WorldWideScience

Sample records for surveyor mgs spacecraft

  1. The Mars Global Surveyor Ka-Band Link Experiment (MGS/KaBLE-II)

    Science.gov (United States)

    Morabito, D.; Butman, S.; Shambayati, S.

    1999-01-01

    The Mars Global Surveyor (MGS) spacecraft, launched on November 7, 1996, carries an experimental space-to-ground telecommunications link at Ka-band (32 GHz) along with the primary X-band (8.4-GHz) downlink. The signals are simultaneously transmitted from a 1.5-m-diameter parabolic antenna on MGS and received by a beam-waveguide (BWG) research and development (R&D) 34-meter a ntenna located in NASA's Goldstone Deep Space Network (DSN) complex near Barstow, California. This Ka-band link experiment (KaBLE-II) allows the performances of the Ka-band and X-band signals to be compared under nearly identical conditions. The two signals have been regularly tracked during the past 2 years. This article presents carrier-signal-level data (P_c/N_o) for both X-band and Ka-band acquired over a wide range of station elevation angles, weather conditions, and solar elongation angles. The cruise phase of the mission covered the period from launch (November 7, 1996) to Mars orbit capture (September 12, 1997). Since September 12, 1997, MGS has been in orbit around Mars. The measurements confirm that Ka-band could increase data capacity by at least a factor of three (5 dB) as compared with X-band. During May 1998, the solar corona experiment, in which the effects of solar plasma on the X-band and Ka-band links were studied, was conducted. In addition, frequency and difference frequency (f_x - f_(Ka)/3.8), ranging, and telemetry data results are presented. MGS/KaBLE-II measured signal strengths (for 54 percent of the experiments conducted) that were in reasonable agreement with predicted values based on preflight knowledge, and frequency residuals that agreed between bands and whose statistics were consistent with expected noise sources. For passes in which measured signal strengths disagreed with predicted values, the problems were traced to known deficiencies, for example, equipment operating under certain conditions, such as a cold Ka-band solid-state power amplifier (SSPA

  2. Summer season variability of the north residual cap of Mars as observed by the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES)

    Science.gov (United States)

    Calvin, W.M.; Titus, T.N.

    2008-01-01

    Previous observations have noted the change in albedo in a number of North Pole bright outliers and in the distribution of bright ice deposits between Mariner 9, Viking, and Mars Global Surveyor (MGS) data sets. Changes over the summer season as well as between regions at the same season (Ls) in different years have been observed. We used the bolometric albedo and brightness temperature channels of the Thermal Emission Spectrometer (TES) on the MGS spacecraft to monitor north polar residual ice cap variations between Mars years and within the summer season for three northern Martian summers between July 1999 and April 2003. Large-scale brightness variations are observed in four general areas: (1) the patchy outlying frost deposits from 90 to 270??E, 75 to 80??N; (2) the large "tail" below the Chasma Boreale and its associated plateau from 315 to 45??E, 80 to 85??N, that we call the "Boreale Tongue" and in Hyperboreae Undae; (3) the troughed terrain in the region from 0 to 120??E longitude (the lower right on a polar stereographic projection) we have called "Shackleton's Grooves" and (4) the unit mapped as residual ice in Olympia Planitia. We also note two areas which seem to persist as cool and bright throughout the summer and between Mars years. One is at the "source" of Chasma Boreale (???15??E, 85??N) dubbed "McMurdo", and the "Cool and Bright Anomaly (CABA)" noted by Kieffer and Titus 2001. TES Mapping of Mars' north seasonal cap. Icarus 154, 162-180] at ???330??E, 87??N called here "Vostok". Overall defrosting occurs early in the summer as the temperatures rise and then after the peak temperatures are reached (Ls???110) higher elevations and outlier bright deposits cold trap and re-accumulate new frost. Persistent bright areas are associated with either higher elevations or higher background albedos suggesting complex feedback mechanisms including cold-trapping of frost due to albedo and elevation effects, as well as influence of mesoscale atmospheric dynamics

  3. Summer season variability of the north residual cap of Mars as observed by the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES)

    Science.gov (United States)

    Calvin, W. M.; Titus, T. N.

    2008-02-01

    Previous observations have noted the change in albedo in a number of North Pole bright outliers and in the distribution of bright ice deposits between Mariner 9, Viking, and Mars Global Surveyor (MGS) data sets. Changes over the summer season as well as between regions at the same season ( Ls) in different years have been observed. We used the bolometric albedo and brightness temperature channels of the Thermal Emission Spectrometer (TES) on the MGS spacecraft to monitor north polar residual ice cap variations between Mars years and within the summer season for three northern Martian summers between July 1999 and April 2003. Large-scale brightness variations are observed in four general areas: (1) the patchy outlying frost deposits from 90 to 270°E, 75 to 80°N; (2) the large "tail" below the Chasma Boreale and its associated plateau from 315 to 45°E, 80 to 85°N, that we call the "Boreale Tongue" and in Hyperboreae Undae; (3) the troughed terrain in the region from 0 to 120°E longitude (the lower right on a polar stereographic projection) we have called "Shackleton's Grooves" and (4) the unit mapped as residual ice in Olympia Planitia. We also note two areas which seem to persist as cool and bright throughout the summer and between Mars years. One is at the "source" of Chasma Boreale (˜15°E, 85°N) dubbed "McMurdo", and the "Cool and Bright Anomaly (CABA)" noted by Kieffer and Titus 2001. TES Mapping of Mars' north seasonal cap. Icarus 154, 162-180] at ˜330°E, 87°N called here "Vostok". Overall defrosting occurs early in the summer as the temperatures rise and then after the peak temperatures are reached ( Ls˜110) higher elevations and outlier bright deposits cold trap and re-accumulate new frost. Persistent bright areas are associated with either higher elevations or higher background albedos suggesting complex feedback mechanisms including cold-trapping of frost due to albedo and elevation effects, as well as influence of mesoscale atmospheric dynamics.

  4. Correcting Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) High Altitude (40 - 65 km) Temperature Retrievals for Instrumental Correlated Noise and Biases

    Science.gov (United States)

    McConnochie, T. H.; Smith, M. D.

    2011-12-01

    Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) nadir-soundings have been used to derive atmospheric temperatures up to roughly 40 km [Conrath et al., JGR 105 2000, Smith et al., JGR 106, 2001], and MGS-TES limb soundings have been used to extend the atmospheric temperature data set to > 60 km in altitude [Smith et al., JGR 106, 2001]. The ~40 - ~65 km altitude range probed by the MGS-TES limb sounding is particularly important for capturing key dynamical features such as the warm winter polar mesosphere [e.g., Smith et al., JGR 106, 2001; McCleese et al., Nature Geoscience 1, 2008], and the response of thermal tides to dust opacity [e.g. Wilson and Hamilton, J. Atmos. Sci. 53, 1996]. Thus accurate and precise temperature profiles at these altitudes are particularly important for constraining global circulation models. They are also critical for interpreting observations of mesospheric condensate aerosols [e.g., Määttänen et al., Icarus 209, 2010; McConnochie et al., Icarus 210, 2010)]. We have indentified correlated noise components in the MGS-TES limb sounding radiances that propagate into very large uncertainties in the retrieved temperatures. We have also identified a slowly varying radiance bias in the limb sounding radiances. Note that the nadir-sounding-based MGS-TES atmospheric temperatures currently available from the Planetary Data System are not affected by either of these issues. These two issues affect the existing MGS-TES limb sounding temperature data set are as follows: Considering, for example, the 1.5 Pascal pressure level (which typically falls between 50 and 60 km altitude), correlated-noise induced standard errors for individual limb-sounding temperature retrievals were 3 - 5 K in Mars Year 24, rising to 5 - 15 K in Mars Year 25 and 10 - 15 K in Mars Year 26 and 27. The radiance bias, although consistent on ~10-sol time scales, is highly variable over the course of the MGS-TES mission. It results in temperatures (at the 1

  5. Analyzing Magnetic Field and Electrical Current Profiles of the Day Side and Terminator of Mars Using Data from Mars Global Surveyor (MGS)

    Science.gov (United States)

    Fogle, A. L.; Ponce, N.; Fillingim, M. O.

