35-5.0 μm range are observed among these objects. Here we report about the results of a comprehensive analysis of more than 3000 disk-integrated observations of regular satellites and small moons acquired by VIMS aboard Cassini mission between 2004 and 2016. These observations, taken from very different illumination and viewing geometries, allow us to classify satellites' and rings' compositions by means of spectral indicators, e.g. 350-550 nm - 550-950 nm spectral slopes and water ice band parameters [1,2,3]. Spectral classification is further supported by indirect retrieval of temperature by means of the 3.6 μm I/F peak wavelength [4,5]. The comparison with syntethic spectra modeled by means of Hapke's theory point to different compositional classes where water ice, amorphous carbon, tholins and CO2 ice in different quantities and mixing modalities are the principal endmembers [3, 6]. When compared to satellites, rings appear much more red at visible wavelengths and show more intense 1.5-2.0 μm band depths [7]. Our analysis shows that spectral classes are detected among the principal satellites with Enceladus and Tethys the ones with stronger water ice band depths and more neutral spectral slopes while Rhea evidences less intense band depths and more red visible spectra. Even more intense reddening in the 0.55-0.95 μm range is observed on Iapetus leading hemisphere [8] and on Hyperion [9]. With an intermediate reddening, the minor moons seems to be the spectral link between the principal satellites and main rings [10]: Prometheus and Pandora appear similar to Cassini Division ring particles. Epimetheus shows more intense water ice bands than Janus. Epimetheus' visible colors are similar to water ice rich moons while Janus is more similar to C ring particles. Finally, Dione and Tethys lagrangian satellites show a very

Diurnal Variations of Titan's Surface Temperatures From Cassini -CIRS Observations

Science.gov (United States)

Cottini, Valeria; Nixon, Conor; Jennings, Don; Anderson, Carrie; Samuelson, Robert; Irwin, Patrick; Flasar, F. Michael

The Cassini Composite Infrared Spectrometer (CIRS) observations of Saturn's largest moon, Titan, are providing us with the ability to detect the surface temperature of the planet by studying its outgoing radiance through a spectral window in the thermal infrared at 19 m (530 cm-1) characterized by low opacity. Since the first acquisitions of CIRS Titan data the in-strument has gathered a large amount of spectra covering a wide range of latitudes, longitudes and local times. We retrieve the surface temperature and the atmospheric temperature pro-file by modeling proper zonally averaged spectra of nadir observations with radiative transfer computations. Our forward model uses the correlated-k approximation for spectral opacity to calculate the emitted radiance, including contributions from collision induced pairs of CH4, N2 and H2, haze, and gaseous emission lines (Irwin et al. 2008). The retrieval method uses a non-linear least-squares optimal estimation technique to iteratively adjust the model parameters to achieve a spectral fit (Rodgers 2000). We show an accurate selection of the wide amount of data available in terms of footprint diameter on the planet and observational conditions, together with the retrieved results. Our results represent formal retrievals of surface brightness temperatures from the Cassini CIRS dataset using a full radiative transfer treatment, and we compare to the earlier findings of Jennings et al. (2009). The application of our methodology over wide areas has increased the planet coverage and accuracy of our knowledge of Titan's surface brightness temperature. In particular we had the chance to look for diurnal variations in surface temperature around the equator: a trend with slowly increasing temperature toward the late afternoon reveals that diurnal temperature changes are present on Titan surface. References: Irwin, P.G.J., et al.: "The NEMESIS planetary atmosphere radiative transfer and retrieval tool" (2008). JQSRT, Vol. 109, pp

Effective stability around the Cassini state in the spin-orbit problem

Science.gov (United States)

Sansottera, Marco; Lhotka, Christoph; Lemaître, Anne

2014-05-01

We investigate the long-time stability in the neighborhood of the Cassini state in the conservative spin-orbit problem. Starting with an expansion of the Hamiltonian in the canonical Andoyer-Delaunay variables, we construct a high-order Birkhoff normal form and give an estimate of the effective stability time in the Nekhoroshev sense. By extensively using algebraic manipulations on a computer, we explicitly apply our method to the rotation of Titan. We obtain physical bounds of Titan's latitudinal and longitudinal librations, finding a stability time greatly exceeding the estimated age of the Universe. In addition, we study the dependence of the effective stability time on three relevant physical parameters: the orbital inclination, , the mean precession of the ascending node of Titan orbit, , and the polar moment of inertia,.

The Hera Saturn Entry Probe Mission: a Proposal in Response to the ESA M5 Call

Science.gov (United States)

Mousis, Olivier; Atkinson, David; Amato, Michael; Aslam, Shahid; Atreya, Sushil; Blanc, Michel; Bolton, Scott; Brugger, Bastien; Calcutt, Simon; Cavalié, Thibault; Charnoz, Sébastien; Coustenis, Athena; Deleuil, Magali; Dobrijevic, Michel; Ferri, Francesca; Fletcher, Leigh; Gautier, Daniel; Guillot, Tristan; Hartogh, Paul; Holland, Andrew

2017-04-01

The Hera Saturn entry probe mission is proposed as an ESA M-class mission to be piggybacked on a NASA spacecraft sent to or past the Saturn system. Hera consists of an atmospheric probe built by ESA and released into the atmosphere of Saturn by its NASA companion Saturn Carrier-Relay spacecraft. Hera will perform in situ measurements of the chemical and isotopic composition as well as the structure and dynamics of Saturn's atmosphere using a single probe, with the goal of improving our understanding of the origin, formation, and evolution of Saturn, the giant planets and their satellite systems, with extrapolation to extrasolar planets. Hera will probe well into and possibly beneath the cloud-forming region of the troposphere, below the region accessible to remote sensing, to locations where certain cosmogenically abundant species are expected to be well mixed. The Hera probe will be designed from ESA elements with possible contributions from NASA, and the Saturn/Carrier-Relay Spacecraft will be supplied by NASA through its selection via the New Frontier 2016 call or in the form of a flagship mission selected by the NASA "Roadmaps to Ocean Worlds" (ROW) program. The Hera probe will be powered by batteries, and we therefore anticipate only one major subsystems to be possibly supplied by the United States, either by direct procurement by ESA or by contribution from NASA: the thermal protection system of the probe. Following the highly successful example of the Cassini-Huygens mission, Hera will carry European and American instruments, with scientists and engineers from both agencies and many affiliates participating in all aspects of mission development and implementation. A Saturn probe is one of the six identified desired themes by the Planetary Science Decadal Survey committee on the NASA New Frontier's list, providing additional indication that a Saturn probe is of extremely high interest and a very high priority for the international community.

Fast forward modeling of Titan’s infrared spectra to invert VIMS/CASSINI hyperspectral images

Science.gov (United States)

Rodriguez, S.; Le Mouélic, S.; Rannou, P.; Combe, J.; Le Corre, L.; Griffith, C. A.; Tobie, G.; Barnes, J. W.; Sotin, C.; Brown, R. H.; Baines, K. H.; Buratti, B. J.; Clark, R. N.

2009-12-01

The surface of Titan, the largest icy moon of Saturn, is veiled by a very thick and hazy atmosphere. The Visual and Infrared Mapping Spectrometer onboard the Cassini spacecraft, in orbit around Saturn since July 2004, has been conducting an intensive survey of Titan with the objective of understanding the complex nature and interaction of the atmosphere and surface of this mysterious moon. Retrieving and separating contributions from the surface and the atmosphere in Titan’s infrared spectra requires accurate radiative transfer modeling, which is often very demanding of computer resources. As Cassini has gathered hitherto millions of spectra of Titan and will continue to observe it until at least 2010, we report here on the development of a new rapid, simple and versatile radiative transfer model specially designed to process VIMS datacubes. Currently, our model accounts for gas absorption, haze scattering and surface reflectance and can be implemented in an inversion scheme. First results of forward modeling provide spectral shapes that are consistent with VIMS measurements, as well as surface and aerosol properties in the range of validity for Titan. Further inversion tests will be carried on VIMS hyperspectral images for the estimate of spatial coherence of the results, accuracy of the surface reflectance within the atmospheric windows, and potential needs for improved input data and modeling. This work was partly performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration. Calibrated VIMS data appear courtesy of the VIMS team. We thank the CNES French agency for its financial support.

Comparison of the Cloud Morphology Spatial Structure Between Jupiter and Saturn Using JunoCam and Cassini ISS

Science.gov (United States)

Garland, Justin; Sayanagi, Kunio M.; Blalock, John J.; Gunnarson, Jacob; McCabe, Ryan M.; Gallego, Angelina; Hansen, Candice; Orton, Glenn S.

2017-10-01

We present an analysis of the spatial-scales contained in the cloud morphology of Jupiter’s southern high latitudes using images captured by JunoCam in 2016 and 2017, and compare them to those on Saturn using images captured using the Imaging Science Subsystem (ISS) on board the Cassini orbiter. For Jupiter, the characteristic spatial scale of cloud morphology as a function of latitude is calculated from images taken in three visual (600-800, 500-600, 420-520 nm) bands and a near-infrared (880- 900 nm) band. In particular, we analyze the transition from the banded structure characteristic of Jupiter’s mid-latitudes to the chaotic structure of the polar region. We apply similar analysis to Saturn using images captured using Cassini ISS. In contrast to Jupiter, Saturn maintains its zonally organized cloud morphology from low latitudes up to the poles, culminating in the cyclonic polar vortices centered at each of the poles. By quantifying the differences in the spatial scales contained in the cloud morphology, our analysis will shed light on the processes that control the banded structures on Jupiter and Saturn. Our work has been supported by the following grants: NASA PATM NNX14AK07G, NASA MUREP NNX15AQ03A, and NSF AAG 1212216.

Storm clouds on Saturn: Lightning-induced chemistry and associated materials consistent with Cassini/VIMS spectra

Science.gov (United States)

Baines, K.H.; Delitsky, M.L.; Momary, T.W.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; Nicholson, P.D.

2009-01-01

Thunderstorm activity on Saturn is associated with optically detectable clouds that are atypically dark throughout the near-infrared. As observed by Cassini/VIMS, these clouds are ~20% less reflective than typical neighboring clouds throughout the spectral range from 0.8 ??m to at least 4.1 ??m. We propose that active thunderstorms originating in the 10-20 bar water-condensation region vertically transport dark materials at depth to the ~1 bar level where they can be observed. These materials in part may be produced by chemical processes associated with lightning, likely within the water clouds near the ~10 bar freezing level of water, as detected by the electrostatic discharge of lightning flashes observed by Cassini/RPWS (e.g., Fischer et al. 2008, Space Sci. Rev., 137, 271-285). We review lightning-induced pyrolytic chemistry involving a variety of Saturnian constituents, including hydrogen, methane, ammonia, hydrogen sulfide, phosphine, and water. We find that the lack of absorption in the 1-2 ??m spectral region by lightning-generated sulfuric and phosphorous condensates renders these constituents as minor players in determining the color of the dark storm clouds. Relatively small particulates of elemental carbon, formed by lightning-induced dissociation of methane and subsequently upwelled from depth - perhaps embedded within and on the surface of spectrally bright condensates such as ammonium hydrosulfide or ammonia - may be a dominant optical material within the dark thunderstorm-related clouds of Saturn. ?? 2009 Elsevier Ltd. All rights reserved.

GPHS-RTGs in support of the Cassini mission. Semi annual technical progress report, 2 October 1995--31 March 1996

International Nuclear Information System (INIS)

1996-01-01

The technical progress achieved during the period 2 October 1995 through 31 March 1996 on Contract No. DE-AC03-91SF18852, Radioisotope Generators and Ancillary Activities is described herein. This report is organized by the program task structure as follows: spacecraft integration and liaison; engineering support; safety; qualified unicouple fabrication; ETG fabrication, assembly, and test; ground support equipment (GSE); RTG shipping and launch support; designs, reviews, and mission applications; project management, quality assurance and reliability, contract changes, non-capital CAGO acquisition, and CAGO maintenance; contract acquired government-owned property (CAGO) acquisition; and program calendars

Last Looks at the Eye of Saturn by Cassini/VIMS During the Grand Finale

Science.gov (United States)

Momary, Thomas W.; Baines, Kevin H.; Badman, Sarah; Brown, Robert H.; Buratti, Bonnie J.; Clark, Roger Nelson; Nicholson, Philip D.; Sotin, Christophe

2017-10-01

A lasting remnant of the Great Storm that erupted on Saturn in late 2010 has been a massive lone anticyclone persisting to the present time in a NH3-dry 5-µm-bright “desert” zone that spans the entire Saturnian globe at 34o N. We have been observing this oval storm with Cassini/VIMS since 2011 and, in 2017, as Cassini performs its Grand Finale orbits close to the planet, have captured it at our highest resolution since January 2012 at 260 km/pixel - enough to resolve spiral structure inside the oval at 5 µm. The spot drifts latitudinally in Saturn’s zonal currents: it was at 35.9o planetocentric latitude in May 2011, wandered northward to 37.8o in 2012, hovered near 37o through 2013, meandered as far south as 36.5o in 2014, drifted northward to 37o in 2015, and then returned back to about 36.3o in 2016, where it remains presently. It has also periodically bumped up against the dark band above it, spinning off material in 2013, 2015, and 2017. We measured a prograde zonal drift speed of 22 m/s in 2012, increasing as much as 60% through 2013, then relaxing to a more moderate 15 m/s in 2014 and 2015. It slowed considerably in 2016 to 4.7 m/s and is currently drifting slightly faster at 8.5 m/s. The spot has varied in size over time as it spins, spanning 4.9o x 3.2o in 2011, elongating to 7.3o x 2.9o by 2013, contracting to 5.5o x 2.9o in 2014, enlarging again to 9o x 4o in 2015, and contracting currently to 7.0o x 3.2o (6100 x 3200 km) in 2017, symmetrically oval in shape. It has varied in terms of cloudiness, being 90% 5-µm dark (obscured) in 2011, whereas by 2013 it was mostly bright (clear) with a thin dark edge. It was 90% dark in 2015, and in 2017 is about 65% obscured, with a bright central eye. Utilizing night observations to isolate thermal flux, we have found that the mean 5-µm flux coming from the anticyclone has diminished steadily by about 75% since 2013. The entire storm latitude of ~34o N itself has remained persistently 5-µm bright since 2011

Jovian decametric radiation seen from Juno, Cassini, STEREO A, WIND, and Earth-based radio observatories

Science.gov (United States)

Imai, M.; Kurth, W. S.; Hospodarsky, G. B.; Bolton, S. J.; Connerney, J. E. P.; Levin, S. M.; Lecacheux, A.; Lamy, L.; Zarka, P.; Clarke, T. E.; Higgins, C. A.

2017-09-01

Jupiter's decametric (DAM) radiation is generated very close to the local gyrofrequency by the electron cyclotron maser instability (CMI). The first two-point common detections of Jovian DAM radiation were made using the Voyager spacecraft and ground-based radio observatories in early 1979, but, due to geometrical constraints and limited flyby duration, a full understanding of the latitudinal beaming of Jovian DAM radiation remains elusive. The stereoscopic DAM radiation viewed from Juno, Cassini, STEREO A, WIND, and Earth-based radio observatories provides a unique opportunity to analyze the CMI emission mechanism and beaming properties.

Reconciling Electrical Properties of Titan's Surface Derived from Cassini RADAR Scatterometer and Radiometer Measurements

Science.gov (United States)

Zebker, H. A.; Wye, L. C.; Janssen, M.; Paganelli, F.; Cassini RADAR Team

2006-12-01

We observe Titan, Saturn's largest moon, using active and passive microwave instruments carried on board the Cassini spacecraft. The 2.2-cm wavelength penetrates the thick atmosphere and provides surface measurements at resolutions from 10-200 km over much of the satellite's surface. The emissivity and reflectivity of surface features are generally anticorrelated, and both values are fairly high. Inversion of either set of data alone yields dielectric constants ranging from 1.5 to 3 or 4, consistent with an icy hydrocarbon or water ice composition. However, the dielectric constants retrieved from radiometric data alone are usually less than those inferred from backscatter measurements, a discrepancy consistent with similar analyses dating back to lunar observations in the 1960's. Here we seek to reconcile Titan's reflectivity and emissivity observations using a single physical model of the surface. Our approach is to calculate the energy scattered by Titan's surface and near subsurface, with the remainder absorbed. In equilibrium the absorption equals the emission, so that both the reflectivity and emissivity are described by the model. We use a form of the Kirchhoff model for modeling surface scatter, and a model based on weak localization of light for the volume scatter. With this model we present dielectric constant and surface roughness parameters that match both sets of Cassini RADAR observations over limited regions on Titan's surface, helping to constrain the composition and roughness of the surface. Most regions display electrical properties consistent with solid surfaces, however some of the darker "lake-like" features at higher latitudes can be modeled as either solid or liquid materials. The ambiguity arises from the limited set of observational angles available.

SORCE: Solar Radiation and Climate Experiment

Science.gov (United States)

Cahalan, Robert; Rottman, Gary; Lau, William K. M. (Technical Monitor)

2002-01-01

Contents include the following: Understanding the Sun's influence on the Earth; How the Sun affect Earth's climate; By how much does the Sun's radiation very; Understanding Solar irradiance; History of Solar irradiance observations; The SORCE mission; How do the SORCE instruments measure solar radiation; Total irradiance monitor (TIM); Spectral irradiance monitor (SIM); Solar stellar irradiance comparison experiment (SOLSTICE); XUV photometer system (XPS).

High-efficiency thermionic power generator, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Planetary missions (e.g., Pioneer, Cassini, or Voyager) and applications with moderate power draw and increased mobility requirements (e.g., Curiosity) have...

Photochemistry, mixing and transport in Jupiter's stratosphere constrained by Cassini

Science.gov (United States)

Hue, V.; Hersant, F.; Cavalié, T.; Dobrijevic, M.; Sinclair, J. A.

2018-06-01

In this work, we aim at constraining the diffusive and advective transport processes in Jupiter's stratosphere, using Cassini/CIRS observations published by Nixon et al. (2007,2010). The Cassini-Huygens flyby of Jupiter on December 2000 provided the highest spatially resolved IR observations of Jupiter so far, with the CIRS instrument. The IR spectrum contains the fingerprints of several atmospheric constituents and allows probing the tropospheric and stratospheric composition. In particular, the abundances of C2H2 and C2H6, the main compounds produced by methane photochemistry, can be retrieved as a function of latitude in the pressure range at which CIRS is sensitive to. CIRS observations suggest a very different meridional distribution for these two species. This is difficult to reconcile with their photochemical histories, which are thought to be tightly coupled to the methane photolysis. While the overall abundance of C2H2 decreases with latitude, C2H6 becomes more abundant at high latitudes. In this work, a new 2D (latitude-altitude) seasonal photochemical model of Jupiter is developed. The model is used to investigate whether the addition of stratospheric transport processes, such as meridional diffusion and advection, are able to explain the latitudinal behavior of C2H2 and C2H6. We find that the C2H2 observations are fairly well reproduced without meridional diffusion. Adding meridional diffusion to the model provides an improved agreement with the C2H6 observations by flattening its meridional distribution, at the cost of a degradation of the fit to the C2H2 distribution. However, meridional diffusion alone cannot produce the observed increase with latitude of the C2H6 abundance. When adding 2D advective transport between roughly 30 mbar and 0.01 mbar, with upwelling winds at the equator and downwelling winds at high latitudes, we can, for the first time, reproduce the C2H6 abundance increase with latitude. In parallel, the fit to the C2H2 distribution is

Radioisotopic heater units warm an interplanetary spacecraft

International Nuclear Information System (INIS)

Franco-Ferreira, E.A.

1998-01-01

The Cassini orbiter and Huygens probe, which were successfully launched on October 15, 1997, constitute NASA's last grand-scale interplanetary mission of this century. The mission, which consists of a four-year, close-up study of Saturn and its moons, begins in July 2004 with Cassini's 60 orbits of Saturn and about 33 fly-bys of the large moon Titan. The Huygens probe will descend and land on Titan. Investigations will include Saturn's atmosphere, its rings and its magnetosphere. The atmosphere and surface of Titan and other icy moons also will be characterized. Because of the great distance of Saturn from the sun, some of the instruments and equipment on both the orbiter and the probe require external heaters to maintain their temperature within normal operating ranges. These requirements are met by Light Weight Radioisotope Heater Units (LWRHUs) designed, fabricated and safety tested at Los Alamos National Laboratory, New Mexico. An improved gas tungsten arc welding procedure lowered costs and decreased processing time for heat units for the Cassini spacecraft

STS-61 mission director's post-mission report

Science.gov (United States)

Newman, Ronald L.

1995-01-01

To ensure the success of the complex Hubble Space Telescope servicing mission, STS-61, NASA established a number of independent review groups to assess management, design, planning, and preparation for the mission. One of the resulting recommendations for mission success was that an overall Mission Director be appointed to coordinate management activities of the Space Shuttle and Hubble programs and to consolidate results of the team reviews and expedite responses to recommendations. This report presents pre-mission events important to the experience base of mission management, with related Mission Director's recommendations following the event(s) to which they apply. All Mission Director's recommendations are presented collectively in an appendix. Other appendixes contain recommendations from the various review groups, including Payload Officers, the JSC Extravehicular Activity (EVA) Section, JSC EVA Management Office, JSC Crew and Thermal Systems Division, and the STS-61 crew itself. This report also lists mission events in chronological order and includes as an appendix a post-mission summary by the lead Payload Deployment and Retrieval System Officer. Recommendations range from those pertaining to specific component use or operating techniques to those for improved management, review, planning, and safety procedures.

Analytical thermal model validation for Cassini radioisotope thermoelectric generator

International Nuclear Information System (INIS)

Lin, E.I.

1997-01-01

The Saturn-bound Cassini spacecraft is designed to rely, without precedent, on the waste heat from its three radioisotope thermoelectric generators (RTGs) to warm the propulsion module subsystem, and the RTG end dome temperature is a key determining factor of the amount of waste heat delivered. A previously validated SINDA thermal model of the RTG was the sole guide to understanding its complex thermal behavior, but displayed large discrepancies against some initial thermal development test data. A careful revalidation effort led to significant modifications and adjustments of the model, which result in a doubling of the radiative heat transfer from the heat source support assemblies to the end domes and bring up the end dome and flange temperature predictions to within 2 C of the pertinent test data. The increased inboard end dome temperature has a considerable impact on thermal control of the spacecraft central body. The validation process offers an example of physically-driven analytical model calibration with test data from not only an electrical simulator but also a nuclear-fueled flight unit, and has established the end dome temperatures of a flight RTG where no in-flight or ground-test data existed before

Cassini Spacecraft Uncertainty Analysis Data and Methodology Review and Update/Volume 1: Updated Parameter Uncertainty Models for the Consequence Analysis

Energy Technology Data Exchange (ETDEWEB)

WHEELER, TIMOTHY A.; WYSS, GREGORY D.; HARPER, FREDERICK T.

2000-11-01

Uncertainty distributions for specific parameters of the Cassini General Purpose Heat Source Radioisotope Thermoelectric Generator (GPHS-RTG) Final Safety Analysis Report consequence risk analysis were revised and updated. The revisions and updates were done for all consequence parameters for which relevant information exists from the joint project on Probabilistic Accident Consequence Uncertainty Analysis by the United States Nuclear Regulatory Commission and the Commission of European Communities.

How to Test the SME with Space Missions?

Science.gov (United States)

Hees, A.; Lamine, B.; Le Poncin-Lafitte, C.; Wolf, P.

2013-01-01

In this communication, we focus on possibilities to constrain SME coefficients using Cassini and Messenger data. We present simulations of radio science observables within the framework of the SME, identify the linear combinations of SME coefficients the observations depend on and determine the sensitivity of these measurements to the SME coefficients. We show that these datasets are very powerful for constraining SME coefficients.

Light-weight radioisotope heater impact tests

International Nuclear Information System (INIS)

Reimus, M.A.H.; Rinehart, G.H.; Herrera, A.

1998-01-01

The light-weight radioisotope heater unit (LWRHU) is a 238 PuO 2 -fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed 238 PuO 2 fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. To compare the performance of the LWRHUs fabricated for the Cassini mission with the performance of those fabricated for the Galileo mission, and to determine a failure threshold, two types of impact tests were conducted. A post-reentry impact test was performed on one of 180 flight-quality units produced for the Cassini mission and a series of sequential impact tests using simulant-fueled LWRHU capsules were conducted respectively. The results showed that deformation and fuel containment of the impacted Cassini LWRHU was similar to that of a previously tested Galileo LWRHU. Both units sustained minimal deformation of the aeroshell and fueled capsule; the fuel was entirely contained by the platinum capsule. Sequential impacting, in both end-on and side-on orientations, resulted in increased damage with each subsequent impact. Sequential impacting of the LWRHU appears to result in slightly greater damage than a single impact at the final impact velocity of 50 m/s

SOLAR OCCULTATION BY TITAN MEASURED BY CASSINI/UVIS

Energy Technology Data Exchange (ETDEWEB)

Capalbo, Fernando J.; Benilan, Yves [Laboratoire Interuniversitaire des Systemes Atmospheriques (LISA), UMR 7583 du CNRS, Universites Paris Est Creteil (UPEC) and Paris Diderot - UPD, 61 avenue du General de Gaulle, 94010 Creteil Cedex (France); Yelle, Roger V.; Koskinen, Tommi T.; Sandel, Bill R. [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721 (United States); Holsclaw, Gregory M.; McClintock, William E., E-mail: fernando.capalbo@lisa.u-pec.fr [Laboratory for Atmospheric and Space Physics, University of Colorado, 3665 Discovery Drive, Boulder, CO 80303 (United States)

2013-04-01

We present the first published analysis of a solar occultation by Titan's atmosphere measured by the Ultraviolet Imaging Spectrograph on board Cassini. The data were measured during flyby T53 in 2009 April and correspond to latitudes between 21 Degree-Sign and 28 Degree-Sign south. The analysis utilizes the absorption of two solar emission lines (584 A and 630 A) in the ionization continuum of the N{sub 2} absorption cross section and solar emission lines around 1085 A where absorption is due to CH{sub 4}. The measured transmission at these wavelengths provides a direct estimate of the N{sub 2} and CH{sub 4} column densities along the line of sight from the spacecraft to the Sun, which we inverted to obtain the number densities. The high signal-to-noise ratio of the data allowed us to retrieve density profiles in the altitude range 1120-1400 km for nitrogen and 850-1300 km for methane. We find an N{sub 2} scale height of {approx}76 km and a temperature of {approx}153 K. Our results are in general agreement with those from previous work, although there are some differences. Particularly, our profiles agree, considering uncertainties, with the density profiles derived from the Voyager 1 Ultraviolet Spectrograph data, and with in situ measurements by the Ion Neutral Mass Spectrometer with revised calibration.

Gravity Field and Interior Structure of Saturn from Cassini Observations

Science.gov (United States)

Anderson, J. D.; Schubert, G.

2007-05-01

We discuss the sources for a determination of Saturn's external gravitational potential, beginning with a Pioneer 11 flyby in September 1979, two Voyager flybys in November 1980 for Voyager 1 and August 1981 for Voyager 2, four useful close approaches by the Cassini orbiter in May and June 2005, and culminating in an extraordinary close approach for Radio Science in September 2006. Results from the 2006 data are not yet available, but even without them, Cassini offers improvements in accuracy over Pioneer and Voyager by a factor of 37 in the zonal coefficient J2, a factor of 14 in J4, and a factor of 5 in J6. These improvements are important to our understanding of the internal structure of Saturn in particular, and to solar and extrasolar giant planets in general. Basically, Saturn can be modeled as a rapidly rotating planet in hydrostatic equilibrium. Consistent with the limited data available, we express the density distribution as a polynomial of fifth degree in the normalized mean radius β = r/R over the real interval zero to one, where R is the radius of a sphere with density equal to the mean density of Saturn. Then the six coefficients of the polynomial are adjusted by nonlinear least squares until they match the measured even zonal gravity coefficients J2,J4,J6 within a fraction of a standard deviation. The gravity coefficients are computed from the density distribution by the method of level surfaces to the third order in the rotational smallness parameter. Two degrees of freedom are removed by applying the constraints that (1)~the derivative of the density distribution is zero at the center, and (2)~the density is zero at the surface. Further, a unique density distribution is obtained by the method of singular value decomposition truncated at rank three. Given this unique density distribution, the internal pressure can be obtained by numerical integration of the equation of hydrostatic equilibrium, expressed in terms of the single independent parameter

Seasonal Variability of Saturn's Tropospheric Temperatures, Winds and Para-H2 from Cassini Far-IR Spectroscopy

Science.gov (United States)

Fletcher, Leigh N.; Irwin, P. G. J; Achterberg, R. K.; Orton, G. S.; Flasar, F. M.

2015-01-01

temperatures, para-H2 and winds. Quantitative differences between the Cassini and Voyager epochs suggest that the oscillation is not in phase with the seasonal cycle at these tropospheric depths (i.e., it should be described as quasi-periodic rather than 'semi annual'). Variability in the zonal wind field derived from latitudinal thermal gradients is small (less than 10 m/s per scale height near the tropopause) and mostly affects the broad retrograde jets, with the notable exception of large variability on the northern flank of the equatorial jet. The meridional potential vorticity (PV) gradient, and hence the 'staircase of PV' associated with spatial variations in the vigour of vertical mixing, has varied over the course of the mission but maintained its overall shape. PV gradients in latitude and altitude are used to estimate the atmospheric refractive index for the propagation of stationary planetary (Rossby) waves, predicting that such wave activity would be confined to regions of real refractivity (tropical regions plus bands at 35-45 in both hemispheres). The penetration depth of these regions into the upper troposphere is temporally variable (potentially associated with stratification changes), whereas the latitudinal structure is largely unchanged over time (associated with the zonal jet system).

The Huygens probe is prepared for transport from the Skid Strip, CCAS

Science.gov (United States)

1997-01-01

The Huygens probe, which will study the clouds, atmosphere and surface of Saturn's largest moon, Titan, as part of the Cassini mission to Saturn, is prepared for transport from the Skid Strip, Cape Canaveral Air Station (CCAS), after being off-loaded from a plane. The probe was designed and developed for the European Space Agency (ESA) by a European industrial consortium led by Aerospatiale as prime contractor. Over the past year, it was integrated and tested at the facilities of Daimler Benz Aerospace Dornier Satellitensysteme in Germany. The probe will be mated to the Cassini orbiter, which was designed and assembled at NASA's Jet Propulsion Laboratory in California. The Cassini launch is targeted for October 6 from CCAS aboard a Titan IVB/Centaur expendable launch vehicle. After arrival at Saturn in 2004, the probe will be released from the Cassini orbiter to slowly descend through the Titan atmosphere to the moon's surface.

Laser Mode Behavior of the Cassini CIRS Fourier Transform Spectrometer at Saturn

Science.gov (United States)

Brasunas, John C.

2012-01-01

The CIRS Fourier transform spectrometer aboard the NASA/ESA/ASI Cassini orbiter has been acquiring spectra of the Saturnian system since 2004. The CIRS reference interferometer employs a laser diode to trigger the interferogram sampling. Although the control of laser diode drive current and operating temperature are stringent enough to restrict laser wavelength variation to a small fraction of CIRS finest resolution element, the CIRS instrument does need to be restarted every year or two, at which time it may start in a new laser mode. By monitoring the Mylar absorption features in uncalibrated spectra due to the beam splitter Mylar substrate, it can be shown that these jumps are to adjacent modes and that most of the eight-year operation so far is restricted to three adjacent modes. For a given mode, the wavelength stability appears consistent with the stability of the laser diode drive curren.t and operating temperature.

An enhanced Planetary Radar Operating Centre (PROC)

Science.gov (United States)

Catallo, C.

2010-12-01

Planetary exploration by means of radar systems, mainly using GPRs is an important role of Italy and numerous scientific international space programs are carried out jointly with ESA and NASA by Italian Space Agency, the scientific community and the industry. Three experiments under Italian leadership ( designed and manufactured by the Italian industry) provided by ASI within a NASA/ESA/ASI joint venture framework are successfully operating: MARSIS on-board MEX, SHARAD on-board MRO and CASSINI Radar on-board Cassini spacecraft: the missions have been further extended . Three dedicated operational centers, namely SHOC, (Sharad Operating Centre), MOC (Marsis Operating Center) and CASSINI PAD are operating from the missions beginning to support all the scientific communities, institutional customers and experiment teams operation Each center is dedicated to a single instrument management and control, data processing and distribution and even if they had been conceived to operate autonomously and independently one from each other, synergies and overlaps have been envisaged leading to the suggestion of a unified center, the Planetary Radar Processing Center (PROC). In order to harmonize operations either from logistics point of view and from HW/SW capabilities point of view PROC is designed and developed for offering improved functionalities to increase capabilities, mainly in terms of data exchange, comparison, interpretation and exploitation. PROC is, therefore, conceived as the Italian support facility to the scientific community for on-going and future Italian planetary exploration programs, such as Europa-Jupiter System Mission (EJSM) The paper describes how the new PROC is designed and developed, to allow SHOC, MOC and CASSINI PAD to operate as before, and to offer improved functionalities to increase capabilities, mainly in terms of data exchange, comparison, interpretation and exploitation aiding scientists to increase their knowledge in the field of surface

Theoretical Calculations on Sediment Transport on Titan, and the Possible Production of Streamlined Forms

Science.gov (United States)

Burr, D. M.; Emery, J. P.; Lorenz, R. D.

2005-01-01

The Cassini Imaging Science System (ISS) has been returning images of Titan, along with other Saturnian satellites. Images taken through the 938 nm methane window see down to Titan's surface. One of the purposes of the Cassini mission is to investigate possible fluid cycling on Titan. Lemniscate features shown recently and radar evidence of surface flow prompted us to consider theoretically the creation by methane fluid flow of streamlined forms on Titan. This follows work by other groups in theoretical consideration of fluid motion on Titan's surface.

OPUS: A Comprehensive Search Tool for Remote Sensing Observations of the Outer Planets. Now with Enhanced Geometric Metadata for Cassini and New Horizons Optical Remote Sensing Instruments.

Science.gov (United States)

Gordon, M. K.; Showalter, M. R.; Ballard, L.; Tiscareno, M.; French, R. S.; Olson, D.

2017-06-01

The PDS RMS Node hosts OPUS - an accurate, comprehensive search tool for spacecraft remote sensing observations. OPUS supports Cassini: CIRS, ISS, UVIS, VIMS; New Horizons: LORRI, MVIC; Galileo SSI; Voyager ISS; and Hubble: ACS, STIS, WFC3, WFPC2.

Using the SPICE system to help plan and interpret space science observations

Science.gov (United States)

Acton, Charles H., Jr.

1993-01-01

A portable multimission information system named SPICE is used to assemble, archive, and provide easy user access to viewing geometry and other ancillary information needed by space scientists to interpret observations of bodies within our solar system. The modular nature of this system lends it to use in planning such observations as well. With a successful proof of concept on Voyager, the SPICE system has been adapted to the Magellan, Galileo and Mars Observer missions, and to a variety of ground based operations. Adaptation of SPICE for Cassini and the Russian Mars 94/96 projects is underway, and work on Cassini will follow, SPICE has been used to support observation planning for moving targets on the Hubble Space Telescope Project. Applications for SPICE on earth science, space physics and other astrophysics missions are under consideration.

GPHS-RTGs in support of the Cassini RTG Program. Addendum to the final technical report, May 1--December 31, 1998

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-01

This Addendum to the Cassini GPHS-RTG Program Final Technical Progress Report describes activities performed during the period 1 May 1998 through 31 December 1998, including effort reflecting contract modification M058. These activities include Earth Gravity Assist (EGA) reentry and related analyses which are detailed in Part A, and effort related to the installation of CAGO equipment within Lockheed Martin`s Building 100 facility in Valley Forge, PA, which is detailed in Part B.

GPHS-RTGs in support of the Cassini RTG Program. Addendum to the final technical report, May 1-December 31, 1998

International Nuclear Information System (INIS)

1998-12-01

This Addendum to the Cassini GPHS-RTG Program Final Technical Progress Report describes activities performed during the period 1 May 1998 through 31 December 1998, including effort reflecting contract modification M058. These activities include Earth Gravity Assist (EGA) reentry and related analyses which are detailed in Part A, and effort related to the installation of CAGO equipment within Lockheed Martin's Building 100 facility in Valley Forge, PA, which is detailed in Part B

Pulling it all together: the self-consistent distribution of neutral tori in Saturn's Magnetosphere based on all Cassini observations

Science.gov (United States)

Smith, H. T.; Richardson, J. D.

2017-12-01

Saturn's magnetosphere is unique in that the plumes from the small icy moon, Enceladus, serve at the primary source for heavy particles in Saturn's magnetosphere. The resulting co-orbiting neutral particles interact with ions, electrons, photons and other neutral particles to generate separate H2O, OH and O tori. Characterization of these toroidal distributions is essential for understanding Saturn magnetospheric sources, composition and dynamics. Unfortunately, limited direct observations of these features are available so modeling is required. A significant modeling challenge involves ensuring that either the plasma and neutral particle populations are not simply input conditions but can provide feedback to each population (i.e. are self-consistent). Jurac and Richardson (2005) executed such a self-consistent model however this research was performed prior to the return of Cassini data. In a similar fashion, we have coupled a 3-D neutral particle model (Smith et al. 2004, 2005, 2006, 2007, 2009, 2010) with a plasma transport model (Richardson 1998; Richardson & Jurac 2004) to develop a self-consistent model which is constrained by all available Cassini observations and current findings on Saturn's magnetosphere and the Enceladus plume source resulting in much more accurate neutral particle distributions. We present a new self-consistent model of the distribution of the Enceladus-generated neutral tori that is validated by all available observations. We also discuss the implications for source rate and variability.

Analyses of the Behavior of Spokes in Saturn's B Ring as Observed in Cassini ISS Images

Science.gov (United States)

Mitchell, Colin; Porco, C.; Dones, L.; Spitale, J.

2008-09-01

We report on analyses of the spokes in Saturn's B ring as observed by the Cassini spacecraft, from the first sighting in September 2005 to the present. Following Porco and Danielson (1982), we calculate as a function of time the spoke activity level, defined as the area-integrated optical depth of the spokes. We convert the spoke I/F into optical depth, using a radiative transfer "doubling code" and assuming that the presence of microscopic particles in the spokes is the only change in the optical properties of the ring region within a spoke. We search for periodicities in the variation of spoke activity and also correlations with magnetic longitude using a magnetic longitude system derived from the emission of the Saturn Kilometric Radiation (SKR), the rotation of which varies slightly from a constant rate (Kurth et al. 2008). Additionally, we track the activity over a period of years in order to characterize the seasonal nature of this phenomenon. We also report on the photometric profiles of spokes during different phases of their evolution. We present an analysis of spoke kinematics, measuring the motion on timescales of tens of minutes of the leading and trailing edges of spokes that appear in multiple consecutive images. Assuming that the small ice particles which comprise the spokes are in circular orbits, the azimuthal motion is a measure of their charge-to-mass ratio. While most spoke edges have exhibited normal Keplerian orbital motion and shear, some spokes were observed during their active phase in which the spoke's optical depth increases and its edges move at different rates, broadening the spoke. We acknowledge the financial support of the Cassini Project.

An Update on the Status of the Supply of Plutonium-238 for Future NASA Missions

Science.gov (United States)

Wham, R. M.

2016-12-01

For more than five decades, Radioisotope Power Systems (RPSs) have enabled space missions to operate in locations where the Sun's intensity is too weak, obscured, or otherwise inadequate for solar power or other conventional power‒generation technologies. The natural decay heat (0.57 W/g) from the radioisotope, plutonium-238 (238Pu), provides the thermal energy source used by an RPS to generate electricity for operation of instrumentation, as well as heat to keep key subsystems warm for missions such as Voyagers 1 and 2, the Cassini mission to Saturn, the New Horizons flyby of Pluto, and the Mars Curiosity rover which were sponsored by the National Aeronautics and Space Administration (NASA). Plutonium-238 is produced by irradiation of neptunium-237 in a nuclear reactor a relatively high neutron flux. The United States has not produced new quantities of 238Pu since the early 1990s. RPS‒powered missions have continued since then using existing 238Pu inventory managed by the U.S. Department of Energy (DOE), including material purchased from Russia. A new domestic supply is needed to ensure the continued availability of RPSs for future NASA missions. NASA and DOE are currently executing a project to reestablish a 238Pu supply capability using its existing facilities and reactors, which are much smaller than the large-scale production reactors and processing canyon equipment used previously. The project is led by the Oak Ridge National Laboratory (ORNL). Target rods, containing NpO2, will be fabricated at ORNL and irradiated in the ORNL High Flux Isotope Reactor and the Advanced Test Reactor at Idaho National Laboratory. Irradiated targets will be processed in chemical separations at the ORNL Radiochemical Engineering Center to recover the plutonium product and unconverted neptunium for recycle. The 238PuO2 product will be shipped to Los Alamos National Laboratory for fabrication of heat source pellets. Key activities, such as transport of the neptunium to ORNL

Examining the Combined Saturn and Ring Exosphere/Ionosphere using Cassini's Proximal orbits

Science.gov (United States)

Tucker, O. J.; Tseng, W. L.; Johnson, R. E.; Perry, M. E.