    2014-12-01

    Mars does not have a global magnetic field, so the interplanetary magnetic field (IMF) can impact the upper atmosphere and induce currents in the Martian ionosphere. During aerobraking maneuvers, Mars Global Surveyor (MGS) made over 1000 passes through the Martian ionosphere. During the aerobraking phase, MGS measured the local magnetic field in the ionosphere. From measuring changes in the magnetic field, we can calculate the ionospheric currents. By only using measurements where the radial component of the magnetic field is zero and making some assumptions about the gradients in the magnetic field, we are allowed to classify data that meets those conditions as "good" data and calculate horizontal currents in the ionosphere. We focus on data taken over regions of Mars that had negligible crustal magnetic fields to simplify our analysis. The data being analyzed is observed at a maximum altitude of 250 kilometers with a solar zenith angle (SZA) range of 0 degrees to 50 degrees for the day side and 50 to 130 degrees for the terminator. For the day side of Mars, it was found that 24.06% of the data observed was usable data under the initial parameters that were set for "good" data. For the terminator, it was found that 32.08% of the data was usable. The currents that are computed using these "good" magnetic field profiles can give us insights into how the changing solar wind and interplanetary magnetic field can effect the upper atmosphere of mars. For example, induced currents can lead to Joule heating of the atmosphere potentially modifying the neutral dynamics.

  6. Simultaneous Mars Express / MGS observations of plasma near Mars

    Science.gov (United States)

    Brain, D.; Luhmann, J.; Halekas, J.; Frahm, R.; Winningham, D.; Barabash, S.

    2006-12-01

    Since late 2003, Mars Express (MEX) and Mars Global Surveyor (MGS) have been making complementary in situ measurements (in terms of both instrument and orbit) of the Martian plasma environment. Study of MGS and MEX data in tandem provides an opportunity to mitigate the shortcomings of each dataset and increase our overall understanding of the Martian solar wind interaction and atmospheric escape. Close passes of spacecraft (conjunctions) are one particularly powerful means of increasing the utility of measurements, as evidenced by the Cluster mission at Earth. At Mars, conjunctions might be used to obtain more complete simultaneous and/or co-located plasma measurements, which can be used to study a variety of phenomena, including measurements of auroral-like particle acceleration near crustal fields and the three-dimensional motion and shape of plasma boundaries. We will present an analysis of approximately forty conjunctions (instances with instantaneous spacecraft separation smaller than 400 km) of MEX and MGS identified between January 2004 and February 2006. The closest pass was ~40~km, near the South Pole. Conjunctions occur both at mid-latitudes (when the surface-projected orbit tracks of the two spacecraft nearly overlap), and at the poles. We will present comparisons of MEX Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) data with MGS Magnetometer and Electron Reflectometer (MAG/ER) data for these events. Our case studies include intercomparison of MEX and MGS electron data, the addition of MGS magnetic field and MEX ion data, and the inclusion of solar wind proxy information to establish context. In addition to these close conjunctions, we will present the preliminary results of a search for times when MEX and MGS pass through the same region of space separated by a delay (for time evolution of plasma populations in certain regions), and times when they occupy the same flux tube (for spatial evolution of particle distributions). Continued study of

  7. Failure Engineering Study and Accelerated Stress Test Results for the Mars Global Surveyor Spacecraft's Power Shunt Assemblies

    Science.gov (United States)

    Gibbel, Mark; Larson, Timothy

    2000-01-01

    An Engineering-of-Failure approach to designing and executing an accelerated product qualification test was performed to support a risk assessment of a "work-around" necessitated by an on-orbit failure of another piece of hardware on the Mars Global Surveyor spacecraft. The proposed work-around involved exceeding the previous qualification experience both in terms of extreme cold exposure level and in terms of demonstrated low cycle fatigue life for the power shunt assemblies. An analysis was performed to identify potential failure sites, modes and associated failure mechanisms consistent with the new use conditions. A test was then designed and executed which accelerated the failure mechanisms identified by analysis. Verification of the resulting failure mechanism concluded the effort.

  8. The Strategy for the Second Phase of Aerobraking Mars Global Surveyor

    Science.gov (United States)

    Johnston, M. D.; Esposito, P. B.; Alwar, V.; Demcak, S. W.; Graat, E. J.; Burkhart, P. D.; Portock, B. M.

    2000-01-01

    On February 19, 1999, the Mars Global Surveyor (MGS) spacecraft was able to propulsively establish its mapping orbit. This event followed the completion of the second phase of aerobraking for the MGS spacecraft on February 4, 1999. For the first time, a spacecraft at Mars had successfully employed aerobraking methods in order to reach its desired pre-launch mapping orbit. This was accomplished despite a damaged spacecraft solar array. The MGS spacecraft was launched on November 7, 1996, and after a ten month interplanetary transit was inserted into a highly elliptical capture orbit at Mars on September 12, 1997. Unlike other interplanetary missions, the MGS spacecraft was launched with a planned mission delta-V ((Delta)V) deficit of nearly 1250 m/s. To overcome this AV deficit, aerobraking techniques were employed. However, damage discovered to one of the spacecraft's two solar arrays after launch forced major revisions to the original aerobraking planning of the MGS mission. In order to avoid a complete structural failure of the array, peak dynamic pressure levels for the spacecraft were established at a major spacecraft health review in November 1997. These peak dynamic pressure levels were roughly one-third of the original mission design values. Incorporating the new dynamic pressure limitations into mission replanning efforts resulted in an 'extended' orbit insertion phase for the mission. This 'extended' orbit insertion phase was characterized by two distinct periods of aerobraking separated by an aerobraking hiatus that would last for several months in an intermediate orbit called the "Science Phasing Orbit" (SPO). This paper describes and focuses on the strategy for the second phase of aerobraking for the MGS mission called "Aerobraking Phase 2." This description will include the baseline aerobraking flight profile, the trajectory control methodology, as well as the key trajectory metrics that were monitored in order to successfully "guide' the spacecraft to

  9. Mars Global Surveyor measurements of solar storms and their effects

    Science.gov (United States)

    Brain, D. A.; Delory, G. T.; Lillis, R. J.; Ulusen, D.; Mitchell, D.; Luhmann, J. G.; Falkenberg, T. V.

    2010-12-01

    Space weather events in the form of solar photons and energetic charged particles provide brief but relatively intense periods of energy input to the Martian plasma environment and atmosphere, with implications for a number of science and exploration-related issues. The Mars Global Surveyor (MGS) spacecraft orbited Mars for more than 9 years, and was capable of indirectly detecting space weather events and their effects. Shocks associated with passing coronal mass ejections are evident in MGS magnetometer data, and in proxies for upstream solar wind pressure at 1.5 AU derived from magnetometer measurements. Fluxes of solar energetic particles with energies greater than ˜30 MeV are sometimes evident in the background count rates of the MGS electron instrument. Measurements of the background count rates at altitudes of ˜400 km over a seven year period provide an unprecedented long-baseline data set of the energetic particle environment at Mars over a significant fraction of a solar cycle. We will present results of analyses pertaining to three main uses of MGS observations of solar storms. First, by combining MGS measurements of solar storms with terrestrial and solar measurements, we have analyzed the propagation of individual solar storm events from the Sun throughout the inner heliosphere. Next, we have used MGS particle and field measurements to study the effect of solar storms on the Martian plasma environment - including increased fluxes of 10-20 keV electrons close to the planet and influences on auroral activity. Finally, we have studied the influence of solar storms on the Martian upper atmosphere - including suprathermal electrons produced in the atmosphere via impact ionization and a correlation of solar storm periods with ionospheric electron density profiles.

  10. Adaptive MGS Phase Retrieval

    Science.gov (United States)

    Basinger, Scott A.; Bikkannavar, Siddarayappa; Cohen, David; Green, Joseph J.; Lou, John; Ohara, Catherine; Redding, David; Shi, Fang

    2008-01-01

    Adaptive MGS Phase Retrieval software uses the Modified Gerchberg-Saxton (MGS) algorithm, an image-based sensing method that can turn any focal plane science instrument into a wavefront sensor, avoiding the need to use external metrology equipment. Knowledge of the wavefront enables intelligent control of active optical systems.

  11. Proton Cyclotron Waves Upstream from Mars: Observations from Mars Global Surveyor

    CERN Document Server

    Romanelli, Norberto; Gomez, Daniel; Mazelle, Christian; Delva, Magda

    2013-01-01

    We present a study on the properties of electromagnetic plasma waves in the region upstream of the Martian bow shock, detected by the magnetometer and electron reflectometer (MAG / ER) onboard the Mars Global Surveyor (MGS) spacecraft during the period known as Science Phasing Orbits (SPO). The frequency of these waves, measured in the MGS reference frame (SC), is close to the local proton cyclotron frequency. Minimum variance analysis (MVA) shows that these 'proton cyclotron frequency' waves (PCWs) are characterized - in the SC frame - by a left-hand, elliptical polarization and propagate almost parallel to the background magnetic field. They also have a small degree of compressibility and an amplitude that decreases with the increase of the interplanetary magnetic field (IMF) cone angle and radial distance from the planet. The latter result supports the idea that the source of these waves is Mars. In addition, we find that these waves are not associated with the foreshock . Empirical evidence and theoretica...

  12. The Gravity Field of Mars From MGS, Mars Odyssey, and MRO Radio Science

    Science.gov (United States)

    Genova, Antonio; Goossens, Sander; Lemoine, Frank G.; Mazarico, Erwan; Smith, David E.; Zuber, Maria T.

    2015-01-01

    The Mars Global Surveyor (MGS), Mars Odyssey (ODY), and Mars Reconnaissance Orbiter (MRO) missions have enabled NASA to conduct reconnaissance and exploration of Mars from orbit for sixteen consecutive years. These radio systems on these spacecraft enabled radio science in orbit around Mars to improve the knowledge of the static structure of the Martian gravitational field. The continuity of the radio tracking data, which cover more than a solar cycle, also provides useful information to characterize the temporal variability of the gravity field, relevant to the planet's internal dynamics and the structure and dynamics of the atmosphere [1]. MGS operated for more than 7 years, between 1999 and 2006, in a frozen sun-synchronous, near-circular, polar orbit with the periapsis at approximately 370 km altitude. ODY and MRO have been orbiting Mars in two separate sun-synchronous orbits at different local times and altitudes. ODY began its mapping phase in 2002 with the periapis at approximately 390 km altitude and 4-5pm Local Solar Time (LST), whereas the MRO science mission started in November 2006 with the periapis at approximately 255 km altitude and 3pm LST. The 16 years of radio tracking data provide useful information on the atmospheric density in the Martian upper atmosphere. We used ODY and MRO radio data to recover the long-term periodicity of the major atmospheric constituents -- CO2, O, and He -- at the orbit altitudes of these two spacecraft [2]. The improved atmospheric model provides a better prediction of the annual and semi-annual variability of the dominant species. Therefore, the inclusion of the recovered model leads to improved orbit determination and an improved gravity field model of Mars with MGS, ODY, and MRO radio tracking data.

  13. Multi-spacecraft Observations of the Martian Plasma Interaction

    Science.gov (United States)

    Brain, David; Luhmann, J.; Halekas, J.; Frahm, R.; Winningham, J.; Barabash, S.

    2006-09-01

    Two spacecraft with complementary instrumentation and orbits are currently making in situ measurements of the Martian plasma environment. Mars Global Surveyor (MGS) measures electrons and magnetic field from a 400 km circular mapping orbit with fixed local time. Mars Express (MEX) measures ions, electrons, and neutral particles from a precessing elliptical orbit. Each spacecraft's dataset has obvious strengths and shortcomings. Exploration of these two datasets in tandem provides an opportunity to increase our overall understanding of the Martian solar wind interaction and atmospheric escape. Close passes of spacecraft (conjunctions) are one particularly powerful means of increasing the utility of measurements, as evidenced by the Cluster mission. At Mars, conjunctions might be used to obtain more complete simultaneous and/or co-located plasma measurements, which can be used to study a variety of phenomena ranging from the motion and 3D shape of plasma boundaries to particle acceleration near crustal magnetic fields. We have identified 40 conjunctions (instances with spacecraft separation pass was 40 km. Conjunctions occur at mid-latitudes (when the surface-projected orbit tracks of the two spacecraft nearly overlap), and at the poles. We will present comparisons of MGS Magnetometer and Electron Reflectometer (MAG/ER) and MEX Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) data for these events, including intercomparison of MGS and MEX electron data, the addition of MGS magnetic field and MES ion data, and the inclusion of solar wind proxy information to establish context. Finally, we will present the results of a search for other useful configurations of MGS and MEX, including times when they are on the same flux tube, times when they pass through the same region of space separated by a delay, and times when they are on opposite sides of plasma boundaries.

  14. Operational Data Reduction Procedure for Determining Density and Vertical Structure of the Martian Upper Atmosphere from Mars Global Surveyor Accelerometer Measurements

    Science.gov (United States)

    Cancro, George J.; Tolson, Robert H.; Keating, Gerald M.

    1998-01-01

    The success of aerobraking by the Mars Global Surveyor (MGS) spacecraft was partly due to the analysis of MGS accelerometer data. Accelerometer data was used to determine the effect of the atmosphere on each orbit, to characterize the nature of the atmosphere, and to predict the atmosphere for future orbits. To interpret the accelerometer data, a data reduction procedure was developed to produce density estimations utilizing inputs from the spacecraft, the Navigation Team, and pre-mission aerothermodynamic studies. This data reduction procedure was based on the calculation of aerodynamic forces from the accelerometer data by considering acceleration due to gravity gradient, solar pressure, angular motion of the MGS, instrument bias, thruster activity, and a vibration component due to the motion of the damaged solar array. Methods were developed to calculate all of the acceleration components including a 4 degree of freedom dynamics model used to gain a greater understanding of the damaged solar array. The total error inherent to the data reduction procedure was calculated as a function of altitude and density considering contributions from ephemeris errors, errors in force coefficient, and instrument errors due to bias and digitization. Comparing the results from this procedure to the data of other MGS Teams has demonstrated that this procedure can quickly and accurately describe the density and vertical structure of the Martian upper atmosphere.