2017-12-01

Neutral molecules that are emitted from Saturn's exobase (i.e., H2) and the main rings (i.e., H2, O2, H) are a source of material for both the Saturn and ring ionospheres as well as Saturn's magnetosphere (Tseng et al., 2013 [PSS 85 164 - 167]). However, the density gradient of H2 produced from the main rings is very different than that produced by Saturn's exospheric flux due to its emission from the ring plane and distance from Saturn. Cassini measurements obtained during the proximal orbits can likely be used to identify contributions from Saturn and the rings. Here we present results obtained from Monte Carlo models of the Saturn and ring exosphere used to analyze INMS data of neutrals and ions measured along the trajectories of the Proximal orbits. Understanding the sources of neutrals and the concomitant ions can help provide insight about the dynamics occurring in the Saturn system.

Searching for a traveling feature in Saturn's rings in Cassini Imaging Science Subsystem data

Science.gov (United States)

Aye, Klaus-Michael; Rehnberg, Morgan; Brown, Zarah; Esposito, Larry W.

2016-10-01

Introduction: Using Cassini UVIS occultation data, a traveling wave feature has been identified in the Saturn rings that is most likely caused by the radial positions swap of the moons Janus and Epimetheus [1]. The hypothesis is that non-linear interferences between the linear density waves when being relocated by the moon swap create a solitary wave that is traveling outward through the rings. The observations in [1] further lead to the derivation of values for the radial travel speeds of the identified traveling features, from 39.6 km/yr for the Janus 5:4 resonance up to 45.8 for the Janus 4:3 resonance.Previous confirmations in ISS data: Work in [1] also identified the feature in Cassini Imaging Science Subsystem (ISS) data that was taken around the time of the UVIS occultations where the phenomenon was first discovered, so far one ISS image for each Janus resonances 2:1, 4:3, 5:4, and 6:5.Search guided by predicted locations: Using the observation-fitted radial velocities from [1], we can extrapolate these to identify Saturn radii at which the traveling feature should be found at later times. Using this and new image analysis and plotting tools available in [2], we have identified a potential candidate feature in an ISS image that was taken 2.5 years after the feature causing moon swap in January 2006. We intend to expand our search by identifying candidate ISS data by a meta-database search constraining the radius at future times corresponding to the predicted future locations of the hypothesized solitary wave and present our findings at this conference.References: [1] Rehnberg, M.E., Esposito, L.W., Brown, Z.L., Albers, N., Sremčević, M., Stewart, G.R., 2016. A Traveling Feature in Saturn's Rings. Icarus, accepted in June 2016. [2] K.-Michael Aye. (2016). pyciss: v0.5.0. Zenodo. 10.5281/zenodo.53092

Confirmation of a traveling feature in Saturn's rings in Cassini Imaging Science Subsystem data

Science.gov (United States)

Aye, K. M.; Rehnberg, M.; Esposito, L. W.

2017-12-01

Introduction: Using Cassini UVIS occultation data, a traveling wave feature has been identified in the Saturn rings that is most likely caused by the radial positions swap of the moons Janus and Epimetheus [1]. The hypothesis is that non-linear interferences between the density waves when being relocated by the moon swap create a solitary wave that is traveling outward through the rings. The observations in [1] further lead to the derivation of values for the radial travel speeds of the identified traveling features, from 39.6 km/yr for the Janus 5:4 resonance up to 45.8 for the Janus 4:3 resonance. Previous confirmations in ISS data: Work in [1] also identified the feature in Cassini Imaging Science Subsystem (ISS) data that was taken around the time of the UVIS occultations where the phenomenon was first discovered, so far one ISS image for each Janus resonances 2:1, 4:3, 5:4, and 6:5. Searches performed in ISS data: Filtering all existing ISS data down to the best resolutions that include both a clearly identifiable minimum and maximum ring radius, we have visually inspected approx. 200 images, both with and without known resonances within the image, but unbeknownst to the inspector. Identification of a feature of interest happens when train waves are being interrupted by anomalies. Comparing the radial locations of identified ISS features with those in UV data of [1], we have identified several at the same radii. Considering the vast differences in radial resolution, we conclude that the traveling feature causes observable anomalies at both small scales of meters, up to large scales of hundreds of meters to kilometers.References: [1] Rehnberg, M.E., Esposito, L.W., Brown, Z.L., Albers, N., Sremčević, M., Stewart, G.R., 2016. A Traveling Feature in Saturn's Rings. Icarus, accepted in June 2016. [2] K.-Michael Aye (2016, November 11). michaelaye/pyciss: . v0.6.0 Zenodo. https://doi.org/10.5281/zenodo.596802

Slim Battery Modelling Features

Science.gov (United States)

Borthomieu, Y.; Prevot, D.

2011-10-01

Saft has developed a life prediction model for VES and MPS cells and batteries. The Saft Li-ion Model (SLIM) is a macroscopic electrochemical model based on energy (global at cell level). The main purpose is to predict the battery performances during the life for GEO, MEO and LEO missions. This model is based on electrochemical characteristics such as Energy, Capacity, EMF, Internal resistance, end of charge voltage. It uses fading and calendar law effects on energy and internal impedance vs. time, temperature, End of Charge voltage. Based on the mission profile, satellite power system characteristics, the model proposes the various battery configurations. For each configuration, the model gives the battery performances using mission figures and profiles: power, duration, DOD, end of charge voltages, temperatures during eclipses and solstices, thermal dissipations and cell failures. For the GEO/MEO missions, eclipse and solstice periods can include specific profile such as plasmic propulsion fires and specific balancing operations. For LEO missions, the model is able to simulate high power peaks to predict radar pulses. Saft's main customers have been using the SLIM model available in house for two years. The purpose is to have the satellite builder power engineers able to perform by themselves in the battery pre-dimensioning activities their own battery simulations. The simulations can be shared with Saft engineers to refine the power system designs. This model has been correlated with existing life and calendar tests performed on all the VES and MPS cells. In comparing with more than 10 year lasting life tests, the accuracy of the model from a voltage point of view is less than 10 mV at end Of Life. In addition, thethe comparison with in-orbit data has been also done. b This paper will present the main features of the SLIM software and outputs comparison with real life tests. b0

[The mission].

Science.gov (United States)

Ruiz Moreno, J; Blanch Mon, A

2000-01-01

After having made a historical review of the concept of mission statement, of evaluating its importance (See Part I), of describing the bases to create a mission statement from a strategic perspective and of analyzing the advantages of this concept, probably more important as a business policy (See Parts I and II), the authors proceed to analyze the mission statement in health organizations. Due to the fact that a mission statement is lacking in the majority of health organizations, the strategy of health organizations are not exactly favored; as a consequence, neither are its competitive advantage nor the development of its essential competencies. After presenting a series of mission statements corresponding to Anglo-Saxon health organizations, the authors highlight two mission statements corresponding to our social context. The article finishes by suggesting an adequate sequence for developing a mission statement in those health organizations having a strategic sense.

On Radiative Factors in Planetary Rings: New Insight Derived from Cassini CIRS Observations at Saturn Equinox

Science.gov (United States)

Brooks, S. M.; Spilker, L. J.; Pilorz, S.; Edgington, S. G.; Deau, E.; Morishima, R.

2012-12-01

Since arriving at Saturn in 2004, Cassini's Composite Infrared Spectrometer has recorded tens of millions of spectra of Saturn's rings (personal communication, M. Segura). CIRS records far infrared radiation (16.7-1000 microns) at focal plane 1 (FP1). Thermal emission from Saturn's rings peaks at FP1 wavelengths. CIRS spectra are well characterized as blackbody emission at an effective temperature Te, multiplied by a scalar factor related to ring emissivity (Spilker et al. [2005, 2006]). CIRS can therefore characterize the rings' temperature and study the thermal environment to which the ring particles are subject. We focus on CIRS data from the 2009 Saturnian equinox. As the Sun's disk crossed the ring plane, CIRS obtained several radial scans of the rings at a variety of phase angles, local hour angles and distances. With the Sun's rays striking the rings at an incidence angle of zero, solar heating is virtually absent, and thermal radiation from Saturn and sunlight reflected by Saturn dominate the thermal environment. These observations appear to present a paradox. Equinox data show that the flux of thermal energy radiated by the rings can even exceed the energy incident upon them as prescribed by thermal models, particularly in the C ring and Cassini Division (Ferrari and Leyrat [2006], Morishima et al. [2009, 2010]). Conservation principles suggest that such models underestimate heating of the rings in these cases, as it is clearly unphysical for the rings to radiate significantly more energy than is incident upon them. In this presentation, we will describe our efforts to resolve this paradox and determine what doing so can teach us about Saturn's rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.

TITAN’S UPPER ATMOSPHERE FROM CASSINI/UVIS SOLAR OCCULTATIONS

Energy Technology Data Exchange (ETDEWEB)

Capalbo, Fernando J.; Bénilan, Yves [Laboratoire Inter-Universitaire des Systèmes Atmosphériques (LISA), UMR 7583 du CNRS, Universités Paris Est Créteil (UPEC) and Paris Diderot - UPD, 61 avenue du Général de Gaulle, F-94010, Créteil Cédex (France); Yelle, Roger V.; Koskinen, Tommi T., E-mail: fernando.capalbo@lisa.u-pec.fr [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721 (United States)

2015-12-01

Titan’s atmosphere is composed mainly of molecular nitrogen, methane being the principal trace gas. From the analysis of 8 solar occultations measured by the Extreme Ultraviolet channel of the Ultraviolet Imaging Spectrograph (UVIS) on board Cassini, we derived vertical profiles of N{sub 2} in the range 1100–1600 km and vertical profiles of CH{sub 4} in the range 850–1300 km. The correction of instrument effects and observational effects applied to the data are described. We present CH{sub 4} mole fractions, and average temperatures for the upper atmosphere obtained from the N{sub 2} profiles. The occultations correspond to different times and locations, and an analysis of variability of density and temperature is presented. The temperatures were analyzed as a function of geographical and temporal variables, without finding a clear correlation with any of them, although a trend of decreasing temperature toward the north pole was observed. The globally averaged temperature obtained is (150 ± 1) K. We compared our results from solar occultations with those derived from other UVIS observations, as well as studies performed with other instruments. The observational data we present confirm the atmospheric variability previously observed, add new information to the global picture of Titan’s upper atmosphere composition, variability, and dynamics, and provide new constraints to photochemical models.

On magnetospheric electron impact ionisation and dynamics in Titan's ram-side and polar ionosphere – a Cassini case study

Directory of Open Access Journals (Sweden)

G. R. Lewis

2007-11-01

Full Text Available We present data from the sixth Cassini flyby of Titan (T5, showing that the magnetosphere of Saturn strongly interacts with the moon's ionosphere and exo-ionosphere. A simple electron ionisation model provides a reasonable agreement with the altitude structure of the ionosphere. Furthermore, we suggest that the dense and cold exo-ionosphere (from the exobase at 1430 km and outward to several Titan radii from the surface can be explained by magnetospheric forcing and other transport processes whereas exospheric ionisation by impacting low energy electrons seems to play a minor role.

Dust analysis on board the Destiny+ mission to 3200 Phaethon

Science.gov (United States)

Krüger, H.; Kobayashi, M.; Arai, T.; Srama, R.; Sarli, B. V.; Kimura, H.; Moragas-Klostermeyer, G.; Soja, R.; Altobelli, N.; Grün, E.

2017-09-01

The Japanese Destiny+ spacecraft will be launched to the active asteroid 3200 Phaethon in 2022. Among the proposed core payload is an in-situ dust instrument based on the Cassini Cosmic Dust Analyzer. We use the ESA Interplanetary Meteoroid Engineering Model (IMEM), to study detection conditions and fluences of interplanetary and interstellar dust with a dust analyzer on board Destiny+.

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technical Program Tasks for October 1, 2005 through September 30, 2006

Energy Technology Data Exchange (ETDEWEB)

None

2007-04-02

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2006. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Programs Tasks for October 1, 2005, through September 30, 2006

Energy Technology Data Exchange (ETDEWEB)

None

2006-09-30

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2006. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.

Annual Technical Progress Report of Radioisotope Power Systems Materials Production and Technology Program Tasks for October 1, 2007 Through September 30,2008

Energy Technology Data Exchange (ETDEWEB)

King, James F [ORNL

2009-04-01

The Office of Radioisotope Power Systems (RPS) of the Department of Energy (DOE) provides RPS for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration (NASA) for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of RPS for fiscal year (FY) 2008. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new RPS.

ANNUAL TECHNICAL PROGRESS REPORT OF RADIOISOTOPE POWER SYSTEM MATERIALS PRODUCTION AND TECHNOLOGY PROGRAM TASKS FOR OCTOBER 1, 2005 THROUGH SEPTEMBER 30, 2006

Energy Technology Data Exchange (ETDEWEB)

King, James F [ORNL

2007-04-01

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2006. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.

Annual Technical Progress Report of Radioisotope Power Systems Materials Production and Technology Program Tasks for October 1, 2006 Through September 30, 2007

Energy Technology Data Exchange (ETDEWEB)

King, James F [ORNL

2008-04-01

The Office of Radioisotope Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. For the Cassini Mission, ORNL produced carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS) used in the generators. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. This report reflects program guidance from the Office of Radioisotope Power Systems for fiscal year (FY) 2007. Production activities for prime quality (prime) CBCF insulator sets, iridium alloy blanks and foil, and CVS are summarized in this report. Technology activities are also reported that were conducted to improve the manufacturing processes, characterize materials, or to develop information for new radioisotope power systems.

Cassini RADAR at Titan : Results in 2013/2014

Science.gov (United States)

Lorenz, Ralph D.; Cassini RadarTeam

2014-05-01

Since the last EGU meeting, several Cassini flybys of Titan have featured significant RADAR observations. These include T91 and T92 (May/July 2013) with SAR and altimetry observations of Ligeia Mare. The latter have placed tight constraints on surface roughness (Zebker et al., in press), showing that wind-driven waves were not present. A remarkable altimetry analysis by Mastrogiuseppe et al. (submitted) detects a bottom echo from the bed of Ligeia, only possible if the liquid is exceptionally radar-transparent. This opens the way to wider radar bathymetry analyses of the northern seas. SAR coverage, augmented by some distant HiSAR observations, has now allowed construction of a more-or-less complete map of the northern polar region. This map now defines the extent of the northern lakes and seas, permitting oceanographic studies. T95 (October 2013) made SAR observations of the impact crater Selk (previously observed by VIMS and RADAR). As well as a closer view of this rather polygonal crater, the observation shows dramatic change in the dune orientation around the crater and its ejecta blanket. The T98 encounter is due to occur in February 2014, and will feature the last prime SAR observation of Ontario Lacus, giving a good baseline for change detection against prior observations. Additionally, close-approach observations (mandated to avoid solar heating constraints on other instruments) will give high-resolution altimetry data on the Shangri-La dunes. Preliminary results may be available in time for the meeting, at which this solicted talk will review analyses of these and other observations.

Iapetus Surface Temperatures, and the Influence of Sublimation on the Albedo Dichotomy: Cassini CIRS Constraints

Science.gov (United States)

Spencer, J. R.; Pearl, J. C.; Segura, M.; Cassini CIRS Team

2005-08-01

The Composite Infrared Spectrometer (CIRS) on the Cassini orbiter obtained extensive observations of Iapetus' thermal emission during the New Year 2005 flyby, with best 8 - 16 μ m spatial resolution of 35 km per pixel. Observed subsolar temperatures on the dark terrain reach nearly 130 K, much warmer than any other satellite surface in the Saturn system, due to the combination of low albedo and slow rotation. These high temperatures mean that, uniquely in the Saturn system, water ice sublimation rates are significant at low latitudes on Iapetus' dark side, and surface water ice is probably not stable there on geological timescales. This result is consistent with the lack of water ice at low latitudes on the dark terrain inferred from Cassini UVIS UV spectra (Hendrix et al., 2005 LPSC). Thermally-controlled migration of water ice may thus contribute to the curious shape of the light/dark boundary on Iapetus, with bright poles and dark terrain extending round the equator onto the trailing side. Impacts of Saturn-centric or prograde heliocentric material cannot alone explain this shape, as their impact flux depends only on distance from the apex of motion (though the impact distribution of Oort cloud comet dust may be consistent with the observed albedo pattern (Cook and Franklin 1970)). We model the ballistic migration of water ice across the surface of Iapetus, determining temperatures and sublimation rates assuming CIRS-constrained thermal inertia and a simple dependence of albedo on distance from the apex of motion. Water ice is lost rapidly from low latitudes on the dark leading side and accumulates near the poles, and is also lost, though more slowly, in equatorial regions near the sub-Saturn and anti-Saturn points. The resulting water ice distribution pattern matches the distribution of Iapetus' bright terrain remarkably well. Albedo modification by thermal migration can thus help to reconcile Iapetus' albedo patterns with albedo control by Saturn-centric or

Mission operations management

Science.gov (United States)

Rocco, David A.

1994-01-01

Redefining the approach and philosophy that operations management uses to define, develop, and implement space missions will be a central element in achieving high efficiency mission operations for the future. The goal of a cost effective space operations program cannot be realized if the attitudes and methodologies we currently employ to plan, develop, and manage space missions do not change. A management philosophy that is in synch with the environment in terms of budget, technology, and science objectives must be developed. Changing our basic perception of mission operations will require a shift in the way we view the mission. This requires a transition from current practices of viewing the mission as a unique end product, to a 'mission development concept' built on the visualization of the end-to-end mission. To achieve this change we must define realistic mission success criteria and develop pragmatic approaches to achieve our goals. Custom mission development for all but the largest and most unique programs is not practical in the current budget environment, and we simply do not have the resources to implement all of our planned science programs. We need to shift our management focus to allow us the opportunity make use of methodologies and approaches which are based on common building blocks that can be utilized in the space, ground, and mission unique segments of all missions.

Water Vapor in Titan's Stratosphere from Cassini CIRS Far-Infrared Spectra

Science.gov (United States)

Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bezard, B.;

June Solstice Equatorial Spread F in the American Sector: A Numerical Assessment of Linear Stability Aided by Incoherent Scatter Radar Measurements

Science.gov (United States)

Zhan, Weijia; S. Rodrigues, Fabiano

2018-01-01

Previous studies have suggested that weakening downward plasma drifts can produce favorable conditions for the ionospheric Generalized Rayleigh-Taylor (GRT) instability and explain the occurrence of postmidnight equatorial spread F (ESF). We evaluated this hypothesis using numerical simulations aided by measurements and attempted to explain ESF events observed in the American sector during June solstice, low solar flux conditions. We analyzed plasma drifts and ESF measurements made by the incoherent scatter radar of the Jicamarca Radio Observatory (11.95° S, 76.87° W, ˜1° dip). We found adequate measurements during a prototypical, quiet time event on 4-5 June 2008 when the downward drifts weakened and a fully developed ESF appeared. The measured drifts were used as input for the SAMI2 model. SAMI2 reproduced an "apparent" uplift of the ionosphere based on h'F measurements that was consistent with expectations and observations. SAMI2 also provided parameters for estimation of the flux tube linear growth rates of GRT instability associated with the weakening drift event. We found that the weakening drifts did produce unstable conditions with positive growth rates. The growth rates, however, were slower than those obtained for typical, premidnight ESF events and those obtained for similar drift conditions in other longitude sectors. We show, however, that departures in the wind pattern, from climatological model predictions, can produce favorable conditions for instability development. Following the hypothesis of Huba and Krall (2013) and using SAMI2 simulations, we show that equatorward winds, when combined with weakening drifts, could have contributed to the unstable conditions responsible for the postmidnight ESF events.

Tidal Control of Jet Eruptions on Enceladus as Observed by Cassini ISS between 2005 and 2007

Science.gov (United States)

Hurford, T. A.; Helfenstein, P.; Spitale, J. N.

2012-01-01

Observations of Enceladus have revealed active jets of material erupting from cracks on its south polar surface. It has previously been proposed that diurnal tidal stress, driven by Enceladus' orbital eccentricity, may actively produce surface movement along these cracks daily and thus may regulate when eruptions occur. Our analysis of the stress on jet source regions identified in Cassini ISS images reveals tidal stress as a plausible controlling mechanism of jet activity. However, the evidence available in the published and preliminary observations of jet activity between 2005 and 2007 may not be able to solidify the link between tidal stress and eruptions from fissures. Ongoing, far more comprehensive analyses based on recent, much higher resolution jetting observations have the potential to prove otherwise.

Designing Mission Operations for the Gravity Recovery and Interior Laboratory Mission

Science.gov (United States)

Havens, Glen G.; Beerer, Joseph G.

2012-01-01

NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, to understand the internal structure and thermal evolution of the Moon, offered unique challenges to mission operations. From launch through end of mission, the twin GRAIL orbiters had to be operated in parallel. The journey to the Moon and into the low science orbit involved numerous maneuvers, planned on tight timelines, to ultimately place the orbiters into the required formation-flying configuration necessary. The baseline GRAIL mission is short, only 9 months in duration, but progressed quickly through seven very unique mission phases. Compressed into this short mission timeline, operations activities and maneuvers for both orbiters had to be planned and coordinated carefully. To prepare for these challenges, development of the GRAIL Mission Operations System began in 2008. Based on high heritage multi-mission operations developed by NASA's Jet Propulsion Laboratory and Lockheed Martin, the GRAIL mission operations system was adapted to meet the unique challenges posed by the GRAIL mission design. This paper describes GRAIL's system engineering development process for defining GRAIL's operations scenarios and generating requirements, tracing the evolution from operations concept through final design, implementation, and validation.

Huygens begins its final journey into the unknown

Science.gov (United States)

2004-12-01

“Today’s release is another successful milestone in the Cassini/Huygens odyssey”, said Dr David Southwood, ESA’s director of science programmes. “This was an amicable separation after seven years of living together. Our thanks to our partners at NASA for the lift. Each spacecraft will now continue on its own but we expect they’ll keep in touch to complete this amazing mission. Now all our hopes and expectations are focused on getting the first in-situ data from a new world we’ve been dreaming of exploring for decades”. Final stage of a 7-year odyssey The Cassini/Huygens mission, jointly developed by NASA, ESA and the Italian space agency (ASI), began on 15 October 1997, when the composite spacecraft were launched from Cape Canaveral, Florida, atop a Titan 4B/Centaur vehicle. Together, the two probes weighed 5548 kg at launch and became the largest space mission ever sent to the outer planets. To gain sufficient velocity to reach Saturn, they had to conduct four gravity-assist manoeuvres by flying twice by Venus, once by the Earth and once by Jupiter. On 1 July Cassini/Huygens eventually became the first spacecraft to enter an orbit around Saturn. On 17 December, while on its third orbit around the ringed planet, the Cassini orbiter performed a manoeuvre to enter a controlled collision trajectory towards Titan. As planned, a fine tuning of the trajectory took place on 22 December to place Huygens on its nominal entry trajectrory. While Huygens will remain on this trajectory till it plunges into Titan’s atmosphere on 14 January, the orbiter will perform a deflection manoeuvre on 28 December to avoid crashing onto the moon. Today’s separation was achieved by the firing of pyrotechnic devices. Under the action of push-off springs, ramps and rollers, the probe was released at a relative velocity of about 0.3 m/s with a spin rate of 7 rpm. Telemetry data confirming the separation were collected by NASA’s Deep Space Network stations in Madrid, Spain

Deep-Space Ka-Band Flight Experience

Science.gov (United States)

Morabito, D. D.

2017-11-01

Lower frequency bands have become more congested in allocated bandwidth as there is increased competition between flight projects and other entities. Going to higher frequency bands offers significantly more bandwidth, allowing for the use of much higher data rates. However, Ka-band is more susceptible to weather effects than lower frequency bands currently used for most standard downlink telemetry operations. Future or prospective flight projects considering deep-space Ka-band (32-GHz) telemetry data links have expressed an interest in understanding past flight experience with received Ka-band downlink performance. Especially important to these flight projects is gaining a better understanding of weather effects from the experience of current or past missions that operated Ka-band radio systems. We will discuss the historical flight experience of several Ka-band missions starting from Mars Observer in 1993 up to present-day deep-space missions such as Kepler. The study of historical Ka-band flight experience allows one to recommend margin policy for future missions. Of particular interest, we will review previously reported-on flight experience with the Cassini spacecraft Ka-band radio system that has been used for radio science investigations as well as engineering studies from 2004 to 2015, when Cassini was in orbit around the planet Saturn. In this article, we will focus primarily on the Kepler spacecraft Ka-band link, which has been used for operational telemetry downlink from an Earth trailing orbit where the spacecraft resides. We analyzed the received Ka-band signal level data in order to characterize link performance over a wide range of weather conditions and as a function of elevation angle. Based on this analysis of Kepler and Cassini flight data, we found that a 4-dB margin with respect to adverse conditions ensures that we achieve at least a 95 percent data return.

Evolution of Orion Mission Design for Exploration Mission 1 and 2

Science.gov (United States)

Gutkowski, Jeffrey P.; Dawn, Timothy F.; Jedrey, Richard M.

2016-01-01

The evolving mission design and concepts of NASA’s next steps have shaped Orion into the spacecraft that it is today. Since the initial inception of Orion, through the Constellation Program, and now in the Exploration Mission frame-work with the Space Launch System (SLS), each mission design concept and pro-gram goal have left Orion with a set of capabilities that can be utilized in many different mission types. Exploration Missions 1 and 2 (EM-1 and EM-2) have now been at the forefront of the mission design focus for the last several years. During that time, different Design Reference Missions (DRMs) were built, analyzed, and modified to solve or mitigate enterprise level design trades to ensure a viable mission from launch to landing. The resulting DRMs for EM-1 and EM-2 were then expanded into multi-year trajectory scans to characterize vehicle performance as affected by variations in Earth-Moon geometry. This provides Orion’s subsystems with stressing reference trajectories to help design their system. Now that Orion has progressed through the Preliminary and Critical Design Reviews (PDR and CDR), there is a general shift in the focus of mission design from aiding the vehicle design to providing mission specific products needed for pre-flight and real time operations. Some of the mission specific products needed include, large quantities of nominal trajectories for multiple monthly launch periods and abort options at any point in the mission for each valid trajectory in the launch window.

Computer graphics aid mission operations. [NASA missions

Science.gov (United States)

Jeletic, James F.

1990-01-01

The application of computer graphics techniques in NASA space missions is reviewed. Telemetric monitoring of the Space Shuttle and its components is discussed, noting the use of computer graphics for real-time visualization problems in the retrieval and repair of the Solar Maximum Mission. The use of the world map display for determining a spacecraft's location above the earth and the problem of verifying the relative position and orientation of spacecraft to celestial bodies are examined. The Flight Dynamics/STS Three-dimensional Monitoring System and the Trajectroy Computations and Orbital Products System world map display are described, emphasizing Space Shuttle applications. Also, consideration is given to the development of monitoring systems such as the Shuttle Payloads Mission Monitoring System and the Attitude Heads-Up Display and the use of the NASA-Goddard Two-dimensional Graphics Monitoring System during Shuttle missions and to support the Hubble Space Telescope.

The Voyager Journey to Interstellar Space

KAUST Repository

Stone, Edward

2017-01-01

on television and the Web. Highlights of his decade of leadership as the Direction of JPL include Galileo's five-year orbital mission to Jupiter, the launch of Cassini to Saturn, the launch of Mars Global Surveyor and a new generation of Earth science satellites

Rotational Dynamics of Icy Satellites : Tidal response and forced longitudinal librations at the surface of a viscoelastic Europa

NARCIS (Netherlands)

Jara Orue, H.M.

2016-01-01

The icy satellites of the giant planets Jupiter and Saturn are among the most interesting celestial bodies in our Solar System. The interpretation of various remote sensing observations performed by the Voyager, Galileo and Cassini-Huygens missions strongly suggests that many icy satellites harbor a

70+ Years of Innovations

Science.gov (United States)

Databases National Security Education Center (NSEC) Center for Nonlinear Studies Engineering Institute Los Alamos developed scientific sensors, launched aboard NASA's Cassini mission that studies Saturn's and harmful liquids-even concealed in a beverage bottle. MagViz: better than X-ray x x 2009 First

Voyager in-situ and Cassini Remote Measurements Suggest a Bubble-like Shape for the Global Heliosphere

Science.gov (United States)

Dialynas, K.; Krimigis, S. M.; Mitchell, D. G.; Decker, R. B.; Roelof, E. C.

2017-12-01

The Low Energy Charged Particle (LECP) in situ measurements from Voyager 1 and Voyager 2 (V1, V2) have revealed the reservoir of ions and electrons that constitute the heliosheath after crossing the termination shock 35 deg north and 32 deg south of the ecliptic plane at 94 and 84 astronomical units (1 AU=1.5x108 km), respectively. In August 2012, at 121.6 AU, V1 crossed the heliopause to enter the interstellar space, while V2 remains in the heliosheath since 2007. The advent of Energetic Neutral Atom (ENA, produced through charge exchange between ions and neutral particles flowing through the heliosphere) imaging, has revealed the global nature of the heliosheath at both high (5.2-55 keV, Cassini/Ion and Neutral Camera-INCA, from 10 AU) and low (INCA global imaging through ENA in overlapping energy bands provides a powerful tool for examining the spatial, temporal, and spectral evolution of the source hot plasma ions. Here we report 5.2-55 keV ENA global images of the heliosphere from Cassini/INCA and compare them with V1,2/LECP 28-53 keV ions measured within the heliosheath over a 13-year period (2003-2016). The similarity between the time profiles of ENA and ions establish that the heliosheath ions are the source of ENA. These measurements also demonstrate that the heliosphere responds promptly, within 2-3 years, to outward propagating solar wind changes (manifested in solar sunspot numbers and solar wind energy input) in both the upstream (nose) and downstream (tail) hemispheres. These results, taken together with the V1 measurement of a 0.5 nT interstellar magnetic field and the enhanced ratio between particle pressure and magnetic pressure in the heliosheath, constrain the shape of the global heliosphere: by contrast to the magnetosphere-like heliotail (that past modeling broadly assumed for more than 55 years), a more symmetric, diamagnetic bubble-like heliosphere, with few substantial tail-like features is revealed.

First Principles Based Reactive Atomistic Simulations to Understand the Effects of Molecular Hypervelocity Impact on Cassini's Ion and Neutral Mass Spectrometer

Science.gov (United States)

Jaramillo-Botero, A.; Cheng, M-J; Cvicek, V.; Beegle, Luther W.; Hodyss, R.; Goddard, W. A., III

2011-01-01

We report here on the predicted impact of species such as ice-water, CO2, CH4, and NH3, on oxidized titanium, as well as HC species on diamond surfaces. These simulations provide the dynamics of product distributions during and after a hypervelocity impact event, ionization fractions, and dissociation probabilities for the various species of interest as a function of impact velocity (energy). We are using these results to determine the relevance of the fragmentation process to Cassini INMS results, and to quantify its effects on the observed spectra.

[Myanmar mission].

Science.gov (United States)

Alfandari, B; Persichetti, P; Pelissier, P; Martin, D; Baudet, J

2004-06-01

The authors report the accomplishment of humanitarian missions in plastic surgery performed by a small team in town practice in Yangon, about their 3 years experience in Myanmar with 300 consultations and 120 surgery cases. They underline the interest of this type of mission and provide us their reflexion about team training, the type of relation with the country where the mission is conducted and the type of right team.

Towards an Understanding of Radiative Factors on Planetary Rings: a Perspective from Cassini CIRS Observations at Saturn Equinox

Science.gov (United States)

Brooks, Shawn M.; Spilker, L.; Edgington, S. G.; Déau, E.; Pilorz, S. H.

2012-10-01

Since arriving at Saturn in 2004, Cassini's Composite Infrared Spectrometer has recorded tens of millions of spectra of Saturn’s rings (personal communication, M. Segura). CIRS records far infrared radiation (16.7-1000 microns) at focal plane 1 (FP1). Thermal emission from Saturn’s rings peaks at FP1 wavelengths. CIRS spectra are well characterized as blackbody emission at an effective temperature Te, multiplied by a scalar factor related to ring emissivity (Spilker et al. [2005, 2006]). CIRS can therefore characterize the rings' temperature and study the thermal environment to which the ring particles are subject. We focus on CIRS data from the 2009 Saturnian equinox. As the Sun's disk crossed the ring plane, CIRS obtained several radial scans of the rings at a variety of phase angles, local hour angles and distances. With the Sun's rays striking the rings at an incidence angle of zero, solar heating is virtually absent, and thermal radiation from Saturn and sunlight reflected by Saturn dominate the thermal environment. These observations present an apparent paradox. Equinox data show that the flux of thermal energy radiated by the rings is roughly equivalent to or even exceeds the energy incident upon them as prescribed by thermal models (Froidevaux [1981], Ferrari and Leyrat [2006], Morishima et al. [2009, 2010]). This apparent energy excess is largest in the C ring and Cassini Division. Conservation principles suggest that models underestimate heating of the rings, as it is clearly unphysical for the rings to radiate significantly more energy than is incident upon them. In this presentation, we will attempt to resolve this paradox and determine what this can teach us about Saturn's rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.

Is the Recently Proposed Mars-Sized Perturber at 65–80 AU Ruled Out by the Cassini Ranging Data?

Energy Technology Data Exchange (ETDEWEB)

Iorio, Lorenzo, E-mail: lorenzo.iorio@libero.it [Ministero dell' Istruzione, dell' Università e della Ricerca, Rome (Italy)

2017-10-26

Recently, the existence of a pointlike pertuber PX with 1 m{sub ♂} ≲ m{sub X} ≲ 2.4 m{sub ⊕} (the symbol “♂” denotes Mars) supposedly moving at 65–80 AU along a moderately inclined orbit has been hypothesized in order to explain certain features of the midplane of the Kuiper Belt Objects (KBOs). We preliminarily selected two possible scenarios for such a PX, and numerically simulated its effect on the Earth-Saturn range ρ(t) by varying some of its orbital parameters over a certain time span; then, we compared our results with some existing actual range residuals. By assuming m{sub X} = 1 m{sub ♂} and a circular orbit, such a putative new member of our Solar System would nominally perturb ρ(t) by a few km over Δt = 12 year (2004 − 2016). However, the Cassini spacecraft accurately measured ρ(t) to the level of σ{sub ρ} ≃ 100 m. Nonetheless, such a scenario should not be considered as necessarily ruled out since the Cassini data were reduced so far without explicitly modeling any PX. Indeed, a NASA JPL team recently demonstrated that an extra-signature as large as 4 km affecting the Kronian range would be almost completely absorbed in fitting incomplete dynamical models, i.e., without PX itself, to such simulated data, thus not showing up in the standard post-fit range residuals. Larger anomalous signatures would instead occur for m{sub X} > 1 m{sub ♂}. Their nominal amplitude could be as large as 50 − 150 km for m{sub X} = 2.4 m{sub ⊕}, thus making less plausible their existence.

Is the Recently Proposed Mars-Sized Perturber at 65–80 AU Ruled Out by the Cassini Ranging Data?

Directory of Open Access Journals (Sweden)

Lorenzo Iorio

2017-10-01

Full Text Available Recently, the existence of a pointlike pertuber PX with 1 m♂ ≲ mX ≲ 2.4 m⊕ (the symbol “♂” denotes Mars supposedly moving at 65–80 AU along a moderately inclined orbit has been hypothesized in order to explain certain features of the midplane of the Kuiper Belt Objects (KBOs. We preliminarily selected two possible scenarios for such a PX, and numerically simulated its effect on the Earth-Saturn range ρ(t by varying some of its orbital parameters over a certain time span; then, we compared our results with some existing actual range residuals. By assuming mX = 1 m♂ and a circular orbit, such a putative new member of our Solar System would nominally perturb ρ(t by a few km over Δt = 12 year (2004 − 2016. However, the Cassini spacecraft accurately measured ρ(t to the level of σρ ≃ 100 m. Nonetheless, such a scenario should not be considered as necessarily ruled out since the Cassini data were reduced so far without explicitly modeling any PX. Indeed, a NASA JPL team recently demonstrated that an extra-signature as large as 4 km affecting the Kronian range would be almost completely absorbed in fitting incomplete dynamical models, i.e., without PX itself, to such simulated data, thus not showing up in the standard post-fit range residuals. Larger anomalous signatures would instead occur for mX > 1 m♂. Their nominal amplitude could be as large as 50 − 150 km for mX = 2.4 m⊕, thus making less plausible their existence.

Measuring the universe our historic quest to chart the horizons of space and time

CERN Document Server

Ferguson, Kitty

1999-01-01

More than 2,000 years ago, Eratosthenes, in Alexandria, used a stick, a hole in the ground, sunllght at summer solstice, and elementary geometry to measure the circumference of the Earth with surprising accuracy, long before anyone was able to circumnavigate it. Today, scientists are attempting to measure the entire universe and to determine its origin. Although the methods have changed, the quest to chart the horizons of space and time continues to be one of the great adventures of science. Measuring the Universe is an eloquent chronicle of the men and women– from Aristarchus to Cassini, Sir Isaac Newton to Henrietta Leavitt and Stephen Hawking–who have gradually unlocked the mysteries of "how far" and in so doing have changed our ideas about the size and nature of the universe and our place in it. Kitty Ferguson reveals their methods to have been as inventive as their results were–and are–eye-opening. Advances such as Copernicus's revolutionary insights about the arrangement of the solar system, Wi...

High-angular-resolution stellar imaging with occultations from the Cassini spacecraft - III. Mira

Science.gov (United States)

Stewart, Paul N.; Tuthill, Peter G.; Nicholson, Philip D.; Hedman, Matthew M.

2016-04-01

We present an analysis of spectral and spatial data of Mira obtained by the Cassini spacecraft, which not only observed the star's spectra over a broad range of near-infrared wavelengths, but was also able to obtain high-resolution spatial information by watching the star pass behind Saturn's rings. The observed spectral range of 1-5 microns reveals the stellar atmosphere in the crucial water-bands which are unavailable to terrestrial observers, and the simultaneous spatial sampling allows the origin of spectral features to be located in the stellar environment. Models are fitted to the data, revealing the spectral and spatial structure of molecular layers surrounding the star. High-resolution imagery is recovered revealing the layered and asymmetric nature of the stellar atmosphere. The observational data set is also used to confront the state-of-the-art cool opacity-sampling dynamic extended atmosphere models of Mira variables through a detailed spectral and spatial comparison, revealing in general a good agreement with some specific departures corresponding to particular spectral features.

An Analysis of Cassini Observations Regarding the Structure of Jupiter's Equatorial Atmosphere

Science.gov (United States)

Choi, David S.; Simon-Miller, Amy A.

2012-01-01

A variety of intriguing atmospheric phenomena reside on both sides of Jupiter's equator. 5-micron bright hot spots and opaque plumes prominently exhibit dynamic behavior to the north, whereas compact, dark chevron-shaped features and isolated anticyclonic disturbances periodically occupy the southern equatorial latitudes. All of these phenomena are associated with the vertical and meridional perturbations of Rossby waves disturbing the mean atmospheric state. As previous observational analysis and numerical simulations have investigated the dynamics of the region, an examination of the atmosphere's vertical structure though radiative transfer analysis is necessary for improved understanding of this unique environment. Here we present preliminary analysis of a multispectral Cassini imaging data set acquired during the spacecraft's flyby of Jupiter in 2000. We evaluated multiple methane and continuum spectral channels at available viewing angles to improve constraints on the vertical structure of the haze and cloud layers comprising these interesting features. Our preliminary results indicate distinct differences in the structure for both hemispheres. Upper troposphere hazes and cloud layers are prevalent in the northern equatorial latitudes, but are not present in corresponding southern latitudes. Continued analysis will further constrain the precise structure present in these phenomena and the differences between them.

Business analysis: The commercial mission of the International Asteroid Mission

Science.gov (United States)

The mission of the International Asteroid Mission (IAM) is providing asteroidal resources to support activities in space. The short term goal is to initiate IAM by mining a near-Earth, hydrous carbonaceous chondrite asteroid to service the nearer-term market of providing cryogenic rocket fuel in low lunar orbit (LLO). The IAM will develop and contract for the building of the transportation vehicles and equipment necessary for this undertaking. The long-term goal is to expand operations by exploiting asteroids in other manners, as these options become commercially viable. The primary business issues are what revenue can be generated from the baseline mission, how much will the mission cost, and how funding for this mission can be raised. These issues are addressed.

A mission to Mercury and a mission to the moons of Mars

Science.gov (United States)

1993-07-01

Two Advanced Design Projects were completed this academic year at Penn State - a mission to the planet Mercury and a mission to the moons of Mars (Phobos and Deimos). At the beginning of the fall semester the students were organized into six groups and given their choice of missions. Once a mission was chosen, the students developed conceptual designs. These designs were then evaluated at the end of the fall semester and combined into two separate mission scenarios. To facilitate the work required for each mission, the class was reorganized in the spring semester by combining groups to form two mission teams. An integration team consisting of two members from each group was formed for each mission team so that communication and exchange of information would be easier among the groups. The types of projects designed by the students evolved from numerous discussions with Penn State faculty and mission planners at the Lewis Research Center Advanced Projects Office. Robotic planetary missions throughout the solar system can be considered valuable precursors to human visits and test beds for innovative technology. For example, by studying the composition of the Martian moons, scientists may be able to determine if their resources may be used or synthesized for consumption during a first human visit.