  15. Energetic particles detected by the Electron Reflectometer instrument on the Mars Global Surveyor, 1999-2006

    DEFF Research Database (Denmark)

    Delory, Gregory T.; Luhmann, Janet G.; Brain, David

    2012-01-01

    We report the observation of galactic cosmic rays and solar energetic particles by the Electron Reflectometer instrument aboard the Mars Global Surveyor (MGS) spacecraft from May of 1999 to the mission conclusion in November 2006. Originally designed to detect low-energy electrons, the Electron...... Reflectometer also measured particles with energies >30 MeV that penetrated the aluminum housing of the instrument and were detected directly by microchannel plates in the instrument interior. Using a combination of theoretical and experimental results, we show how the Electron Reflectometer microchannel plates...... recorded high energy galactic cosmic rays with similar to 45% efficiency. Comparisons of this data to galactic cosmic ray proton fluxes obtained from the Advanced Composition Explorer yield agreement to within 10% and reveal the expected solar cycle modulation as well as shorter timescale variations. Solar...

  16. HUBBLE WATCHES THE RED PLANET AS MARS GLOBAL SURVEYOR BEGINS AEROBRAKING

    Science.gov (United States)

    2002-01-01

    his NASA Hubble Space Telescope picture of Mars was taken on Sept. 12, one day after the arrival of the Mars Global Surveyor (MGS) spacecraft and only five hours before the beginning of autumn in the Martian northern hemisphere. (Mars is tilted on its axis like Earth, so it has similar seasonal changes, including an autumnal equinox when the Sun crosses Mars' equator from the northern to the southern hemisphere). This Hubble picture was taken in support of the MGS mission. Hubble is monitoring the Martian weather conditions during the early phases of MGS aerobraking; in particular, the detection of large dust storms are important inputs into the atmospheric models used by the MGS mission to plan aerobraking operations. Though a dusty haze fills the giant Hellas impact basin south of the dark fin-shaped feature Syrtis Major, the dust appears to be localized within Hellas. Unless the region covered expands significantly, the dust will not be of concern for MGS aerobraking. Other early signs of seasonal transitions on Mars are apparent in the Hubble picture. The northern polar ice cap is blanketed under a polar hood of clouds that typically start forming in late northern summer. As fall progresses, sunlight will dwindle in the north polar region and the seasonal polar cap of frozen carbon dioxide will start condensing onto the surface under these clouds. Hubble observations will continue until October 13, as MGS carefully uses the drag of the Martian atmosphere to circularize its orbit about the Red Planet. After mid-October, Mars will be too close to the Sun, in angular separation, for Hubble to safely view. The image is a composite of three separately filtered colored images taken with the Wide Field Planetary Camera 2 (WFPC2). Resolution is 35 miles (57 kilometers) per pixel (picture element). The Pathfinder landing site near Ares Valles is about 2200 miles (3600 kilometers) west of the center of this image, so was not visible during this observation. Mars was 158

  17. Two spacecraft measurements of the Martian plasma environment

    Science.gov (United States)

    Brain, David; Luhmann, Janet G.; Barabash, Stas; Fedorov, A.; Winningham, D. L.; Acuna, Mario; Frahm, Rudy

    For a period of nearly three years from early 2004 through late 2006, two spacecraft made complementary in situ measurements of the Martian plasma environment. The Mars Global Surveyor magnetometer and electron reflectometer (MGS MAG/ER) measured magnetic fields and suprathermal electrons from an orbit fixed in local time and altitude. The Mars Express Analyzer of Space Plasma and Energetic Atoms (MEX ASPERA-3) measured and still measures ions and suprathermal electrons from a precessing elliptical orbit. MGS lacked an ion instrument, and MEX lacks a magnetometer. Study of the two sets of measurements together provides an opportunity to better understand the complete Martian plasma environment spatially and temporally. We will discuss several advantageous configurations of MEX and MGS, and present examples of each. 'Close conjunctions' are defined as periods when the spacecraft passed very close to each other, within an ion gyroradius or inertial length, allowing examination of more complete particle and field measurements in a given region. 'Delay conjunctions' are defined as instances when the two spacecraft passed through the same region of space separated by a time delay, allowing examination of the evolution of electron distributions in a given region. 'Flux tube conjunctions' are defined as instances when it was likely that the two spacecraft occupied the same flux tube some distance apart, allowing study of the spatial evolution of plasma as it moves along a flux tube. We will also present examples of other fortuitous configurations of MEX and MGS, such as times when they were on opposite sides of a given plasma boundary.

  18. Accelerated Adaptive MGS Phase Retrieval

    Science.gov (United States)

    Lam, Raymond K.; Ohara, Catherine M.; Green, Joseph J.; Bikkannavar, Siddarayappa A.; Basinger, Scott A.; Redding, David C.; Shi, Fang

    2011-01-01

    The Modified Gerchberg-Saxton (MGS) algorithm is an image-based wavefront-sensing method that can turn any science instrument focal plane into a wavefront sensor. MGS characterizes optical systems by estimating the wavefront errors in the exit pupil using only intensity images of a star or other point source of light. This innovative implementation of MGS significantly accelerates the MGS phase retrieval algorithm by using stream-processing hardware on conventional graphics cards. Stream processing is a relatively new, yet powerful, paradigm to allow parallel processing of certain applications that apply single instructions to multiple data (SIMD). These stream processors are designed specifically to support large-scale parallel computing on a single graphics chip. Computationally intensive algorithms, such as the Fast Fourier Transform (FFT), are particularly well suited for this computing environment. This high-speed version of MGS exploits commercially available hardware to accomplish the same objective in a fraction of the original time. The exploit involves performing matrix calculations in nVidia graphic cards. The graphical processor unit (GPU) is hardware that is specialized for computationally intensive, highly parallel computation. From the software perspective, a parallel programming model is used, called CUDA, to transparently scale multicore parallelism in hardware. This technology gives computationally intensive applications access to the processing power of the nVidia GPUs through a C/C++ programming interface. The AAMGS (Accelerated Adaptive MGS) software takes advantage of these advanced technologies, to accelerate the optical phase error characterization. With a single PC that contains four nVidia GTX-280 graphic cards, the new implementation can process four images simultaneously to produce a JWST (James Webb Space Telescope) wavefront measurement 60 times faster than the previous code.

  19. Mars Global Surveyor Ka-Band Frequency Data Analysis

    Science.gov (United States)

    Morabito, D.; Butman, S.; Shambayati, S.