Backward Planetary Protection Issues and Possible Solutions for Icy Plume Sample Return Missions from Astrobiological Targets

Science.gov (United States)

Yano, Hajime; McKay, Christopher P.; Anbar, Ariel; Tsou, Peter

The recent report of possible water vapor plumes at Europa and Ceres, together with the well-known Enceladus plume containing water vapor, salt, ammonia, and organic molecules, suggests that sample return missions could evolve into a generic approach for outer Solar System exploration in the near future, especially for the benefit of astrobiology research. Sampling such plumes can be accomplished via fly-through mission designs, modeled after the successful Stardust mission to capture and return material from Comet Wild-2 and multiple, precise trajectory controls of the Cassini mission to fly through Enceladus’ plume. The proposed LIFE (Life Investigation For Enceladus) mission to Enceladus, which would sample organic molecules from the plume of that apparently habitable world, provides one example of the appealing scientific return of such missions. Beyond plumes, the upper atmosphere of Titan could also be sampled in this manner. The SCIM mission to Mars, also inspired by Stardust, would sample and return aerosol dust in the upper atmosphere of Mars and thus extends this concept even to other planetary bodies. Such missions share common design needs. In particular, they require large exposed sampler areas (or sampler arrays) that can be contained to the standards called for by international planetary protection protocols that COSPAR Planetary Protection Policy (PPP) recommends. Containment is also needed because these missions are driven by astrobiologically relevant science - including interest in organic molecules - which argues against heat sterilization that could destroy scientific value of samples. Sample containment is a daunting engineering challenge. Containment systems must be carefully designed to appropriate levels to satisfy the two top requirements: planetary protection policy and the preserving the scientific value of samples. Planning for Mars sample return tends to center on a hermetic seal specification (i.e., gas-tight against helium escape

Robotic exploration of the solar system

CERN Document Server

Ulivi, Paolo

In Robotic Exploration of the Solar System, Paolo Ulivi and David Harland provide a comprehensive account of the design and managment of deep-space missions, the spacecraft involved - some flown, others not - their instruments, and their scientific results. This third volume in the series covers launches in the period 1997 to 2003 and features: - a chapter entirely devoted to the Cassini-Huygens mission to Saturn; - coverage of planetary missions of the period, including the Deep Space 1 mission and the Stardust and Hayabusa sample returns from comets and asteroids; - extensive coverage of Mars exploration, the failed 1999 missions, Mars Odyssey, Mars Express, and the twin rovers Spirit and Opportunity. The story will continue in Part 4.

Water masers in the Kronian system

NARCIS (Netherlands)

Pogrebenko, Sergei V.; Gurvits, Leonid I.; Elitzur, Moshe; Cosmovici, Cristiano B.; Avruch, Ian M.; Pluchino, Salvatore; Montebugnoli, Stelio; Salerno, Emma; Maccaferri, Giuseppe; Mujunen, Ari; Ritakari, Jouko; Molera, Guifre; Wagner, Jan; Uunila, Minttu; Cimo, Giuseppe; Schilliro, Francesco; Bartolini, Marco; Fernández, J. A.; Lazzaro, D.; Prialnik, D.; Schulz, R.

2010-01-01

The presence of water has been considered for a long time as a key condition for life in planetary environments. The Cassini mission discovered water vapour in the Kronian system by detecting absorption of UV emission from a background star (Hansen et al. 2006). Prompted by this discovery, we

Bomber Deterrence Missions: Criteria To Evaluate Mission Effectiveness

Science.gov (United States)

2016-02-16

international security, the practice of general deterrence usually occurs when nations feel insecure , suspicious or even hostility towards them but...both a deterrence and assurance mission even though it was not planned or advertised as such. Since the intent of this mission was partly perceived

The Impact of Mission Duration on a Mars Orbital Mission

Science.gov (United States)

Arney, Dale; Earle, Kevin; Cirillo, Bill; Jones, Christopher; Klovstad, Jordan; Grande, Melanie; Stromgren, Chel

2017-01-01

Performance alone is insufficient to assess the total impact of changing mission parameters on a space mission concept, architecture, or campaign; the benefit, cost, and risk must also be understood. This paper examines the impact to benefit, cost, and risk of changing the total mission duration of a human Mars orbital mission. The changes in the sizing of the crew habitat, including consumables and spares, was assessed as a function of duration, including trades of different life support strategies; this was used to assess the impact on transportation system requirements. The impact to benefit is minimal, while the impact on cost is dominated by the increases in transportation costs to achieve shorter total durations. The risk is expected to be reduced by decreasing total mission duration; however, large uncertainty exists around the magnitude of that reduction.

Logistics Needs for Potential Deep Space Mission Scenarios Post Asteroid Crewed Mission

Science.gov (United States)

Lopez, Pedro, Jr.

2015-01-01

A deep-space mission has been proposed to identify and redirect an asteroid to a distant retrograde orbit around the moon, and explore it by sending a crew using the Space Launch System and the Orion spacecraft. The Asteroid Redirect Crewed Mission (ARCM), which represents the third segment of the Asteroid Redirect Mission (ARM), could be performed on EM-3 or EM-4 depending on asteroid return date. Recent NASA studies have raised questions on how we could progress from current Human Space Flight (HSF) efforts to longer term human exploration of Mars. This paper will describe the benefits of execution of the ARM as the initial stepping stone towards Mars exploration, and how the capabilities required to send humans to Mars could be built upon those developed for the asteroid mission. A series of potential interim missions aimed at developing such capabilities will be described, and the feasibility of such mission manifest will be discussed. Options for the asteroid crewed mission will also be addressed, including crew size and mission duration.

The STEREO Mission

CERN Document Server

2008-01-01

The STEREO mission uses twin heliospheric orbiters to track solar disturbances from their initiation to 1 AU. This book documents the mission, its objectives, the spacecraft that execute it and the instruments that provide the measurements, both remote sensing and in situ. This mission promises to unlock many of the mysteries of how the Sun produces what has become to be known as space weather.

Spectroscopy, morphometry, and photoclinometry of Titan's dunefields from Cassini/VIMS

Science.gov (United States)

Barnes, J.W.; Brown, R.H.; Soderblom, L.; Sotin, Christophe; Le, Mouelic S.; Rodriguez, S.; Jaumann, R.; Beyer, R.A.; Buratti, B.J.; Pitman, K.; Baines, K.H.; Clark, R.; Nicholson, P.

2008-01-01

Fine-resolution (500 m/pixel) Cassini Visual and Infrared Mapping Spectrometer (VIMS) T20 observations of Titan resolve that moon's sand dunes. The spectral variability in some dune regions shows that there are sand-free interdune areas, wherein VIMS spectra reveal the exposed dune substrate. The interdunes from T20 are, variously, materials that correspond to the equatorial bright, 5-??m-bright, and dark blue spectral units. Our observations show that an enigmatic "dark red" spectral unit seen in T5 in fact represents a macroscopic mixture with 5-??m-bright material and dunes as its spectral endmembers. Looking more broadly, similar mixtures of varying amounts of dune and interdune units of varying composition can explain the spectral and albedo variability within the dark brown dune global spectral unit that is associated with dunes. The presence of interdunes indicates that Titan's dunefields are both mature and recently active. The spectrum of the dune endmember reveals the sand to be composed of less water ice than the rest of Titan; various organics are consistent with the dunes' measured reflectivity. We measure a mean dune spacing of 2.1 km, and find that the dunes are oriented on the average in an east-west direction, but angling up to 10?? from parallel to the equator in specific cases. Where no interdunes are present, we determine the height of one set of dunes photoclinometrically to be between 30 and 70 m. These results pave the way for future exploration and interpretation of Titan's sand dunes. ?? 2007 Elsevier Inc. All rights reserved.

VEGA Space Mission

Science.gov (United States)

Moroz, V.; Murdin, P.

2000-11-01

VEGA (mission) is a combined spacecraft mission to VENUS and COMET HALLEY. It was launched in the USSR at the end of 1984. The mission consisted of two identical spacecraft VEGA 1 and VEGA 2. VEGA is an acronym built from the words `Venus' and `Halley' (`Galley' in Russian spelling). The basic design of the spacecraft was the same as has been used many times to deliver Soviet landers and orbiter...

Parker Solar Probe: A NASA Mission to Touch the Sun: Mission Status Update

Science.gov (United States)

Fox, N. J.

2017-12-01

The newly renamed, Parker Solar Probe (PSP) mission will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Parker Solar Probe mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. PSP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the science objectives. In this presentation, we provide an update on the progress of the Parker Solar Probe mission as we prepare for the July 2018 launch.

Cassini UVIS solar occultations by Saturn's F ring and the detection of collision-produced micron-sized dust

Science.gov (United States)

Becker, Tracy M.; Colwell, Joshua E.; Esposito, Larry W.; Attree, Nicholas O.; Murray, Carl D.

2018-05-01

We present an analysis of eleven solar occultations by Saturn's F ring observed by the Ultraviolet Imaging Spectrograph (UVIS) on the Cassini spacecraft. In four of the solar occultations we detect an unambiguous signal from diffracted sunlight that adds to the direct solar signal just before or after the occultations occur. The strongest detection was a 10% increase over the direct signal that was enabled by the accidental misalignment of the instrument's pointing. We compare the UVIS data with images of the F ring obtained by the Cassini Imaging Science Subsystem (ISS) and find that in each instance of an unambiguous diffraction signature in the UVIS data, the ISS data shows that there was a recent disturbance in that region of the F ring. Similarly, the ISS images show a quiescent region of the F ring for all solar occultations in which no diffraction signature was detected. We therefore conclude that collisions in the F ring produce a population of small ring particles that can produce a detectable diffraction signal immediately interior or exterior to the F ring. The clearest example of this connection comes from the strong detection of diffracted light in the 2007 solar occultation, when the portion of the F ring that occulted the Sun had suffered a large collisional event, likely with S/2004 S 6, several months prior. This collision was observed in a series of ISS images (Murray et al., 2008). Our spectral analysis of the data shows no significant spectral features in the F ring, indicating that the particles must be at least 0.2 μm in radius. We apply a forward model of the solar occultations, accounting for the effects of diffracted light and the attenuated direct solar signal, to model the observed solar occultation light curves. These models constrain the optical depth, radial width, and particle size distribution of the F ring. We find that when the diffraction signature is present, we can best reproduce the occultation data using a particle population

Logistics Needs for Potential Deep Space Mission Scenarios Post Asteroid Redirect Crewed Mission

Science.gov (United States)

Lopez, Pedro, Jr.; Shultz, Eric; Mattfeld, Bryan; Stromgren, Chel; Goodliff, Kandyce

2015-01-01

The Asteroid Redirect Mission (ARM) is currently being explored as the next step towards deep space human exploration, with the ultimate goal of reaching Mars. NASA is currently investigating a number of potential human exploration missions, which will progressively increase the distance and duration that humans spend away from Earth. Missions include extended human exploration in cis-lunar space which, as conceived, would involve durations of around 60 days, and human missions to Mars, which are anticipated to be as long as 1000 days. The amount of logistics required to keep the crew alive and healthy for these missions is significant. It is therefore important that the design and planning for these missions include accurate estimates of logistics requirements. This paper provides a description of a process and calculations used to estimate mass and volume requirements for crew logistics, including consumables, such as food, personal items, gasses, and liquids. Determination of logistics requirements is based on crew size, mission duration, and the degree of closure of the environmental control life support system (ECLSS). Details are provided on the consumption rates for different types of logistics and how those rates were established. Results for potential mission scenarios are presented, including a breakdown of mass and volume drivers. Opportunities for mass and volume reduction are identified, along with potential threats that could possibly increase requirements.

High-resolution CASSINI-VIMS mosaics of Titan and the icy Saturnian satellites

Science.gov (United States)

Jaumann, R.; Stephan, K.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; McCord, T.B.; Coradini, A.; Capaccioni, F.; Filacchione, G.; Cerroni, P.; Baines, K.H.; Bellucci, G.; Bibring, J.-P.; Combes, M.; Cruikshank, D.P.; Drossart, P.; Formisano, V.; Langevin, Y.; Matson, D.L.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe; Soderbloom, L.A.; Griffith, C.; Matz, K.-D.; Roatsch, Th.; Scholten, F.; Porco, C.C.

2006-01-01

The Visual Infrared Mapping Spectrometer (VIMS) onboard the CASSINI spacecraft obtained new spectral data of the icy satellites of Saturn after its arrival at Saturn in June 2004. VIMS operates in a spectral range from 0.35 to 5.2 ??m, generating image cubes in which each pixel represents a spectrum consisting of 352 contiguous wavebands. As an imaging spectrometer VIMS combines the characteristics of both a spectrometer and an imaging instrument. This makes it possible to analyze the spectrum of each pixel separately and to map the spectral characteristics spatially, which is important to study the relationships between spectral information and geological and geomorphologic surface features. The spatial analysis of the spectral data requires the determination of the exact geographic position of each pixel on the specific surface and that all 352 spectral elements of each pixel show the same region of the target. We developed a method to reproject each pixel geometrically and to convert the spectral data into map projected image cubes. This method can also be applied to mosaic different VIMS observations. Based on these mosaics, maps of the spectral properties for each Saturnian satellite can be derived and attributed to geographic positions as well as to geological and geomorphologic surface features. These map-projected mosaics are the basis for all further investigations. ?? 2006 Elsevier Ltd. All rights reserved.

Enabling Telescopes of the Future: Long-Range Technology Investing

Science.gov (United States)

Thronson, Harley

2004-01-01

The Office of Space Science at NASA Headquarters has a current staff of about 60 professionals (aka, scientists, engineers, budget analysts) and an annual budget of $2.5 B out of NASA s $15.0 B. About 35 missions or programs in various stages of development or operation are managed by OSS, notable among them are Hubble Space Telescope, Mars Global Surveyor, Mars 2001 Odyssey, Chandra X-ray Observatory, TRACE (solar observatory), Cassini (mission to Saturn), Galileo (mission at Jupiter), and Next Generation Space Telescope. OSS has an annual technology budget of several hundred million dollars. So, what is it that we are doing?

At Saturn: Tripping the Flight Fantastic

Science.gov (United States)

Porco, Carolyn C.

2008-05-01

Boulder planetary scientist Carolyn Porco, leader of the imaging team for NASA's Cassini mission to Saturn and science advisor for the forthcoming movie "Star Trek," guides you on a magical mystery tour around the ringed planet. Come and witness the wonders, discoveries, and the awesome natural beauty of this amazing planet and its family of rings and moons.

On the shape and properties of the global heliosphere over the Solar Cycle with Voyager/LECP ions and Cassini/INCA ENAs

Science.gov (United States)

Dialynas, Konstantinos; Krimigis, Stamatios; Mitchell, Donald; Decker, Robert; Roelof, Edmond

2017-04-01

Voyager 1 (V1) and Voyager 2 (V2) have crossed the termination shock in 2004 (V1) and 2007(V2) and traversing the Heliosheath (HS) in the upstream (nose) hemisphere, while the Ion and Neutral Camera (INCA) on Cassini enables Energetic Neutral Atom (ENA) images of the celestial sphere that place the local ion measurements by each Voyager in a global context. We present an analysis of 5.2-55 keV ENA global images of the HS and 28-53 keV in-situ ions over an 11-year period (2003-2014) that corresponds to the declining phase of solar cycle 23 (SC23) and onset of SC24. The measurements reveal a coherent decrease and recovery between ENA in the global heliosphere and in-situ ions at V1/V2 during this time period, in overlapping energy bands, establishing that the HS ions are the source of >28 keV ENA. The similarity in the overall appearance of the images throughout the INCA energy range (5.2-55 keV), reveals that the source of ENAs at 5.2 keV ENA and ion variations with the Solar Sunspot Numbers (SSN) and solar wind parameters indicates that the Heliosphere responds promptly, within 2-3 years, to outward propagating solar wind changes in both the nose and anti-nose (tail) directions following the Solar Cycle (SC) phases. A detailed latitudinal examination of the global ENA emissions, verifies that the peak intensities between the nose and anti-nose directions are nearly similar, the power law ENA spectral index (γ) is largely the same near the equator in both the nose and anti-nose directions and displays similar spatial dependence with latitude. The totality of the ENA and in situ ion observations, together with the V1 measurement of a 0.5 nT interstellar magnetic field (ISMF) and recent modeling, suggest a "bubble-shape" heliosphere, i.e with little substantial tail-like feature. These observations are essential in determining the context for the measurements anticipated by the forthcoming IMAP mission.

End of mission report on seismic safety review mission for Belene NPP site

International Nuclear Information System (INIS)

Gurpinar, A.; Mohammadioun, B.; Schneider, H.; Serva, L.

1995-01-01

Upon the invitation of the Bulgarian government through the Committee for the Peaceful Uses of Atomic Energy and within the framework of the implementation of the Technical Cooperation project BUL/9/012 related to site and seismic of NPPs, a mission visited Sofia 3 - 7 July 1995. The mission constituted a follow-up of the interim review of subjects related to tectonic stability and seismic hazard characterization of the site which was performed in September 1993. The main objective of the mission was the final review of the subjects already reviewed in September 1993 as well as issues related to geotechnical engineering and foundation safety. The main terms of reference of the present mission was to verify the implementation of the recommendations of the Site Safety Review Mission of June 1990. This document gives findings on geology-tectonics, seismology and foundation safety. In the end conclusions and recommendations of the mission are presented

Bathymetry and composition of Titan's Ontario Lacus derived from Monte Carlo-based waveform inversion of Cassini RADAR altimetry data

Science.gov (United States)

Mastrogiuseppe, M.; Hayes, A. G.; Poggiali, V.; Lunine, J. I.; Lorenz, R. D.; Seu, R.; Le Gall, A.; Notarnicola, C.; Mitchell, K. L.; Malaska, M.; Birch, S. P. D.

2018-01-01

Recently, the Cassini RADAR was used to sound hydrocarbon lakes and seas on Saturn's moon Titan. Since the initial discovery of echoes from the seabed of Ligeia Mare, the second largest liquid body on Titan, a dedicated radar processing chain has been developed to retrieve liquid depth and microwave absorptivity information from RADAR altimetry of Titan's lakes and seas. Herein, we apply this processing chain to altimetry data acquired over southern Ontario Lacus during Titan fly-by T49 in December 2008. The new signal processing chain adopts super resolution techniques and dedicated taper functions to reveal the presence of reflection from Ontario's lakebed. Unfortunately, the extracted waveforms from T49 are often distorted due to signal saturation, owing to the extraordinarily strong specular reflections from the smooth lake surface. This distortion is a function of the saturation level and can introduce artifacts, such as signal precursors, which complicate data interpretation. We use a radar altimetry simulator to retrieve information from the saturated bursts and determine the liquid depth and loss tangent of Ontario Lacus. Received waveforms are represented using a two-layer model, where Cassini raw radar data are simulated in order to reproduce the effects of receiver saturation. A Monte Carlo based approach along with a simulated waveform look-up table is used to retrieve parameters that are given as inputs to a parametric model which constrains radio absorption of Ontario Lacus and retrieves information about the dielectric properties of the liquid. We retrieve a maximum depth of 50 m along the radar transect and a best-fit specific attenuation of the liquid equal to 0.2 ± 0.09 dB m-1 that, when converted into loss tangent, gives tanδ = 7 ± 3 × 10-5. When combined with laboratory measured cryogenic liquid alkane dielectric properties and the variable solubility of nitrogen in ethane-methane mixtures, the best-fit loss tangent is consistent with a

Atmospheric structure and helium abundance on Saturn from Cassini/UVIS and CIRS observations

Science.gov (United States)

Koskinen, T. T.; Guerlet, S.

2018-06-01

We combine measurements from stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph (UVIS) and limb scans observed by the Composite Infrared Spectrometer (CIRS) to create empirical atmospheric structure models for Saturn corresponding to the locations probed by the occultations. The results cover multiple locations at low to mid-latitudes between the spring of 2005 and the fall of 2015. We connect the temperature-pressure (T-P) profiles retrieved from the CIRS limb scans in the stratosphere to the T-P profiles in the thermosphere retrieved from the UVIS occultations. We calculate the altitudes corresponding to the pressure levels in each case based on our best fit composition model that includes H2, He, CH4 and upper limits on H. We match the altitude structure to the density profile in the thermosphere that is retrieved from the occultations. Our models depend on the abundance of helium and we derive a volume mixing ratio of 11 ± 2% for helium in the lower atmosphere based on a statistical analysis of the values derived for 32 different occultation locations. We also derive the mean temperature and methane profiles in the upper atmosphere and constrain their variability. Our results are consistent with enhanced heating at the polar auroral region and a dynamically active upper atmosphere.

A Survey of Cassini CAPS Ion Observations During Titan Flybys TA-T83

Science.gov (United States)

Woodson, A. K.; Johnson, R. E.; Smith, H. T.; Crary, F. J.

2015-12-01

The Cassini Plasma Spectrometer (CAPS) sampled Titan's plasma environment during each of 83 encounters with the moon between orbit insertion on June 30, 2004 and June 1, 2012. The CAPS Ion Mass Spectrometer (IMS) acquired energy- and mass-per-charge-discriminated time-of-flight (TOF) spectra associated with ionospheric H+, H2+, H3+, CHx+, and C2Hx+ during at least 68 of those encounters. Herein we discuss ion energy distributions extracted from these spectra, each accumulated over an ~4 minute interval along the spacecraft trajectory. This is accomplished by fitting calibration peak models to TOF spectra in order to determine the TOF range associated with each aforementioned ion group, and then summing counts over each TOF range to obtain well-resolved energy peaks for each group. Energy distributions are determined by fitting the logistic power peak function to each of the resulting energy spectra. We then plot the resulting distribution parameters (peak energy, peak amplitude, and peak width or temperature) for each species and each encounter against Titan latitude, longitude, and altitude to generate a map of ion parameters. In addition, the encounters are grouped according to ambient plasma and magnetic field measurements in order to characterize the ion distribution parameters in different regions of Saturn's magnetosphere.

Water Vapor on Titan: The Stratospheric Vertical Profile from Cassini/CIRS Infrared Spectra

Science.gov (United States)

Cottini, V.; Jennings, D. E.; Nixon, C. A.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Achterberg, R. K.; Teanby, N. A.; deKok, R.;

B plant mission analysis report

International Nuclear Information System (INIS)

Lund, D.P.

1995-01-01

This report further develops the mission for B Plant originally defined in WHC-EP-0722, ''System Engineering Functions and Requirements for the Hanford Cleanup Mission: First Issue.'' The B Plant mission analysis will be the basis for a functional analysis that breaks down the B Plant mission statement into the necessary activities to accomplish the mission. These activities are the product of the functional analysis and will then be used in subsequent steps of the systems engineering process, such as identifying requirements and allocating those requirements to B Plant functions. The information in this mission analysis and the functional and requirements analysis are a part of the B Plant technical baseline

Missions to Venus

Science.gov (United States)

Titov, D. V.; Baines, K. H.; Basilevsky, A. T.; Chassefiere, E.; Chin, G.; Crisp, D.; Esposito, L. W.; Lebreton, J.-P.; Lellouch, E.; Moroz, V. I.; Nagy, A. F.; Owen, T. C.; Oyama, K.-I.; Russell, C. T.; Taylor, F. W.; Young, R. E.

2002-10-01

Venus has always been a fascinating objective for planetary studies. At the beginning of the space era Venus became one of the first targets for spacecraft missions. Our neighbour in the solar system and, in size, the twin sister of Earth, Venus was expected to be very similar to our planet. However, the first phase of Venus spacecraft exploration in 1962-1992 by the family of Soviet Venera and Vega spacecraft and US Mariner, Pioneer Venus, and Magellan missions discovered an entirely different, exotic world hidden behind a curtain of dense clouds. These studies gave us a basic knowledge of the conditions on the planet, but generated many more questions concerning the atmospheric composition, chemistry, structure, dynamics, surface-atmosphere interactions, atmospheric and geological evolution, and the plasma environment. Despite all of this exploration by more than 20 spacecraft, the "morning star" still remains a mysterious world. But for more than a decade Venus has been a "forgotten" planet with no new missions featuring in the plans of the world space agencies. Now we are witnessing the revival of interest in this planet: the Venus Orbiter mission is approved in Japan, Venus Express - a European orbiter mission - has successfully passed the selection procedure in ESA, and several Venus Discovery proposals are knocking at the doors of NASA. The paper presents an exciting story of Venus spacecraft exploration, summarizes open scientific problems, and builds a bridge to the future missions.

RTG's for space exploration at the end of the 20th century

International Nuclear Information System (INIS)

Chimielewski, A.

1989-01-01

The radioisotope thermoelectric generators (RTG's) are the only type of energy conversion devices that are available for spacecraft designed for environments where sunlight is weak. The two upcoming missions Galileo and Ulysses will both use General Purpose Heat Source (GPHS) RTG's. Two other missions that are planned for mid nineties and will carry RTG's on board are: Comet Rendezvous Astroid Flyby (CRAF) and Cassini. Another mission that might become a program start in the last decade of the 20th century is Solarprobe. Solarprobe is most likely to use Modular RTG's. Several other missions that are in different planning stages are in need of RTG's to meet their power requirements: Mars Rover Sample Return, planetary penetrators, microspacecraft and Mars Egg. The paper briefly describes all of these missions stressing their RTG requirements

THE VARIABILITY OF HCN IN TITAN’S UPPER ATMOSPHERE AS IMPLIED BY THE CASSINI ION-NEUTRAL MASS SPECTROMETER MEASUREMENTS

Energy Technology Data Exchange (ETDEWEB)

Cui, J.; Cao, Y.-T. [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Lavvas, P. P. [Groupe de Spectroscopie Moleculaire et Atmospherique, Universite de Reims, Champagne-Ardenne, CNRS UMR F-7331 (France); Koskinen, T. T. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

2016-07-20

HCN is an important constituent in Titan’s upper atmosphere, serving as the main coolant in the local energy budget. In this study, we derive the HCN abundance at the altitude range of 960–1400 km, combining the Ion-Neutral Mass Spectrometer data acquired during a large number of Cassini flybys with Titan. Typically, the HCN abundance declines modestly with increasing altitude and flattens to a near constant level above 1200 km. The data reveal a tendency for dayside depletion of HCN, which is clearly visible below 1000 km but weakens with increasing altitude. Despite the absence of convincing anti-correlation between HCN volume mixing ratio and neutral temperature, we argue that the variability in HCN abundance makes an important contribution to the large temperature variability observed in Titan’s upper atmosphere.

Cassini results on Titan's atmospheric and surface properties changes since the northern equinox

Science.gov (United States)

Coustenis, Athena; Drossart, Pierre; Flasar, F. Michael; Achterberg, Richard K.; Rodriguez, Sebastien; Nixon, Conor; Bampasidis, Georgios; Solomonidou, Anezina; Jennings, Donald; Lavvas, Panayiotis

2016-07-01

Since 2010, we observe the set in and enhancement at Titan's south pole of several trace species, such as HC3N and C6H6, observed only at high northern latitudes before equinox. We will present an analysis of spectra acquired by Cassini/CIRS at high resolution from 2012 in nadir mode. We investigated here several latitudes of 70°S to 70°N since 2010 (after the Southern Autumnal Equinox) until end of 2014 [1]. For some of the most abundant and longest-lived hydrocarbons (C2H2, C2H6 and C3H8) and CO2, the evolution in the past 4 years at a given latitude is not very significant within error bars especially until mid-2013 [1]. In more recent dates, these molecules show a dramatic trend for increase in the south. The 70°S and 50°S or mid-latitudes show different behavior demonstrating that they are subject to different dynamical processes in and out of the polar vortex region. For most species, we find higher abundances at 50°N compared to 50°S, with the exception of C3H8, CO2, C6H6 and HC3N, which arrive at similar mixing ratios after mid-2013 [1]. While the 70°N data show generally no change with a trend rather to a small decrease for most species within 2014, the 70°S results indicate a strong enhancement in trace stratospheric gases after 2012. In particular, HC3N, HCN and C6H6 have increased by 3 orders of magnitude over the past 3-4 years while other molecules, including C2H4, C3H4 and C4H2, have increased less sharply (by 1-2 orders of magnitude). This is a strong indication of the rapid and sudden buildup of the gaseous inventory in the southern stratosphere during 2013-2014, as expected as the pole moves deeper into winter shadow. Subsidence gases that accumulate in the absence of ultraviolet sunlight, evidently increased quickly since 2012 and some of them may be responsible also for the reported haze decrease in the north and its appearance in the south at the same time [2]. Clearly Titan is a dynamic system with indications of short and long

Solar Probe Plus: A NASA Mission to Touch the SunMission Status Update

Science.gov (United States)

Fox, N. J.

2016-12-01

Solar Probe Plus (SPP), currently in Phase D, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Solar Probe Plus mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives. In this presentation, we provide an update on the progress of the Solar Probe Plus mission as we prepare for the July 2018 launch.

The Messenger Mission to Mercury

CERN Document Server

Domingue, D. L

2007-01-01

NASA’s MESSENGER mission, launched on 3 August, 2004 is the seventh mission in the Discovery series. MESSENGER encounters the planet Mercury four times, culminating with an insertion into orbit on 18 March 2011. It carries a comprehensive package of geophysical, geological, geochemical, and space environment experiments to complete the complex investigations of this solar-system end member, which begun with Mariner 10. The articles in this book, written by the experts in each area of the MESSENGER mission, describe the mission, spacecraft, scientific objectives, and payload. The book is of interest to all potential users of the data returned by the MESSENGER mission, to those studying the nature of the planet Mercury, and by all those interested in the design and implementation of planetary exploration missions.

Synergies Between the Kepler, K2 and TESS Missions with the PLATO Mission (Revised)

Science.gov (United States)

Jenkins, Jon M.

2017-01-01

Two transit survey missions will have been flown by NASA prior to the launch of ESA's PLATO Mission in 2026, laying the groundwork for exoplanet discovery via the transit method. The Kepler Mission, which launched in 2009, collected data on its 100+ square degree field of view for four years before failure of a reaction wheel ended its primary mission. The results from Kepler include 2300+ confirmed or validated exoplanets, 2200+ planetary candidates, 2100+ eclipsing binaries. Kepler also revolutionized the field of asteroseismology by measuring the pressure mode oscillations of over 15000 solar-like stars spanning the lifecycle of such stars from hydrogen-burning dwarfs to helium-burning red giants. The re-purposed Kepler Mission, dubbed K2, continues to observe fields of view in and near the ecliptic plane for 80 days each, significantly broadening the scope of the astrophysical investigations as well as discovering an additional 156 exoplanets to date. The TESS mission will launch in 2017 to conduct an all-sky survey for small exoplanets orbiting stars 10X closer and 100X brighter than Kepler exoplanet host stars, allowing for far greater follow-up and characterization of their masses as well as their sizes for at least 50 small planets. Future assets such as James Webb Space Telescope, and ground-based assets such as ESOs Very Large Telescope (VLT) array, the Exremely Large Telescope (ELT), and the Thirty Meter Telescope (TMT) will be able to characterize the atmospheric composition and properties of these small planets. TESS will observe each 24 X 96 field of view for 30 days and thereby cover first the southern and then the northern hemisphere over 13 pointings during each year of the primary mission. The pole-most camera will observe the James Webb continuous viewing zone for one year in each hemisphere, permitting much longer period planets to be detected in this region. The PLATO mission will seek to detect habitable Earth-like planets with an instrument

EUCLID mission design

Science.gov (United States)

Wallner, Oswald; Ergenzinger, Klaus; Tuttle, Sean; Vaillon, L.; Johann, Ulrich

2017-11-01

EUCLID, a medium-class mission candidate of ESA's Cosmic Vision 2015-2025 Program, currently in Definition Phase (Phase A/B1), shall map the geometry of the Dark Universe by investigating dark matter distributions, the distance-redshift relationship, and the evolution of cosmic structures. EUCLID consists of a 1.2 m telescope and two scientific instruments for ellipticity and redshift measurements in the visible and nearinfrared wavelength regime. We present a design concept of the EUCLID mission which is fully compliant with the mission requirements. Preliminary concepts of the spacecraft and of the payload including the scientific instruments are discussed.

Exact Cavity Perturbation Technique to Determine Complex Permittivity of Dielectric Materials

Science.gov (United States)

Starr, Charles H.; Barmatz, Martin B.

2011-01-01

Cassini is an international spacecraft mission facilitated by NASA and ESA which seeks to understand the Saturn planetary system, including rings and moons. Launched in 1997, the Cassini spacecraft contains two major components: the Cassini orbiter that has been orbiting Saturn since October 2004, and the European-built Huygens probe that landed on Titan's surface in December 2004 to study its geology and atmosphere. Titan, Saturn's largest moon and the second largest moon in the solar system, possesses surface and atmospheric features similar to those of Earth, including lakes, seas, and mountains. A physical characterization of these features is critical to understanding the origin and evolution of Titan, whose surface composition reflects its geological history. Because Titan's atmosphere is largely composed of methane, it is believed that surfaces lakes are filled with mixtures of liquid hydrocarbons. The Cassini orbiter's RADAR instrument has been scanning Titan's surface at the atmosphere-penetrating microwave frequency of 13.8 Gigahertz since 2004. However, accurate interpretation of these data is limited by a lack of knowledge regarding dielectric properties of liquid hydrocarbons at cryogenic temperatures. Therefore, it is of specific interest to experimentally determine values for the complex permittivities of various liquid hydrocarbon mixtures at the surface conditions of Titan. In particular, more accurate values for complex permittivity would improve estimates of lake depth and surface composition obtained from the instrument's altimetry and backscatter modes.

Mission operations technology

Science.gov (United States)

Varsi, Giulio

In the last decade, the operation of a spacecraft after launch has emerged as a major component of the total cost of the mission. This trend is sustained by the increasing complexity, flexibility, and data gathering capability of the space assets and by their greater reliability and consequent longevity. The trend can, however, be moderated by the progressive transfer of selected functions from the ground to the spacecraft and by application, on the ground, of new technology. Advances in ground operations derive from the introduction in the mission operations environment of advanced microprocessor-based workstations in the class of a few million instructions per second and from the selective application of artificial intelligence technology. In the last few years a number of these applications have been developed, tested in operational settings and successfully demonstrated to users. Some are now being integrated in mission operations facilities. An analysis of mission operations indicates that the key areas are: concurrent control of multiple missions; automated/interactive production of command sequences of high integrity at low cost; automated monitoring of spacecraft health and automated aides for fault diagnosis; automated allocation of resources; automated processing of science data; and high-fidelity, high-speed spacecraft simulation. Examples of major advances in selected areas are described.

Liquid Effluents Program mission analysis

International Nuclear Information System (INIS)

Lowe, S.S.

1994-01-01

Systems engineering is being used to identify work to cleanup the Hanford Site. The systems engineering process transforms an identified mission need into a set of performance parameters and a preferred system configuration. Mission analysis is the first step in the process. Mission analysis supports early decision-making by clearly defining the program objectives, and evaluating the feasibility and risks associated with achieving those objectives. The results of the mission analysis provide a consistent basis for subsequent systems engineering work. A mission analysis was performed earlier for the overall Hanford Site. This work was continued by a ''capstone'' team which developed a top-level functional analysis. Continuing in a top-down manner, systems engineering is now being applied at the program and project levels. A mission analysis was conducted for the Liquid Effluents Program. The results are described herein. This report identifies the initial conditions and acceptable final conditions, defines the programmatic and physical interfaces and sources of constraints, estimates the resources to carry out the mission, and establishes measures of success. The mission analysis reflects current program planning for the Liquid Effluents Program as described in Liquid Effluents FY 1995 Multi-Year Program Plan

Lunar Exploration Missions Since 2006

Science.gov (United States)

Lawrence, S. J. (Editor); Gaddis, L. R.; Joy, K. H.; Petro, N. E.

2017-01-01

The announcement of the Vision for Space Exploration in 2004 sparked a resurgence in lunar missions worldwide. Since the publication of the first "New Views of the Moon" volume, as of 2017 there have been 11 science-focused missions to the Moon. Each of these missions explored different aspects of the Moon's geology, environment, and resource potential. The results from this flotilla of missions have revolutionized lunar science, and resulted in a profoundly new emerging understanding of the Moon. The New Views of the Moon II initiative itself, which is designed to engage the large and vibrant lunar science community to integrate the results of these missions into new consensus viewpoints, is a direct outcome of this impressive array of missions. The "Lunar Exploration Missions Since 2006" chapter will "set the stage" for the rest of the volume, introducing the planetary community at large to the diverse array of missions that have explored the Moon in the last decade. Content: This chapter will encompass the following missions: Kaguya; ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun); Chang’e-1; Chandrayaan-1; Moon Impact Probe; Lunar Reconnaissance Orbiter (LRO); Lunar Crater Observation Sensing Satellite (LCROSS); Chang’e-2; Gravity Recovery and Interior Laboratory (GRAIL); Lunar Atmosphere and Dust Environment Explorer (LADEE); Chang’e-3.

Integrated Human-Robotic Missions to the Moon and Mars: Mission Operations Design Implications

Science.gov (United States)

Mishkin, Andrew; Lee, Young; Korth, David; LeBlanc, Troy

2007-01-01

For most of the history of space exploration, human and robotic programs have been independent, and have responded to distinct requirements. The NASA Vision for Space Exploration calls for the return of humans to the Moon, and the eventual human exploration of Mars; the complexity of this range of missions will require an unprecedented use of automation and robotics in support of human crews. The challenges of human Mars missions, including roundtrip communications time delays of 6 to 40 minutes, interplanetary transit times of many months, and the need to manage lifecycle costs, will require the evolution of a new mission operations paradigm far less dependent on real-time monitoring and response by an Earthbound operations team. Robotic systems and automation will augment human capability, increase human safety by providing means to perform many tasks without requiring immediate human presence, and enable the transfer of traditional mission control tasks from the ground to crews. Developing and validating the new paradigm and its associated infrastructure may place requirements on operations design for nearer-term lunar missions. The authors, representing both the human and robotic mission operations communities, assess human lunar and Mars mission challenges, and consider how human-robot operations may be integrated to enable efficient joint operations, with the eventual emergence of a unified exploration operations culture.

GRACE Status at Mission End

Science.gov (United States)

Tapley, B. D.; Flechtner, F. M.; Watkins, M. M.; Bettadpur, S. V.

2017-12-01

The twin satellites of the Gravity Recovery and Climate Experiment (GRACE) were launched on March 17, 2002 and have operated for nearly 16 years. The mission objectives are to observe the spatial and temporal variations of the Earth's mass through its effects on the gravity field at the GRACE satellite altitude. The mass changes observed are related to both the changes within the solid earth and the change within and between the Erath system components. A significant cause of the time varying mass is water motion and the GRACE mission has provided a continuous decade long measurement sequence which characterizes the seasonal cycle of mass transport between the oceans, land, cryosphere and atmosphere; its inter-annual variability; and the climate driven secular, or long period, mass transport signals. The fifth reanalysis on the mission data set, the RL05 data, were released in mid-2013. With the planned launch of GRACE Follow-On in early 2018, plans are underway for a reanalysis that will be consistent with the GRACE FO processing standards. The mission is entering the final phases of its operation life with mission end expected to occur in early 2018. The current mission operations strategy emphasizes extending the mission lifetime to obtain an overlap with the GRACE FO. This presentation will review the mission status and the projections for mission lifetime, describe the current operations philosophy and its impact on the science data, discuss the issues related to achieving the GRACE and GRACE FO connection and discuss issues related to science data products during this phase of the mission period.

Overview of Mission Design for NASA Asteroid Redirect Robotic Mission Concept

Science.gov (United States)

Strange, Nathan; Landau, Damon; McElrath, Timothy; Lantoine, Gregory; Lam, Try; McGuire, Melissa; Burke, Laura; Martini, Michael; Dankanich, John

2013-01-01

Part of NASA's new asteroid initiative would be a robotic mission to capture a roughly four to ten meter asteroid and redirect its orbit to place it in translunar space. Once in a stable storage orbit at the Moon, astronauts would then visit the asteroid for science investigations, to test in space resource extraction, and to develop experience with human deep space missions. This paper discusses the mission design techniques that would enable the redirection of a 100-1000 metric ton asteroid into lunar orbit with a 40-50 kW Solar Electric Propulsion (SEP) system.

Mission requirements for a manned earth observatory. Task 2: Reference mission definition and analyiss, volume 2

Science.gov (United States)

1973-01-01

The mission requirements and conceptual design of manned earth observatory payloads for the 1980 time period are discussed. Projections of 1980 sensor technology and user data requirements were used to formulate typical basic criteria pertaining to experiments, sensor complements, and reference missions. The subjects discussed are: (1) mission selection and prioritization, (2) baseline mission analysis, (3) earth observation data handling and contingency plans, and (4) analysis of low cost mission definition and rationale.