    2000-01-01

    The Mars Global Surveyor (MGS) spacecraft, launched on November 7, 1996, carries an experimental space-to-ground telecommunications link at Ka-band (32 GHz) along with the primary X-band (8.4 GHz) downlink. The signals are simultaneously transmitted from a 1.5-in diameter parabolic high gain antenna (HGA) on MGS and received by a beam-waveguide (BWG) R&D 34-meter antenna located in NASA's Goldstone Deep Space Network (DSN) complex near Barstow, California. The projected 5-dB link advantage of Ka-band relative to X-band was confirmed in previous reports using measurements of MGS signal strength data acquired during the first two years of the link experiment from December 1996 to December 1998. Analysis of X-band and Ka-band frequency data and difference frequency (fx-fka)/3.8 data will be presented here. On board the spacecraft, a low-power sample of the X-band downlink from the transponder is upconverted to 32 GHz, the Ka-band frequency, amplified to I-W using a Solid State Power Amplifier, and radiated from the dual X/Ka HGA. The X-band signal is amplified by one of two 25 W TWTAs. An upconverter first downconverts the 8.42 GHz X-band signal to 8 GHz and then multiplies using a X4 multiplier producing the 32 GHz Ka-band frequency. The frequency source selection is performed by an RF switch which can be commanded to select a VCO (Voltage Controlled Oscillator) or USO (Ultra-Stable Oscillator) reference. The Ka-band frequency can be either coherent with the X-band downlink reference or a hybrid combination of the USO and VCO derived frequencies. The data in this study were chosen such that the Ka-band signal is purely coherent with the X-band signal, that is the downconverter is driven by the same frequency source as the X-band downlink). The ground station used to acquire the data is DSS-13, a 34-meter BWG antenna which incorporates a series of mirrors inside beam waveguide tubes which guide the energy to a subterranean pedestal room, providing a stable environment

  20. Analysis of Properties of the North Polar Layered Deposits: THEMIS Data in Context of MGS Data

    Science.gov (United States)

    Ivanov, A. B.; Byrne, S.; Richardson, M. I.; Vasavada, A. R.; Titus, T. N.; Bell, J. F.; McConnochie, T. H.; Christensen, P. R.

    2003-01-01

    One of the many questions of Martian exploration is to uncover the history of Mars, through analysis of the polar layered deposits (PLD). Martian polar ice caps hold most of the exposed water on the surface on Mars and yet their history and physical processed involved in their formation are unclear. We will attempt to contribute to our knowledge of the composition and stratigraphy of the polar deposits. In this work we present the latest imaging data acquired by the Mars Odyssey THermal EMission Imaging System (THEMIS) and place it into context of the Mars Global Surveyor (MGS) data. THEMIS provides capabilities for imaging in both thermal IR and visible color wavelengths. These observations are affected by atmospheric scattering and topography. The Mars Orbiter Laser Altimeter (MOLA) and Thermal Emission Spectrometer (TES) instruments on board of the MGS spacecraft can provide context information for THEMIS data. Of particular interest are Mars Orbiter Camera (MOC) images, which provide high resolution data. We are primarily interested in the seasonal evolution of ice cap temperatures during the first northern summer of THEMIS observations. Morphology, stratigraphy and composition of the layered deposits can be addressed by THEMIS VIS color images, along with MOC high resolution data and MOLA Digital Elevation Models (DEM). This work is intentionally descriptive. Based on the knowledge obtained by the orbiting spacecraft and described here, we will attempt to expose major directions for modeling and further understanding of of the physical processes involved in the formation of the polar layered terrain 2 Available data 2.1 THEMIS IR The THEMIS IR camera has 10 bands from 6 to 15 m. Due to to signal-to-noise restrictions the most useful band for polar observations is band 9 (12.57 m ). Band 10 (14.88 m ) data can be used for atmospheric calibration. An example of seasonal evolution observed by the THEMIS IR subsystem is shown in Figure 1. We have projected all IR

  1. Spacecraft aerodynamics and trajectory simulation during aerobraking

    Institute of Scientific and Technical Information of China (English)

    Wen-pu ZHANG; Bo HAN; Cheng-yi ZHANG

    2010-01-01

    This paper uses a direct simulation Monte Carlo(DSMC)approach to simulate rarefied aerodynamic characteristics during the aerobraking process of the NASA Mars Global Surveyor(MGS)spacecraft.The research focuses on the flowfield and aerodynamic characteristics distribution under various free stream densities.The variation regularity of aerodynamic coefficients is analyzed.The paper also develops an aerodynamics-aeroheating-trajectory integrative simulation model to preliminarily calculate the aerobraking orbit transfer by combining the DSMC technique and the classical kinematics theory.The results show that the effect of the planetary atmospheric density,the spacecraft yaw,and the pitch attitudes on the spacecraft aerodynamics is significant.The numerical results are in good agreement with the existing results reported in the literature.The aerodynamics-aeroheating-trajectory integrative simulation model can simulate the orbit tran,sfer in the complete aerobraking mission.The current results of the spacecraft trajectory show that the aerobraking maneuvers have good performance of attitude control.

  2. Constraints on the Within Season and Between Year Variability of the North Residual Cap from MGS-TES

    Science.gov (United States)

    Calvin, W. M.; Titus, T. N.; Mahoney, S. A.

    2003-01-01

    There is a long history of telescopic and spacecraft observations of the polar regions of Mars. The finely laminated ice deposits and surrounding layered terrains are commonly thought to contain a record of past climate conditions and change. Understanding the basic nature of the deposits and their mineral and ice constituents is a continued focus of current and future orbited missions. Unresolved issues in Martian polar science include a) the unusual nature of the CO2 ice deposits ("Swiss Cheese", "slab ice" etc.) b) the relationship of the ice deposits to underlying layered units (which differs from the north to the south), c) understanding the seasonal variations and their connections to the finely laminated units observed in high-resolution images and d) the relationship of dark materials in the wind-swept lanes and reentrant valleys to the surrounding dark dune and surface materials. Our work focuses on understanding these issues in relationship to the north residual ice cap. Recent work using Mars Global Surveyor (MGS) data sets have described evolution of the seasonal CO2 frost deposits. In addition, the north polar residual ice cap exhibits albedo variations between Mars years and within the summer season. The Thermal Emission Spectrometer (TES) data set can augment these observations providing additional constraints such as temperature evolution and spectral properties associated with ice and rocky materials. Exploration of these properties is the subject of our current study.

  3. Martian clouds observed by Mars Global Surveyor Mars Orbiter Camera

    OpenAIRE

    Wang, Huiqun; Ingersoll, Andrew P.

    2002-01-01

    We have made daily global maps that cover both polar and equatorial regions of Mars for Ls 135°–360° and 0°–111° using the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) red and blue wide-angle swaths taken from May 1999 to January 2001. We study the seasonal distribution of condensate clouds and dust clouds during roughly 1 Martian year using these daily global maps. We present the development and decay of the tropical cloud belt and the polar hoods, the spatial and temporal distributi...

  4. Discovery Mondays: Surveyors' Tools

    CERN Multimedia

    2003-01-01

    Surveyors of all ages, have your rulers and compasses at the ready! This sixth edition of Discovery Monday is your chance to learn about the surveyor's tools - the state of the art in measuring instruments - and see for yourself how they work. With their usual daunting precision, the members of CERN's Surveying Group have prepared some demonstrations and exercises for you to try. Find out the techniques for ensuring accelerator alignment and learn about high-tech metrology systems such as deviation indicators, tracking lasers and total stations. The surveyors will show you how they precisely measure magnet positioning, with accuracy of a few thousandths of a millimetre. You can try your hand at precision measurement using different types of sensor and a modern-day version of the Romans' bubble level, accurate to within a thousandth of a millimetre. You will learn that photogrammetry techniques can transform even a simple digital camera into a remarkable measuring instrument. Finally, you will have a chance t...