Exoplanets -New Results from Space and Ground-based Surveys

Science.gov (United States)

Udry, Stephane

The exploration of the outer solar system and in particular of the giant planets and their environments is an on-going process with the Cassini spacecraft currently around Saturn, the Juno mission to Jupiter preparing to depart and two large future space missions planned to launch in the 2020-2025 time frame for the Jupiter system and its satellites (Europa and Ganymede) on the one hand, and the Saturnian system and Titan on the other hand [1,2]. Titan, Saturn's largest satellite, is the only other object in our Solar system to possess an extensive nitrogen atmosphere, host to an active organic chemistry, based on the interaction of N2 with methane (CH4). Following the Voyager flyby in 1980, Titan has been intensely studied from the ground-based large telescopes (such as the Keck or the VLT) and by artificial satellites (such as the Infrared Space Observatory and the Hubble Space Telescope) for the past three decades. Prior to Cassini-Huygens, Titan's atmospheric composition was thus known to us from the Voyager missions and also through the explorations by the ISO. Our perception of Titan had thus greatly been enhanced accordingly, but many questions remained as to the nature of the haze surrounding the satellite and the composition of the surface. The recent revelations by the Cassini-Huygens mission have managed to surprise us with many discoveries [3-8] and have yet to reveal more of the interesting aspects of the satellite. The Cassini-Huygens mission to the Saturnian system has been an extraordinary success for the planetary community since the Saturn-Orbit-Insertion (SOI) in July 2004 and again the very successful probe descent and landing of Huygens on January 14, 2005. One of its main targets was Titan. Titan was revealed to be a complex world more like the Earth than any other: it has a dense mostly nitrogen atmosphere and active climate and meteorological cycles where the working fluid, methane, behaves under Titan conditions the way that water does on

The Exploration of Titan and the Saturnian System

Science.gov (United States)

Coustenis, Athena

The exploration of the outer solar system and in particular of the giant planets and their environments is an on-going process with the Cassini spacecraft currently around Saturn, the Juno mission to Jupiter preparing to depart and two large future space missions planned to launch in the 2020-2025 time frame for the Jupiter system and its satellites (Europa and Ganymede) on the one hand, and the Saturnian system and Titan on the other hand [1,2]. Titan, Saturn's largest satellite, is the only other object in our Solar system to possess an extensive nitrogen atmosphere, host to an active organic chemistry, based on the interaction of N2 with methane (CH4). Following the Voyager flyby in 1980, Titan has been intensely studied from the ground-based large telescopes (such as the Keck or the VLT) and by artificial satellites (such as the Infrared Space Observatory and the Hubble Space Telescope) for the past three decades. Prior to Cassini-Huygens, Titan's atmospheric composition was thus known to us from the Voyager missions and also through the explorations by the ISO. Our perception of Titan had thus greatly been enhanced accordingly, but many questions remained as to the nature of the haze surrounding the satellite and the composition of the surface. The recent revelations by the Cassini-Huygens mission have managed to surprise us with many discoveries [3-8] and have yet to reveal more of the interesting aspects of the satellite. The Cassini-Huygens mission to the Saturnian system has been an extraordinary success for the planetary community since the Saturn-Orbit-Insertion (SOI) in July 2004 and again the very successful probe descent and landing of Huygens on January 14, 2005. One of its main targets was Titan. Titan was revealed to be a complex world more like the Earth than any other: it has a dense mostly nitrogen atmosphere and active climate and meteorological cycles where the working fluid, methane, behaves under Titan conditions the way that water does on

Mapping Ring Particle Cooling across Saturn's Rings with Cassini CIRS

Science.gov (United States)

Brooks, Shawn M.; Spilker, L. J.; Edgington, S. G.; Pilorz, S. H.; Deau, E.

2010-10-01

Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and quick temperature responses are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid, coherent particles can be expected to have higher thermal inertias (Ferrari et al. 2005). Cassini's Composite Infrared Spectrometer has recorded millions of spectra of Saturn's rings since its arrival at Saturn in 2004 (personal communication, M. Segura). CIRS records far infrared radiation between 10 and 600 cm-1 (16.7 and 1000 µm) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn's rings peaks in this wavelength range. FP1 spectra can be used to infer ring temperatures. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The thermal budget of the rings is dominated by the solar radiation absorbed by its constituent particles. When ring particles enter Saturn's shadow this source of energy is abruptly cut off. As a result, ring particles cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

Transient surface liquid in Titan's south polar region from Cassini

Science.gov (United States)

Hayes, A.G.; Aharonson, O.; Lunine, J.I.; Kirk, R.L.; Zebker, H.A.; Wye, L.C.; Lorenz, R.D.; Turtle, E.P.; Paillou, P.; Mitri, Giuseppe; Wall, S.D.; Stofan, E.R.; Mitchell, K.L.; Elachi, C.

2011-01-01

Cassini RADAR images of Titan's south polar region acquired during southern summer contain lake features which disappear between observations. These features show a tenfold increases in backscatter cross-section between images acquired one year apart, which is inconsistent with common scattering models without invoking temporal variability. The morphologic boundaries are transient, further supporting changes in lake level. These observations are consistent with the exposure of diffusely scattering lakebeds that were previously hidden by an attenuating liquid medium. We use a two-layer model to explain backscatter variations and estimate a drop in liquid depth of approximately 1-m-per-year. On larger scales, we observe shoreline recession between ISS and RADAR images of Ontario Lacus, the largest lake in Titan's south polar region. The recession, occurring between June 2005 and July 2009, is inversely proportional to slopes estimated from altimetric profiles and the exponential decay of near-shore backscatter, consistent with a uniform reduction of 4 ± 1.3 m in lake depth. Of the potential explanations for observed surface changes, we favor evaporation and infiltration. The disappearance of dark features and the recession of Ontario's shoreline represents volatile transport in an active methane-based hydrologic cycle. Observed loss rates are compared and shown to be consistent with available global circulation models. To date, no unambiguous changes in lake level have been observed between repeat images in the north polar region, although further investigation is warranted. These observations constrain volatile flux rates in Titan's hydrologic system and demonstrate that the surface plays an active role in its evolution. Constraining these seasonal changes represents the first step toward our understanding of longer climate cycles that may determine liquid distribution on Titan over orbital time periods.

Meteorology of Jupiter's Equatorial Hot Spots and Plumes from Cassini

Science.gov (United States)

Choi, David Sanghun; Showman, Adam P.; Vasavada, Ashwin R.; Simon-Miller, Amy A.

2013-01-01

We present an updated analysis of Jupiter's equatorial meteorology from Cassini observations. For two months preceding the spacecraft's closest approach, the Imaging Science Subsystem (ISS) onboard regularly imaged the atmosphere. We created time-lapse movies from this period in order to analyze the dynamics of equatorial hot spots and their interactions with adjacent latitudes. Hot spots are relatively cloud-free regions that emit strongly at 5 lm; improved knowledge of these features is crucial for fully understanding Galileo probe measurements taken during its descent through one. Hot spots are quasistable, rectangular dark areas on visible-wavelength images, with defined eastern edges that sharply contrast with surrounding clouds, but diffuse western edges serving as nebulous boundaries with adjacent equatorial plumes. Hot spots exhibit significant variations in size and shape over timescales of days and weeks. Some of these changes correspond with passing vortex systems from adjacent latitudes interacting with hot spots. Strong anticyclonic gyres present to the south and southeast of the dark areas appear to circulate into hot spots. Impressive, bright white plumes occupy spaces in between hot spots. Compact cirrus-like 'scooter' clouds flow rapidly through the plumes before disappearing within the dark areas. These clouds travel at 150-200 m/s, much faster than the 100 m/s hot spot and plume drift speed. This raises the possibility that the scooter clouds may be more illustrative of the actual jet stream speed at these latitudes. Most previously published zonal wind profiles represent the drift speed of the hot spots at their latitude from pattern matching of the entire longitudinal image strip. If a downward branch of an equatorially-trapped Rossby wave controls the overall appearance of hot spots, however, the westward phase velocity of the wave leads to underestimates of the true jet stream speed.

A Model of Titan-like Chemistry to Connect Experiments and Cassini Observations

Science.gov (United States)

Raymond, Alexander W.; Sciamma-O’Brien, Ella; Salama, Farid; Mazur, Eric

2018-02-01

A numerical model is presented for interpreting the chemical pathways that lead to the experimental mass spectra acquired in the Titan Haze Simulation (THS) laboratory experiments and for comparing the electron density and temperature of the THS plasma to observations made at Titan by the Cassini spacecraft. The THS plasma is a pulsed glow-discharge experiment designed to simulate the reaction of N2/CH4-dominated gas in Titan's upper atmosphere. The transient, one-dimensional model of THS chemistry tracks the evolution of more than 120 species in the direction of the plasma flow. As the minor species C2H2 and C2H4 are added to the N2/CH4-based mixture, the model correctly predicts the emergence of reaction products with up to five carbon atoms in relative abundances that agree well with measured mass spectra. Chemical growth in Titan's upper atmosphere transpires through ion–neutral and neutral–neutral chemistry, and the main reactions involving a series of known atmospheric species are retrieved from the calculation. The model indicates that the electron density and chemistry are steady during more than 99% of the 300 μs long discharge pulse. The model also suggests that the THS ionization fraction and electron temperature are comparable to those measured in Titan's upper atmosphere. These findings reaffirm that the THS plasma is a controlled analog environment for studying the first and intermediate steps of chemistry in Titan's upper atmosphere.

Community College Mission: A '60s Mission Looking at a Y2K World.

Science.gov (United States)

Levin, Bernard H.

Although the world has changed considerably in the past three decades, community colleges and their guiding missions have largely not adapted to changing conditions. College mission statements tend to be unfocused documents that provide overly broad goals. In the business world, the mission statements of effective companies are brief, crisp, and…

Annual Technical Progress Report of Radioisotope Power System Materials Production and Technology Program Tasks for October 1, 2002 Through September 30, 2003

Energy Technology Data Exchange (ETDEWEB)

King, J.F.

2004-05-18

The Office of Space and Defense Power Systems of the Department of Energy (DOE) provides Radioisotope Power Systems (RPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of 1997 to study the planet Saturn. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. For the Cassini Mission, for example, ORNL was involved in the production of carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVS). This report has been divided into three sections to reflect program guidance from the Office of Space and Defense Power Systems for fiscal year (FY) 2003. The first section deals primarily with maintenance of the capability to produce flight quality (FQ) CBCF insulator sets, iridium alloy blanks and foil, and CVS. In all three cases, production maintenance is assured by the manufacture of limited quantities of FQ components. The second section deals with several technology activities to improve the manufacturing processes, characterize materials, or to develop technologies for new radioisotope power systems. The last section is dedicated to studies related to the production of {sup 238}Pu.

Space Nuclear Power Public and Stakeholder Risk Communication

Science.gov (United States)

Dawson, Sandra M.; Sklar, Maria

2005-01-01

The 1986 Challenger accident coupled with the Chernobyl nuclear reactor accident increased public concern about the safety of spacecraft using nuclear technology. While three nuclear powered spacecraft had been launched before 1986 with little public interest, future nuclear powered missions would see significantly more public concern and require NASA to increase its efforts to communicate mission risks to the public. In 1987 a separate risk communication area within the Launch Approval Planning Group of the Jet Propulsion Laboratory was created to address public concern about the health, environmental, and safety risks of NASA missions. The lessons learned from the risk communication strategies developed for the nuclear powered Galileo, Ulysses, and Cassini missions are reviewed in this paper and recommendations are given as to how these lessons can be applied to future NASA missions that may use nuclear power systems and other potentially controversial NASA missions.

Mission operations update for the restructured Earth Observing System (EOS) mission

Science.gov (United States)

Kelly, Angelita Castro; Chang, Edward S.

1993-01-01

The National Aeronautics and Space Administration's (NASA) Earth Observing System (EOS) will provide a comprehensive long term set of observations of the Earth to the Earth science research community. The data will aid in determining global changes caused both naturally and through human interaction. Understanding man's impact on the global environment will allow sound policy decisions to be made to protect our future. EOS is a major component of the Mission to Planet Earth program, which is NASA's contribution to the U.S. Global Change Research Program. EOS consists of numerous instruments on multiple spacecraft and a distributed ground system. The EOS Data and Information System (EOSDIS) is the major ground system developed to support EOS. The EOSDIS will provide EOS spacecraft command and control, data processing, product generation, and data archival and distribution services for EOS spacecraft. Data from EOS instruments on other Earth science missions (e.g., Tropical Rainfall Measuring Mission (TRMM)) will also be processed, distributed, and archived in EOSDIS. The U.S. and various International Partners (IP) (e.g., the European Space Agency (ESA), the Ministry of International Trade and Industry (MITI) of Japan, and the Canadian Space Agency (CSA)) participate in and contribute to the international EOS program. The EOSDIS will also archive processed data from other designated NASA Earth science missions (e.g., UARS) that are under the broad umbrella of Mission to Planet Earth.

Intelligent Mission Controller Node

National Research Council Canada - National Science Library

Perme, David

2002-01-01

The goal of the Intelligent Mission Controller Node (IMCN) project was to improve the process of translating mission taskings between real-world Command, Control, Communications, Computers, and Intelligence (C41...

Life support approaches for Mars missions

Science.gov (United States)

Drysdale, A. E.; Ewert, M. K.; Hanford, A. J.

Life support approaches for Mars missions are evaluated using an equivalent system mass (ESM) approach, in which all significant costs are converted into mass units. The best approach, as defined by the lowest mission ESM, depends on several mission parameters, notably duration, environment and consequent infrastructure costs, and crew size, as well as the characteristics of the technologies which are available. Generally, for the missions under consideration, physicochemical regeneration is most cost effective. However, bioregeneration is likely to be of use for producing salad crops for any mission, for producing staple crops for medium duration missions, and for most food, air and water regeneration for long missions (durations of a decade). Potential applications of in situ resource utilization need to be considered further.

Mission of Mercy.

Science.gov (United States)

Humenik, Mark

2014-01-01

Some dentists prefer solo charity work, but there is much to be said for collaboration within the profession in reaching out to those who are dentally underserved. Mission of Mercy (MOM) programs are regularly organized across the country for this purpose. This article describes the structure, reach, and personal satisfaction to be gained from such missions.

A change of seasons in Saturn's stratosphere from Cassini/CIRS: evolution of the equatorial oscillation and reversal of hemispheric transport.

Science.gov (United States)

Guerlet, Sandrine; Fouchet, Thierry; Hesman, Brigette; Bjoraker, Gordon; Spiga, Aymeric; Cassini/CIRS Team

2016-10-01

Due to its axial tilt of 26.7°, Saturn's atmosphere undergoes significant seasonal variations in insolation that impact its thermal structure, chemistry and dynamics. The exceptional longevity of the Cassini mission enables us to uniquely investigate these changes over almost half a Saturn year. In this study, thermal infrared spectra acquired in 2015 by CIRS in limb viewing geometry are analyzed to map the temperature and the meridional distribution of five hydrocarbons from the lower to the upper stratosphere (10 mbar - 10 microbar). These new maps represent a snapshot of Saturn's atmosphere at the end of the northern spring and are compared to previous results obtained during northern winter (2005/2006) and early spring (2010/2011) (Guerlet et al., Icarus, 2009; Sylvestre et al., Icarus, 2015). Spectacular seasonal changes in temperature are observed, not only at high latitudes where the most extreme insolation variations take place, but also at 20N-20S where the mechanical forcing of the equatorial oscillation induces temperature anomalies of up to +/-20K. These results are compared with predictions from a radiative climate model (Guerlet et al., Icarus, 2014). Apart from the equatorial region, the seasonal warming and cooling trends observed by CIRS are, to first order, consistent with the predictions. One notable exception is that the region under the ring's shadow is found warmer than expected from the radiative model, both in 2005 and 2015. The spatial distribution of hydrocarbons, by-products of the methane photochemistry, also undergoes significant seasonal change in the upper stratosphere. In 2005, a local maximum of hydrocarbons was observed at 20-30N, at odds with the low photochemical production in this region (under the ring's shadow at that time). Together with the high temperature anomaly, we had interpreted this result as the signature of a downwelling branch of the meridional circulation. In 2015, not only has this local maximum vanished, but a

NANOGRAIN DENSITY OUTSIDE SATURN’S A RING

Energy Technology Data Exchange (ETDEWEB)

Johnson, Robert E. [Engineering Physics, University of Virginia, Charlottesville, VA 22902 (United States); Tseng, Wei-Ling [National Taiwan Normal University, No. 88, Sec. 4, Tingzhou Road, Wenshan District, Taipei 11677, Taiwan (China); Elrod, M. K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Persoon, A. M., E-mail: rej@virginia.edu, E-mail: wltseng@ntnu.edu.tw, E-mail: meredith.k.elrod@nasa.gov, E-mail: ann-persoon@uiowa.edu [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States)

2017-01-01

The observed disparity between the radial dependence of the ion and electron densities measured by the Cassini plasma (CAPS) and radio (RPWS) science instruments are used to show that the region between the outer edge of Saturn’s main rings and its tenuous G ring is permeated with small charged grains (nanograins). These grains emanate from the edge of the A ring and from the tenuous F and G rings. This is a region of Saturn’s magnetosphere that is relatively unexplored, but will be a focus of Cassini ’s F ring orbits prior to the end of mission in 2017 September. Confirmation of the grain densities predicted here will enhance our ability to describe the formation and destruction of material in this important region of Saturn’s magnetosphere.

A Saturn Ring Observer Mission Using Multi-Mission Radioisotope Power Systems

International Nuclear Information System (INIS)

Abelson, Robert D.; Spilker, Thomas R.; Shirley, James H.

2006-01-01

Saturn remains one of the most fascinating planets within the solar system. To better understand the complex ring structure of this planet, a conceptual Saturn Ring Observer (SRO) mission is presented that would spend one year in close proximity to Saturn's A and B rings, and perform detailed observations and measurements of the ring particles and electric and magnetic fields. The primary objective of the mission would be to understand ring dynamics, including the microphysics of individual particles and small scale (meters to a few kilometers) phenomena such as particle agglomeration behavior. This would be accomplished by multispectral imaging of the rings at multiple key locations within the A and B rings, and by ring-particle imaging at an unprecedented resolution of 0.5 cm/pixel. The SRO spacecraft would use a Venus-Earth-Earth-Jupiter Gravity Assist (VEEJGA) and be aerocaptured into Saturn orbit using an advanced aeroshell design to minimize propellant mass. Once in orbit, the SRO would stand off from the ring plane 1 to 1.4 km using chemical thrusters to provide short propulsive maneuvers four times per revolution, effectively causing the SRO vehicle to 'hop' above the ring plane. The conceptual SRO spacecraft would be enabled by the use of a new generation of multi-mission Radioisotope Power Systems (RPSs) currently being developed by NASA and DOE. These RPSs include the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) and Stirling Radioisotope Generator (SRG). The RPSs would generate all necessary electrical power (≥330 We at beginning of life) during the 10-year cruise and 1-year science mission (∼11 years total). The RPS heat would be used to maintain the vehicle's operating and survival temperatures, minimizing the need for electrical heaters. Such a mission could potentially launch in the 2015-2020 timeframe, with operations at Saturn commencing in approximately 2030

Integrated payload and mission planning, phase 3. Volume 3: Ground real-time mission operations

Science.gov (United States)

White, W. J.

1977-01-01

The payloads tentatively planned to fly on the first two Spacelab missions were analyzed to examine the cost relationships of providing mission operations support from onboard vs the ground-based Payload Operations Control Center (POCC). The quantitative results indicate that use of a POCC, with data processing capability, to support real-time mission operations is the most cost effective case.

NANODUST DETECTION BETWEEN 1 AND 5 AU USING CASSINI WAVE MEASUREMENTS

Energy Technology Data Exchange (ETDEWEB)

Schippers, P.; Vernet, N. Meyer-; Lecacheux, A.; Belheouane, S.; Moncuquet, M. [LESIA—CNRS—Observatoire de Paris, 5 place Jules Janssen, F-92195 Meudon (France); Kurth, W. S. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA (United States); Mann, I. [EISCAT Scientific Association, Kiruna, Sweden and Department of Physics Umeå University (Sweden); Mitchell, D. G. [Applied Physics Laboratory, John Hopkins University, Laurel, MD (United States); André, N. [IRAP, 9 Avenue du Colonel Roche, F-31028 Toulouse (France)

2015-06-10

The solar system contains solids of all sizes, ranging from kilometer-sized bodies to nano-sized particles. Nanograins have been detected in situ in the Earth's atmosphere, near cometary and giant planet environments, and more recently in the solar wind at 1 AU. The latter nanograins are thought to be formed in the inner solar system dust cloud, mainly through the collisional break-up of larger grains, and are then picked up and accelerated by the magnetized solar wind because of their large charge-to-mass ratio. In the present paper, we analyze the low frequency bursty noise identified in the Cassini radio and plasma wave data during the spacecraft cruise phase inside Jupiter's orbit. The magnitude, spectral shape, and waveform of this broadband noise are consistent with the signatures of the nano particles that traveled at solar wind speed and impinged on the spacecraft surface. Nanoparticles were observed whenever the radio instrument was turned on and able to detect them at different heliocentric distances between Earth and Jupiter, suggesting their ubiquitous presence in the heliosphere. We analyzed the radial dependence of the nanodust flux with heliospheric distance and found that it is consistent with the dynamics of nanodust originating from the inner heliosphere and picked up by the solar wind. The contribution of the nanodust produced in the asteroid belt appears to be negligible compared to the trapping region in the inner heliosphere. In contrast, further out, nanodust is mainly produced by the volcanism of active moons such as Io and Enceladus.

A decision model for planetary missions

Science.gov (United States)

Hazelrigg, G. A., Jr.; Brigadier, W. L.

1976-01-01

Many techniques developed for the solution of problems in economics and operations research are directly applicable to problems involving engineering trade-offs. This paper investigates the use of utility theory for decision making in planetary exploration space missions. A decision model is derived that accounts for the objectives of the mission - science - the cost of flying the mission and the risk of mission failure. A simulation methodology for obtaining the probability distribution of science value and costs as a function spacecraft and mission design is presented and an example application of the decision methodology is given for various potential alternatives in a comet Encke mission.

The Case for Deep Space Telecommunications Relay Stations

Science.gov (United States)

Chandler, Charles W.; Miranda, Felix A. (Technical Monitor)

2004-01-01

Each future mission to Jupiter and beyond must carry the traditional suite of telecommunications systems for command and control and for mission data transmission to earth. The telecommunications hardware includes the large antenna and the high-power transmitters that enable the communications link. Yet future spacecraft will be scaled down from the hallmark missions of Galileo and Cassini to Jupiter and Saturn, respectively. This implies that a higher percentage of the spacecraft weight and power must be dedicated to telecommunications system. The following analysis quantifies this impact to future missions and then explores the merits of an alternative approach using deep space relay stations for the link back to earth. It will be demonstrated that a telecommunications relay satellite would reduce S/C telecommunications weight and power sufficiently to add one to two more instruments.

Critical Robotic Lunar Missions

Science.gov (United States)

Plescia, J. B.

2018-04-01

Perhaps the most critical missions to understanding lunar history are in situ dating and network missions. These would constrain the volcanic and thermal history and interior structure. These data would better constrain lunar evolution models.

Global Precipitation Measurement Mission: Architecture and Mission Concept

Science.gov (United States)

Bundas, David

2005-01-01

The Global Precipitation Measurement (GPM) Mission is a collaboration between the National Aeronautics and Space Administration (NASA) and the Japanese Aerospace Exploration Agency (JAXA), and other partners, with the goal of monitoring the diurnal and seasonal variations in precipitation over the surface of the earth. These measurements will be used to improve current climate models and weather forecasting, and enable improved storm and flood warnings. This paper gives an overview of the mission architecture and addresses some of the key trades that have been completed, including the selection of the Core Observatory s orbit, orbit maintenance trades, and design issues related to meeting orbital debris requirements.

A review of Spacelab mission management approach

Science.gov (United States)

Craft, H. G., Jr.

1979-01-01

The Spacelab development program is a joint undertaking of the NASA and ESA. The paper addresses the initial concept of Spacelab payload mission management, the lessons learned, and modifications made as a result of the actual implementation of Spacelab Mission 1. The discussion covers mission management responsibilities, program control, science management, payload definition and interfaces, integrated payload mission planning, integration requirements, payload specialist training, payload and launch site integration, payload flight/mission operations, and postmission activities. After 3.5 years the outlined overall mission manager approach has proven to be most successful. The approach does allow the mission manager to maintain the lowest overall mission cost.

Dukovany ASSET mission preparation

International Nuclear Information System (INIS)

Kouklik, I.

1996-01-01

We are in the final stages of the Dukovany ASSET mission 1996 preparation. I would like to present some of our recent experiences. Maybe they would be helpful to other plants, that host ASSET missions in future

Dukovany ASSET mission preparation

Energy Technology Data Exchange (ETDEWEB)

Kouklik, I [NPP Dukovany (Czech Republic)

1997-12-31

We are in the final stages of the Dukovany ASSET mission 1996 preparation. I would like to present some of our recent experiences. Maybe they would be helpful to other plants, that host ASSET missions in future.

Psychosocial interactions during ISS missions

Science.gov (United States)

Kanas, N. A.; Salnitskiy, V. P.; Ritsher, J. B.; Gushin, V. I.; Weiss, D. S.; Saylor, S. A.; Kozerenko, O. P.; Marmar, C. R.

2007-02-01

Based on anecdotal reports from astronauts and cosmonauts, studies of space analog environments on Earth, and our previous research on the Mir Space Station, a number of psychosocial issues have been identified that can lead to problems during long-duration space expeditions. Several of these issues were studied during a series of missions to the International Space Station. Using a mood and group climate questionnaire that was completed weekly by crewmembers in space and personnel in mission control, we found no evidence to support the presence of predicted decrements in well-being during the second half or in any specific quarter of the missions. The results did support the predicted displacement of negative feelings to outside supervisors among both crew and ground subjects. There were several significant differences in mood and group perceptions between Americans and Russians and between crewmembers and mission control personnel. Crewmembers related cohesion to the support role of their leader, and mission control personnel related cohesion to both the task and support roles of their leader. These findings are discussed with reference to future space missions.

Human exploration mission studies

Science.gov (United States)

Cataldo, Robert L.

1989-01-01

The Office of Exploration has established a process whereby all NASA field centers and other NASA Headquarters offices participate in the formulation and analysis of a wide range of mission strategies. These strategies were manifested into specific scenarios or candidate case studies. The case studies provided a systematic approach into analyzing each mission element. First, each case study must address several major themes and rationale including: national pride and international prestige, advancement of scientific knowledge, a catalyst for technology, economic benefits, space enterprise, international cooperation, and education and excellence. Second, the set of candidate case studies are formulated to encompass the technology requirement limits in the life sciences, launch capabilities, space transfer, automation, and robotics in space operations, power, and propulsion. The first set of reference case studies identify three major strategies: human expeditions, science outposts, and evolutionary expansion. During the past year, four case studies were examined to explore these strategies. The expeditionary missions include the Human Expedition to Phobos and Human Expedition to Mars case studies. The Lunar Observatory and Lunar Outpost to Early Mars Evolution case studies examined the later two strategies. This set of case studies established the framework to perform detailed mission analysis and system engineering to define a host of concepts and requirements for various space systems and advanced technologies. The details of each mission are described and, specifically, the results affecting the advanced technologies required to accomplish each mission scenario are presented.

Flight mission control for multiple spacecraft

Science.gov (United States)

Ryan, Robert E.

1990-10-01

A plan developed by the Jet Propulsion Laboratory for mission control of unmanned spacecraft is outlined. A technical matrix organization from which, in the past, project teams were formed to uniquely support a mission is replaced in this new plan. A cost effective approach was needed to make best use of limited resources. Mission control is a focal point operations and a good place to start a multimission concept. Co-location and sharing common functions are the keys to obtaining efficiencies at minimum additional risk. For the projects, the major changes are sharing a common operations area and having indirect control of personnel. The plan identifies the still direct link for the mission control functions. Training is a major element in this plan. Personnel are qualified for a position and certified for a mission. This concept is more easily accepted by new missions than the ongoing missions.

L'astronomie dans le monde - 09/2001

OpenAIRE

Manfroid, Jean

2001-01-01

Nouveau scénario de mission pour Cassini-Huygens;Céres détrôné; Fred Hoyle (1915-2001); Pollution lumineuse; La météorite du Lac Tagish; LS5039; Un trou noir pour M33?; Activité stellaire extrême et trou noir supermassif dans la galaxie M81; Image gravitationnelle sextuple; Un diplôme officiel d'astrologie

Sustainable, Reliable Mission-Systems Architecture

Science.gov (United States)

O'Neil, Graham; Orr, James K.; Watson, Steve

2007-01-01

A mission-systems architecture, based on a highly modular infrastructure utilizing: open-standards hardware and software interfaces as the enabling technology is essential for affordable and sustainable space exploration programs. This mission-systems architecture requires (a) robust communication between heterogeneous system, (b) high reliability, (c) minimal mission-to-mission reconfiguration, (d) affordable development, system integration, and verification of systems, and (e) minimal sustaining engineering. This paper proposes such an architecture. Lessons learned from the Space Shuttle program and Earthbound complex engineered system are applied to define the model. Technology projections reaching out 5 years are mde to refine model details.

308 Building deactivation mission analysis report

International Nuclear Information System (INIS)

Lund, D.P.

1995-01-01

This report presents the results of the 308 Building (Fuels Development Laboratory) Deactivation Project mission analysis. Hanford systems engineering (SE) procedures call for a mission analysis. The mission analysis is an important first step in the SE process. The functions and requirements to successfully accomplish this mission, the selected alternatives and products will later be defined using the SE process

309 Building deactivation mission analysis report

International Nuclear Information System (INIS)

Lund, D.P.

1995-01-01

This report presents the results of the 309 Building (Plutonium Fuels Utilization Program) Deactivation Project mission analysis. Hanford systems engineering (SE) procedures call for a mission analysis. The mission analysis is an important first step in the SE process. The functions and requirements to successfully accomplish this mission, the selected alternatives and products will later be defined using the SE process

Crew Transportation System Design Reference Missions

Science.gov (United States)

Mango, Edward J.

2015-01-01

Contains summaries of potential design reference mission goals for systems to transport humans to andfrom low Earth orbit (LEO) for the Commercial Crew Program. The purpose of this document is to describe Design Reference Missions (DRMs) representative of the end-to-end Crew Transportation System (CTS) framework envisioned to successfully execute commercial crew transportation to orbital destinations. The initial CTS architecture will likely be optimized to support NASA crew and NASA-sponsored crew rotation missions to the ISS, but consideration may be given in this design phase to allow for modifications in order to accomplish other commercial missions in the future. With the exception of NASA’s mission to the ISS, the remaining commercial DRMs are notional. Any decision to design or scar the CTS for these additional non-NASA missions is completely up to the Commercial Provider. As NASA’s mission needs evolve over time, this document will be periodically updated to reflect those needs.

Improving the Operations of the Earth Observing One Mission via Automated Mission Planning

Science.gov (United States)

Chien, Steve A.; Tran, Daniel; Rabideau, Gregg; Schaffer, Steve; Mandl, Daniel; Frye, Stuart

2010-01-01

We describe the modeling and reasoning about operations constraints in an automated mission planning system for an earth observing satellite - EO-1. We first discuss the large number of elements that can be naturally represented in an expressive planning and scheduling framework. We then describe a number of constraints that challenge the current state of the art in automated planning systems and discuss how we modeled these constraints as well as discuss tradeoffs in representation versus efficiency. Finally we describe the challenges in efficiently generating operations plans for this mission. These discussions involve lessons learned from an operations model that has been in use since Fall 2004 (called R4) as well as a newer more accurate operations model operational since June 2009 (called R5). We present analysis of the R5 software documenting a significant (greater than 50%) increase in the number of weekly observations scheduled by the EO-1 mission. We also show that the R5 mission planning system produces schedules within 15% of an upper bound on optimal schedules. This operational enhancement has created value of millions of dollars US over the projected remaining lifetime of the EO-1 mission.

Temporal evolution of the EIA along 95°E as obtained from GNSS TEC measurements and SAMI3 model

Science.gov (United States)

Kakoti, Geetashree; Kalita, Bitap Raj; Hazarika, Rumajyoti; Bhuyan, Pradip Kumar; Sharma, Sanjay; Tiwari, Ramesh Chandra

2018-06-01

The total electron content (TEC) derived from GNSS measurements at a trans-hemispheric meridional chain of ground stations around 95°E longitude are used to study the quiet time inter-hemispheric structure and dynamics of the equatorial ionization anomaly (EIA) during the period March 2015 to February 2016. The stations are Dibrugarh (27.5°N, 95°E, 43° dip), Kohima (25.6°N, 94.1°E, 39° dip), Aizawl (23.7°N, 92.8°E, 36° dip), Port Blair (11.63°N, 92.71°E, 9° dip) and Cocos Islands (12.2°S, 96.8°E, 43° dip). The observation shows that the northern crest of the EIA lies in the south of 23°N (Aizawl) in all seasons but recedes further south towards the equator during December solstice. The largest poleward expansion of the northern (southern) EIA is observed in the March equinox (December solstice). The equinoctial and hemispherical asymmetry of TEC is noted. The winter anomaly is observed in the northern hemisphere but not in the southern hemisphere. The highest midday TEC over any station is observed in the March equinox. The TEC in southern summer (December solstice) is significantly higher than that in the northern summer (June solstice). The observed northern EIA contracts equatorward in the postsunset period of solstice but the southern EIA persists late into the midnight in the December solstice. The asymmetry may be attributed to the different geographic location of the magnetically conjugate stations. The SAMI3 simulations broadly capture the EIA structure and the inter-hemispheric asymmetry during solstices. The difference between observations and the SAMI3 is higher in March equinox and December solstice. The higher E × B vertical drift in the 90-100°E sector and the large geographic-geomagnetic offset in observing stations may have contributed to the observed differences.

The Bible and mission in faith perspective: J.Hudson Taylor and the early China Inland Mission

NARCIS (Netherlands)

Wigram, C.E.M.

2007-01-01

The thesis 'The Bible and Mission in Faith Perspective: J.Hudson Taylor and the Early China Inland Mission' by Christopher E.M. Wigram analysis the hermeneutical assumptions that underlay Hudson Taylor's approach to biblical interpretation, and the significance of his approach for the mission which

The PROPEL Electrodynamic Tether Demonstration Mission

Science.gov (United States)

Bilen, Sven G.; Johnson, C. Les; Wiegmann, Bruce M.; Alexander, Leslie; Gilchrist, Brian E.; Hoyt, Robert P.; Elder, Craig H.; Fuhrhop, Keith P.; Scadera, Michael

2012-01-01

The PROPEL ("Propulsion using Electrodynamics") mission will demonstrate the operation of an electrodynamic tether propulsion system in low Earth orbit and advance its technology readiness level for multiple applications. The PROPEL mission has two primary objectives: first, to demonstrate the capability of electrodynamic tether technology to provide robust and safe, near-propellantless propulsion for orbit-raising, de-orbit, plane change, and station keeping, as well as to perform orbital power harvesting and formation flight; and, second, to fully characterize and validate the performance of an integrated electrodynamic tether propulsion system, qualifying it for infusion into future multiple satellite platforms and missions with minimal modification. This paper provides an overview of the PROPEL system and design reference missions; mission goals and required measurements; and ongoing PROPEL mission design efforts.

Orbit determination for ISRO satellite missions

Science.gov (United States)

Rao, Ch. Sreehari; Sinha, S. K.

Indian Space Research Organisation (ISRO) has been successful in using the in-house developed orbit determination and prediction software for satellite missions of Bhaskara, Rohini and APPLE. Considering the requirements of satellite missions, software packages are developed, tested and their accuracies are assessed. Orbit determination packages developed are SOIP, for low earth orbits of Bhaskara and Rohini missions, ORIGIN and ODPM, for orbits related to all phases of geo-stationary missions and SEGNIP, for drift and geo-stationary orbits. Software is tested and qualified using tracking data of SIGNE-3, D5-B, OTS, SYMPHONIE satellites with the help of software available with CNES, ESA and DFVLR. The results match well with those available from these agencies. These packages have supported orbit determination successfully throughout the mission life for all ISRO satellite missions. Member-Secretary

Composable Mission Framework for Rapid End-to-End Mission Design and Simulation, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The innovation proposed here is the Composable Mission Framework (CMF) a model-based software framework that shall enable seamless continuity of mission design and...

Centralized mission planning and scheduling system for the Landsat Data Continuity Mission

Science.gov (United States)

Kavelaars, Alicia; Barnoy, Assaf M.; Gregory, Shawna; Garcia, Gonzalo; Talon, Cesar; Greer, Gregory; Williams, Jason; Dulski, Vicki

2014-01-01

Satellites in Low Earth Orbit provide missions with closer range for studying aspects such as geography and topography, but often require efficient utilization of space and ground assets. Optimizing schedules for these satellites amounts to a complex planning puzzle since it requires operators to face issues such as discontinuous ground contacts, limited onboard memory storage, constrained downlink margin, and shared ground antenna resources. To solve this issue for the Landsat Data Continuity Mission (LDCM, Landsat 8), all the scheduling exchanges for science data request, ground/space station contact, and spacecraft maintenance and control will be coordinated through a centralized Mission Planning and Scheduling (MPS) engine, based upon GMV’s scheduling system flexplan9 . The synchronization between all operational functions must be strictly maintained to ensure efficient mission utilization of ground and spacecraft activities while working within the bounds of the space and ground resources, such as Solid State Recorder (SSR) and available antennas. This paper outlines the functionalities that the centralized planning and scheduling system has in its operational control and management of the Landsat 8 spacecraft.

Titan's Surface Composition from Cassini VIMS Solar Occultation Observations

Science.gov (United States)

McCord, Thomas; Hayne, Paul; Sotin, Christophe

2013-04-01

Titan's surface is obscured by a thick absorbing and scattering atmosphere, allowing direct observation of the surface within only a few spectral win-dows in the near-infrared, complicating efforts to identify and map geologi-cally important materials using remote sensing IR spectroscopy. We there-fore investigate the atmosphere's infrared transmission with direct measure-ments using Titan's occultation of the Sun as well as Titan's reflectance measured at differing illumination and observation angles observed by Cas-sini's Visual and Infrared Mapping Spectrometer (VIMS). We use two im-portant spectral windows: the 2.7-2.8-mm "double window" and the broad 5-mm window. By estimating atmospheric attenuation within these windows, we seek an empirical correction factor that can be applied to VIMS meas-urements to estimate the true surface reflectance and map inferred composi-tional variations. Applying the empirical corrections, we correct the VIMS data for the viewing geometry-dependent atmospheric effects to derive the 5-µm reflectance and 2.8/2.7-µm reflectance ratio. We then compare the cor-rected reflectances to compounds proposed to exist on Titan's surface. We propose a simple correction to VIMS Titan data to account for atmospheric attenuation and diffuse scattering in the 5-mm and 2.7-2.8 mm windows, generally applicable for airmass water ice for the majority of the low-to-mid latitude area covered by VIMS measurements. Four compositional units are defined and mapped on Titan's surface based on the positions of data clusters in 5-mm vs. 2.8/2.7-mm scatter plots; a simple ternary mixture of H2O, hydrocarbons and CO2 might explain the reflectance properties of these surface units. The vast equatorial "dune seas" are compositionally very homogeneous, perhaps suggesting transport and mixing of particles over very large distances and/or and very consistent formation process and source material. The composi-tional branch characterizing Tui Regio and Hotei Regio is

Looking For Thermal IR Polarization In Saturn's Rings With Cassini/CIRS

Science.gov (United States)

Edgington, Scott G.; Spilker, L. J.; Jennings, D. E.; Altobelli, N.; Pilorz, S. H.; Pearl, J. C.; Leyrat, C.; CIRS Team

2007-10-01

The Cassini Composite Infrared Spectrometer (CIRS) FP1 channel is a polarizing interferometer covering the spectral range from 10 to 600 cm-1. By rotating the instrument about its optical axis, it is possible to measure the IR polarization of target objects over that spectral range. This requires the FP1 footprint on the rings, the emission angle, and the phase angle to be fairly constant for the duration of the observation. With these constraints, we turned two composition observations, both allocated long periods of time for sitting-and-staring, into polarization observations. The time was divided equally amongst observations of the A, B, and C rings, with one observation taking place on the lit side and the other on the unlit side. We chose relative rotations of 0, 30, and 60 degrees (future observations will use 0, 45, 90, and 135 degree rotations). For each ring, we will determine the Stokes Vector (I, Q, U, V) and the degree of polarization, (Q+U+V)/I. We will also examine the degree to which the temperature and emissivity varies with the orientation of the field of view. One of the observation takes place at low phase angles. At low phase angles, the filling factor of the C-Ring has been shown to increase steeply with decreasing spacecraft elevation (Altobelli, et al., 2007). We will determine the limitations of this physical effect on the determination of the polarization of the C-ring. Successful measurements should provide information on the microscopic roughness of ring particles. We will report on results of these observations. For a similar analysis pertaining to Iapetus' surface, see J. C. Pearl, et al. (this meeting). The research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

The Ring System of Saturn as Seen by Cassini-VIMS (Invited)

Science.gov (United States)

Filacchione, G.; Ciarniello, M.; Capaccioni, F.