  5. The Rapid Transient Surveyor

    CERN Document Server

    Baranec, Christoph; Wright, Shelley A; Tonry, John; Tully, R Brent; Szapudi, István; Takamiya, Marianne; Hunter, Lisa; Riddle, Reed; Chen, Shaojie; Chun, Mark

    2016-01-01

    The Rapid Transient Surveyor (RTS) is a proposed rapid-response, high-cadence adaptive optics (AO) facility for the UH 2.2-m telescope on Maunakea. RTS will uniquely address the need for high-acuity and sensitive near-infrared spectral follow-up observations of tens of thousands of objects in mere months by combining an excellent observing site, unmatched robotic observational efficiency, and an AO system that significantly increases both sensitivity and spatial resolving power. We will initially use RTS to obtain the infrared spectra of ~4,000 Type Ia supernovae identified by the Asteroid Terrestrial-Impact Last Alert System over a two year period that will be crucial to precisely measuring distances and mapping the distribution of dark matter in the z < 0.1 universe. RTS will comprise an upgraded version of the Robo-AO laser AO system and will respond quickly to target-of-opportunity events, minimizing the time between discovery and characterization. RTS will acquire simultaneous-multicolor images with a...

  6. The rapid transient surveyor

    Science.gov (United States)

    Baranec, C.; Lu, J. R.; Wright, S. A.; Tonry, J.; Tully, R. B.; Szapudi, I.; Takamiya, M.; Hunter, L.; Riddle, R.; Chen, S.; Chun, M.

    2016-07-01

    The Rapid Transient Surveyor (RTS) is a proposed rapid-response, high-cadence adaptive optics (AO) facility for the UH 2.2-m telescope on Maunakea. RTS will uniquely address the need for high-acuity and sensitive near-infrared spectral follow-up observations of tens of thousands of objects in mere months by combining an excellent observing site, unmatched robotic observational efficiency, and an AO system that significantly increases both sensitivity and spatial resolving power. We will initially use RTS to obtain the infrared spectra of 4,000 Type Ia supernovae identified by the Asteroid Terrestrial-Impact Last Alert System over a two year period that will be crucial to precisely measuring distances and mapping the distribution of dark matter in the z efficiency prism integral field unit spectrograph: R = 70-140 over a total bandpass of 840-1830nm with an 8.7" by 6.0" field of view (0.15" spaxels). The AO correction boosts the infrared point-source sensitivity of the spectrograph against the sky background by a factor of seven for faint targets, giving the UH 2.2-m the H-band sensitivity of a 5.7-m telescope without AO.

  7. Rapid geophysical surveyor

    Energy Technology Data Exchange (ETDEWEB)

    Roybal, L.G.; Carpenter, G.S.; Josten, N.E.

    1993-01-01

    The Rapid Geophysical Surveyor (RGS) is a system designed to rapidly and economically collect closely-spaced geophysical data used for characterization of Department of Energy (DOE) waste sites. Geophysical surveys of waste sites are an important first step in the remediation and closure of these sites; especially older sties where historical records are inaccurate and survey benchmarks have changed due to refinements in coordinate controls and datum changes. Closely-spaced data are required to adequately differentiate pits, trenches, and soil vault rows whose edges may be only a few feet from each other. A prototype vehicle designed to collect magnetic field data was built at the Idaho national Engineering Laboratory (INEL) during the summer of 1992. The RGS was one of several projects funded by the Buried Waste Integrated Demonstration (BWID) program. This vehicle was demonstrated at the Subsurface Disposal Area (SDA) within the Radioactive Waste Management Complex (RWMC) on the INEL in September of 1992. Magnetic data were collected over two areas in the SDA, with a total survey area of about 1.7 acres. Data were collected at a nominal density of 2 1/2 inches along survey lines spaced 1 foot apart. Over 350,000 data points were collected over a 6 day period corresponding to about 185 man-days using conventional ground survey techniques. This report documents the design and demonstration of the RGS concept including the presentation of magnetic data collected at the SDA. The surveys were able to show pit and trench boundaries and determine details of their spatial orientation never before achieved.

  8. Rapid geophysical surveyor

    Energy Technology Data Exchange (ETDEWEB)

    Roybal, L.G.; Carpenter, G.S.; Josten, N.E.

    1993-07-01

    The Rapid Geophysical Surveyor (RGS) is a system designed to rapidly and economically collect closely-spaced geophysical data used for characterization of Department of Energy (DOE) waste sites. Geophysical surveys of waste sites are an important first step in the remediation and closure of these sites; especially older sties where historical records are inaccurate and survey benchmarks have changed due to refinements in coordinate controls and datum changes. Closely-spaced data are required to adequately differentiate pits, trenches, and soil vault rows whose edges may be only a few feet from each other. A prototype vehicle designed to collect magnetic field data was built at the Idaho national Engineering Laboratory (INEL) during the summer of 1992. The RGS was one of several projects funded by the Buried Waste Integrated Demonstration (BWID) program. This vehicle was demonstrated at the Subsurface Disposal Area (SDA) within the Radioactive Waste Management Complex (RWMC) on the INEL in September of 1992. Magnetic data were collected over two areas in the SDA, with a total survey area of about 1.7 acres. Data were collected at a nominal density of 2 1/2 inches along survey lines spaced 1 foot apart. Over 350,000 data points were collected over a 6 day period corresponding to about 185 man-days using conventional ground survey techniques. This report documents the design and demonstration of the RGS concept including the presentation of magnetic data collected at the SDA. The surveys were able to show pit and trench boundaries and determine details of their spatial orientation never before achieved.

  9. The Rapid Transient Surveyor

    Science.gov (United States)

    Baranec, Christoph; Tonry, John; Wright, Shelley; Tully, R. Brent; Lu, Jessica R.; Takamiya, Marianne Y.; Hunter, Lisa

    2016-01-01

    The next decade of astronomy will be dominated by large area surveys (see the detailed discussion in the Astro-2010 Decadal survey and NRC's recent OIR System Report). Ground-based optical transient surveys, e.g., LSST, ZTF and ATLAS and space-based exoplanet, supernova, and lensing surveys such as TESS and WFIRST will join the Gaia all-sky astrometric survey in producing a flood of data that will enable leaps in our understanding of the universe. There is a critical need for further characterization of these discoveries through high angular resolution images, deeper images, spectra, or observations at different cadences or periods than the main surveys. Such follow-up characterization must be well matched to the particular surveys, and requires sufficient additional observing resources and time to cover the extensive number of targets.We describe plans for the Rapid Transient Surveyor (RTS), a permanently mounted, rapid-response, high-cadence facility for follow-up characterization of transient objects on the U. of Hawai'i 2.2-m telescope on Maunakea. RTS will comprise an improved robotic laser adaptive optics system, based on the prototype Robo-AO system (formerly at the Palomar 1.5-m and now at the Kitt Peak 2.2-m telescope), with simultaneous visible and near-infrared imagers as well as a near-infrared integral field spectrograph (R~100, λ = 850 - 1830 nm, 0.15″ spaxels, 8.7″×6.0″ FoV). RTS will achieve an acuity of ~0.07″ in visible wavelengths and automated detection and characterization of astrophysical transients during a sustained observing campaign will yield the necessary statistics to precisely map dark matter in the local universe.