2015-08-01

Since 2004 the Visual and Infrared Mapping Spectrometer (VIMS) aboard Cassini has acquired numerous hyperspectral mosaics in the 0.35-5.1 μm spectral range of Saturn's main rings in very different illumination and viewing geometries. These observations have allowed us to infer the ring particles physical properties and composition: water ice abundance is estimated through the 1.25-1.5-2.0 μm band depths, chromophores distribution is derived from visible spectral slopes while organic material is traced by the aliphatic compounds signature at 3.42 μm which appears stronger on CD and C ring than on A-B rings (Filacchione et al., 2014). Observed reflectance spectra are fitted with a spectrophotometric model based on Montecarlo ray-tracing with the scope to infer particles composition while disentangling photometric effects (caused by multiple scattering, opposition surge and forward scattering) which depend on illumination/viewing geometries. Spectral bond albedo for different regions of the rings has been best-fitted using Hapke's radiative transfer modeling (Ciarniello et al, 2011) by choosing different mixtures of water ice, tholin, and amorphous carbon particles populations. While tholin distribution seems to be fairly constant across the rings, the amorphous carbon appears anti-correlated with optical depth. Moreover, dark material contamination is less effective on densest regions, where the more intense rejuvenation processes occur, in agreement with the ballistic transport theory (Cuzzi and Estrada,1998). Finally, the 3.6 μm continuum peak wavelength is used to infer particles temperature, which is anti-correlated with the albedo and the optical depth (tau): low-albedo/low-tau C ring and CD have higher temperatures than A-B rings where albedo and tau are high. This trend matches direct temperature measurements by CIRS (Spilker et al., 2013).

Investigation of Jupiter's Equatorial Hotspots and Plumes Using Cassini ISS Observations

Science.gov (United States)

Choi, David S.; Showman, A. P.; Vasavada, A. R.; Simon-Miller, A. A.

2012-01-01

We present updated analysis of Jupiter's equatorial meteorology from Cassini observations. For two months preceding the spacecraft's closest approach, the ISS onboard regularly imaged the atmosphere. We created time-lapse movies from this period in order to analyze the dynamics of equatorial 5-micron hot spots and their interactions with adjacent latitudes. Hot spots are quasi-stable, rectangular dark areas on visible-wavelength images, with defined eastern edges that sharply contrast with surrounding clouds, but a diffuse western edge serving as a nebulous boundary with adjacent equatorial plumes. Hot spots exhibit significant variations in size and shape over timescales of days and weeks. Some of these changes correspond with passing vortex systems from adjacent latitudes interacting with hot spots. Strong anticyclonic gyres present to the south and southeast of the dark areas appear to circulate into hot spots. Impressive, bright white plumes occupy spaces in between hot spots. Compact cirrus-iike 'scooter' clouds flow rapidly through the plumes before disappearing within the dark areas. This raises the possibility that the plumes and fast-moving clouds are at higher altitudes, because their speed does not match previously published zonal wind profiles. Most profiles represent the drift speed of the hot spots at their latitude from pattern matching of the entire longitudinal image strip. If a downward branch of an equatorially-trapped Rossby waves controls the overall appearance of hot spots, however, the westward phase velocity of the wave leads to underestimates of the true jet stream speed. Instead, our expanded data set demonstrating the rapid flow of these scooter clouds may be more illustrative of the actual jet stream speed at these latitudes. This research was supported by a NASA JDAP grant and the NASA Postdoctoral Program.

Spacelab Mission Implementation Cost Assessment (SMICA)

Science.gov (United States)

Guynes, B. V.

1984-01-01

A total savings of approximately 20 percent is attainable if: (1) mission management and ground processing schedules are compressed; (2) the equipping, staffing, and operating of the Payload Operations Control Center is revised, and (3) methods of working with experiment developers are changed. The development of a new mission implementation technique, which includes mission definition, experiment development, and mission integration/operations, is examined. The Payload Operations Control Center is to relocate and utilize new computer equipment to produce cost savings. Methods of reducing costs by minimizing the Spacelab and payload processing time during pre- and post-mission operation at KSC are analyzed. The changes required to reduce costs in the analytical integration process are studied. The influence of time, requirements accountability, and risk on costs is discussed. Recommendation for cost reductions developed by the Spacelab Mission Implementation Cost Assessment study are listed.

Spacelab life sciences 2 post mission report

Science.gov (United States)

Buckey, Jay C.

1994-01-01

Jay C. Buckey, M.D., Assistant Professor of Medicine at The University of Texas Southwestern Medical Center at Dallas served as an alternate payload specialist astronaut for the Spacelab Life Sciences 2 Space Shuttle Mission from January 1992 through December 1993. This report summarizes his opinions on the mission and offers suggestions in the areas of selection, training, simulations, baseline data collection and mission operations. The report recognizes the contributions of the commander, payload commander and mission management team to the success of the mission. Dr. Buckey's main accomplishments during the mission are listed.

The 'Granite' collegial mission of dialogue. Report; Mission collegiale de concertation Granite. Rapport

Energy Technology Data Exchange (ETDEWEB)

Boisson, P; Huet, Ph; Mingasson, J

2000-06-01

The aim of the 'Granite' collegial mission of dialogue is to inform the French authorities, associations and population about the project of construction of an underground laboratory for the study of the disposal of high level and long-life radioactive wastes in a granitic environment. The aim of the dialogue was not to select a site but to collect the public reactions and advices about such a project. However, such a dialogue has partially failed because of a misunderstanding of the population about the aims of the mission. However, the mission has collected many point of views and questions which are developed in this report. The first and second chapters recall the process of the mission and its progress, while a third chapter stresses on the questions asked by the public and which concern the fear of nuclear wastes and the incompatibility between the disposal of wastes and the socio-economical development of the region concerned. Thanks to the lessons drawn from this experience, the mission has formulated some recommendations (chapter 4) concerning the need for a better information of the population about any topic in relation with the radioactive wastes. Some complementary information is provided in appendixes. (J.S.)

KEPLER Mission: development and overview

International Nuclear Information System (INIS)

Borucki, William J

2016-01-01

The Kepler Mission is a space observatory launched in 2009 by NASA to monitor 170 000 stars over a period of four years to determine the frequency of Earth-size and larger planets in and near the habitable zone of Sun-like stars, the size and orbital distributions of these planets, and the types of stars they orbit. Kepler is the tenth in the series of NASA Discovery Program missions that are competitively-selected, PI-directed, medium-cost missions. The Mission concept and various instrument prototypes were developed at the Ames Research Center over a period of 18 years starting in 1983. The development of techniques to do the 10 ppm photometry required for Mission success took years of experimentation, several workshops, and the exploration of many ‘blind alleys’ before the construction of the flight instrument. Beginning in 1992 at the start of the NASA Discovery Program, the Kepler Mission concept was proposed five times before its acceptance for mission development in 2001. During that period, the concept evolved from a photometer in an L2 orbit that monitored 6000 stars in a 50 sq deg field-of-view (FOV) to one that was in a heliocentric orbit that simultaneously monitored 170 000 stars with a 105 sq deg FOV. Analysis of the data to date has detected over 4600 planetary candidates which include several hundred Earth-size planetary candidates, over a thousand confirmed planets, and Earth-size planets in the habitable zone (HZ). These discoveries provide the information required for estimates of the frequency of planets in our galaxy. The Mission results show that most stars have planets, many of these planets are similar in size to the Earth, and that systems with several planets are common. Although planets in the HZ are common, many are substantially larger than Earth. (review article)

Saturn's Misbegotten Moonlets

Science.gov (United States)

Spitale, Joseph N.

2017-06-01

Saturn's rings are interspersed with numerous narrow (tens of km wide) gaps. Two of the largest of these gaps -- Encke and Keeler -- contain satellites -- Pan and Daphnis -- that maintain their respective gaps via the classical Goldreich/Tremaine-style shepherding mechanism wherein angular momentum is transferred across the essentially empty gap via torques acting between the satellites and the ring. Other prominent gaps are shepherded by resonances with external satellites or planetary modes: Mimas shepherds the outer edge of the B ring, clearing the inner part of the Cassini Division, Titan shepherds the Columbo ringlet / gap, and the Maxwell ringlet / gap is likely maintained by a resonance with a planetary mode. Prior to Cassini, it was expected that all of the gaps would be shepherded in a similar manner.However, many small gaps do not correspond with known resonances, and no satellites were spotted within those gaps during Cassini's prime and extended mission. To address this issue, a series of Cassini imaging observations were planned to examine 11 gaps in the C ring and Cassini division at a resolution and longitudinal coverage sufficient to either discover the shepherds or rule out their presence. The survey discovered no embedded satellites. Longitudinal coverage was incomplete, but within longitudes covered by the survey, satellites are ruled out to sizes in the 100-m range, far too small keep the observed gaps open. It is possible (about even odds) that there could be a larger satellite residing at a longitude not covered in the survey, but the probability that the survey was unfortunate enough to miss significant satellites in all 11 gaps is exceedingly small (~0.002%). Moreover, these gaps appear in earlier imaging sequences, with some high-resolution coverage, so the true probability is smaller yet. Therefore, a new theory is likely needed to explain the presence of the gaps.

IRIS Mission Operations Director's Colloquium

Science.gov (United States)

Carvalho, Robert; Mazmanian, Edward A.

2014-01-01

Pursuing the Mysteries of the Sun: The Interface Region Imaging Spectrograph (IRIS) Mission. Flight controllers from the IRIS mission will present their individual experiences on IRIS from development through the first year of flight. This will begin with a discussion of the unique nature of IRISs mission and science, and how it fits into NASA's fleet of solar observatories. Next will be a discussion of the critical roles Ames contributed in the mission including spacecraft and flight software development, ground system development, and training for launch. This will be followed by experiences from launch, early operations, ongoing operations, and unusual operations experiences. The presentation will close with IRIS science imagery and questions.

MMPM - Mars MetNet Precursor Mission

Science.gov (United States)

Harri, A.-M.; Schmidt, W.; Pichkhadze, K.; Linkin, V.; Vazquez, L.; Uspensky, M.; Polkko, J.; Genzer, M.; Lipatov, A.; Guerrero, H.; Alexashkin, S.; Haukka, H.; Savijarvi, H.; Kauhanen, J.

2008-09-01

We are developing a new kind of planetary exploration mission for Mars - MetNet in situ observation network based on a new semi-hard landing vehicle called the Met-Net Lander (MNL). The eventual scope of the MetNet Mission is to deploy some 20 MNLs on the Martian surface using inflatable descent system structures, which will be supported by observations from the orbit around Mars. Currently we are working on the MetNet Mars Precursor Mission (MMPM) to deploy one MetNet Lander to Mars in the 2009/2011 launch window as a technology and science demonstration mission. The MNL will have a versatile science payload focused on the atmospheric science of Mars. Detailed characterization of the Martian atmospheric circulation patterns, boundary layer phenomena, and climatology cycles, require simultaneous in-situ measurements by a network of observation posts on the Martian surface. The scientific payload of the MetNet Mission encompasses separate instrument packages for the atmospheric entry and descent phase and for the surface operation phase. The MetNet mission concept and key probe technologies have been developed and the critical subsystems have been qualified to meet the Martian environmental and functional conditions. Prototyping of the payload instrumentation with final dimensions was carried out in 2003-2006.This huge development effort has been fulfilled in collaboration between the Finnish Meteorological Institute (FMI), the Russian Lavoschkin Association (LA) and the Russian Space Research Institute (IKI) since August 2001. Currently the INTA (Instituto Nacional de Técnica Aeroespacial) from Spain is also participating in the MetNet payload development. To understand the behavior and dynamics of the Martian atmosphere, a wealth of simultaneous in situ observations are needed on varying types of Martian orography, terrain and altitude spanning all latitudes and longitudes. This will be performed by the Mars MetNet Mission. In addition to the science aspects the

Mission to the Solar System: Exploration and Discovery. A Mission and Technology Roadmap

Science.gov (United States)

Gulkis, S. (Editor); Stetson, D. S. (Editor); Stofan, E. R. (Editor)

1998-01-01

Solar System exploration addresses some of humanity's most fundamental questions: How and when did life form on Earth? Does life exist elsewhere in the Solar System or in the Universe? - How did the Solar System form and evolve in time? - What can the other planets teach us about the Earth? This document describes a Mission and Technology Roadmap for addressing these and other fundamental Solar System Questions. A Roadmap Development Team of scientists, engineers, educators, and technologists worked to define the next evolutionary steps in in situ exploration, sample return, and completion of the overall Solar System survey. Guidelines were to "develop aa visionary, but affordable, mission and technology development Roadmap for the exploration of the Solar System in the 2000 to 2012 timeframe." The Roadmap provides a catalog of potential flight missions. (Supporting research and technology, ground-based observations, and laboratory research, which are no less important than flight missions, are not included in this Roadmap.)

Quarterly Technical Progress Report of Radioisotope Power System Materials Production and Technology Program tasks for January 2000 through March 2000

International Nuclear Information System (INIS)

Moore, J.P.

2000-01-01

The Office of Space and Defense Power Systems (OSDPS) of the Department of Energy (DOE) provides radioisotope Power Systems (BPS) for applications where conventional power systems are not feasible. For example, radioisotope thermoelectric generators were supplied by the DOE to the National Aeronautics and Space Administration for deep space missions including the Cassini Mission launched in October of .I 997 to study the planet Saturn. The Oak Ridge National Laboratory (ORNL) has been involved in developing materials and technology and producing components for the DOE for more than three decades. For the Cassini Mission, for example, ORNL was involved in the production of carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, and clad vent sets (CVSs) and weld shields (WSs). This quarterly report has been divided into three sections to reflect program guidance from OSDPS for fiscal year (FY) 2000. The first section deals primarily with maintenance of the capability to produce flight quality carbon-bonded carbon fiber (CBCF) insulator sets, iridium alloy blanks and foil, clad vent sets (CVSs), and weld shields (WSs). In all three cases, production maintenance is assured by the manufacture of limited quantities of flight quality (FQ) components. The second section deals with several technology activities to improve the manufacturing processes, characterize materials, or to develop technologies for two new RPS. The last section is dedicated to studies of the potential for the production of 238Pu at OBNL

Mission Critical Occupation (MCO) Charts

Data.gov (United States)

Office of Personnel Management — Agencies report resource data and targets for government-wide mission critical occupations and agency specific mission critical and/or high risk occupations. These...

Rings Research in the Next Decade

Science.gov (United States)

Burns, J. A.; Tiscareno, M. S.

2009-12-01

The study of planetary ring systems forms a key component of planetary science for several reasons: 1) The evolution and current states of planets and their satellites are affected in many ways by rings, while 2) conversely, properties of planets and moons and other solar system populations are revealed by their effects on rings; 3) highly structured and apparently delicate ring systems may be bellwethers, constraining various theories of the origin and evolution of their entire planetary system; and finally, 4) planetary rings provide an easily observable analogue to other astrophysical disk systems, enabling real “ground truth” results applicable to disks much more remote in space and/or time, including proto-planetary disks, circum-stellar disks, and even galaxies. Significant advances have been made in rings science in the past decade. The highest-priority rings research recommendations of the last Planetary Science Decadal Survey were to operate and extend the Cassini orbiter mission at Saturn; this has been done with tremendous success, accounting for much of the progress made on key science questions, as we will describe. Important progress in understanding the rings of Saturn and other planets has also come from Earth-based observational and theoretical work, again as prioritized by the last Decadal Survey. However, much important work remains to be done. At Saturn, the Cassini Solstice Mission must be brought to a successful completion. Priority should also be placed on sending spacecraft to Neptune and/or Uranus, now unvisited for more than 20 years. At Jupiter and Pluto, opportunities afforded by visiting spacecraft capable of studying rings should be exploited. On Earth, the need for continued research and analysis remains strong, including in-depth analysis of rings data already obtained, numerical and theoretical modeling work, laboratory analysis of materials and processes analogous to those found in the outer solar system, and continued Earth

Evaluation of full and degraded mission reliability and mission dependability for intermittently operated, multi-functional systems

International Nuclear Information System (INIS)

Sols, Alberto; Ramirez-Marquez, Jose E.; Verma, Dinesh; Vitoriano, Begona

2007-01-01

Availability is one of the metrics often used in the evaluation of system effectiveness. Its use as an effectiveness metric is often dictated by the nature of the system under consideration. While some systems operate continuously, many others operate on an intermittent basis where each operational period may often involve a different set of missions. This is the most likely scenario for complex multi-functional systems, where each specific system mission may require the availability of a different combination of system elements. Similarly, for these systems, not only is it important to know whether a mission can be initiated, it is just as important to know whether the system is capable of completing such a mission. Thus, for these systems, additional measures become relevant to provide a more holistic assessment of system effectiveness. This paper presents techniques for the evaluation of both full and degraded mission reliability and mission dependability for coherent, intermittently operated multi-functional systems. These metrics complement previously developed availability and degraded availability measures of multi-functional systems, in the comprehensive assessment of system effectiveness

Multi-Mission SDR, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Wireless transceivers used for NASA space missions have traditionally been highly custom and mission specific. Programs such as the GRC Space Transceiver Radio...

The NASA X-Ray Mission Concepts Study

Science.gov (United States)

Petre, Robert; Ptak, A.; Bookbinder, J.; Garcia, M.; Smith, R.; Bautz, M.; Bregman, J.; Burrows, D.; Cash, W.; Jones-Forman, C.;

Science Mission Definition Studies for TROPIX

Science.gov (United States)

Fennell, J. F.

1997-01-01

This document summarizes the results of mission definition studies for solar electric propulsion missions that have been carried out over the last approximately three years. The major output from the studies has been two proposals which were submitted to NASA in response to Announcements of Opportunity for missions and an ongoing Global Magnetospheric Dynamics mission study. The bulk of this report consists of copies of the proposals and preliminary materials from the GMD study that will be completed in the coming months.

Automated trajectory planning for multiple-flyby interplanetary missions

Science.gov (United States)

Englander, Jacob

including direct transcription with nonlinear programming (DTNLP), the inverse-polynomial shapebased method, and feasible region analysis. However the only physical model and optimization method that proved reliable enough were the Sims-Flanagan transcription coupled with a nonlinear programming solver and the monotonic basin hopping (MBH) global search heuristic. The methods developed here are demonstrated to optimize a set of example trajectories, including a recreation of the Cassini mission, a Galileo-like mission, and conceptual continuous-thrust missions to Jupiter, Mercury, and Uranus.

The Asteroid Redirect Mission (ARM)

Science.gov (United States)

Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

2016-07-01

To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human spaceflight missions. Today, human flight experience extends only to Low-Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human spaceflight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM). Mission Description: NASA's ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), the first robotic mission to visit a large (greater than ~100 m diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, demonstrate a planetary defense technique, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to Earth with samples. NASA's proposed

L-band nighttime scintillations at the northern edge of the EIA along 95°E during the ascending half of the solar cycle 24

Science.gov (United States)

Dutta, Barsha; Kalita, Bitap Raj; Bhuyan, Pradip Kumar

2018-04-01

The characteristics of nighttime ionospheric scintillations measured at the L-band frequency of 1.575 GHz over Dibrugarh (27.5°N, 95°E, MLAT ∼ 17°N, 43° dip) during the ascending half of the solar cycle 24 from 2010 to 2014 have been investigated and the results are presented in this paper. The measurement location is within or outside the zone of influence of the equatorial ionization anomaly depending on solar and geomagnetic activity. Maximum scintillation is observed in the equinoxes irrespective of solar activity with clear asymmetry between March and September. The occurrence frequency in the solstices shifts from minimum in the June solstice in low solar activity to a minimum in the December solstice in high solar activity years. A significant positive correlation of occurrence of scintillations in the June solstice with solar activity has been observed. However, earlier reports from the Indian zone (∼75°E) indicate negative or no correlation of scintillation in June solstice with solar activity. Scintillations activity/occurrence in solstices indicates a clear positive correlation with Es recorded simultaneously by a collocated Ionosonde. In equinoxes, maximum scintillations occur in the pre-midnight hours while in solstices the occurrence frequency peaks just after sunset. The incidence of strong scintillations (S4 ≥ 0.4) increases with increase in solar activity. Strong (S4 ≥ 0.4) ionospheric scintillations accompanied by TEC depletions in the pre-midnight period is attributed to equatorial irregularities whereas the dusk period scintillations are related to the sporadic-E activity. Present results thus indicate that the current location at the northern edge of the EIA behaves as low as well as mid-latitude location.

IceBridge Mission Flight Reports

Data.gov (United States)

National Aeronautics and Space Administration — The IceBridge Mission Flight Reports data set contains flight reports from NASA Operation IceBridge Greenland, Arctic, Antarctic, and Alaska missions. Flight reports...

Seasonal shift in climatic limiting factors on tree transpiration: evidence from sap flow observations at alpine treelines in southeast Tibet

Directory of Open Access Journals (Sweden)

Liu Xinsheng

2016-07-01

Full Text Available Alpine and northern treelines are primarily controlled by low temperatures. However, little is known about the impact of low soil temperature on tree transpiration at treelines. We aim to test the hypothesis that in cold-limited forests, the main limiting factors for tree transpiration switch from low soil temperature before summer solstice to atmospheric evaporative demand after summer solstice, which generally results in low transpiration in the early growing season. Sap flow, meteorological factors and predawn needle water potential were continuously monitored throughout one growing season across Smith fir (Abies georgei var. smithii and juniper (Juniperus saltuaria treelines in southeast Tibet. Sap flow started in early May and corresponded to a threshold mean air-temperature of 0 oC. Across tree species, transpiration was mainly limited by low soil temperature prior to the summer solstice but by vapor pressure deficit and solar radiation post-summer solstice, which was further confirmed on a daily scale. As a result, tree transpiration for both tree species was significantly reduced in the pre-summer solstice period as compared to post-summer solstice, resulting in a lower predawn needle water potential for Smith fir trees in the early growing season. Our data supported the hypothesis, suggesting that tree transpiration mainly responds to soil temperature variations in the early growing season. The results are important for understanding the hydrological response of cold-limited forest ecosystems to climate change.

Mission,System Design and Payload Aspects of ESA's Mercury Cornerstone Mission

Science.gov (United States)

Ferri, A.; Anselmi, A.; Scoon, G. E. N.

1999-09-01

Aim of this paper is to summarise the 1-year study performed by Alenia Aerospazio in close co-operation with the European Space Agency, on the Mercury Cornerstone System and Technology Study, as a part of Horizon 2000+ Scientific Programme plan. ESA's definition study towards a mission to Mercury conceives the launch of a S/C in 2009, on a two to three years journey, plus a one-year scientific observations and data take. The mission's primary objectives are manyfolded, aiming at approaching basic scientific questions on the origin and evolution of Mercury: identify and map the chemical and mineral composition of the surface, measure the topography of surface landforms, define the gravitational field, investigate particles and magnetic fields. The mission is also intended to resolve the librational state of the planet, in a system experiment requiring high accuracy inertial attitude (arcsecond level) and orbit (m-level) reconstitution. This experiment will allow to infer whether Mercury has a molten core, which is crucial to theories of magnetic field generation, and theories of the thermal history of terrestrial type planets. A hard-lander is planned to perform in-situ surface geochemical analysis. The mission is expected to provide scientists with a global portrait of Mercury returning about 1200 Gbits of scientific data, during a 1-year observation phase. The crucial aspects of the spacecraft design have to do with the high-temperature and high-radiation environment. Thermal control is achieved by a combination of orbit selection, attitude law, and special design provisions for IR shielding and HT insulation. Ad-hoc design provisions are envisaged for power and antenna mechanisms. Though the conceptual objectives of this industrial study focused on system architectures and enabling technologies for a "Cornerstone" class mission, in this paper emphasis is given on the scientific payload aspects.

Photometric Modeling and VIS-IR Albedo Maps of Dione From Cassini-VIMS

Science.gov (United States)

Filacchione, G.; Ciarniello, M.; D'Aversa, E.; Capaccioni, F.; Cerroni, P.; Buratti, B. J.; Clark, R. N.; Stephan, K.; Plainaki, C.

2018-03-01

We report about visible and infrared albedo maps and spectral indicators of Dione's surface derived from the complete Visual and Infrared Mapping Spectrometer (VIMS) data set acquired between 2004 and 2017 during the Cassini tour in Saturn's system. Maps are derived by applying a photometric correction necessary to disentangle the intrinsic albedo of the surface from illumination and viewing geometry occurring at the time of the observation. The photometric correction is based on the Shkuratov et al. (2011, https://doi.org/10.1016/j.pss.2011.06.011) method which yields values of the surface equigonal albedo. Dione's surface albedo maps are rendered at five visible (VIS: 0.35, 0.44, 0.55, 0.7, and 0.95 μm) and five infrared (IR: 1.046, 1.540, 1.822, 2.050, and 2.200 μm) wavelengths in cylindrical projection with a 0.5° × 0.5° angular resolution in latitude and longitude, corresponding to a spatial resolution of 4.5 km/bin. Apart from visible and infrared albedo maps, we report about the distribution of the two visible spectral slopes (0.35-0.55 and 0.55-0.95 μm) and water ice 2.050 μm band depth computed after having applied the photometric correction. The derived spectral indicators are employed to trace Dione's composition variability on both global and local scales allowing to study the dichotomy between the bright‐leading and dark‐trailing hemispheres, the distribution of fresh material on the impact craters and surrounding ejecta, and the resurfacing of the bright material within the chasmata caused by tectonism.

Towards A Shared Mission

DEFF Research Database (Denmark)

Staunstrup, Jørgen; Orth Gaarn-Larsen, Carsten

A mission shared by stakeholders, management and employees is a prerequisite for an engaging dialog about the many and substantial changes and challenges currently facing universities. Too often this essen-tial dialog reveals mistrust and misunderstandings about the role and outcome of the univer......A mission shared by stakeholders, management and employees is a prerequisite for an engaging dialog about the many and substantial changes and challenges currently facing universities. Too often this essen-tial dialog reveals mistrust and misunderstandings about the role and outcome...... on a shared mission aiming at value creation (in the broadest interpretation). One important aspect of choosing value as the cornerstone of the mission of universities is to stress that the outcome is measured by external stakeholders and by their standards. Most of the paper is devoted to discussing value...... it possible to lead through processes that engage and excite while creating transparency and accountability. The paper will be illustrated with examples from Denmark and the Helios initiative taken by the Danish Academy of Technical Sciences (ATV) under the headline “The value creating university – courage...

Mission-Critical Systems Design Framework

Directory of Open Access Journals (Sweden)

Kyriakos Houliotis

2018-03-01

Full Text Available Safety-critical systems are well documented and standardized (e.g. IEC 61508, RTCA DO-178B within system design cycles. However in Defence and Security, systems that are critical to the success of a Mission are not defined within the literature nor are there any guidelines in defining criticality in their design or operational capabilities. When it comes to Vetronics (Vehicle Electronics, a mission-critical system, is a system with much complexity and mixed criticality levels that is a part of the overall platform (military vehicle offering integrated system capabilities. In this paper, a framework is presented, providing guidelines in designing efficiently and effectively mission-critical systems considering principles of Interoperable Open Architectures (IOA, mission-critical integrity levels and following new standardization activities such as NATO Generic Vehicle Architecture (NGVA. A Defensive Aid Suite (DAS system is used as a case study to illustrate how this framework can be exploited. The indention of this extension is to provide an approach to precisely estimate threats in order to de-risk missions in the very early stages.

Approach to Spacelab Payload mission management

Science.gov (United States)

Craft, H. G.; Lester, R. C.

1978-01-01

The nucleus of the approach to Spacelab Payload mission management is the establishment of a single point of authority for the entire payload on a given mission. This single point mission manager will serve as a 'broker' between the individual experiments and the STS, negotiating agreements by two-part interaction. The payload mission manager, along with a small support team, will represent the users in negotiating use of STS accommodations. He will provide the support needed by each individual experimenter to meet the scientific, technological, and applications objectives of the mission with minimum cost and maximum efficiency. The investigator will assume complete responsibility for his experiment hardware definition and development and will take an active role in the integration and operation of his experiment.

EU Police Mission and EU Mission for Security Sector Reform in the Democratic Republic of the Congo

DEFF Research Database (Denmark)

Højstrup Christensen, Gitte; Mandrup, Thomas

after the signing of two peace agreements (EUSEC). The EUPOL mission was terminated in 2014 and the EUSEC in 2016. Both missions were successful in some areas and failed in others. Despite their shortcomings, the EUPOL and EUSEC missions can provide valuable lessons for future EU Common Security...

ACADEMIC MISSION - FROM AUTOCRACY TO BUREAUCRACY

Directory of Open Access Journals (Sweden)

LIVIU NEAMŢU

2015-12-01

Full Text Available The mission is generic expression of reason for the existence of an organization. Organizational mission ensure continuity of existence beyond the objectives and targets of activities. It is the expression of an organization's responsibilities towards the environment in which it belongs. As the organization grows and its activities or environmental conditions change, managers adapt their strategies, but stated mission will remain valid for a period of time or unchanged throughout the life of the organization. All managerial elements of the organization are aligned with stated mission, starting from the organization structure, management behavior or specific business processes. The focus of the mission of an higher education institution on a need or several integrated needs, on customers who manifest this need and on how they can be met, that really means defining of its strategic domanin, as a sphere of influence of the organization in their environment. In this sphere of influence, three components integrate on three levels of the mission: to establish needs; identify the customer type to which an organization adress and key competencies that differentiate it from the rest competitors. To that context identifies four specific forms of academic institutions starting from their mission and strategic area: autocratic academic institutions, meritocrate academic institutions, democratic academic institutions, bureaucrats academic institutions.

Follow the plume: the habitability of Enceladus.

Science.gov (United States)

McKay, Christopher P; Anbar, Ariel D; Porco, Carolyn; Tsou, Peter

2014-04-01

The astrobiological exploration of other worlds in our Solar System is moving from initial exploration to more focused astrobiology missions. In this context, we present the case that the plume of Enceladus currently represents the best astrobiology target in the Solar System. Analysis of the plume by the Cassini mission indicates that the steady plume derives from a subsurface liquid water reservoir that contains organic carbon, biologically available nitrogen, redox energy sources, and inorganic salts. Furthermore, samples from the plume jetting out into space are accessible to a low-cost flyby mission. No other world has such well-studied indications of habitable conditions. Thus, the science goals that would motivate an Enceladus mission are more advanced than for any other Solar System body. The goals of such a mission must go beyond further geophysical characterization, extending to the search for biomolecular evidence of life in the organic-rich plume. This will require improved in situ investigations and a sample return.

INIR: Integrated Nuclear Infrastructure Review Missions. Guidance on Preparing and Conducting INIR Missions (Rev. 1)

International Nuclear Information System (INIS)

2011-04-01

The IAEA's Integrated Nuclear Infrastructure Review (INIR) missions are designed to assist Member States, at their request, in evaluating the status of their national infrastructure for the introduction of a nuclear power programme. Each INIR mission is coordinated and led by the IAEA and conducted by a team of international experts drawn from Member States who have experience in different aspects of developing and deploying nuclear infrastructure. The IAEA publication Milestones in the Development of a National Infrastructure for Nuclear Power (IAEA Nuclear Energy Series No. NG-G-3.1) contains a description of 19 infrastructure issues to be considered during the different stages of development of a nuclear power programme. The starting point for an INIR mission is a self-evaluation performed by the Member State against these infrastructure issues. Following the self-evaluation, the INIR mission reviews the status of the national nuclear infrastructure, identifies existing gaps in specific infrastructure-related areas and proposes recommendations to fill these gaps. The INIR mission provides Member State representatives with an opportunity to have in depth discussions with international experts about experiences and best practices in different countries. In developing its recommendations, the INIR team takes into account the comments made by the relevant national organizations. Implementation of any of the team's recommendations is at the discretion of the Member State requesting the mission. The results of the INIR mission are expected to help the Member State to develop an action plan to fill any gaps, which in turn will help the development of the national nuclear infrastructure. The IAEA stands ready to assist, as requested and appropriate, in the different steps of this action plan. This guidance publication is directed to assist in preparing and conducting the INIR missions. It was developed under the coordination of the IAEA Integrated Nuclear Infrastructure

Early Mission Maneuver Operations for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

Science.gov (United States)

Roberts, Craig; Case, Sara; Reagoso, John; Webster, Cassandra

2015-01-01

The Deep Space Climate Observatory mission launched on February 11, 2015, and inserted onto a transfer trajectory toward a Lissajous orbit around the Sun-Earth L1 libration point. This paper presents an overview of the baseline transfer orbit and early mission maneuver operations leading up to the start of nominal science orbit operations. In particular, the analysis and performance of the spacecraft insertion, mid-course correction maneuvers, and the deep-space Lissajous orbit insertion maneuvers are discussed, com-paring the baseline orbit with actual mission results and highlighting mission and operations constraints..

Linking Knowledge and Skills to Mission Essential Competency-Based Syllabus Development for Distributed Mission Operations

National Research Council Canada - National Science Library

Symons, Steve; France, Michael; Bell, Jeffrey; Bennett, Jr, Winston

2006-01-01

... of Mission Essential Competencies (MECs). MECs are defined as the higher order individual, team, and inter-team competencies that a fully prepared pilot, crew, or flight requires for successful mission completion under adverse conditions...

Ultra High Resolution Imaging of Enceladus Tiger Stripe Thermal Emission with Cassini CIRS

Science.gov (United States)

Spencer, John R.; Gorius, Nicolas; Howett, Carly; Verbiscer, Anne J.; Cassini CIRS Team

2017-10-01

In October 2015, Cassini flew within 48 km of Enceladus’ south pole. The spacecraft attitude was fixed during the flyby, but the roll angle of the spacecraft was chosen so that the remote sensing instrument fields of view passed over Damascus, Baghdad, and Cairo Sulci. The Composite Infrared Spectrometer (CIRS) instrument obtained a single interferometer scan during the flyby, using a special mode, enabled by a flight software update, which bypassed numerical filters to improve the fidelity of the interferograms. This generated a total of 11 interferograms, at 5 contiguous spatial locations for each of the 7 - 9 micron (FP4) and 9 - 17 micron (FP3) focal planes, and a single larger field of view for the 17 - 500 micron focal plane (FP1). Strong spikes were seen in the interferograms when crossing each of the sulci, due to the rapid passage of warm material through the field of view. For FP3 and FP4, the temporal variations of the signals from the 5 contiguous detectors can be used to generated 5-pixel-wide images of the thermal emission, which show excellent agreement between the two focal planes. FP3 and FP4 spatial resolution, limited along track by the 5 msec time sampling of the interferogram, and across track by the CIRS field of view, is a remarkable 40 x 40 meters. At this resolution, the tiger stripe thermal emission shows a large amount of structure, including both continuous emission along the fractures, discrete hot spots less than 100 meters across, and extended emission with complex structure.

Equatorial Oscillation and Planetary Wave Activity in Saturn's Stratosphere Through the Cassini Epoch

Science.gov (United States)

Guerlet, S.; Fouchet, T.; Spiga, A.; Flasar, F. M.; Fletcher, L. N.; Hesman, B. E.; Gorius, N.

2018-01-01

Thermal infrared spectra acquired by Cassini/Composite InfraRed Spectrometer (CIRS) in limb-viewing geometry in 2015 are used to derive 2-D latitude-pressure temperature and thermal wind maps. These maps are used to study the vertical structure and evolution of Saturn's equatorial oscillation (SEO), a dynamical phenomenon presenting similarities with the Earth's quasi-biennal oscillation (QBO) and semi-annual oscillation (SAO). We report that a new local wind maximum has appeared in 2015 in the upper stratosphere and derive the descent rates of other wind extrema through time. The phase of the oscillation observed in 2015, as compared to 2005 and 2010, remains consistent with a ˜15 year period. The SEO does not propagate downward at a regular rate but exhibits faster descent rate in the upper stratosphere, combined with a greater vertical wind shear, compared to the lower stratosphere. Within the framework of a QBO-type oscillation, we estimate the absorbed wave momentum flux in the stratosphere to be on the order of ˜7 × 10-6 N m-2. On Earth, interactions between vertically propagating waves (both planetary and mesoscale) and the mean zonal flow drive the QBO and SAO. To broaden our knowledge on waves potentially driving Saturn's equatorial oscillation, we searched for thermal signatures of planetary waves in the tropical stratosphere using CIRS nadir spectra. Temperature anomalies of amplitude 1-4 K and zonal wave numbers 1 to 9 are frequently observed, and an equatorial Rossby (n = 1) wave of zonal wave number 3 is tentatively identified in November 2009.

Prospects for Measuring Planetary Spin and Frame-Dragging in Spacecraft Timing Signals

Energy Technology Data Exchange (ETDEWEB)

Schärer, Andreas; Bondarescu, Ruxandra [Department of Physics, University of Zurich, Zurich (Switzerland); Saha, Prasenjit [Department of Physics, University of Zurich, Zurich (Switzerland); Institute for Computational Science, University of Zurich, Zurich (Switzerland); Angélil, Raymond [Institute for Computational Science, University of Zurich, Zurich (Switzerland); Helled, Ravit [Institute for Computational Science, University of Zurich, Zurich (Switzerland); Department of Geosciences, Tel Aviv University, Tel Aviv (Israel); Jetzer, Philippe, E-mail: andreas.schaerer@physik.uzh.ch [Department of Physics, University of Zurich, Zurich (Switzerland)

2017-09-05

Satellite tracking involves sending electromagnetic signals to Earth. Both the orbit of the spacecraft and the electromagnetic signals themselves are affected by the curvature of spacetime. The arrival time of the pulses is compared to the ticks of local clocks to reconstruct the orbital path of the satellite to high accuracy, and implicitly measure general relativistic effects. In particular, Schwarzschild space curvature (static) and frame-dragging (stationary) due to the planet's spin affect the satellite's orbit. The dominant relativistic effect on the path of the signal photons is Shapiro delays due to static space curvature. We compute these effects for some current and proposed space missions, using a Hamiltonian formulation in four dimensions. For highly eccentric orbits, such as in the Juno mission and in the Cassini Grand Finale, the relativistic effects have a kick-like nature, which could be advantageous for detecting them if their signatures are properly modeled as functions of time. Frame-dragging appears, in principle, measurable by Juno and Cassini, though not by Galileo 5 and 6. Practical measurement would require disentangling frame-dragging from the Newtonian “foreground” such as the gravitational quadrupole which has an impact on both the spacecraft's orbit and the signal propagation. The foreground problem remains to be solved.

Social Tagging of Mission Data

Science.gov (United States)

Norris, Jeffrey S.; Wallick, Michael N.; Joswig, Joseph C.; Powell, Mark W.; Torres, Recaredo J.; Mittman, David S.; Abramyan, Lucy; Crockett, Thomas M.; Shams, Khawaja S.; Fox, Jason M.;

Reading, Writing & Rings: Science Literacy for K-4 Students

Science.gov (United States)

McConnell, S.; Spilker, L.; Zimmerman-Brachman, R.

2007-12-01

Scientific discovery is the impetus for the K-4 Education program, "Reading, Writing & Rings." This program is unique because its focus is to engage elementary students in reading and writing to strengthen these basic academic skills through scientific content. As science has been increasingly overtaken by the language arts in elementary classrooms, the Cassini Education Program has taken advantage of a new cross-disciplinary approach to use language arts as a vehicle for increasing scientific content in the classroom. By utilizing the planet Saturn and the Cassini-Huygens mission as a model in both primary reading and writing students in these grade levels, young students can explore science material while at the same time learning these basic academic skills. Content includes reading, thinking, and hands-on activities. Developed in partnership with the Cassini-Huygens Education and Public Outreach Program, the Bay Area Writing Project/California Writing Project, Foundations in Reading Through Science & Technology (FIRST), and the Caltech Pre-College Science Initiative (CAPSI), and classroom educators, "Reading, Writing & Rings" blends the excitement of space exploration with reading and writing. All materials are teacher developed, aligned with national science and language education standards, and are available from the Cassini-Huygens website: http://saturn.jpl.nasa.gov/education/edu-k4.cfm Materials are divided into two grade level units. One unit is designed for students in grades 1 and 2 while the other unit focuses on students in grades 3 and 4. Each includes a series of lessons that take students on a path of exploration of Saturn using reading and writing prompts.

Explorer of Enceladus and Titan (E2T): Investigating ocean worlds' evolution and habitability in the solar system

Science.gov (United States)

Mitri, Giuseppe; Postberg, Frank; Soderblom, Jason M.; Wurz, Peter; Tortora, Paolo; Abel, Bernd; Barnes, Jason W.; Berga, Marco; Carrasco, Nathalie; Coustenis, Athena; Paul de Vera, Jean Pierre; D'Ottavio, Andrea; Ferri, Francesca; Hayes, Alexander G.; Hayne, Paul O.; Hillier, Jon K.; Kempf, Sascha; Lebreton, Jean-Pierre; Lorenz, Ralph D.; Martelli, Andrea; Orosei, Roberto; Petropoulos, Anastassios E.; Reh, Kim; Schmidt, Juergen; Sotin, Christophe; Srama, Ralf; Tobie, Gabriel; Vorburger, Audrey; Vuitton, Véronique; Wong, Andre; Zannoni, Marco

2018-06-01

Titan, with its organically rich and dynamic atmosphere and geology, and Enceladus, with its active plume, both harbouring global subsurface oceans, are prime environments in which to investigate the habitability of ocean worlds and the conditions for the emergence of life. We present a space mission concept, the Explorer of Enceladus and Titan (E2T), which is dedicated to investigating the evolution and habitability of these Saturnian satellites. E2T is proposed as a medium-class mission led by ESA in collaboration with NASA in response to ESA's M5 Cosmic Vision Call. E2T proposes a focused payload that would provide in-situ composition investigations and high-resolution imaging during multiple flybys of Enceladus and Titan using a solar-electric powered spacecraft in orbit around Saturn. The E2T mission would provide high-resolution mass spectrometry of the plume currently emanating from Enceladus' south polar terrain and of Titan's changing upper atmosphere. In addition, high-resolution infrared (IR) imaging would detail Titan's geomorphology at 50-100 m resolution and the temperature of the fractures on Enceladus' south polar terrain at meter resolution. These combined measurements of both Titan and Enceladus would enable the E2T mission scenario to achieve two major scientific goals: 1) Study the origin and evolution of volatile-rich ocean worlds; and 2) Explore the habitability and potential for life in ocean worlds. E2T's two high-resolution time-of-flight mass spectrometers would enable resolution of the ambiguities in chemical analysis left by the NASA/ESA/ASI Cassini-Huygens mission regarding the identification of low-mass organic species, detect high-mass organic species for the first time, further constrain trace species such as the noble gases, and clarify the evolution of solid and volatile species. The high-resolution IR camera would reveal the geology of Titan's surface and the energy dissipated by Enceladus' fractured south polar terrain and plume

SPICE for ESA Planetary Missions

Science.gov (United States)

Costa, M.