  10. Mutation detection using Surveyor nuclease.

    Science.gov (United States)

    Qiu, Peter; Shandilya, Harini; D'Alessio, James M; O'Connor, Kevin; Durocher, Jeffrey; Gerard, Gary F

    2004-04-01

    We have developed a simple and flexible mutation detection technology for the discovery and mapping of both known and unknown mutations. This technology is based on a new mismatch-specific DNA endonuclease from celery, Surveyor nuclease, which is a member of the CEL nuclease family of plant DNA endonucleases. Surveyor nuclease cleaves with high specificity at the 3' side of any mismatch site in both DNA strands, including all base substitutions and insertion/deletions up to at least 12 nucleotides. Surveyor nuclease technology involves four steps: (i) PCR to amplify target DNA from both mutant and wild-type reference DNA; (ii) hybridization to form heteroduplexes between mutant and wild-type reference DNA; (iii) treatment of annealed DNA with Surveyor nuclease to cleave heteroduplexes; and (iv) analysis of digested DNA products using the detection/separation platform of choice. The technology is highly sensitive, detecting rare mutants present at as low as 1 in 32 copies. Unlabeled Surveyor nuclease digestion products can be analyzed using conventional gel electrophoresis or high-performance liquid chromatography (HPLC), while end labeled digestion products are suitable for analysis by automated gel or capillary electrophoresis. The entire protocol can be performed in less than a day and is suitable for automated and high-throughput procedures.

  11. Determination of Net Martian Polar Dust Flux from MGS-TES Observations

    Science.gov (United States)

    Blackmon, M. A.; Murphy, J. R.

    2003-01-01

    Using atmospheric dust abundance and atmospheric temperature observation data from the Thermal Emission Spectrometer (TES) on board the Mars Global Surveyor (MGS), the net flux of dust into and out of the Martian polar regions will be examined. Mars polar regions possess layered terrain , believed to be comprised of a mixture of ice and dust, with the different layers possibly representing different past climate regimes. These changes in climate may reflect changes in the deposition of dust and volatiles through impacts, volcanism, changes in resources of ice and dust, and response to Milankovitch type cycles (changes in eccentricity of orbit, obliquity and precession of axis). Understanding how rapidly such layers can be generated is an important element to understanding Mars climate history. This study uses the observed vertical temperature data and dust content measurements from TES to analyze the sign (gain or loss) of dust at high latitudes.

  12. Challenges to Building Surveyors From The Perspectives Of Non Surveyors

    Directory of Open Access Journals (Sweden)

    Isnin Zarina

    2016-01-01

    Full Text Available Awareness on the importance of Building Surveyors in Malaysia is still low as the role and skills of this profession are not fully understood. Although studies indicated that Building Surveyors are still in demand, even without the Building Surveyor Act, many graduates are experiencing inadequate employment opportunities in the current economic situation. Little is known on the views from other stakeholders about BS. This research aims to examine the awareness and opinions on BS in Malaysia amongst construction stakeholders. Questionnaire surveys were collected from 120 respondents from construction, maintenance and insurance companies and interviews were conducted to selected built environment respondents. It was found that awareness and knowledge on BS are still low as they lack information on the profession and professional recognitions. Some views indicated on a major identity crisis for having fragmented and disparate range of modules. The cause may have resulted in problems on public recognition, poor understanding of the surveyor’s skills, and fewer job opportunities. Several suggested the profession to have a clear, coherent and relevant identity, with strong professional structures in order for the profession to survive and gain recognition from the government. Graduates are also recommended to acquire other skills and training in order for them to be significant to the construction industry.

  13. Asymmetric penetration of solar wind perturbations down to 400-km altitudes at Mars observed by Mars Global Surveyor

    Science.gov (United States)

    Matsunaga, K.; Seki, K.; Hara, T.; Brain, D. A.

    2012-12-01

    Since Mars has no intrinsic global magnetic field, the exchange of energy, momentum, and material with the planet takes place through interaction between the solar wind and the Martin upper atmosphere. It is thought that solar wind encountering Mars can penetrate into the point where the solar wind dynamic pressure and the plasma thermal pressure in the Martin ionosphere are almost balanced and the solar wind flow is deflected around the boundary. However, the actual interaction can be complicated, since both plasma processes and the existence of crustal magnetic fields can modify the structure of the boundary. The Kelvin-Helmholtz (K-H) instability at the Martian ionopause is one of important candidate process to cause the modification. The dDistribution of ionopause surface waves generated by the K-H instability can should exhibit a clear asymmetry between hemispheres of upward and downward solar wind motional electric fields [e.g., Terada et al., 2002]. It is also suggested that the crustal magnetic fields can locally push the MPB (magnetic pileup boundary) upward [e.g., Brain et al., 2003]. It is also reported that the boundary between the solar wind and Martian ionosphere is located at an altitude of 380 km on average in the dayside [e.g., Mitchell et al., 2001]. However, this boundary location can change significantly depending on solar wind conditions. While it is considered that the solar wind can penetrate to lower altitudes than usual when the solar wind pressure is high, the frequency of the solar wind penetration and its quantitative dependence on the solar wind conditions are not yet well understood. In this study, we focused on penetration of solar wind electromagnetic disturbances, which are a characteristic feature of the shocked solar wind (magnetosheath), down to 400-km altitude at Mars. Using Mars Global Surveyor (MGS) data, we investigated the observational frequency and characteristics of the penetration events. We used data from the MGS

  14. 46 CFR 153.1101 - Procedures for getting a Surveyor: Approval of Surveyors.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Procedures for getting a Surveyor: Approval of Surveyors. 153.1101 Section 153.1101 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Approval of Surveyors...

  15. Global-scale external magnetic fields at Mars from Mars Global Surveyor data

    Science.gov (United States)

    Mittelholz, A.; Johnson, C. L.

    2015-12-01

    The martian magnetic field is unique among those of the terrestrial planets. It is the net result of the interaction of the solar wind and interplanetary magnetic field (IMF) with crustal remnant magnetization and a planetary ionosphere. Internal fields of crustal origin have been the subject of extensive studies; the focus of our work is identification and characterization of contributions from external magnetic fields using the Mars Global Surveyor (MGS) vector magnetic field data. We investigate the magnitude, average spatial structure and temporal variability of the external magnetic field at the MGS mapping altitude of 400 km by first subtracting expected contributions from crustal fields using existing global crustal field models. We identify contributions to the residual dayside fields from two sources: the draped IMF and a source that we interpret to be of ionospheric origin. As observed in previous work, nightside external fields are minimal at mapping orbit altitudes. The IMF contribution changes polarity every 13 days due to the geometry of the heliospheric magnetic field and Mars' orbit. This allows us to calculate the amplitude of the IMF at mapping orbit altitudes. The ionospheric contribution results in a quasi-steady dayside signal in the MGS observations because of the limited local time sampling of the MGS mapping orbit. The ionospheric contribution can be isolated by averaging the external fields over timescales longer than several Carrington rotations, to average out the IMF contribution. We present a global average of the ionopsheric field for the duration of the mapping orbit (2000-2006) and analyze daytime and nightime fields separately. We show that some structure in the time-averaged ionospheric field is organized in the Mars body-fixed frame, due for example, to the influence of crustal fields. We also show that the ionospheric fields vary in amplitude and geometry with martian season. Broader local time coverage over a restricted latitude

  16. Seasonal and static gravity field of Mars from MGS, Mars Odyssey and MRO radio science

    Science.gov (United States)

    Genova, Antonio; Goossens, Sander; Lemoine, Frank G.; Mazarico, Erwan; Neumann, Gregory A.; Smith, David E.; Zuber, Maria T.