2018-04-01

The ESA SPICE Service leads the SPICE operations for ESA missions and is responsible for the generation of the SPICE Kernel Dataset for ESA missions. This contribution will describe the status of these datasets and outline the future developments.

Parametric cost estimation for space science missions

Science.gov (United States)

Lillie, Charles F.; Thompson, Bruce E.

2008-07-01

Cost estimation for space science missions is critically important in budgeting for successful missions. The process requires consideration of a number of parameters, where many of the values are only known to a limited accuracy. The results of cost estimation are not perfect, but must be calculated and compared with the estimates that the government uses for budgeting purposes. Uncertainties in the input parameters result from evolving requirements for missions that are typically the "first of a kind" with "state-of-the-art" instruments and new spacecraft and payload technologies that make it difficult to base estimates on the cost histories of previous missions. Even the cost of heritage avionics is uncertain due to parts obsolescence and the resulting redesign work. Through experience and use of industry best practices developed in participation with the Aerospace Industries Association (AIA), Northrop Grumman has developed a parametric modeling approach that can provide a reasonably accurate cost range and most probable cost for future space missions. During the initial mission phases, the approach uses mass- and powerbased cost estimating relationships (CER)'s developed with historical data from previous missions. In later mission phases, when the mission requirements are better defined, these estimates are updated with vendor's bids and "bottoms- up", "grass-roots" material and labor cost estimates based on detailed schedules and assigned tasks. In this paper we describe how we develop our CER's for parametric cost estimation and how they can be applied to estimate the costs for future space science missions like those presented to the Astronomy & Astrophysics Decadal Survey Study Committees.

The deep space 1 extended mission

Science.gov (United States)

Rayman, Marc D.; Varghese, Philip

2001-03-01

The primary mission of Deep Space 1 (DS1), the first flight of the New Millennium program, completed successfully in September 1999, having exceeded its objectives of testing new, high-risk technologies important for future space and Earth science missions. DS1 is now in its extended mission, with plans to take advantage of the advanced technologies, including solar electric propulsion, to conduct an encounter with comet 19P/Borrelly in September 2001. During the extended mission, the spacecraft's commercial star tracker failed; this critical loss prevented the spacecraft from achieving three-axis attitude control or knowledge. A two-phase approach to recovering the mission was undertaken. The first involved devising a new method of pointing the high-gain antenna to Earth using the radio signal received at the Deep Space Network as an indicator of spacecraft attitude. The second was the development of new flight software that allowed the spacecraft to return to three-axis operation without substantial ground assistance. The principal new feature of this software is the use of the science camera as an attitude sensor. The differences between the science camera and the star tracker have important implications not only for the design of the new software but also for the methods of operating the spacecraft and conducting the mission. The ambitious rescue was fully successful, and the extended mission is back on track.

Massively Clustered CubeSats NCPS Demo Mission

Science.gov (United States)

Robertson, Glen A.; Young, David; Kim, Tony; Houts, Mike

2013-01-01

Technologies under development for the proposed Nuclear Cryogenic Propulsion Stage (NCPS) will require an un-crewed demonstration mission before they can be flight qualified over distances and time frames representative of a crewed Mars mission. In this paper, we describe a Massively Clustered CubeSats platform, possibly comprising hundreds of CubeSats, as the main payload of the NCPS demo mission. This platform would enable a mechanism for cost savings for the demo mission through shared support between NASA and other government agencies as well as leveraged commercial aerospace and academic community involvement. We believe a Massively Clustered CubeSats platform should be an obvious first choice for the NCPS demo mission when one considers that cost and risk of the payload can be spread across many CubeSat customers and that the NCPS demo mission can capitalize on using CubeSats developed by others for its own instrumentation needs. Moreover, a demo mission of the NCPS offers an unprecedented opportunity to invigorate the public on a global scale through direct individual participation coordinated through a web-based collaboration engine. The platform we describe would be capable of delivering CubeSats at various locations along a trajectory toward the primary mission destination, in this case Mars, permitting a variety of potential CubeSat-specific missions. Cameras on various CubeSats can also be used to provide multiple views of the space environment and the NCPS vehicle for video monitoring as well as allow the public to "ride along" as virtual passengers on the mission. This collaborative approach could even initiate a brand new Science, Technology, Engineering and Math (STEM) program for launching student developed CubeSat payloads beyond Low Earth Orbit (LEO) on future deep space technology qualification missions. Keywords: Nuclear Propulsion, NCPS, SLS, Mars, CubeSat.

Gas mission; Mission gaz

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

This preliminary report analyses the desirable evolutions of gas transport tariffing and examines some questions relative to the opening of competition on the French gas market. The report is made of two documents: a synthesis of the previous report with some recommendations about the tariffing of gas transport, about the modalities of network access to third parties, and about the dissociation between transport and trade book-keeping activities. The second document is the progress report about the opening of the French gas market. The first part presents the European problem of competition in the gas supply and its consequences on the opening and operation of the French gas market. The second part presents some partial syntheses about each topic of the mission letter of the Ministry of Economics, Finances and Industry: future evolution of network access tariffs, critical analysis of contractual documents for gas transport and delivery, examination of auxiliary services linked with the access to the network (modulation, balancing, conversion), consideration about the processing of network congestions and denied accesses, analysis of the metering dissociation between the integrated activities of gas operators. Some documents are attached in appendixes: the mission letter from July 9, 2001, the detailed analysis of the new temporary tariffs of GdF and CFM, the offer of methane terminals access to third parties, the compatibility of a nodal tariffing with the presence of three transport operators (GdF, CFM and GSO), the contract-type for GdF supply, and the contract-type for GdF connection. (J.S.)

Mission Reliability Estimation for Repairable Robot Teams

Science.gov (United States)

Trebi-Ollennu, Ashitey; Dolan, John; Stancliff, Stephen

2010-01-01

A mission reliability estimation method has been designed to translate mission requirements into choices of robot modules in order to configure a multi-robot team to have high reliability at minimal cost. In order to build cost-effective robot teams for long-term missions, one must be able to compare alternative design paradigms in a principled way by comparing the reliability of different robot models and robot team configurations. Core modules have been created including: a probabilistic module with reliability-cost characteristics, a method for combining the characteristics of multiple modules to determine an overall reliability-cost characteristic, and a method for the generation of legitimate module combinations based on mission specifications and the selection of the best of the resulting combinations from a cost-reliability standpoint. The developed methodology can be used to predict the probability of a mission being completed, given information about the components used to build the robots, as well as information about the mission tasks. In the research for this innovation, sample robot missions were examined and compared to the performance of robot teams with different numbers of robots and different numbers of spare components. Data that a mission designer would need was factored in, such as whether it would be better to have a spare robot versus an equivalent number of spare parts, or if mission cost can be reduced while maintaining reliability using spares. This analytical model was applied to an example robot mission, examining the cost-reliability tradeoffs among different team configurations. Particularly scrutinized were teams using either redundancy (spare robots) or repairability (spare components). Using conservative estimates of the cost-reliability relationship, results show that it is possible to significantly reduce the cost of a robotic mission by using cheaper, lower-reliability components and providing spares. This suggests that the

Trajectory Design Considerations for Exploration Mission 1

Science.gov (United States)

Dawn, Timothy F.; Gutkowski, Jeffrey P.; Batcha, Amelia L.; Williams, Jacob; Pedrotty, Samuel M.

2018-01-01

Exploration Mission 1 (EM-1) will be the first mission to send an uncrewed Orion Multi-Purpose Crew Vehicle (MPCV) to cislunar space in the fall of 2019. EM-1 was originally conceived as a lunar free-return mission, but was later changed to a Distant Retrograde Orbit (DRO) mission as a precursor to the Asteroid Redirect Mission. To understand the required mission performance (i.e., propellant requirement), a series of trajectory optimization runs was conducted using JSC's Copernicus spacecraft trajectory optimization tool. In order for the runs to be done in a timely manner, it was necessary to employ a parallelization approach on a computing cluster using a new trajectory scan tool written in Python. Details of the scan tool are provided and how it is used to perform the scans and post-process the results. Initially, a scan of daily due east launched EM-1 DRO missions in 2018 was made. Valid mission opportunities are ones that do not exceed the useable propellant available to perform the required burns. The initial scan data showed the propellant and delta-V performance patterns for each launch period. As questions were raised from different subsystems (e.g., power, thermal, communications, flight operations, etc.), the mission parameters or data that were of interest to them were added to the scan output data file. The additional data includes: (1) local launch and landing times in relation to sunrise and sunset, (2) length of eclipse periods during the in-space portion of the mission, (3) Earth line of sight from cislunar space, (4) Deep Space Network field of view looking towards cislunar space, and (5) variation of the downrange distance from Earth entry interface to splashdown. Mission design trades can also be performed based on the information that the additional data shows. For example, if the landing is in darkness, but the recovery operations team desires a landing in daylight, then an analysis is performed to determine how to change the mission design

Hierarchthis: An Interactive Interface for Identifying Mission-Relevant Components of the Advanced Multi-Mission Operations System

Science.gov (United States)

Litomisky, Krystof

2012-01-01

Even though NASA's space missions are many and varied, there are some tasks that are common to all of them. For example, all spacecraft need to communicate with other entities, and all spacecraft need to know where they are. These tasks use tools and services that can be inherited and reused between missions, reducing systems engineering effort and therefore reducing cost.The Advanced Multi-Mission Operations System, or AMMOS, is a collection of multimission tools and services, whose development and maintenance are funded by NASA. I created HierarchThis, a plugin designed to provide an interactive interface to help customers identify mission-relevant tools and services. HierarchThis automatically creates diagrams of the AMMOS database, and then allows users to show/hide specific details through a graphical interface. Once customers identify tools and services they want for a specific mission, HierarchThis can automatically generate a contract between the Multimission Ground Systems and Services Office, which manages AMMOS, and the customer. The document contains the selected AMMOS components, along with their capabilities and satisfied requirements. HierarchThis reduces the time needed for the process from service selections to having a mission-specific contract from the order of days to the order of minutes.

The Double Star mission

Directory of Open Access Journals (Sweden)

Liu

2005-11-01

Full Text Available The Double Star Programme (DSP was first proposed by China in March, 1997 at the Fragrant Hill Workshop on Space Science, Beijing, organized by the Chinese Academy of Science. It is the first mission in collaboration between China and ESA. The mission is made of two spacecraft to investigate the magnetospheric global processes and their response to the interplanetary disturbances in conjunction with the Cluster mission. The first spacecraft, TC-1 (Tan Ce means "Explorer", was launched on 29 December 2003, and the second one, TC-2, on 25 July 2004 on board two Chinese Long March 2C rockets. TC-1 was injected in an equatorial orbit of 570x79000 km altitude with a 28° inclination and TC-2 in a polar orbit of 560x38000 km altitude. The orbits have been designed to complement the Cluster mission by maximizing the time when both Cluster and Double Star are in the same scientific regions. The two missions allow simultaneous observations of the Earth magnetosphere from six points in space. To facilitate the comparison of data, half of the Double Star payload is made of spare or duplicates of the Cluster instruments; the other half is made of Chinese instruments. The science operations are coordinated by the Chinese DSP Scientific Operations Centre (DSOC in Beijing and the European Payload Operations Service (EPOS at RAL, UK. The spacecraft and ground segment operations are performed by the DSP Operations and Management Centre (DOMC and DSOC in China, using three ground station, in Beijing, Shanghai and Villafranca.

FORMOSAT-3/COSMIC Spacecraft Constellation System, Mission Results, and Prospect for Follow-On Mission

Directory of Open Access Journals (Sweden)

Chen-Joe Fong

2009-01-01

Full Text Available The FORMOSAT-3/COSMIC spacecraft constellation consisting of six LEO satellites is the world's first operational GPS Radio Occultation (RO mission. The mission is jointly developed by Taiwan¡¦s National Space Organization (NSPO and the United States¡¦UCAR in collaboration with NSF, USAF, NOAA, NASA, NASA's Jet Propulsion Laboratory, and the US Naval Research Laboratory. The FORMOSAT-3/COSMIC satellites were successfully launched from Vandenberg US AFB in California at 0140 UTC 15 April 2006 into the same orbit plane of the designated 516 km altitude. The mission goal is to deploy the six satellites into six orbit planes at 800 km altitude with a 30-degree separation for evenly distributed global coverage. All six FORMOSAT-3/COSMIC satellites are currently maintaining a satisfactory good state-of-health. Five out of six satellites have reached their final mission orbit of 800 km as of November 2007. The data as received by FORMOSAT-3/COSMIC satellites constellation have been processed in near real time into 2500 good ionospheric profiles and 1800 good atmospheric profiles per day. These have outnumbered the worldwide radiosondes (~900 mostly over land launched from the ground per day. The processed atmospheric RO data have been assimilated into the Numerical Weather Prediction (NWP models for real-time weather prediction and typhoon/hurricane forecasting by many major weather centers in the world. This paper describes the FORMOSAT-3/COSMIC satellite constellation system performance and the mission results that span the period from April 2006 to October 2007; and reviews the prospect of a future follow-on mission.

75 FR 43919 - Energy and Infrastructure Mission to Saudi Arabia: Third City Stop Added to the Trade Mission...

Science.gov (United States)

2010-07-27

... and Dhahran; and Networking receptions in two cities of the trade mission. Proposed Mission Timetable... Saudi Arabia: Third City Stop Added to the Trade Mission Itinerary AGENCY: International Trade... expansion at Jubail Industrial City II with around 20 petrochemical and infrastructure projects worth more...

INTEGRITY -- Integrated Human Exploration Mission Simulation Facility

Science.gov (United States)

Henninger, D.; Tri, T.; Daues, K.

It is proposed to develop a high -fidelity ground facil ity to carry out long-duration human exploration mission simulations. These would not be merely computer simulations - they would in fact comprise a series of actual missions that just happen to stay on earth. These missions would include all elements of an actual mission, using actual technologies that would be used for the real mission. These missions would also include such elements as extravehicular activities, robotic systems, telepresence and teleoperation, surface drilling technology--all using a simulated planetary landscape. A sequence of missions would be defined that get progressively longer and more robust, perhaps a series of five or six missions over a span of 10 to 15 years ranging in durat ion from 180 days up to 1000 days. This high-fidelity ground facility would operate hand-in-hand with a host of other terrestrial analog sites such as the Antarctic, Haughton Crater, and the Arizona desert. Of course, all of these analog mission simulations will be conducted here on earth in 1-g, and NASA will still need the Shuttle and ISS to carry out all the microgravity and hypogravity science experiments and technology validations. The proposed missions would have sufficient definition such that definitive requirements could be derived from them to serve as direction for all the program elements of the mission. Additionally, specific milestones would be established for the "launch" date of each mission so that R&D programs would have both good requirements and solid milestones from which to build their implementation plans. Mission aspects that could not be directly incorporated into the ground facility would be simulated via software. New management techniques would be developed for evaluation in this ground test facility program. These new techniques would have embedded metrics which would allow them to be continuously evaluated and adjusted so that by the time the sequence of missions is completed

Deep space propagation experiments at Ka-band

Science.gov (United States)

Butman, Stanley A.

1990-01-01

Propagation experiments as essential components of the general plan to develop an operational deep space telecommunications and navigation capability at Ka-band (32 to 35 GHz) by the end of the 20th century are discussed. Significant benefits of Ka-band over the current deep space standard X-band (8.4 GHz) are an improvement of 4 to 10 dB in telemetry capacity and a similar increase in radio navigation accuracy. Propagation experiments are planned on the Mars Observer Mission in 1992 in preparation for the Cassini Mission to Saturn in 1996, which will use Ka-band in the search for gravity waves as well as to enhance telemetry and navigation at Saturn in 2002. Subsequent uses of Ka-band are planned for the Solar Probe Mission and the Mars Program.

A nuclear source term analysis for spacecraft power systems

International Nuclear Information System (INIS)

McCulloch, W.H.

1998-01-01

All US space missions involving on board nuclear material must be approved by the Office of the President. To be approved the mission and the hardware systems must undergo evaluations of the associated nuclear health and safety risk. One part of these evaluations is the characterization of the source terms, i.e., the estimate of the amount, physical form, and location of nuclear material, which might be released into the environment in the event of credible accidents. This paper presents a brief overview of the source term analysis by the Interagency Nuclear Safety Review Panel for the NASA Cassini Space Mission launched in October 1997. Included is a description of the Energy Interaction Model, an innovative approach to the analysis of potential releases from high velocity impacts resulting from launch aborts and reentries

Definition phase of Grand Tour missions/radio science investigations study for outer planets missions

Science.gov (United States)

Tyler, G. L.

1972-01-01

Scientific instrumentation for satellite communication and radio tracking systems in the outer planet exploration mission is discussed. Mission planning considers observations of planetary and satellite-masses, -atmospheres, -magnetic fields, -surfaces, -gravitational fields, solar wind composition, planetary radio emissions, and tests of general relativity in time delay and ray bending experiments.

A revised model of Jupiter's inner electron belts: Updating the Divine radiation model

Science.gov (United States)

Garrett, Henry B.; Levin, Steven M.; Bolton, Scott J.; Evans, Robin W.; Bhattacharya, Bidushi

2005-02-01

In 1983, Divine presented a comprehensive model of the Jovian charged particle environment that has long served as a reference for missions to Jupiter. However, in situ observations by Galileo and synchrotron observations from Earth indicate the need to update the model in the inner radiation zone. Specifically, a review of the model for 1 MeV data. Further modifications incorporating observations from the Galileo and Cassini spacecraft will be reported in the future.

MASER: Measuring, Analysing, Simulating low frequency Radio Emissions.

Science.gov (United States)

Cecconi, B.; Le Sidaner, P.; Savalle, R.; Bonnin, X.; Zarka, P. M.; Louis, C.; Coffre, A.; Lamy, L.; Denis, L.; Griessmeier, J. M.; Faden, J.; Piker, C.; André, N.; Genot, V. N.; Erard, S.; King, T. A.; Mafi, J. N.; Sharlow, M.; Sky, J.; Demleitner, M.

2017-12-01

The MASER (Measuring, Analysing and Simulating Radio Emissions) project provides a comprehensive infrastructure dedicated to low frequency radio emissions (typically Radioastronomie de Nançay and the CDPP deep archive. These datasets include Cassini/RPWS, STEREO/Waves, WIND/Waves, Ulysses/URAP, ISEE3/SBH, Voyager/PRA, Nançay Decameter Array (Routine, NewRoutine, JunoN), RadioJove archive, swedish Viking mission, Interball/POLRAD... MASER also includes a Python software library for reading raw data.

Mission Level Autonomy for USSV

Science.gov (United States)

Huntsberger, Terry; Stirb, Robert C.; Brizzolara, Robert

2011-01-01

On-water demonstration of a wide range of mission-proven, advanced technologies at TRL 5+ that provide a total integrated, modular approach to effectively address the majority of the key needs for full mission-level autonomous, cross-platform control of USV s. Wide baseline stereo system mounted on the ONR USSV was shown to be an effective sensing modality for tracking of dynamic contacts as a first step to automated retrieval operations. CASPER onboard planner/replanner successfully demonstrated realtime, on-water resource-based analysis for mission-level goal achievement and on-the-fly opportunistic replanning. Full mixed mode autonomy was demonstrated on-water with a seamless transition between operator over-ride and return to current mission plan. Autonomous cooperative operations for fixed asset protection and High Value Unit escort using 2 USVs (AMN1 & 14m RHIB) were demonstrated during Trident Warrior 2010 in JUN 2010

Space Mission Human Reliability Analysis (HRA) Project

Science.gov (United States)

Boyer, Roger

2014-01-01

The purpose of the Space Mission Human Reliability Analysis (HRA) Project is to extend current ground-based HRA risk prediction techniques to a long-duration, space-based tool. Ground-based HRA methodology has been shown to be a reasonable tool for short-duration space missions, such as Space Shuttle and lunar fly-bys. However, longer-duration deep-space missions, such as asteroid and Mars missions, will require the crew to be in space for as long as 400 to 900 day missions with periods of extended autonomy and self-sufficiency. Current indications show higher risk due to fatigue, physiological effects due to extended low gravity environments, and others, may impact HRA predictions. For this project, Safety & Mission Assurance (S&MA) will work with Human Health & Performance (HH&P) to establish what is currently used to assess human reliabiilty for human space programs, identify human performance factors that may be sensitive to long duration space flight, collect available historical data, and update current tools to account for performance shaping factors believed to be important to such missions. This effort will also contribute data to the Human Performance Data Repository and influence the Space Human Factors Engineering research risks and gaps (part of the HRP Program). An accurate risk predictor mitigates Loss of Crew (LOC) and Loss of Mission (LOM).The end result will be an updated HRA model that can effectively predict risk on long-duration missions.

GSFC Safety and Mission Assurance Organization

Science.gov (United States)

Kelly, Michael P.

2010-01-01

This viewgraph presentation reviews NASA Goddard Space Flight Center's approach to safety and mission assurance. The contents include: 1) NASA GSFC Background; 2) Safety and Mission Assurance Directorate; 3) The Role of SMA-D and the Technical Authority; 4) GSFC Mission assurance Requirements; 5) GSFC Systems Review Office (SRO); 6) GSFC Supply Chain Management Program; and 7) GSFC ISO9001/AS9100 Status Brief.

The OICETS mission

Science.gov (United States)

Jono, Takashi; Arai, Katsuyoshi

2017-11-01

The Optical Inter-orbit Communications Engineering Test Satellite (OICETS) was successfully launched on 23th August 2005 and thrown into a circular orbit at the altitude of 610 km. The main mission is to demonstrate the free-space inter satellite laser communications with the cooperation of the Advanced Relay and Technology Mission (ARTEMIS) geostationary satellite developed by the European Space Agency. This paper presents the overview of the OICETS and laser terminal, a history of international cooperation between Japan Aerospace Exploration Agency (JAXA) and ESA and typical results of the inter-orbit laser communication experiment carried out with ARTEMIS.

Explorer of Enceladus and Titan (E2T): Investigating Ocean Worlds' Evolution and Habitability in the Saturn System

Science.gov (United States)

Mitri, Giuseppe

2017-04-01

The NASA-ESA Cassini-Huygens mission has revealed Titan and Enceladus to be two of the most interesting worlds in the Solar System. Titan, with its organically rich and dynamic atmosphere and geology, and Enceladus, with its active plumes, both harboring subsurface oceans, are prime environments in which to investigate the conditions for the emergence of life and the habitability of ocean worlds. Explorer of Enceladus and Titan (E2T) is dedicated to investigating the evolution and habitability of these Saturnian satellites and is proposed in response to ESA's M5 Call as a medium-class mission led by ESA in collaboration with NASA. E2T has a focused payload that will provide in-situ composition investigations and high-resolution imaging during multiple flybys of Enceladus and Titan using a solar-electric powered spacecraft in orbit around Saturn. The E2T mission will provide high-resolution mass spectroscopy of the plumes currently emanating from Enceladus's south polar terrain (SPT) and of Titan's changing upper atmosphere. In addition, high-resolution IR imaging will detail Titan's geomorphology at 50-100 m resolution and the source fractures on Enceladus's SPT at meter resolution. These combined measurements of both Titan and Enceladus will permit to achieve the two major scientific goals of the E2T mission: 1) Study the origin and evolution of volatile-rich ocean worlds; and 2) Explore the habitability and potential for life in ocean worlds. More in detail, these goals will be achieved by measuring the nature, abundance and isotopic properties of solid- and vapor-phase species in Enceladus's plume and Titan's upper atmosphere, and determining the processes that are transporting and transforming organic materials on the surface of Titan and the mechanisms controlling, and the energy dissipated by, Enceladus's plumes. E2T's two high-resolution time-of-flight mass spectrometers will enable us to resolve the ambiguities left by Cassini regarding the identification

STS-51J Mission Insignia

Science.gov (United States)

1985-01-01

The 51-J mission insignia, designed by Atlantis's first crew, pays tribute to the Statue of Liberty and the ideas it symbolizes. The historical gateway figure bears additional significance for Astronauts Karol J. Bobko, mission commander; and Ronald J. Grabe, pilot, both New Your Natives.

The Mothership Mission Architecture

Science.gov (United States)

Ernst, S. M.; DiCorcia, J. D.; Bonin, G.; Gump, D.; Lewis, J. S.; Foulds, C.; Faber, D.

2015-12-01

The Mothership is considered to be a dedicated deep space carrier spacecraft. It is currently being developed by Deep Space Industries (DSI) as a mission concept that enables a broad participation in the scientific exploration of small bodies - the Mothership mission architecture. A Mothership shall deliver third-party nano-sats, experiments and instruments to Near Earth Asteroids (NEOs), comets or moons. The Mothership service includes delivery of nano-sats, communication to Earth and visuals of the asteroid surface and surrounding area. The Mothership is designed to carry about 10 nano-sats, based upon a variation of the Cubesat standard, with some flexibility on the specific geometry. The Deep Space Nano-Sat reference design is a 14.5 cm cube, which accommodates the same volume as a traditional 3U CubeSat. To reduce cost, Mothership is designed as a secondary payload aboard launches to GTO. DSI is offering slots for nano-sats to individual customers. This enables organizations with relatively low operating budgets to closely examine an asteroid with highly specialized sensors of their own choosing and carry out experiments in the proximity of or on the surface of an asteroid, while the nano-sats can be built or commissioned by a variety of smaller institutions, companies, or agencies. While the overall Mothership mission will have a financial volume somewhere between a European Space Agencies' (ESA) S- and M-class mission for instance, it can be funded through a number of small and individual funding sources and programs, hence avoiding the processes associated with traditional space exploration missions. DSI has been able to identify a significant interest in the planetary science and nano-satellite communities.

Core Science Systems--Mission overview

Science.gov (United States)

Gallagher, Kevin T.

2012-01-01

The Core Science Systems Mission Area delivers nationally focused Earth systems and information science that provides fundamental research and data that underpins all Mission Areas of the USGS, the USGS Science Strategy, and Presidential, Secretarial, and societal priorities. —Kevin T. Gallagher, Associate Director, Core Science Systems

48 CFR 752.7013 - Contractor-mission relationships.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contractor-mission....7013 Contractor-mission relationships. For use in all USAID contracts involving performance overseas.... Contractor-Mission Relationships (OCT 1989) (a) The Contractor acknowledges that this contract is an...

The LISA Pathfinder Mission

International Nuclear Information System (INIS)

Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

2015-01-01

LISA Pathfinder (LPF), the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology validation mission for future spaceborne gravitational wave detectors, such as the proposed eLISA mission. LISA Pathfinder, and its scientific payload - the LISA Technology Package - will test, in flight, the critical technologies required for low frequency gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through technology comprising inertial sensors, high precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system. LISA Pathfinder is due to be launched in mid-2015, with first results on the performance of the system being available 6 months thereafter.The paper introduces the LISA Pathfinder mission, followed by an explanation of the physical principles of measurement concept and associated hardware. We then provide a detailed discussion of the LISA Technology Package, including both the inertial sensor and interferometric readout. As we approach the launch of the LISA Pathfinder, the focus of the development is shifting towards the science operations and data analysis - this is described in the final section of the paper (paper)

Titan Orbiter Aerorover Mission

Science.gov (United States)

Sittler Jr., E. C.; Acuna, M.; Burchell, M. J.; Coates, A.; Farrell, W.; Flasar, M.; Goldstein, B. E.; Gorevan, S.; Hartle, R. E.; Johnson, W. T. K.

2001-01-01

We propose a combined Titan orbiter and Titan Aerorover mission with an emphasis on both in situ and remote sensing measurements of Titan's surface, atmosphere, ionosphere, and magnetospheric interaction. The biological aspect of the Titan environment will be emphasized by the mission (i.e., search for organic materials which may include simple organics to 'amono' analogues of amino acids and possibly more complex, lightening detection and infrared, ultraviolet, and charged particle interactions with Titan's surface and atmosphere). An international mission is assumed to control costs. NASA will provide the orbiter, launch vehicle, DSN coverage and operations, while international partners will provide the Aerorover and up to 30% of the cost for the scientific instruments through collaborative efforts. To further reduce costs we propose a single PI for orbiter science instruments and a single PI for Aerorover science instruments. This approach will provide single command/data and power interface between spacecraft and orbiter instruments that will have redundant central DPU and power converter for their instruments. A similar approach could be used for the Aerorover. The mission profile will be constructed to minimize conflicts between Aerorover science, orbiter radar science, orbiter radio science, orbiter imaging science, and orbiter fields and particles (FP) science. Additional information is contained in the original extended abstract.

JPL future missions and energy storage technology implications

Science.gov (United States)

Pawlik, Eugene V.

1987-01-01

The mission model for JPL future programs is presented. This model identifies mission areas where JPL is expected to have a major role and/or participate in a significant manner. These missions are focused on space science and applications missions, but they also include some participation in space station activities. The mission model is described in detail followed by a discussion on the needs for energy storage technology required to support these future activities.

Vorticity and energy diagnostics from the 2000 Cassini Jupiter flyby

Science.gov (United States)

Young, R. M. B.; Read, P. L.; Armstrong, D.; Lancaster, A.

2011-10-01

The Cassini spacecraft flew by Jupiter in December 2000, returning hundreds of images near closest approach [1]. We have been analysing the images spanning four Jupiter rotation periods at closest approach using automated cloud tracking software to obtain horizontal velocity fields. Our method has some advantages over other methods used for this purpose in that it accounts for both cloud deformation and rotation in addition to the standard translation. We shall present detailed horizontal velocity vectors and related vorticity and energy fields over four Jupiter rotation periods. We also intend to produce derived energy and turbulence diagnostics that will help us to understand the interplay between processes acting on different length scales. It may also be possible to relate these diagnostics to 'zonostrophic' jets and small-scale turbulence studied in the laboratory using the Coriolis rotating tank, work itself motivated by jets in giant planet atmospheres [2]. In the future we intend to combine velocity fields with temperature data to produce fully-3D velocity and potential vorticity fields for Jupiter's troposphere and stratosphere. The cloud tracking method is based on correlation image velocimetry (CIV) and was originally developed by the Coriolis facility team at LEGI, Université de Grenoble [3], where it is used to extract velocity fields from data obtained in their 13m diameter rotating tank experiment. The method has two stages. First, velocity vectors are calculated using translation only, where the velocity is defined by the highest correlation between two images taken 63 minutes apart of a small pixel patch moving within a larger search box. In the second stage the correlation analysis is repeated, but instead of just translation of the pixel patch, rotation and deformation (shearing, stretching) are taken into account. We use the first stage velocity field as an estimate of the velocity vector and search within a small window around this, including

Solar Probe Plus: Mission design challenges and trades

Science.gov (United States)

Guo, Yanping

2010-11-01

NASA plans to launch the first mission to the Sun, named Solar Probe Plus, as early as 2015, after a comprehensive feasibility study that significantly changed the original Solar Probe mission concept. The original Solar Probe mission concept, based on a Jupiter gravity assist trajectory, was no longer feasible under the new guidelines given to the mission. A complete redesign of the mission was required, which called for developing alternative trajectories that excluded a flyby of Jupiter. Without the very powerful gravity assist from Jupiter it was extremely difficult to get to the Sun, so designing a trajectory to reach the Sun that is technically feasible under the new mission guidelines became a key enabler to this highly challenging mission. Mission design requirements and challenges unique to this mission are reviewed and discussed, including various mission scenarios and six different trajectory designs utilizing various planetary gravity assists that were considered. The V 5GA trajectory design using five Venus gravity assists achieves a perihelion of 11.8 solar radii ( RS) in 3.3 years without any deep space maneuver (DSM). The V 7GA trajectory design reaches a perihelion of 9.5 RS using seven Venus gravity assists in 6.39 years without any DSM. With nine Venus gravity assists, the V 9GA trajectory design shows a solar orbit at inclination as high as 37.9° from the ecliptic plane can be achieved with the time of flight of 5.8 years. Using combined Earth and Venus gravity assists, as close as 9 RS from the Sun can be achieved in less than 10 years of flight time at moderate launch C3. Ultimately the V 7GA trajectory was chosen as the new baseline mission trajectory. Its design allowing for science investigation right after launch and continuing for nearly 7 years is unprecedented for interplanetary missions. The redesigned Solar Probe Plus mission is not only feasible under the new guidelines but also significantly outperforms the original mission concept

NASA Laboratory Analysis for Manned Exploration Missions

Science.gov (United States)

Krihak, Michael K.; Shaw, Tianna E.

2014-01-01

The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability Element under the NASA Human Research Program. ELA instrumentation is identified as an essential capability for future exploration missions to diagnose and treat evidence-based medical conditions. However, mission architecture limits the medical equipment, consumables, and procedures that will be available to treat medical conditions during human exploration missions. Allocated resources such as mass, power, volume, and crew time must be used efficiently to optimize the delivery of in-flight medical care. Although commercial instruments can provide the blood and urine based measurements required for exploration missions, these commercial-off-the-shelf devices are prohibitive for deployment in the space environment. The objective of the ELA project is to close the technology gap of current minimally invasive laboratory capabilities and analytical measurements in a manner that the mission architecture constraints impose on exploration missions. Besides micro gravity and radiation tolerances, other principal issues that generally fail to meet NASA requirements include excessive mass, volume, power and consumables, and nominal reagent shelf-life. Though manned exploration missions will not occur for nearly a decade, NASA has already taken strides towards meeting the development of ELA medical diagnostics by developing mission requirements and concepts of operations that are coupled with strategic investments and partnerships towards meeting these challenges. This paper focuses on the remote environment, its challenges, biomedical diagnostics requirements and candidate technologies that may lead to successful blood-urine chemistry and biomolecular measurements in future space exploration missions.

The 'Granite' collegial mission of dialogue. Report; Mission collegiale de concertation Granite. Rapport

Energy Technology Data Exchange (ETDEWEB)

Boisson, P.; Huet, Ph.; Mingasson, J

2000-06-01

The aim of the 'Granite' collegial mission of dialogue is to inform the French authorities, associations and population about the project of construction of an underground laboratory for the study of the disposal of high level and long-life radioactive wastes in a granitic environment. The aim of the dialogue was not to select a site but to collect the public reactions and advices about such a project. However, such a dialogue has partially failed because of a misunderstanding of the population about the aims of the mission. However, the mission has collected many point of views and questions which are developed in this report. The first and second chapters recall the process of the mission and its progress, while a third chapter stresses on the questions asked by the public and which concern the fear of nuclear wastes and the incompatibility between the disposal of wastes and the socio-economical development of the region concerned. Thanks to the lessons drawn from this experience, the mission has formulated some recommendations (chapter 4) concerning the need for a better information of the population about any topic in relation with the radioactive wastes. Some complementary information is provided in appendixes. (J.S.)

Variations in Ring Particle Cooling across Saturn's Rings with Cassini CIRS

Science.gov (United States)

Brooks, S. M.; Spilker, L. J.; Pilorz, S.; Edgington, S. G.; Déau, E.; Altobelli, N.

2010-12-01

Cassini's Composite Infrared Spectrometer has recorded over two million of spectra of Saturn's rings in the far infrared since arriving at Saturn in 2004. CIRS records far infrared radiation between 10 and 600 cm-1 ( 16.7 and 1000 μ {m} ) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn’s rings peaks in this wavelength range. Ring temperatures can be inferred from FP1 data. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and rapidly changing temperatures are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid particles can be expected to have higher thermal inertias. Ferrari et al. (2005) fit thermal inertia values of 5218 {Jm)-2 {K}-1 {s}-1/2 to their B ring data and 6412 {Jm)-2 {K}-1 {s}-1/2 to their C ring data. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The rings’ thermal budget is dominated by its absorption of solar radiation. As a result, ring particles abruptly cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

What does Cassini ENA observations tell us about gas around Europa?

Science.gov (United States)

Brandt, Pontus; Mauk, Barry; Westlake, Joseph; Smith, Todd; Mitchell, Donald

2015-04-01

From about December 2000 to January 2001 the Ion and Neutral Camera (INCA) imaged Jupiter in Energetic Neutral Atoms (ENA) from a distance of about 137-250 Jovian planetary radii (RJ) over an energy range from about 10 to 300 keV. A forward model is employed to derive column densities and assumes a neutral gas-plasma model and an energetic ion distribution based on Galileo in-situ measurements. We demonstrate that Jupiter observations by INCA are consistent with a column density peaking around Europa's orbit in the range from 2x1012 cm-2 to 7x1012 cm-2, assuming H2, and are consistent with the upper limits reported from the Cassini/UVIS observations. Most of the INCA observations are consistent with a roughly azimuthally symmetric gas distribution, but some appear consistent with an asymmetric gas distribution centred on Europa, which would directly imply that Europa is the source of the gas. Although our neutral gas model assumes a Europa source, we explore other explanations of the INCA observations including: (1) ENAs are produced by charge exchange between energetic ions and neutral hydrogen originating from charge-exchanged protons in the Io plasma torus. However, estimated densities by Cheng (1986) are about one order of magnitude too low to explain the INCA observations; (2) ENAs are produced by charge exchange between energetic ions and plasma ions such as O+ and S+ originating from Io. However, that would require O+ plasma densities higher than expected to compensate for the low charge-exchange cross section between protons and O+; (3) We re-examine the INCA Point-Spread Function (PSF) to determine if the ENA emissions in the vicinity of Europa's orbit could be explained by internal scattering of ENAs originating from Jupiter's high-latitude upper atmosphere. However, the PSF was well constrained by using Jupiter from distances where it could be considered a point source.

Mapping the Thermal Inertia of Saturn’s Rings with Cassini CIRS

Science.gov (United States)

Brooks, Shawn M.; Spilker, L. J.; PIlorz, S. H.; Showalter, M. R.

2013-10-01

We use data from Cassini's Composite Infrared Spectrometer to map out the thermal response of Saturn's ring particles passing through Saturn's shadow and to determine variations in ring thermal inertia. CIRS records far infrared radiation in three separate detectors, each of which covers a distinct wavelength range. In this work, we analyze rings spectra recorded at focal plane 1 (FP1), as its wavelength response (16.7-1000 microns) is well suited to detecting direct thermal emission from Saturn's rings. The thermal budget of the rings is typically dominated by solar radiation. When ring particles enter Saturn’s shadow this source of energy is abruptly cut off with a consequential drop in ring temperature. Likewise, temperatures rebound when particles exit the shadow. To characterize these heating and cooling events, FP1 was repeatedly scanned across the main rings. Each scan was offset from either the ingress or egress shadow boundary by an amount corresponding to a fraction of a Keplerian orbit. By resampling these scans onto a common radial grid, we can map out the rings’ response to the abrupt changes in insolation at shadow ingress and egress. Periods near equinox represent a unique situation. During this time the Sun's disk crosses the ring plane and its rays strike the rings at zero incidence. Solar heating is virtually absent, and thermal radiation from Saturn and sunlight reflected by Saturn dominate the thermal environment. While ring temperature variations at equinox are much more subtle, they represent temperature contrasts that vary at the unique timescale corresponding to variations in Saturn contributions to the rings’ thermal budget. By analyzing CIRS data at a variety of locations and epochs, we will map out thermal inertia across the rings and attempt to tease out structural information about the particles which comprise Saturn’s rings. This presentation will report upon our progress towards these ends. This research was carried out at the

It Takes a Village. Collaborative Outer Planet Missions

Science.gov (United States)

Rymer, A. M.; Turtle, E. P.; Hofstadter, M. D.; Simon, A. A.; Hospodarsky, G. B.

2017-01-01

A mission to one or both of our local Ice Giants (Uranus and Neptune) emerged as a high priority in the most recent Planetary Science Decadal Survey and was also specifically mentioned supportively in the Heliophysics Decadal Survey. In 2016, NASA convened a science definition team to study ice giant mission concepts in more detail. Uranus and Neptune represent the last remaining planetary type in our Solar System to have a dedicated orbiting mission. The case for a Uranus mission has been made eloquently in the Decadal Surveys. Here we summarize some of the major drivers that lead to enthusiastic support for an Ice Giant mission in general, and use the example of a Uranus Mission concept to illustrate opportunities such a mission might provide for cross-division collaboration and cost-sharing.

Plutonium Finishing Plant Transition Project mission analysis report

International Nuclear Information System (INIS)

Courson, D.B.

1994-01-01

This report defines the mission for the Plutonium Finishing Plant Transition Project (PFPTP) using a systems engineering approach. This mission analysis will be the basis for the functional analysis which will further define and break down the mission statement into all of the detailed functions required to accomplish the mission. The functional analysis is then used to develop requirements, allocate those requirements to functions, and eventually be used to design the system. This report: presents the problem which will be addressed, defines PFP Transition Project, defines the overall mission statement, describes the existing, initial conditions, defines the desired, final conditions, identifies the mission boundaries and external interfaces, identifies the resources required to carry out the mission, describes the uncertainties and risks, and discusses the measures which will be used to determine success

DYNAMIC: A Decadal Survey and NASA Roadmap Mission

Science.gov (United States)

Paxton, L. J.; Oberheide, J.

2016-12-01

In this talk we will review the DYNAMIC mission science and implementation plans. DYNAMIC is baselined as a two satellite mission to delineate the dynamical behavior and structure of the ionosphere, thermosphere and mesosphere system. DYNAMIC was considered the top priority in the Decadal Survey upper atmosphere missions by the AIMI panel. The NASA Heliophysics Roadmap recommended that consideration be given to flying DYNAMIC as the STP 5 (next STP mission) rather than IMAP given the time-lag between the Decadal Survey recommendations and the flight of the STP 5 mission. It certainly seems as though STP 5 will be the IMAP mission. In that case what is the status of DYNAMIC? DYNAMIC could be STP 6 or some portion of the DYNAMIC mission could be executed as the next MidEx mission. In this talk we discuss the DYNAMIC science questions and goals and how they might be addressed. We note that DYNAMIC is not a mission just for the space community. DYNAMIC will enable new groundbased investigations and provide a global context for the long and rich history of groundbased observations of the dynamical state of the ITM system. Issues include: How and to what extent do waves and tides in the lower atmosphere contribute to the variability and mean state of the IT system? [Mission driver: Must have two spacecraft separated in local solar time in near polar orbits] How does the AIM system respond to outside forcing? [Mission Driver: Must measure high latitude inputs] How do neutral-plasma interactions produce neutral and ionospheric density changes over regional and global scales? [Mission Driver: Must measure all major species (O, N2, O2, H, He) and their ions] What part of the IT response occurs in the form of aurorally generated waves? [Mission Driver: Must measure small and mesoscale phenomena at high latitudes] What is the relative importance of thermal expansion, upwelling and advection in defining total mass density changes? [Mission Driver: Must determine the mid

Stakeholder Orientation in Cruise Lines’ Mission Statements

Directory of Open Access Journals (Sweden)

Lara Penco

2017-11-01

Full Text Available Consistent with the extant management literature, mission statements are crucial for the sustainability and growth of any firms and have been considered to be a tool for the strategic management process. Despite the considerable attention awarded to this theme, the role of the mission statement in the strategic management of tourism firms has not been sufficiently highlighted. The present paper tries to bridge this literature gap and aims to (i analyze the content of mission statements; and (ii investigate the stakeholder orientation of cruise line mission statements. We apply a content analysis method to analyze the mission statements of 44 cruise lines, employing three different perspectives: (1 the inclusion of stakeholder groups; (2 mentions of specific “mission” components; (3 reference to four goals usually assigned to mission statements. The analysis was performed using the software package QDA-Miner. The results suggest that it is possible to identify four clusters of firms that present similar content in their mission statements, and that cruise companies tend to reserve a major attention to customers. This contribution presents some valuable research implications mainly useful for researchers and academics, but also maybe of benefit to professionals and investors.

ESASky: a new Astronomy Multi-Mission Interface

Science.gov (United States)

Baines, D.; Merin, B.; Salgado, J.; Giordano, F.; Sarmiento, M.; Lopez Marti, B.; Racero, E.; Gutierrez, R.; De Teodoro, P.; Nieto, S.

2016-06-01

ESA is working on a science-driven discovery portal for all its astronomy missions at ESAC called ESASky. The first public release of this service will be shown, featuring interfaces for sky exploration and for single and multiple targets. It requires no operational knowledge of any of the missions involved. A first public beta release took place in October 2015 and gives users world-wide simplified access to high-level science-ready data products from ESA Astronomy missions plus a number of ESA-produced source catalogues. XMM-Newton data, metadata and products were some of the first to be accessible through ESASky. In the next decade, ESASky aims to include not only ESA missions but also access to data from other space and ground-based astronomy missions and observatories. From a technical point of view, ESASky is a web application that offers all-sky projections of full mission datasets using a new-generation HEALPix projection called HiPS; detailed geometrical footprints to connect all-sky mosaics to individual observations; direct access to the underlying mission-specific science archives and catalogues. The poster will be accompanied by a demo booth at the conference.

The Ulysses mission: An introduction

International Nuclear Information System (INIS)

Marsden, R.G.

1996-01-01

On 30 September 1995, Ulysses completed its initial, highly successful, survey of the polar regions of the heliosphere in both southern and northern hemispheres, thereby fulfilling its prime mission. The results obtained to date are leading to a revision of many earlier ideas concerning the solar wind and the heliosphere. Now embarking on the second phase of the mission, Ulysses will continue along its out-of-ecliptic flight path for another complete orbit of the Sun. In contrast to the high-latitude phase of the prime mission, which occurred near solar minimum, the next polar passes (in 2000 and 2001) will take place when the Sun is at its most active

Mars Stratigraphy Mission

Science.gov (United States)

Budney, C. J.; Miller, S. L.; Cutts, J. A.

2000-01-01

The Mars Stratigraphy Mission lands a rover on the surface of Mars which descends down a cliff in Valles Marineris to study the stratigraphy. The rover carries a unique complement of instruments to analyze and age-date materials encountered during descent past 2 km of strata. The science objective for the Mars Stratigraphy Mission is to identify the geologic history of the layered deposits in the Valles Marineris region of Mars. This includes constraining the time interval for formation of these deposits by measuring the ages of various layers and determining the origin of the deposits (volcanic or sedimentary) by measuring their composition and imaging their morphology.

Seasonal evolution of Titan’s stratosphere near the poles from Cassini/CIRS data

Science.gov (United States)

Coustenis, Athena; Jennings, Donald E.; Achterberg, Richard K.; Bampasidis, Georgios; Cottini, Valeria; Nixon, Conor A.; Flasar, F. Michael

2017-10-01

We report on the monitoring of the seasonal evolution near Titan’s poles. Since 2010, we observe at Titan’s south pole a strong temperature decrease and the onset of a dramatic enhancement of several trace species such as complex hydrocarbons and nitriles (HC3N and C6H6 in particular) previously observed only at high northern latitudes (Coustenis et al. 2016 and references therein). This is due to the transition of Titan’s seasons from northern winter in 2002 to northern summer in 2017 and, at the same time, the advent of winter in the south pole, during which time species with longer chemical lifetimes remain in the north for a little longer undergoing slow photochemical destruction, while those with shorter lifetimes disappear, reappearing in the south. An opposite effect has been expected in the North, but not observed with any significant certainty until 2016. We present here an analysis of nadir spectra acquired by Cassini/CIRS (Jennings et al., 2017) at high resolution in the past years and describe the newly observed decrease in chemical abundances of the components in the North. From 2013 until 2016, the Northern polar region has shown a temperature increase of 10 K, while the South had shown a more significant decrease in a similar period of time. The chemical content in the North is finally showing a clear depletion for most molecules since 2015 (Coustenis et al., 2017).References: Coustenis et al., 2016, Icarus 270, 409-420 ; Coustenis et al., 2017, in preparation; Jennings et al., 2017, Applied Optics 56, no 18, 5274-5294.

(abstract) Telecommunications for Mars Rovers and Robotic Missions

Science.gov (United States)

Cesarone, Robert J.; Hastrup, Rolf C.; Horne, William; McOmber, Robert

1997-01-01

Telecommunications plays a key role in all rover and robotic missions to Mars both as a conduit for command information to the mission and for scientific data from the mission. Telecommunications to the Earth may be accomplished using direct-to-Earth links via the Deep Space Network (DSN) or by relay links supported by other missions at Mars. This paper reviews current plans for missions to Mars through the 2005 launch opportunity and their capabilities in support of rover and robotic telecommunications.

Mission analysis for the Martian Moons Explorer (MMX) mission

Science.gov (United States)

Campagnola, Stefano; Yam, Chit Hong; Tsuda, Yuichi; Ogawa, Naoko; Kawakatsu, Yasuhiro

2018-05-01

Mars Moon eXplorer (MMX) is JAXA's next candidate flagship mission to be launched in the early 2020s. MMX will explore the Martian moons and return a sample from Phobos. This paper presents the mission analysis work, focusing on the transfer legs and comparing several architectures, such as hybrid options with chemical and electric propulsion modules. The selected baseline is a chemical-propulsion Phobos sample return, which is discussed in detail with the launch- and return-window analysis. The trajectories are optimized with the jTOP software, using planetary ephemerides for Mars and the Earth; Earth re-entry constraints are modeled with simple analytical equations. Finally, we introduce an analytical approximation of the three-burn capture strategy used in the Mars system. The approximation can be used together with a Lambert solver to quickly determine the transfer Δ v costs.

Telecentre Network Startup : Bangladesh - Mission 2011 | IDRC ...

International Development Research Centre (IDRC) Digital Library (Canada)

The second generation of telecentres has seen the emergence of national-level networks in various parts of the word including the Ugandan Telecentre Network, Mission 2007 in India and Mission Swaabhimaan in Nepal. Telecentre stakeholders in Bangladesh would like to replicate the methodology used in Mission 2007, ...

The Economics of NASA Mission Cost Reserves

Science.gov (United States)

Whitley, Sally; Shinn, Stephen

2012-01-01

Increases in NASA mission costs have led to analysis of the causes and magnitude of historical mission overruns as well as mitigation and prevention attempts. This paper hypothesizes that one cause is that the availability of reserves may reduce incentives to control costs. We draw a comparison to the insurance concept of moral hazard, and we use actuarial techniques to better understand the increase in mission costs due to the availability of reserves. NASA's CADRe database provided the data against which we tested our hypothesis and discovered that there is correlation between the amount of available reserves and project overruns, particularly for mission hardware cost increases. We address the question of how to prevent reserves from increasing mission spending without increasing cost risk to projects.

PUREX Plant deactivation mission analysis report

International Nuclear Information System (INIS)

Lund, D.P.

1995-01-01

The purpose of the PUREX Deactivation Project mission analysis is to define the problem to be addressed by the PUREX mission, and to lay the ground work for further system definition. The mission analysis is an important first step in the System Engineering (SE) process. This report presents the results of the PUREX Deactivation Project mission analysis. The purpose of the PUREX Deactivation Project is to prepare PUREX for Decontamination and Decommissioning within a five year time frame. This will be accomplished by establishing a passively safe and environmentally secure configuration of the PUREX Plant, that can be preserved for a 10-year horizon. During deactivation, appropriate portions of the safety envelop will be maintained to ensure deactivation takes place in a safe and regulatory compliant manner

Mission to the comets

International Nuclear Information System (INIS)

Hughes, D.

1980-01-01

The plans of space agencies in the United States and Europe for an exploratory comet mission including a one year rendezvous with comet Temple-2 and a fast fly-by of comet Halley are discussed. The mission provides an opportunity to make comparative measurements on the two different types of comets and also satisfies the three major scientific objectives of cometary missions namely: (1) To determine the chemical nature and the physical structure of cometary nuclei, and the changes that occur with time and orbital position. (2) To study the chemical and physical nature of the atmospheres and ionospheres of comets, the processes that occur in them, and their development with time and orbital position. (3) To determine the nature of the tails of comets and the processes by which they are formed, and to characterise the interaction of comets with solar wind. (UK)

Country programming mission. Namibia

International Nuclear Information System (INIS)

1991-01-01

In response to a request from the Government of Namibia conveyed in a letter dated 29 November 1990 IAEA provided a multi-disciplinary Programming Mission which visited Namibia from 15 - 19 July 1991. The terms of reference of the Mission were: 1. To assess the possibilities and benefits of nuclear energy applications in Namibia's development; 2. To advise on the infrastructure required for nuclear energy projects; 3. To assist in the formulation of project proposals which could be submitted for Agency assistance. This report is based on the findings of the Mission and falls into 3 sections with 8 appendices. The first section is a country profile providing background information, the second section deals with sectorial needs and institutional review of the sectors of agriculture including animal production, life sciences (nuclear medicine and radiotherapy) and radiation protection. The third section includes possible future technical co-operation activities

IntroductionThe Cluster mission

Directory of Open Access Journals (Sweden)

M. Fehringer

Full Text Available The Cluster mission, ESA’s first cornerstone project, together with the SOHO mission, dating back to the first proposals in 1982, was finally launched in the summer of 2000. On 16 July and 9 August, respectively, two Russian Soyuz rockets blasted off from the Russian cosmodrome in Baikonour to deliver two Cluster spacecraft, each into their proper orbit. By the end of August 2000, the four Cluster satellites had reached their final tetrahedral constellation. The commissioning of 44 instruments, both individually and as an ensemble of complementary tools, was completed five months later to ensure the optimal use of their combined observational potential. On 1 February 2001, the mission was declared operational. The main goal of the Cluster mission is to study the small-scale plasma structures in three dimensions in key plasma regions, such as the solar wind, bow shock, magnetopause, polar cusps, magnetotail and the auroral zones. With its unique capabilities of three-dimensional spatial resolution, Cluster plays a major role in the International Solar Terrestrial Program (ISTP, where Cluster and the Solar and Heliospheric Observatory (SOHO are the European contributions. Cluster’s payload consists of state-of-the-art plasma instrumentation to measure electric and magnetic fields from the quasi-static up to high frequencies, and electron and ion distribution functions from energies of nearly 0 eV to a few MeV. The science operations are coordinated by the Joint Science Operations Centre (JSOC, at the Rutherford Appleton Laboratory (UK, and implemented by the European Space Operations Centre (ESOC, in Darmstadt, Germany. A network of eight national data centres has been set up for raw data processing, for the production of physical parameters, and their distribution to end users all over the world. The latest information on the Cluster mission can be found at http://sci.esa.int/cluster/.

IntroductionThe Cluster mission

Directory of Open Access Journals (Sweden)

C. P. Escoubet

2001-09-01

Full Text Available The Cluster mission, ESA’s first cornerstone project, together with the SOHO mission, dating back to the first proposals in 1982, was finally launched in the summer of 2000. On 16 July and 9 August, respectively, two Russian Soyuz rockets blasted off from the Russian cosmodrome in Baikonour to deliver two Cluster spacecraft, each into their proper orbit. By the end of August 2000, the four Cluster satellites had reached their final tetrahedral constellation. The commissioning of 44 instruments, both individually and as an ensemble of complementary tools, was completed five months later to ensure the optimal use of their combined observational potential. On 1 February 2001, the mission was declared operational. The main goal of the Cluster mission is to study the small-scale plasma structures in three dimensions in key plasma regions, such as the solar wind, bow shock, magnetopause, polar cusps, magnetotail and the auroral zones. With its unique capabilities of three-dimensional spatial resolution, Cluster plays a major role in the International Solar Terrestrial Program (ISTP, where Cluster and the Solar and Heliospheric Observatory (SOHO are the European contributions. Cluster’s payload consists of state-of-the-art plasma instrumentation to measure electric and magnetic fields from the quasi-static up to high frequencies, and electron and ion distribution functions from energies of nearly 0 eV to a few MeV. The science operations are coordinated by the Joint Science Operations Centre (JSOC, at the Rutherford Appleton Laboratory (UK, and implemented by the European Space Operations Centre (ESOC, in Darmstadt, Germany. A network of eight national data centres has been set up for raw data processing, for the production of physical parameters, and their distribution to end users all over the world. The latest information on the Cluster mission can be found at http://sci.esa.int/cluster/.

Mission Applications Support at NASA: Coastal Applications of SWOT Mission Data

Science.gov (United States)

Srinivasan, M. M.; Peterson, C. A.; Chao, Y.

2014-12-01

The Surface Water and Ocean Topography (SWOT) mission is an international collaboration of two scientific communities focused on a better understanding of the world's oceans and its terrestrial surface waters. SWOT will produce the first global survey of Earth's surface water by measuring sea surface height and the heights, slopes, and inundated areas of rivers, lakes, and wetlands. These coastal, lake and river measurements will be useful for monitoring the hydrologic cycle, flooding, and climate impacts of a changing environment. NASA and their French, Canadian and the United Kingdom space agency partners are developing new wide swath altimetry technology that will cover most of the world's ocean and surface freshwater bodies, and will have the capability to make observations with unprecedented resolution compared to existing technologies and will have the capability of measuring how water bodies change over time. Along with existing altimetry datasets, simulated SWOT data sets are being planned to assess the quality and potential value of anticipated SWOT measurements to both oceanography and hydrology applications. With the surface water measurements anticipated from SWOT, a broad range of applications may inform coastal managers and marine operators of offshore conditions and currents relevant to their regions. One study proposed to the NASA ASP would highlight coastal and estuary applications potential of the future SWOT mission. This study would promote the use of remote sensing measurements to improve the understanding, monitoring and management of estuaries and deltas for a broad range of users. In addition, the AirSWOT airborne mission to demonstrate the wide swath technology of SWOT is providing preliminary data products in inland and coastal regions that may be useful for early assessment by users of the future value of SWOT. NASA's Applied Sciences Program (ASP), along with the international SWOT project teams, is supporting a program that promotes

Mechanical design of the Mars Pathfinder mission

Science.gov (United States)

Eisen, Howard Jay; Buck, Carl W.; Gillis-Smith, Greg R.; Umland, Jeffrey W.

1997-01-01

The Mars Pathfinder mission and the Sojourner rover is reported on, with emphasis on the various mission steps and the performance of the technologies involved. The mechanical design of mission hardware was critical to the success of the entry sequence and the landing operations. The various mechanisms employed are considered.

Pastoral ministry in a missional age: Towards a practical theological understanding of missional pastoral care

Directory of Open Access Journals (Sweden)

Guillaume H. Smit

2015-03-01

Full Text Available This article concerns itself with the development of a missional ecclesiology and the practices that may accept the challenge of conducting pastoral ministry in the context of South African, middleclass congregations adapting to a rapidly changing, post-apartheid environment. Some practical theological perspectives on pastoral counselling are investigated, whilst Narrative Therapy is explored as an emerging theory of deconstruction to enable the facilitating of congregational change towards a missional understanding of church life in local communities. Subsequently, the theological paradigm of missional ecclesiology is investigated before drawing the broad lines of a theory for pastoral ministry within missional ecclesiology.Intradisciplinary and/or interdisciplinary implications: In this article, a missional base theory is proposed for pastoral counselling, consisting of interdisciplinary insights gained from the fields of Missiology, Practical Theology, Narrative Therapy and Cognitive Behaviour Therapy. The implications of this proposal for the development of a missional pastoral theory focus on the following three aspects:� re-establishing pastoral identity: exploring Christ� pastoral development: intentional faith formation� pastoral ministry: enabling Christ-centred lives.In such a missional pastoral theory four practices should be operationalised: first of all, a cognitive approach to increasing knowledge of the biblical narrative is necessary. This provides the hermeneutical skills necessary to enable people to internalise the biblical ethics and character traits ascribed to the Christian life. Secondly, a pastoral theory needs to pay close attention to development of emotional intelligence. Thirdly, this should be done in the context of small groups, where the focus falls on the personality development of members. Finally, missional pastoral theory should also include the acquisition of life coaching skills, where leaders can be

Teamwork Reasoning and Multi-Satellite Missions

Science.gov (United States)

Marsella, Stacy C.; Plaunt, Christian (Technical Monitor)

2002-01-01

NASA is rapidly moving towards the use of spatially distributed multiple satellites operating in near Earth orbit and Deep Space. Effective operation of such multi-satellite constellations raises many key research issues. In particular, the satellites will be required to cooperate with each other as a team that must achieve common objectives with a high degree of autonomy from ground based operations. The multi-agent research community has made considerable progress in investigating the challenges of realizing such teamwork. In this report, we discuss some of the teamwork issues that will be faced by multi-satellite operations. The basis of the discussion is a particular proposed mission, the Magnetospheric MultiScale mission to explore Earth's magnetosphere. We describe this mission and then consider how multi-agent technologies might be applied in the design and operation of these missions. We consider the potential benefits of these technologies as well as the research challenges that will be raised in applying them to NASA multi-satellite missions. We conclude with some recommendations for future work.

Cryogenic propulsion for lunar and Mars missions

Science.gov (United States)

Redd, Larry

1988-01-01

Future missions to the moon and Mars have been investigated with regard to propulsion system selection. The results of this analysis show that near state-of-the-art LO2/LH2 propulsion technology provides a feasible means of performing lunar missions and trans-Mars injections. In other words, existing cryogenic space engines with certain modifications and product improvements would be suitable for these missions. In addition, present day cryogenic system tankage and structural weights appear to scale reasonably when sizing for large payload and high energy missions such as sending men to Mars.

The EXIST Mission Concept Study

Science.gov (United States)

Fishman, Gerald J.; Grindlay, J.; Hong, J.

2008-01-01

EXIST is a mission designed to find and study black holes (BHs) over a wide range of environments and masses, including: 1) BHs accreting from binary companions or dense molecular clouds throughout our Galaxy and the Local Group, 2) supermassive black holes (SMBHs) lying dormant in galaxies that reveal their existence by disrupting passing stars, and 3) SMBHs that are hidden from our view at lower energies due to obscuration by the gas that they accrete. 4) the birth of stellar mass BHs which is accompanied by long cosmic gamma-ray bursts (GRBs) which are seen several times a day and may be associated with the earliest stars to form in the Universe. EXIST will provide an order of magnitude increase in sensitivity and angular resolution as well as greater spectral resolution and bandwidth compared with earlier hard X-ray survey telescopes. With an onboard optical-infra red (IR) telescope, EXIST will measure the spectra and redshifts of GRBs and their utility as cosmological probes of the highest z universe and epoch of reionization. The mission would retain its primary goal of being the Black Hole Finder Probe in the Beyond Einstein Program. However, the new design for EXIST proposed to be studied here represents a significant advance from its previous incarnation as presented to BEPAC. The mission is now less than half the total mass, would be launched on the smallest EELV available (Atlas V-401) for a Medium Class mission, and most importantly includes a two-telescope complement that is ideally suited for the study of both obscured and very distant BHs. EXIST retains its very wide field hard X-ray imaging High Energy Telescope (HET) as the primary instrument, now with improved angular and spectral resolution, and in a more compact payload that allows occasional rapid slews for immediate optical/IR imaging and spectra of GRBs and AGN as well as enhanced hard X-ray spectra and timing with pointed observations. The mission would conduct a 2 year full sky survey in

TandEM: Titan and Enceladus mission

Science.gov (United States)

Coustenis, A.; Atreya, S.K.; Balint, T.; Brown, R.H.; Dougherty, M.K.; Ferri, F.; Fulchignoni, M.; Gautier, D.; Gowen, R.A.; Griffith, C.A.; Gurvits, L.I.; Jaumann, R.; Langevin, Y.; Leese, M.R.; Lunine, J.I.; McKay, C.P.; Moussas, X.; Muller-Wodarg, I.; Neubauer, F.; Owen, T.C.; Raulin, F.; Sittler, E.C.; Sohl, F.; Sotin, Christophe; Tobie, G.; Tokano, T.; Turtle, E.P.; Wahlund, J.-E.; Waite, J.H.; Baines, K.H.; Blamont, J.; Coates, A.J.; Dandouras, I.; Krimigis, T.; Lellouch, E.; Lorenz, R.D.; Morse, A.; Porco, C.C.; Hirtzig, M.; Saur, J.; Spilker, T.; Zarnecki, J.C.; Choi, E.; Achilleos, N.; Amils, R.; Annan, P.; Atkinson, D.H.; Benilan, Y.; Bertucci, C.; Bezard, B.; Bjoraker, G.L.; Blanc, M.; Boireau, L.; Bouman, J.; Cabane, M.; Capria, M.T.; Chassefiere, E.; Coll, P.; Combes, M.; Cooper, J.F.; Coradini, A.; Crary, F.; Cravens, T.; Daglis, I.A.; de Angelis, E.; De Bergh, C.; de Pater, I.; Dunford, C.; Durry, G.; Dutuit, O.; Fairbrother, D.; Flasar, F.M.; Fortes, A.D.; Frampton, R.; Fujimoto, M.; Galand, M.; Grasset, O.; Grott, M.; Haltigin, T.; Herique, A.; Hersant, F.; Hussmann, H.; Ip, W.; Johnson, R.; Kallio, E.; Kempf, S.; Knapmeyer, M.; Kofman, W.; Koop, R.; Kostiuk, T.; Krupp, N.; Kuppers, M.; Lammer, H.; Lara, L.-M.; Lavvas, P.; Le, Mouelic S.; Lebonnois, S.; Ledvina, S.; Li, Ji; Livengood, T.A.; Lopes, R.M.; Lopez-Moreno, J. -J.; Luz, D.; Mahaffy, P.R.; Mall, U.; Martinez-Frias, J.; Marty, B.; McCord, T.; Salvan, C.M.; Milillo, A.; Mitchell, D.G.; Modolo, R.; Mousis, O.; Nakamura, M.; Neish, Catherine D.; Nixon, C.A.; Mvondo, D.N.; Orton, G.; Paetzold, M.; Pitman, J.; Pogrebenko, S.; Pollard, W.; Prieto-Ballesteros, O.; Rannou, P.; Reh, K.; Richter, L.; Robb, F.T.; Rodrigo, R.; Rodriguez, S.; Romani, P.; Bermejo, M.R.; Sarris, E.T.; Schenk, P.; Schmitt, B.; Schmitz, N.; Schulze-Makuch, D.; Schwingenschuh, K.; Selig, A.; Sicardy, B.; Soderblom, L.; Spilker, L.J.; Stam, D.; Steele, A.; Stephan, K.; Strobel, D.F.; Szego, K.; Szopa,

2009-01-01

TandEM was proposed as an L-class (large) mission in response to ESA’s Cosmic Vision 2015–2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini–Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini–Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (Montgolfière) and possibly several landing probes to be delivered through the atmosphere.

The inner magnetosphere imager mission

International Nuclear Information System (INIS)

Johnson, L.; Herrmann, M.

1993-01-01

After 30 years of in situ measurements of the Earth's magnetosphere, scientists have assembled an incomplete picture of its global composition and dynamics. Imaging the magnetosphere from space will enable scientists to better understand the global shape of the inner magnetosphere, its components and processes. The proposed inner magnetosphere imager (IMI) mission will obtain the first simultaneous images of the component regions of the inner magnetosphere and will enable scientists to relate these global images to internal and external influences as well as local observations. To obtain simultaneous images of component regions of the inner magnetosphere, measurements will comprise: the ring current and inner plasma sheet using energetic neutral atoms; the plasmasphere using extreme ultraviolet; the electron and proton auroras using far ultraviolet (FUV) and x rays; and the geocorona using FUV. The George C. Marshall Space Flight Center (MSFC) is performing a concept definition study of the proposed mission. NASA's Office of Space Science and Applications has placed the IMI third in its queue of intermediate-class missions for launch in the 1990's. An instrument complement of approximately seven imagers will fly in an elliptical Earth orbit with a seven Earth Radii (R E ) altitude apogee and approximately 4,800-kin altitude perigee. Several spacecraft concepts were examined for the mission. The first concept utilizes a spinning spacecraft with a despun platform. The second concept splits the instruments onto a spin-stabilized spacecraft and a complementary three-axis stabilized spacecraft. Launch options being assessed for the spacecraft range from a Delta 11 for the single and dual spacecraft concepts to dual Taurus launches for the two smaller spacecraft. This paper will address the mission objectives, the spacecraft design considerations, the results of the MSFC concept definition study, and future mission plans

Preliminary design of an asteroid hopping mission

Science.gov (United States)

Scheppa, Michael D.

In 2010, NASA announced that its new vision is to support private space launch operations. It is anticipated that this new direction will create the need for new and innovative ideas that push the current boundaries of space exploration and contain the promise of substantial gain, both in research and capital. The purpose of the study is to plan and estimate the feasibility of a mission to visit a number of near Earth asteroids (NEAs). The mission would take place before the end of the 21st century, and would only use commercially available technology. Throughout the mission design process, while holding astronaut safety paramount, it was the goal to maximize the return while keeping the cost to a minimum. A mission of the nature would appeal to the private space industry because it could be easily adapted and set into motion. The mission design was divided into three main parts; mission timeline, vehicle design and power sources, with emphasis on nuclear and solar electric power, were investigated. The timeline and associated trajectories were initially selected using a numerical estimation and then optimized using Satellite Tool Kit (STK) 9.s's Design Explorer Optimizer [1]. Next, the spacecraft was design using commercially available parts that would support the mission requirements. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) was and instrumental piece in maximizing the number of NEAs visited. Once the spacecraft was designed, acceptable power supply options were investigated. The VASIMR VX-200 requires 200 kilowatts of power to maintain thrust. This creates the need for a substantial power supply that consists of either a nuclear reactor of massive solar arrays. STK 9.1's Design Explorer Optimizer was able to create a mission time line that allowed for the exploration of seven NEAs in under two years, while keeping the total mission DeltaV under 71 kilometers per second. Based on these initial findings, it is determined that a mission of this

The Exo-S probe class starshade mission

Science.gov (United States)

Seager, Sara; Turnbull, Margaret; Sparks, William; Thomson, Mark; Shaklan, Stuart B.; Roberge, Aki; Kuchner, Marc; Kasdin, N. Jeremy; Domagal-Goldman, Shawn; Cash, Webster; Warfield, Keith; Lisman, Doug; Scharf, Dan; Webb, David; Trabert, Rachel; Martin, Stefan; Cady, Eric; Heneghan, Cate

2015-09-01

Exo-S is a direct imaging space-based mission to discover and characterize exoplanets. With its modest size, Exo-S bridges the gap between census missions like Kepler and a future space-based flagship direct imaging exoplanet mission. With the ability to reach down to Earth-size planets in the habitable zones of nearly two dozen nearby stars, Exo-S is a powerful first step in the search for and identification of Earth-like planets. Compelling science can be returned at the same time as the technological and scientific framework is developed for a larger flagship mission. The Exo-S Science and Technology Definition Team studied two viable starshade-telescope missions for exoplanet direct imaging, targeted to the $1B cost guideline. The first Exo-S mission concept is a starshade and telescope system dedicated to each other for the sole purpose of direct imaging for exoplanets (The "Starshade Dedicated Mission"). The starshade and commercial, 1.1-m diameter telescope co-launch, sharing the same low-cost launch vehicle, conserving cost. The Dedicated mission orbits in a heliocentric, Earth leading, Earth-drift away orbit. The telescope has a conventional instrument package that includes the planet camera, a basic spectrometer, and a guide camera. The second Exo-S mission concept is a starshade that launches separately to rendezvous with an existing on-orbit space telescope (the "Starshade Rendezvous Mission"). The existing telescope adopted for the study is the WFIRST-AFTA (Wide-Field Infrared Survey Telescope Astrophysics Focused Telescope Asset). The WFIRST-AFTA 2.4-m telescope is assumed to have previously launched to a Halo orbit about the Earth-Sun L2 point, away from the gravity gradient of Earth orbit which is unsuitable for formation flying of the starshade and telescope. The impact on WFIRST-AFTA for starshade readiness is minimized; the existing coronagraph instrument performs as the starshade science instrument, while formation guidance is handled by the

The Europa Ocean Discovery mission

Energy Technology Data Exchange (ETDEWEB)

Edwards, B.C. [Los Alamos National Lab., NM (United States); Chyba, C.F. [Univ. of Arizona, Tucson, AZ (United States); Abshire, J.B. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center] [and others

1997-06-01

Since it was first proposed that tidal heating of Europa by Jupiter might lead to liquid water oceans below Europa`s ice cover, there has been speculation over the possible exobiological implications of such an ocean. Liquid water is the essential ingredient for life as it is known, and the existence of a second water ocean in the Solar System would be of paramount importance for seeking the origin and existence of life beyond Earth. The authors present here a Discovery-class mission concept (Europa Ocean Discovery) to determine the existence of a liquid water ocean on Europa and to characterize Europa`s surface structure. The technical goal of the Europa Ocean Discovery mission is to study Europa with an orbiting spacecraft. This goal is challenging but entirely feasible within the Discovery envelope. There are four key challenges: entering Europan orbit, generating power, surviving long enough in the radiation environment to return valuable science, and complete the mission within the Discovery program`s launch vehicle and budget constraints. The authors will present here a viable mission that meets these challenges.

Mars MetNet Mission Status

Science.gov (United States)

Harri, A.-M.; Aleksashkin, S.; Arruego, I.; Schmidt, W.; Genzer, M.; Vazquez, L.; Haukka, H.; Palin, M.; Nikkanen, T.

2015-10-01

New kind of planetary exploration mission for Mars is under development in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semihard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor [1] mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide significant insights in to the Martian atmospheric behavior. The key technologies of the MetNet Lander have been qualified and the electrical qualification model (EQM) of the payload bay has been built and successfully tested.

MIV Project: Mission scenario

DEFF Research Database (Denmark)

Ravazzotti, Mariolina T.; Jørgensen, John Leif; Thuesen, Gøsta

1997-01-01

Under the ESA contract #11453/95/NL/JG(SC), aiming at assessing the feasibility of Rendez-vous and docking of unmanned spacecrafts, a msiision scenario was defined. This report describes the secquence of manouvres and task allocations for such missions.......Under the ESA contract #11453/95/NL/JG(SC), aiming at assessing the feasibility of Rendez-vous and docking of unmanned spacecrafts, a msiision scenario was defined. This report describes the secquence of manouvres and task allocations for such missions....

Understanding NEOs: The Role of Characterization Missions

Science.gov (United States)

Morrison, David

2007-10-01

NEOs are important from multiple perspectives, including science, hazard mitigation, space resources, and as targets for human missions. Much can be learned from ground-based studies, especially with radar, but the unique value of in situ investigation has been shown by missions such as NEAR-Shoemaker and Hayabusa to asteroids Eros and Itokawa, and Deep Impact and Stardust to comets. The next mission targets are likely to be NEAs in the subkilometer size range. Because these smaller objects are much more numerous, they are the objects we most need to understand from a defense perspective, and they are also the most likely targets for early human missions. However, there are unique challenges in sending spacecraft to investigate sub-km asteroids. Reconnaissance flybys are of little use, orbiting requires active control, and landing on such a low-gravity surface is perhaps better described as docking. Yet we need to operate close to the target, and probably to land, to obtain crucial information about interior structure. This paper deals primarily with small landers like the Near Earth Asteroid Trailblazer Mission (NEAT) studied at Ames Research Center. The NEAT objectives are to provide global reconnaissance (shape, mass, density, dynamical state), in situ surface characterization, and long-term precision tracking. Alternative approaches use deep-penetrating radar and electromagnetic sounding to probe interior structure. A third class of missions is ballistic impactors such as the ESA Don Quijote, which test one of the technologies for deflecting small asteroids. If the targets are selected for their accessibility, such missions could be implemented with low-cost launchers such as Pegasus, Falcon, or Minotaur. Such missions will have high science return. But from the perspective of defense, we have not yet developed a consensus strategy for the role of such characterization missions.

Planetary protection considerations for sample-return missions

Science.gov (United States)

Rummel, J.

The analysis on Earth of materials returned from other solar system bodies, and beyond, is likely one of the most effective ways for us to learn about the origins, history, and present state of the universe outside of our home planet. In the past, the Apollo missions were able to return large quantities of material from the Moon, while missions currently flying (Genesis and Stardust) intend to return much smaller quantities of material. Planned and conceptualized future missions (cf., MUSES-C) intend to return a wide variety of samples such as those from a near-Earth asteroid, the surface and atmosphere of Mars , and perhaps once more from the Earth's Moon. In some cases, the bodies targeted for sample return missions may have the capability of harboring indigenous life, while in other cases there is scant possibility of that. Considerations in determining the potential for extraterrestrial contamination from sample return missions have been studied, and include such factors as the availability of liquid water in or on the target body, the availability of m tabolicallye useful energy sources, the likelihood that organic matter was available, and the overall temperature and radiation history of the sampled areas. Also of note is the potential that the natural influx to Earth of that materials in question (e.g., meteorites, etc.) might overwhelm the ability of a targeted sample-return mission to contribute something novel to the Earth's environment. Missions thought to pose a risk of extraterrestrial biological contamination are subject to a containment provision that may be very difficult to implement on a single, moderate-cost mission, but such steps are necessary to protect both our own planet and the health of solar-system exploration missions and the science they can do.

Analysis of Electric Propulsion System for Exploration of Saturn

Directory of Open Access Journals (Sweden)

Carlos Renato Huaura Solórzano

2009-01-01

Full Text Available Exploration of the outer planets has experienced new interest with the launch of the Cassini and the New Horizons Missions. At the present time, new technologies are under study for the better use of electric propulsion system in deep space missions. In the present paper, the method of the transporting trajectory is used to study this problem. This approximated method for the flight optimization with power-limited low thrust is based on the linearization of the motion of a spacecraft near a keplerian orbit that is close to the transfer trajectory. With the goal of maximizing the mass to be delivered in Saturn, several transfers were studied using nuclear, radioisotopic and solar electric propulsion systems.

A Centaur Reconnaissance Mission: a NASA JPL Planetary Science Summer Seminar mission design experience

Science.gov (United States)

Chou, L.; Howell, S. M.; Bhattaru, S.; Blalock, J. J.; Bouchard, M.; Brueshaber, S.; Cusson, S.; Eggl, S.; Jawin, E.; Marcus, M.; Miller, K.; Rizzo, M.; Smith, H. B.; Steakley, K.; Thomas, N. H.; Thompson, M.; Trent, K.; Ugelow, M.; Budney, C. J.; Mitchell, K. L.

2017-12-01

The NASA Planetary Science Summer Seminar (PSSS), sponsored by the Jet Propulsion Laboratory (JPL), offers advanced graduate students and recent doctoral graduates the unique opportunity to develop a robotic planetary exploration mission that answers NASA's Science Mission Directorate's Announcement of Opportunity for the New Frontiers Program. Preceded by a series of 10 weekly webinars, the seminar is an intensive one-week exercise at JPL, where students work directly with JPL's project design team "TeamX" on the process behind developing mission concepts through concurrent engineering, project design sessions, instrument selection, science traceability matrix development, and risks and cost management. The 2017 NASA PSSS team included 18 participants from various U.S. institutions with a diverse background in science and engineering. We proposed a Centaur Reconnaissance Mission, named CAMILLA, designed to investigate the geologic state, surface evolution, composition, and ring systems through a flyby and impact of Chariklo. Centaurs are defined as minor planets with semi-major axis that lies between Jupiter and Neptune's orbit. Chariklo is both the largest Centaur and the only known minor planet with rings. CAMILLA was designed to address high priority cross-cutting themes defined in National Research Council's Vision and Voyages for Planetary Science in the Decade 2013-2022. At the end of the seminar, a final presentation was given by the participants to a review board of JPL scientists and engineers as well as NASA headquarters executives. The feedback received on the strengths and weaknesses of our proposal provided a rich and valuable learning experience in how to design a successful NASA planetary exploration mission and generate a successful New Frontiers proposal. The NASA PSSS is an educational experience that trains the next generation of NASA's planetary explorers by bridging the gap between scientists and engineers, allowing for participants to learn

78 FR 11101 - Air Quality: Revision to Definition of Volatile Organic Compounds-Exclusion of trans

Science.gov (United States)

2013-02-15

... Review of Solstice\\TM\\ 1233zd(E) D. Significant New Alternatives Policy Program Review of Solstice\\TM... compounds creates an incentive for industry to use negligibly reactive compounds in place of more highly reactive compounds that are regulated as VOCs. The EPA lists compounds that it has determined to be...

New Global Missions for Strategic Command

National Research Council Canada - National Science Library

Graham, David

2002-01-01

.... The focus of this White Paper is on the external decisions that will be needed to provide the Command with a clear mission, and the authority, resources and organizational support necessary to perform the mission...

Mercury Lander Mission Concept Study Summary

Science.gov (United States)

Eng, D. A.

2018-05-01

Provides a summary of the Mercury Lander Mission Concept Study performed as part of the last Planetary Decadal Survey. The presentation will focus on engineering trades and the challenges of developing a Mercury lander mission.

Constraining the physical properties of Titan's empty lake basins using nadir and off-nadir Cassini RADAR backscatter

Science.gov (United States)

Michaelides, R. J.; Hayes, A. G.; Mastrogiuseppe, M.; Zebker, H. A.; Farr, T. G.; Malaska, M. J.; Poggiali, V.; Mullen, J. P.

2016-05-01

We use repeat synthetic aperture radar (SAR) observations and complementary altimetry passes acquired by the Cassini spacecraft to study the scattering properties of Titan's empty lake basins. The best-fit coefficients from fitting SAR data to a quasi-specular plus diffuse backscatter model suggest that the bright basin floors have a higher dielectric constant, but similar facet-scale rms surface facet slopes, to surrounding terrain. Waveform analysis of altimetry returns reveals that nadir backscatter returns from basin floors are greater than nadir backscatter returns from basin surroundings and have narrower pulse widths. This suggests that floor deposits are structurally distinct from their surroundings, consistent with the interpretation that some of these basins may be filled with evaporitic and/or sedimentary deposits. Basin floor deposits also express a larger diffuse component to their backscatter, which is likely due to variations in subsurface structure or an increase in roughness at the wavelength scale (Hayes, A.G. et al. [2008]. Geophys. Res. Lett. 35, 9). We generate a high-resolution altimetry radargram of the T30 altimetry pass over an empty lake basin, with which we place geometric constraints on the basin's slopes, rim heights, and depth. Finally, the importance of these backscatter observations and geometric measurements for basin formation mechanisms is briefly discussed.

Applied research of Primary Pump Mission Profile construction

International Nuclear Information System (INIS)

Zheng, Gang-yang; Zhang, Zhi-jian; Ye, Quan-liu; Du, Zhi-hao; Ma, Ying-fei; Zhang, Hua-zhi

2017-01-01

Highlights: • Minimum Associated Subtask (MAS) and Minimum Effective Component (MEC) are presented in Mission Profile analysis. • Via applying MAS and MEC, Mission Profile plays a more important role in complex system reliability analysis. • Mission Profile has already been used in the reliability analysis of localized Chinese 1000 MW NPP Primary Pump. - Abstract: The traditional Mission Profile analysis did not clarify the accurate concept of minimum subtask and component. However, there are several components, which could be the influencing key element of the system reliability; and there are several subtasks, which could be used as a basic and crucial mission. In this paper, traditional method of Mission Profile has been extended by incorporating two new ideas: Minimum Associated Subtask (MAS) and Minimum Effective Component (MEC). This method of Mission Profile modeling is derived from Chinese 1000 MW NPP Primary Pump localization. A case study on Primary Pump reliability has been presented; then, MAS and MEC have been existed as vital elements in its lifecycle profile construction. By means of MAS and MEC, Mission Profile plays a more important role on complex system (Primary Pump) reliability analysis.

Haze and cloud structure of Saturn's North Pole and Hexagon Wave from Cassini/ISS imaging

Science.gov (United States)

Sanz-Requena, J. F.; Pérez-Hoyos, S.; Sánchez-Lavega, A.; Antuñano, A.; Irwin, Patrick G. J.

2018-05-01

In this paper we present a study of the vertical haze and cloud structure in the upper two bars of Saturn's Northern Polar atmosphere using the Imaging Science Subsystem (ISS) instrument onboard the Cassini spacecraft. We focus on the characterization of latitudes from 53° to 90° N. The observations were taken during June 2013 with five different filters (VIO, BL1, MT2, CB2 and MT3) covering spectral range from the 420 nm to 890 nm (in a deep methane absorption band). Absolute reflectivity measurements of seven selected regions at all wavelengths and several illumination and observation geometries are compared with the values produced by a radiative transfer model. The changes in reflectivity at these latitudes are mostly attributed to changes in the tropospheric haze. This includes the haze base height (from 600 ± 200 mbar at the lowest latitudes to 1000 ± 300 mbar in the pole), its particle number density (from 20 ± 2 particles/cm3 to 2 ± 0.5 particles/cm3 at the haze base) and its scale height (from 18 ± 0.1 km to 50 ± 0.1 km). We also report variability in the retrieved particle size distribution and refractive indices. We find that the Hexagonal Wave dichotomizes the studied stratospheric and tropospheric hazes between the outer, equatorward regions and the inner, Polar Regions. This suggests that the wave or the jet isolates the particle distribution at least at tropospheric levels.

Sleep and cognitive function of crewmembers and mission controllers working 24-h shifts during a simulated 105-day spaceflight mission

Science.gov (United States)

Barger, Laura K.; Wright, Kenneth P.; Burke, Tina M.; Chinoy, Evan D.; Ronda, Joseph M.; Lockley, Steven W.; Czeisler, Charles A.

2014-01-01

The success of long-duration space missions depends on the ability of crewmembers and mission support specialists to be alert and maintain high levels of cognitive function while operating complex, technical equipment. We examined sleep, nocturnal melatonin levels and cognitive function of crewmembers and the sleep and cognitive function of mission controllers who participated in a high-fidelity 105-day simulated spaceflight mission at the Institute of Biomedical Problems (Moscow). Crewmembers were required to perform daily mission duties and work one 24-h extended duration work shift every sixth day. Mission controllers nominally worked 24-h extended duration shifts. Supplemental lighting was provided to crewmembers and mission controllers. Participants' sleep was estimated by wrist-actigraphy recordings. Overall, results show that crewmembers and mission controllers obtained inadequate sleep and exhibited impaired cognitive function, despite countermeasure use, while working extended duration shifts. Crewmembers averaged 7.04±0.92 h (mean±SD) and 6.94±1.08 h (mean±SD) in the two workdays prior to the extended duration shifts, 1.88±0.40 h (mean±SD) during the 24-h work shift, and then slept 10.18±0.96 h (mean±SD) the day after the night shift. Although supplemental light was provided, crewmembers' average nocturnal melatonin levels remained elevated during extended 24-h work shifts. Naps and caffeine use were reported by crewmembers during ˜86% and 45% of extended night work shifts, respectively. Even with reported use of wake-promoting countermeasures, significant impairments in cognitive function were observed. Mission controllers slept 5.63±0.95 h (mean±SD) the night prior to their extended duration work shift. On an average, 89% of night shifts included naps with mission controllers sleeping an average of 3.4±1.0 h (mean±SD) during the 24-h extended duration work shift. Mission controllers also showed impaired cognitive function during extended

Fast mission reliability prediction for Unmanned Aerial Vehicles

International Nuclear Information System (INIS)

Andrews, J.D.; Poole, J.; Chen, W.H.

2013-01-01

There is currently a significant interest in the use of autonomous vehicles in many industrial sectors. One such example is the ever increasing use of Unmanned Aerial Vehicles (UAVs), particularly in military operations. This enables dangerous missions to be accomplished without risk to a pilot. UAVs also have potential civil applications which would require their certification and the demonstration that they are able to respond safety to any potential circumstances. The aircraft would therefore need to be capable of responding safely to the occurrence of component failures, the emergence of threats such as other aircraft in the neighboring airspace, and changing weather conditions. The likelihood that an aircraft will successfully complete any mission can be predicted using phased mission analysis techniques. The predicted mission unreliability can be updated in response to changing circumstances. In the event that the likelihood of mission failure becomes too high then changes have to be made to the mission plan. If these calculations could be carried out fast enough then the quantification procedure could be used to establish an acceptable response to any new conditions. With a view to using the methodology in the context described above, this paper investigates ways in which phased mission analysis can be improved to reduce the calculation time. The methodology improves the processing capability for a UAV phased mission analysis by taking into account the specific characteristics of the fault tree structures which provide the causes of phase failure for a UAV mission. It also carries out as much of the quantification as possible in advance of the mission plan being formulated

Dawn Mission Update

Science.gov (United States)

Sykes, M. V.; Russell, C. T.; Coradini, A.; Christensen, U.; de Sanctis, M. C.; Feldman, W. C.; Jaumann, R.; Keller, U.; Konopliv, A. S.; McCord, T. B.; McFadden, L. A.; McSween, H. Y.; Mottola, S.; Neukum, G.; Pieters, C. M.; Prettyman, T. H.; Raymond, C. A.; Smith, D. E.; Williams, B. G.; Wise, J.; Zuber, M. T.

2004-11-01

Dawn, the ninth Discovery mission, will be the first spacecraft to rendezvous with two solar system bodies, the main belt asteroids Vesta and Ceres. This is made possible by utilizing ion propulsion to reach its targets and to maneuver into (and depart) orbits about these bodies. Vesta and Ceres are two terrestrial protoplanets that have survived since the earliest epoch of the solar system and will provide important insights into planet building processes and their evolution under very different circumstances, with and without water. Dawn carries a double framing camera, a visible and infrared mapping spectrometer, and a gamma ray and neutron detector. At Vesta our studies will include the volcanic emplacement of basalts, its differentiation, the possible exposure of its interior near the south pole. At Ceres our studies will include the role of water in its evolution, hydration processes on its surface, and the possible existence of a subsurface ocean. The mission has passed its critical design review and is scheduled to be launched in June 2006 with arrival at Vesta in 2011 and Ceres in 2015. Operation strategies will be presented. Groundbased observations of Vesta, Ceres, and Vesta family members over broad wavelengths, periods and phases will play an important role in detailed mission planning.

Energetic Neutral Atom (ENA) intensity gradients in the heliotail during year 2003, using Cassini/INCA measurements

International Nuclear Information System (INIS)

Dialynas, K; Krimigis, S M; Mitchell, D G; Roelof, E C

2015-01-01

In the present study we use all-sky energy-resolved (5-55 keV) energetic neutral atom (ENA) maps obtained by the Ion and Neutral CAmera (INCA) on board Cassini during the time period DOY 265/2003 to 268/2003, to investigate the properties of the peak-to-basin ENA emissions in the direction of the heliotail. Our conclusions can be summarized as follows: (1) a relatively smooth boundary (called t ransition region ) between the very low (basin) and high (tail) ENA emissions from the heliosheath, with a spatial width of ∼30° deg in ecl. longitude, that no theory had predicted to date, is identified in the energy range of 5-55 keV; (2) the ENA intensity gradient in this transition region is almost invariant as a function of both ecl. Latitude and energy, with an average value of ∼2.4% per degree; (3) the deduced partial plasma pressure distributions in the 5-55 keV energy range are consistent with the ENA intensity distributions in the same energy range, while the ENA intensity gradient translates to a corresponding partial pressure gradient that occurs in the transition region; and (4) this partial pressure gradient is possibly not consistent with a tail magnetic field configuration that is similar to the measured magnetic fields by the Voyagers in the nose hemisphere

Collaboration support system for "Phobos-Soil" space mission.

Science.gov (United States)

Nazarov, V.; Nazirov, R.; Zakharov, A.

2009-04-01

Rapid development of communication facilities leads growth of interactions done via electronic means. However we can see some paradox in this segment in last times: Extending of communication facilities increases collaboration chaos. And it is very sensitive for space missions in general and scientific space mission particularly because effective decision of this task provides successful realization of the missions and promises increasing the ratio of functional characteristic and cost of mission at all. Resolving of this problem may be found by using respective modern technologies and methods which widely used in different branches and not in the space researches only. Such approaches as Social Networking, Web 2.0 and Enterprise 2.0 look most prospective in this context. The primary goal of the "Phobos-Soil" mission is an investigation of the Phobos which is the Martian moon and particularly its regolith, internal structure, peculiarities of the orbital and proper motion, as well as a number of different scientific measurements and experiments for investigation of the Martian environment. A lot of investigators involved in the mission. Effective collaboration system is key facility for information support of the mission therefore. Further to main goal: communication between users of the system, modern approaches allows using such capabilities as self-organizing community, user generated content, centralized and federative control of the system. Also it may have one unique possibility - knowledge management which is very important for space mission realization. Therefore collaboration support system for "Phobos-Soil" mission designed on the base of multilayer model which includes such levels as Communications, Announcement and Information, Data sharing and Knowledge management. The collaboration support system for "Phobos-Soil" mission will be used as prototype for prospective Russian scientific space missions and the presentation describes its architecture

Possible LISA Technology Applications for Other Missions

Science.gov (United States)

Livas, Jeffrey

2018-01-01

The Laser Interferometer Space Antenna (LISA) has been selected as the third large class mission launch opportunity of the Cosmic Visions Program by the European Space Agency (ESA). LISA science will explore a rich spectrum of astrophysical gravitational-wave sources expected at frequencies between 0.0001 and 0.1 Hz and complement the work of other observatories and missions, both space and ground-based, electromagnetic and non-electromagnetic. Similarly, LISA technology may find applications for other missions. This paper will describe the capabilities of some of the key technologies and discuss possible contributions to other missions.

A missional perspective on funerals and bereavement counselling

Directory of Open Access Journals (Sweden)

Peter Kotze

2015-08-01

Full Text Available This article deals with the importance of a missional approach to the funeral and bereavement counselling process in congregational praxis in the midst of a context of secularisation. The creation of a missional perspective on the funeral and bereavement counselling could support the nature and praxis of a congregation in a secular society, especially if the congregation finds its relevance in the expression of the missio Dei. The basic theoretical research for missional ecclesiology, which is the systematic study directed toward greater knowledge of the fundamental aspects of missional ecclesiology (National Science Foundation 1953:38, is based on the premise that God is the source of all missions. The expression missio Dei means to join God in the mission he is already busy with in the world. As the one who sends, God the Father sends the Son, the Son sends the Holy Spirit, and the Holy Spirit sends the church. The church only participates in the mission God is already busy with. It is a mission that uses both words and deeds and brings hope in the midst of tragedy. It is the hope of the kingdom of God and the incarnation of Christ that can already be experienced and expressed in the present. It is also the hope of the transformation of everything to form a new heaven and earth. Hope and mission can therefore not be separated. The concretisation of the expression of the kingdom of Christ in the world is hope, and a strong emphasis is therefore placed on mission as action in hope. Hope must be present where tragedy reigns, and the funeral and bereavement counselling can be used as a vehicle for this hope. Hope can then become an instrument of healing. The church can thus participate in God’s mission in the midst of tragedy and make an impact on society by taking on a missional character of hope.

Lean Mission Operations Systems Design - Using Agile and Lean Development Principles for Mission Operations Design and Development

Science.gov (United States)

Trimble, Jay Phillip

2014-01-01

The Resource Prospector Mission seeks to rove the lunar surface with an in-situ resource utilization payload in search of volatiles at a polar region. The mission operations system (MOS) will need to perform the short-duration mission while taking advantage of the near real time control that the short one-way light time to the Moon provides. To maximize our use of limited resources for the design and development of the MOS we are utilizing agile and lean methods derived from our previous experience with applying these methods to software. By using methods such as "say it then sim it" we will spend less time in meetings and more time focused on the one outcome that counts - the effective utilization of our assets on the Moon to meet mission objectives.

OPUS - Outer Planets Unified Search with Enhanced Surface Geometry Parameters - Not Just for Rings

Science.gov (United States)

Gordon, Mitchell; Showalter, Mark Robert; Ballard, Lisa; Tiscareno, Matthew S.; Heather, Neil

2016-10-01

In recent years, with the massive influx of data into the PDS from a wide array of missions and instruments, finding the precise data you need has been an ongoing challenge. For remote sensing data obtained from Jupiter to Pluto, that challenge is being addressed by the Outer Planets Unified Search, more commonly known as OPUS.OPUS is a powerful search tool available at the PDS Ring-Moon Systems Node (RMS) - formerly the PDS Rings Node. While OPUS was originally designed with ring data in mind, its capabilities have been extended to include all of the targets within an instrument's field of view. OPUS provides preview images of search results, and produces a zip file for easy download of selected products, including a table of user specified metadata. For Cassini ISS and Voyager ISS we have generated and include calibrated versions of every image.Currently OPUS supports data returned by Cassini ISS, UVIS, VIMS, and CIRS (Saturn data through June 2010), New Horizons Jupiter LORRI, Galileo SSI, Voyager ISS and IRIS, and Hubble (ACS, WFC3 and WFPC2).At the RMS Node, we have developed and incorporated into OPUS detailed geometric metadata, based on the most recent SPICE kernels, for all of the bodies in the Cassini Saturn observations. This extensive set of geometric metadata is unique to the RMS Node and enables search constraints such as latitudes and longitudes (Saturn, Titan, and icy satellites), viewing and illumination geometry (phase, incidence and emission angles), and distances and resolution.Our near term plans include adding the full set of Cassini CIRS Saturn data (with enhanced geometry), New Horizons MVIC Jupiter encounter images, New Horizons LORRI and MVIC Pluto data, HST STIS observations, and Cassini and Voyager ring occultations. We also plan to develop enhanced geometric metadata for the New Horizons LORRI and MVIC instruments for both the Jupiter and the Pluto encounters.OPUS: http://pds-rings.seti.org/search/

The evolution of Titan's high-altitude aerosols under ultraviolet irradiation

Science.gov (United States)

Carrasco, Nathalie; Tigrine, Sarah; Gavilan, Lisseth; Nahon, Laurent; Gudipati, Murthy S.

2018-04-01

The Cassini-Huygens space mission revealed that Titan's thick brownish haze is initiated high in the atmosphere at an altitude of about 1,000 km, before a slow transportation down to the surface. Close to the surface, at altitudes below 130 km, the Huygens probe provided information on the chemical composition of the haze. So far, we have not had insights into the possible photochemical evolution of the aerosols making up the haze during their descent. Here, we address this atmospheric aerosol aging process, simulating in the laboratory how solar vacuum ultraviolet irradiation affects the aerosol optical properties as probed by infrared spectroscopy. An important evolution was found that could explain the apparent contradiction between the nitrogen-poor infrared spectroscopic signature observed by Cassini below 600 km of altitude in Titan's atmosphere and a high nitrogen content as measured by the aerosol collector and pyrolyser of the Huygens probe at the surface of Titan.

Estimating the Backup Reaction Wheel Orientation Using Reaction Wheel Spin Rates Flight Telemetry from a Spacecraft

Science.gov (United States)

Rizvi, Farheen

2013-01-01

A report describes a model that estimates the orientation of the backup reaction wheel using the reaction wheel spin rates telemetry from a spacecraft. Attitude control via the reaction wheel assembly (RWA) onboard a spacecraft uses three reaction wheels (one wheel per axis) and a backup to accommodate any wheel degradation throughout the course of the mission. The spacecraft dynamics prediction depends upon the correct knowledge of the reaction wheel orientations. Thus, it is vital to determine the actual orientation of the reaction wheels such that the correct spacecraft dynamics can be predicted. The conservation of angular momentum is used to estimate the orientation of the backup reaction wheel from the prime and backup reaction wheel spin rates data. The method is applied in estimating the orientation of the backup wheel onboard the Cassini spacecraft. The flight telemetry from the March 2011 prime and backup RWA swap activity on Cassini is used to obtain the best estimate for the backup reaction wheel orientation.

NASA Technology Demonstrations Missions Program Overview

Science.gov (United States)

Turner, Susan

2011-01-01

The National Aeronautics and Space Administration (NASA) Fiscal Year 2010 (FY10) budget introduced a new strategic plan that placed renewed emphasis on advanced missions beyond Earth orbit. This supports NASA s 2011 strategic goal to create innovative new space technologies for our exploration, science, and economic future. As a result of this focus on undertaking many and more complex missions, NASA placed its attention on a greater investment in technology development, and this shift resulted in the establishment of the Technology Demonstrations Missions (TDM) Program. The TDM Program, within the newly formed NASA Office of the Chief Technologist, supports NASA s grand challenges by providing a steady cadence of advanced space technology demonstrations (Figure 1), allowing the infusion of flexible path capabilities for future exploration. The TDM Program's goal is to mature crosscutting capabilities to flight readiness in support of multiple future space missions, including flight test projects where demonstration is needed before the capability can transition to direct mission The TDM Program has several unique criteria that set it apart from other NASA program offices. For instance, the TDM Office matures a small number of technologies that are of benefit to multiple customers to flight technology readiness level (TRL) 6 through relevant environment testing on a 3-year development schedule. These technologies must be crosscutting, which is defined as technology with potential to benefit multiple mission directorates, other government agencies, or the aerospace industry, and they must capture significant public interest and awareness. These projects will rely heavily on industry partner collaboration, and funding is capped for all elements of the flight test demonstration including planning, hardware development, software development, launch costs, ground operations, and post-test assessments. In order to inspire collaboration across government and industry

The mission execution crew assistant : Improving human-machine team resilience for long duration missions

OpenAIRE

Neerincx, M.A.; Lindenberg, J.; Smets, N.J.J.M.; Bos, A.; Breebaart, L.; Grant, T.; Olmedo-Soler, A.; Brauer, U.; Wolff, M.

2008-01-01

Manned long-duration missions to the Moon and Mars set high operational, human factors and technical demands for a distributed support system, which enhances human-machine teams' capabilities to cope autonomously with unexpected, complex and potentially hazardous situations. Based on a situated Cognitive Engineering (sCE) method, we specified a theoretical and empirical founded Requirements Baseline (RB) for such a system (called Mission Execution Crew Assistant; MECA), and its rational consi...

The Mars 2020 Rover Mission: EISD Participation in Mission Science and Exploration

Science.gov (United States)

Fries, M.; Bhartia, R.; Beegle, L.; Burton, A. S.; Ross, A.

2014-01-01

The Mars 2020 Rover mission will search for potential biosignatures on the martian surface, use new techniques to search for and identify tracelevel organics, and prepare a cache of samples for potential return to Earth. Identifying trace organic compounds is an important tenet of searching for potential biosignatures. Previous landed missions have experienced difficulty identifying unambiguously martian, unaltered organic compounds, possibly because any organic species have been destroyed on heating in the presence of martian perchlorates and/or other oxidants. The SHERLOC instrument on Mars 2020 will use ultraviolet (UV) fluorescence and Raman spectroscopy to identify trace organic compounds without heating the samples.

Irregular Saturnian Moon Lightcurves from Cassini-ISS Observations: Update

Science.gov (United States)

Denk, Tilmann; Mottola, S.

2013-10-01

Cassini ISS-NAC observations of the irregular moons of Saturn revealed various physical information on these objects. 16 synodic rotational periods: Hati (S43): 5.45 h; Mundilfari (S25): 6.74 h; Suttungr (S23): ~7.4 h; Kari (S45): 7.70 h; Siarnaq (S29): 10.14 h; Tarvos (S21): 10.66 h; Ymir (S19, sidereal period): 11.92220 h ± 0.1 s; Skathi (S27): ~12 h; Hyrrokkin (S44): 12.76 h; Ijiraq (S22): 13.03 h; Albiorix (S26): 13.32 h; Bestla (S39): 14.64 h; Bebhionn (S37): ~15.8 h; Kiviuq (S24): 21.82 h; Thrymr (S30): ~27 h; Erriapus (S28): ~28 h. The average period for the prograde-orbiting moons is ~16 h, for the retrograde moons ~11½ h (includes Phoebe's 9.2735 h from Bauer et al., AJ, 2004). Phase-angle dependent behavior of lightcurves: The phase angles of the observations range from 2° to 105°. The lightcurves which were obtained at low phase (<40°) show the 2-maxima/ 2-minima pattern expected for this kind of objects. At higher phases, more complicated lightcurves emerge, giving rough indications on shapes. Ymir pole and shape: For satellite Ymir, a convex-hull shape model and the pole-axis orientation have been derived. Ymir's north pole points toward λ = 230°±180°, β = -85°±10°, or RA = 100°±20°, Dec = -70°±10°. This is anti-parallel to the rotation axes of the major planets, indicating that Ymir not just orbits, but also rotates in a retrograde sense. The shape of Ymir resembles a triangular prism with edge lengths of ~20, ~24, and ~25 km. The ratio between the longest 25 km) and shortest axis (pole axis, ~15 km) is ~1.7. Erriapus seasons: The pole direction of object Erriapus has probably a low ecliptic latitude. This gives this moon seasons similar to the Uranian regular moons with periods where the sun stands very high in the sky over many years, and with years-long periods of permanent night. Hati density: The rotational frequency of the fastest rotator (Hati) is close to the frequency where the object would lose material from the surface if

Calculation of Operations Efficiency Factors for Mars Surface Missions

Science.gov (United States)

Laubach, Sharon

2014-01-01

The duration of a mission--and subsequently, the minimum spacecraft lifetime--is a key component in designing the capabilities of a spacecraft during mission formulation. However, determining the duration is not simply a function of how long it will take the spacecraft to execute the activities needed to achieve mission objectives. Instead, the effects of the interaction between the spacecraft and ground operators must also be taken into account. This paper describes a method, using "operations efficiency factors", to account for these effects for Mars surface missions. Typically, this level of analysis has not been performed until much later in the mission development cycle, and has not been able to influence mission or spacecraft design. Further, the notion of moving to sustainable operations during Prime Mission--and the effect that change would have on operations productivity and mission objective choices--has not been encountered until the most recent rover missions (MSL, the (now-cancelled) joint NASA-ESA 2018 Mars rover, and the proposed rover for Mars 2020). Since MSL had a single control center and sun-synchronous relay assets (like MER), estimates of productivity derived from MER prime and extended missions were used. However, Mars 2018's anticipated complexity (there would have been control centers in California and Italy, and a non-sun-synchronous relay asset) required the development of an explicit model of operations efficiency that could handle these complexities. In the case of the proposed Mars 2018 mission, the model was employed to assess the mission return of competing operations concepts, and as an input to component lifetime requirements. In this paper we provide examples of how to calculate the operations efficiency factor for a given operational configuration, and how to apply the factors to surface mission scenarios. This model can be applied to future missions to enable early effective trades between operations design, science mission

Mars MetNet Mission Payload Overview

Science.gov (United States)

Harri, A.-M.; Haukka, H.; Alexashkin, S.; Guerrero, H.; Schmidt, W.; Genzer, M.; Vazquez, L.

2012-09-01

A new kind of planetary exploration mission for Mars is being developed in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission [1] is based on a new semi-hard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide crucial scientific data about the Martian atmospheric phenomena.

Mars MetNet Mission Status

Science.gov (United States)

Harri, Ari-Matti; Aleksashkin, Sergei; Arruego, Ignacio; Schmidt, Walter; Genzer, Maria; Vazquez, Luis; Haukka, Harri

2015-04-01

New kind of planetary exploration mission for Mars is under development in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semi-hard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor [1] mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide significant insights in to the Martian atmospheric behavior. The key technologies of the MetNet Lander have been qualified and the electrical qualification model (EQM) of the payload bay has been built and successfully tested. 1. MetNet Lander The MetNet landing vehicles are using an inflatable entry and descent system instead of rigid heat shields and parachutes as earlier semi-hard landing devices have used. This way the ratio of the payload mass to the overall mass is optimized. The landing impact will burrow the payload container into the Martian soil providing a more favorable thermal environment for the electronics and a suitable orientation of the telescopic boom with external sensors and the radio link antenna. It is planned to deploy several tens of MNLs on the Martian surface operating at least partly at the same time to allow meteorological network science. 2. Scientific Payload The payload of the two MNL precursor models includes the following instruments: Atmospheric instruments: 1. MetBaro Pressure device 2. MetHumi Humidity device 3. MetTemp Temperature sensors Optical devices: 1. PanCam Panoramic 2. MetSIS Solar irradiance sensor with OWLS optical wireless system for data transfer 3. DS Dust sensor The descent processes dynamic properties are monitored by a special 3-axis accelerometer combined with a 3-axis gyrometer. The data will be sent via auxiliary beacon antenna throughout the

Deep Space 2: The Mars Microprobe Mission

Science.gov (United States)

Smrekar, Suzanne; Catling, David; Lorenz, Ralph; Magalhães, Julio; Moersch, Jeffrey; Morgan, Paul; Murray, Bruce; Presley-Holloway, Marsha; Yen, Albert; Zent, Aaron; Blaney, Diana

The Mars Microprobe Mission will be the second of the New Millennium Program's technology development missions to planetary bodies. The mission consists of two penetrators that weigh 2.4 kg each and are being carried as a piggyback payload on the Mars Polar Lander cruise ring. The spacecraft arrive at Mars on December 3, 1999. The two identical penetrators will impact the surface at ~190 m/s and penetrate up to 0.6 m. They will land within 1 to 10 km of each other and ~50 km from the Polar Lander on the south polar layered terrain. The primary objective of the mission is to demonstrate technologies that will enable future science missions and, in particular, network science missions. A secondary goal is to acquire science data. A subsurface evolved water experiment and a thermal conductivity experiment will estimate the water content and thermal properties of the regolith. The atmospheric density, pressure, and temperature will be derived using descent deceleration data. Impact accelerometer data will be used to determine the depth of penetration, the hardness of the regolith, and the presence or absence of 10 cm scale layers.

Discovery touches down after successful mission STS-95

Science.gov (United States)

1998-01-01

Orbiter Discovery touches down on runway 33 at the Shuttle Landing Facility after a successful mission of nearly nine days and 3.6 million miles. Main gear touchdown was at 12:04 p.m. EST, landing on orbit 135. The STS-95 crew consists of Mission Commander Curtis L. Brown Jr.; Pilot Steven W. Lindsey; Mission Specialist Scott E. Parazynski; Mission Specialist Stephen K. Robinson; Payload Specialist John H. Glenn Jr., a senator from Ohio; Mission Specialist Pedro Duque, with the European Space Agency (ESA); and Payload Specialist Chiaki Mukai, M.D., with the National Space Development Agency of Japan (NASDA). The mission included research payloads such as the Spartan solar-observing deployable spacecraft, the Hubble Space Telescope Orbital Systems Test Platform, the International Extreme Ultraviolet Hitchhiker, as well as the SPACEHAB single module with experiments on space flight and the aging process.

AGILE: A gamma-ray mission

International Nuclear Information System (INIS)

Tavani, M.; Caraveo, P.; Mereghetti, S.; Perotti, F.; Vercellone, S.; Barbiellini, G.; Budini, G.; Longo, F.; Prest, M.; Vallazza, E.; Cocco, V.; Morselli, A.; Picozza, P.; Pittori, C.; Costa, E.; Feroci, M.; Lapshov, I.; Morelli, E.; Rubini, A.; Soffitta, P.

2000-01-01

AGILE is an innovative, cost-effective gamma-ray mission selected by the Italian Space Agency for a Program of Small Scientific Missions. The AGILE gamma-ray imaging detector (GRID, made of a Silicon tracker and CsI Mini-Calorimeter) is designed to detect and image photons in the 30 MeV-50 GeV energy band with good sensitivity and very large field of view (FOV ∼3 sr). The X-ray detector, Super-AGILE, sensitive in the 10-40 keV band and integrated on top of the GRID gamma-ray tracker will provide imaging (1-3 arcmin) and moderate spectroscopy. For selected sky areas, AGILE might achieve a flux sensitivity (above 100 MeV) better than 5x10 -8 ph cm 2 s -1 at the completion of its scientific program. AGILE will operate as an Observatory open to the international community and is planned to be operational during the year 2002 for a nominal 2-year mission. It will be an ideal 'bridge' between EGRET and GLAST, and the only mission entirely dedicated to high-energy astrophysics above 30 MeV during that period

A brief history of Sandia's National security missions.

Energy Technology Data Exchange (ETDEWEB)

Drewien, Celeste A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); O' Canna, Myra Lynn [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stikar, John Anthony. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-09-01

To help members of the workforce understand what factors contribute to Sandia National Laboratories national security mission, the authors describe the evolution of Sandias core mission and its other mission components. The mission of Sandia first as a division of Los Alamos and later as Sandia Corporation underlies our core nuclear weapon mission of today. Sandias mission changed in 1963 and twice more in the 1970s. This report should help staff and management appreciate the need for mission evolution. A clear definition and communication of a consistent corporate mission statement is still needed.

LISA Mission and System architectures and performances

International Nuclear Information System (INIS)

Gath, Peter F; Weise, Dennis; Schulte, Hans-Reiner; Johann, Ulrich

2009-01-01

In the context of the LISA Mission Formulation Study, the LISA System was studied in detail and a new baseline architecture for the whole mission was established. This new baseline is the result of trade-offs on both, mission and system level. The paper gives an overview of the different mission scenarios and configurations that were studied in connection with their corresponding advantages and disadvantages as well as performance estimates. Differences in the required technologies and their influence on the overall performance budgets are highlighted for all configurations. For the selected baseline concept, a more detailed description of the configuration is given and open issues in the technologies involved are discussed.

LISA Mission and System architectures and performances

Energy Technology Data Exchange (ETDEWEB)

Gath, Peter F; Weise, Dennis; Schulte, Hans-Reiner; Johann, Ulrich, E-mail: peter.gath@astrium.eads.ne [Astrium GmbH Satellites, 88039 Friedrichshafen (Germany)

2009-03-01

In the context of the LISA Mission Formulation Study, the LISA System was studied in detail and a new baseline architecture for the whole mission was established. This new baseline is the result of trade-offs on both, mission and system level. The paper gives an overview of the different mission scenarios and configurations that were studied in connection with their corresponding advantages and disadvantages as well as performance estimates. Differences in the required technologies and their influence on the overall performance budgets are highlighted for all configurations. For the selected baseline concept, a more detailed description of the configuration is given and open issues in the technologies involved are discussed.

Lessons learned from IAEA fire safety missions

International Nuclear Information System (INIS)

Lee, S.P.

1998-01-01

The IAEA has conducted expert missions to evaluate fire safety at the following nuclear power plants: the Zaporozhe plant in the Ukraine, the Borselle plant in the Netherlands, the Medzamor plant in Armenia, the Karachi plant in Pakistan, the Temelin plant in the Czech Republic, and the Laguna Verde plant in Mexico. The scope of these missions varied in subject and depth. The teams sent from the IAEA consisted of external fire experts and IAEA staff. All the missions were of great use to the host countries. The participating experts also benefited significantly. A summary of the missions and their findings is given. (author)

The Hypersonic Inflatable Aerodynamic Decelerator (HIAD) Mission Applications Study

Science.gov (United States)

Bose, David M.; Winski, Richard; Shidner, Jeremy; Zumwalt, Carlie; Johnston, Christopher O.; Komar, D. R.; Cheatwood, F. M.; Hughes, Stephen J.

2013-01-01

The objective of the HIAD Mission Applications Study is to quantify the benefits of HIAD infusion to the concept of operations of high priority exploration missions. Results of the study will identify the range of mission concepts ideally suited to HIADs and provide mission-pull to associated technology development programs while further advancing operational concepts associated with HIAD technology. A summary of Year 1 modeling and analysis results is presented covering missions focusing on Earth and Mars-based applications. Recommended HIAD scales are presented for near term and future mission opportunities and the associated environments (heating and structural loads) are described.

Cassini RTG Program. Monthly technical progress report, 27 November--31 December 1995

International Nuclear Information System (INIS)

1996-01-01

This monthly technical progress report provided information on the following tasks: spacecraft integration and liaison; engineering support; safety analysis; qualified unicouple fabrication; ETG fabrication, assembly, and test; ground support equipment (GSE); RTG shipping and launch support; designs, reviews, and mission applications; project management, quality assurance, and reliability, and contractor acquired government owned (CAGO) property acquisition

A Strong High Altitude Narrow Jet At Saturn'S Equator From Cassini/ISS Images

Science.gov (United States)

Garcia-Melendo, Enrique; Sánchez-Lavega, A.; Legarreta, J.; Pérez-Hoyos, S.; Hueso, R.

2010-10-01

The intense equatorial eastward jets observed at cloud level in Jupiter and Saturn, represent a major challenge for geophysical fluid dynamics. Saturn's equatorial jet is of particular interest in view of its three dimensional structure, suspected large temporal variability, and related stratospheric semiannual oscillation. Here we report the discovery at the upper cloud level of an extremely narrow and strong jet centered in the middle of the broad equatorial jet. Previously published works on Saturn's equatorial winds at cloud level provided only a partial coverage. Automatic correlation of brightness scans and manually tracked cloud features, retrieved from images obtained by the Cassini Imaging Science Subsystem (ISS), show that the jet reaches 430 ms-1 with a peak speed difference of 180 ms-1 relative to nearby latitudes at 60 mbar and 390 ms-1 at depths > 500 mbar. Images were obtained in two filters: MT3, centred at the 889nm strong methane absorption band, and CB3 centred at the near infrared 939nm continuum, which are sensitive to different altitude levels at the upper clouds and hazes. Contrarily to what is observed in other latitudes, its velocity increases with altitude. Our findings helps to extend the view we have of the equatorial stratospheric dynamics of fast rotating planets beyond the best known terrestrial environment, and extract more general consequences of the interaction between waves and mean flow. It remains to be known if this equatorial jet structure, now determined in detail in three dimensions, is permanent or variable with the seasonal solar insolation cycle, including the variable shadow cast by the rings. EGM, ASL, JL, SPH, and RH have been funded by the Spanish MICIIN AYA2009-10701 with FEDER support and ASL, JL, SPH, and RH by Grupos Gobierno Vasco IT-464-07

2015 Science Mission Directorate Technology Highlights

Science.gov (United States)

Seablom, Michael S.

2016-01-01

The role of the Science Mission Directorate (SMD) is to enable NASA to achieve its science goals in the context of the Nation's science agenda. SMD's strategic decisions regarding future missions and scientific pursuits are guided by Agency goals, input from the science community including the recommendations set forth in the National Research Council (NRC) decadal surveys and a commitment to preserve a balanced program across the major science disciplines. Toward this end, each of the four SMD science divisions -- Heliophysics, Earth Science, Planetary Science, and Astrophysics -- develops fundamental science questions upon which to base future research and mission programs. Often the breakthrough science required to answer these questions requires significant technological innovation, e.g., instruments or platforms with capabilities beyond the current state of the art. SMD's targeted technology investments fill technology gaps, enabling NASA to build the challenging and complex missions that accomplish groundbreaking science.

MIOSAT Mission Scenario and Design

Science.gov (United States)

Agostara, C.; Dionisio, C.; Sgroi, G.; di Salvo, A.

2008-08-01

MIOSAT ("Mssione Ottica su microSATellite") is a low-cost technological / scientific microsatellite mission for Earth Observation, funded by Italian Space Agency (ASI) and managed by a Group Agreement between Rheinmetall Italia - B.U. Spazio - Contraves as leader and Carlo Gavazzi Space as satellite manufacturer. Several others Italians Companies, SME and Universities are involved in the development team with crucial roles. MIOSAT is a microsatellite weighting around 120 kg and placed in a 525 km altitude sun-synchronuos circular LEO orbit. The microsatellite embarks three innovative optical payloads: Sagnac multi spectral radiometer (IFAC-CNR), Mach Zehender spectrometer (IMM-CNR), high resolution pancromatic camera (Selex Galileo). In addition three technological experiments will be tested in-flight. The first one is an heat pipe based on Marangoni effect with high efficiency. The second is a high accuracy Sun Sensor using COTS components and the last is a GNSS SW receiver that utilizes a Leon2 processor. Finally a new generation of 28% efficiency solar cells will be adopted for the power generation. The platform is highly agile and can tilt along and cross flight direction. The pointing accuracy is in the order of 0,1° for each axe. The pointing determination during images acquisition is <0,02° for the axis normal to the boresight and 0,04° for the boresight. This paper deals with MIOSAT mission scenario and definition, highlighting trade-offs for mission implementation. MIOSAT mission design has been constrained from challenging requirements in terms of satellite mass, mission lifetime, instrument performance, that have implied the utilization of satellite agility capability to improve instruments performance in terms of S/N and resolution. The instruments provide complementary measurements that can be combined in effective ways to exploit new applications in the fields of atmosphere composition analysis, Earth emissions, antropic phenomena, etc. The Mission

Micro-Pressure Sensors for Future Mars Missions

Science.gov (United States)

Catling, David C.

1996-01-01

The joint research interchange effort was directed at the following principal areas: u further development of NASA-Ames' Mars Micro-meteorology mission concept as a viable NASA space mission especially with regard to the science and instrument specifications u interaction with the flight team from NASA's New Millennium 'Deep-Space 2' (DS-2) mission with regard to selection and design of micro-pressure sensors for Mars u further development of micro-pressure sensors suitable for Mars The research work undertaken in the course of the Joint Research Interchange should be placed in the context of an ongoing planetary exploration objective to characterize the climate system on Mars. In particular, a network of small probes globally-distributed on the surface of the planet has often been cited as the only way to address this particular science goal. A team from NASA Ames has proposed such a mission called the Micrometeorology mission, or 'Micro-met' for short. Surface pressure data are all that are required, in principle, to calculate the Martian atmospheric circulation, provided that simultaneous orbital measurements of the atmosphere are also obtained. Consequently, in the proposed Micro-met mission a large number of landers would measure barometric pressure at various locations around Mars, each equipped with a micro-pressure sensor. Much of the time on the JRI was therefore spent working with the engineers and scientists concerned with Micro-met to develop this particular mission concept into a more realistic proposition.

A Korean perspective on megachurches as missional churches

Directory of Open Access Journals (Sweden)

Cornelius J.P. Niemandt

2015-03-01

Full Text Available Both the megachurch and the missional church are on-going global phenomena. Working from the premise that the church has to be missional, this article operates from a Korean perspective and researches whether a megachurch can be missional. The megachurch is not simply a very large church in terms of membership or the physical size of its building(s � because of the influence of the interaction between socio-cultural, historical, and theological backgrounds, the megachurch has its own missiological and ecclesiological perspectives. The megachurch understands that the growth of an individual church implies the expansion of the kingdom of God, which means that the individual church has a responsibility to be both functionally and structurally sound, in order to ensure the efficient growth of the kingdom. This is an influential tendency that is found not only in larger size churches, but in all churches who are trying to achieve the quantitative growth of the church by way of evangelisation. The Korean megachurches, represented by the Poongsunghan Church, display these characteristics. The missional church is not simply a mission-driven church, sending many missionaries to other countries; the missional church believes that all churches are sent to the world by God, who wants to reconcile the whole universe with himself. The implication of this is that the church has to restore its missional essence in order to be able to participate in the mission of God. Thus, the missional church is a reforming movement that witnesses to God�s rule by recovering its apostolic nature. The characteristics of this movement are clearly visible in one of the case studies � the Bundang Woori Church. The importance of the missional movement for Korean churches is emphasised.Interdisciplinary and/or interdisciplinary implications: The research is a case study of Korean megachurches from a missional perspective. The research represents a critique of practises in

Logistics Reduction Technologies for Exploration Missions

Science.gov (United States)