    2016-07-01

    We present a spherical harmonic solution of the static gravity field of Mars to degree and order 120, GMM-3, that has been calculated using the Deep Space Network tracking data of the NASA Mars missions, Mars Global Surveyor (MGS), Mars Odyssey (ODY), and the Mars Reconnaissance Orbiter (MRO). We have also jointly determined spherical harmonic solutions for the static and time-variable gravity field of Mars, and the Mars k2 Love numbers, exclusive of the gravity contribution of the atmosphere. Consequently, the retrieved time-varying gravity coefficients and the Love number k2 solely yield seasonal variations in the mass of the polar caps and the solid tides of Mars, respectively. We obtain a Mars Love number k2 of 0.1697 ± 0.0027 (3-σ). The inclusion of MRO tracking data results in improved seasonal gravity field coefficients C30 and, for the first time, C50. Refinements of the atmospheric model in our orbit determination program have allowed us to monitor the odd zonal harmonic C30 for ∼1.5 solar cycles (16 years). This gravity model shows improved correlations with MOLA topography up to 15% larger at higher harmonics (l = 60-80) than previous solutions.

  17. Rapid Geophysical Surveyor. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Roybal, L.G.; Carpenter, G.S.; Josten, N.E.

    1993-01-01

    The Rapid Geophysical Surveyor (RGS) is a system designed to rapidly and economically collect closely-spaced geophysical data used for characterization of US Department of Energy waste sites. Geophysical surveys of waste sites are an important first step in the remediation and closure of these sites; especially older sites where historical records are inaccurate and survey benchmarks have changed because of refinements in coordinate controls and datum changes. Closely-spaced data are required to adequately differentiate pits, trenches, and soil vault rows whose edges may be only a few feet from each other. A prototype vehicle designed to collect magnetic field data was built at the Idaho National Engineering Laboratory (INEL) during the summer of 1992. The RGS was funded by the Buried Waste Integrated Demonstration program. This vehicle was demonstrated at the Subsurface Disposal Area (SDA) within the Radioactive Waste Management Complex at the INEL in September 1992. Magnetic data were collected over two areas in the SDA, with a total survey area of about 1.7 acres. Data were collected at a nominal density of 2{1/2} in. along survey lines spaced 1-ft apart. Over 350,000 data points were collected over a 6 day period corresponding to about 185 worker-days using conventional ground survey techniques.

  18. Further Analysis on the Mystery of the Surveyor III Dust Deposits

    Science.gov (United States)

    Metzger, Philip; Hintze, Paul; Trigwell, Steven; Lane, John

    2011-01-01

    The Apollo 12 lunar module (LM) landing near the Surveyor 1lI spacecraft at the end of 1969 has remained the primary experimental verification of the predicted physics of plume ejecta effects from a rocket engine interacting with the surface of the moon. This was made possible by the return of the Surveyor 1lI camera housing by the Apollo 12 astronauts, allowing detailed analysis of the composition of dust deposited by the Apollo 12 LM plume. It was soon realized after the initial analysis of the camera housing that the LM plume tended to remove more dust than it had deposited. In the present study, coupons from the camera housing were reexamined by a KSC research team using SEM/EDS and XPS analysis. In addition, plume effects recorded in landing videos from each Apollo mission have been studied for possible clues. Several likely scenarios are proposed to explain the Surveyor III dust observations. These include electrostatic attraction of the dust to the surface of the Surveyor as a result of electrostatic charging of the jet gas exiting the engine nozzle during descent; dust blown by the Apollo 12 LM fly-by while on its descent trajectory; dust ejected from the lunar surface due to gas forced into the soil by the Surveyor 1lI rocket nozzle, based on Darcy's law; and mechanical movement of dust during the Surveyor landing. Even though an absolute answer is not possible based on available data and theory, various computational models are employed to estimate the feasibility of each of these proposed mechanisms. Scenarios are then discussed which combine multiple mechanisms to produce results consistent with observations.

  19. MGS-TES thermal inertia study of the Arsia Mons Caldera

    Science.gov (United States)

    Cushing, G.E.; Titus, T.N.

    2008-01-01

    Temperatures of the Arsia Mons caldera floor and two nearby control areas were obtained by the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES). These observations revealed that the Arsia Mons caldera floor exhibits thermal behavior different from the surrounding Tharsis region when compared with thermal models. Our technique compares modeled and observed data to determine best fit values of thermal inertia, layer depth, and albedo. Best fit modeled values are accurate in the two control regions, but those in the Arsia Mons' caldera are consistently either up to 15 K warmer than afternoon observations, or have albedo values that are more than two standard deviations higher than the observed mean. Models of both homogeneous and layered (such as dust over bedrock) cases were compared, with layered-cases indicating a surface layer at least thick enough to insulate itself from diurnal effects of an underlying substrate material. Because best fit models of the caldera floor poorly match observations, it is likely that the caldera floor experiences some physical process not incorporated into our thermal model. Even on Mars, Arsia Mons is an extreme environment where CO2 condenses upon the caldera floor every night, diurnal temperatures range each day by a factor of nearly 2, and annual average atmospheric pressure is only around one millibar. Here, we explore several possibilities that may explain the poor modeled fits to caldera floor and conclude that temperature dependent thermal conductivity may cause thermal inertia to vary diurnally, and this effect may be exaggerated by presence of water-ice clouds, which occur frequently above Arsia Mons. Copyright 2008 by the American Geophysical Union.

  20. Extending MGS-TES Temperature Retrievals in the Martian Atmosphere up to 90 Km: Retrieval Approach and Results

    Science.gov (United States)

    Feofilov, A. G.; Kutepov, A. A.; Rezac, L.; Smith, M. D.

    2015-01-01

    This paper describes a methodology for performing a temperature retrieval in the Martian atmosphere in the 50-90 km altitude range using spectrally integrated 15 micrometers C02 limb emissions measured by the Thermal Emission Spectrometer (TES), the thermal infrared spectrometer on board the Mars Global Surveyor (MGS). We demonstrate that temperature retrievals from limb observations in the 75-90 km altitude range require accounting for the non-local thermodynamic equilibrium (non-LTE) populations of the C02(v2) vibrational levels. Using the methodology described in the paper, we have retrieved approximately 1200 individual temperature profiles from MGS TES limb observations in the altitude range between 60 and 90 km. 0ur dataset of retrieved temperature profiles is available for download in supplemental materials of this paper. The temperature retrieval uncertainties are mainly caused by radiance noise, and are estimated to be about 2 K at 60 km and below, 4 K at 70 km, 7 K at 80 km, 10 K at 85 km, and 20 K at 90 km. We compare the retrieved profiles to Mars Climate Database temperature profiles and find good qualitative agreement. Quantitatively, our retrieved profiles are in general warmer and demonstrate strong variability with the following values for bias and standard deviations (in brackets) compared to the Martian Year 24 dataset of the Mars Climate Database: 6 (+/-20) K at 60 km, 7.5 (+/-25) K at 65 km, 9 (+/-27) K at 70 km, 9.5 (+/-27) K at 75 km, 10 (+/-28) K at 80 km, 11 (+/-29) K at 85 km, and 11.5 (+/-31) K at 90 km. Possible reasons for the positive temperature bias are discussed. carbon dioxide molecular vibrations

  1. Further Analysis on the Mystery of the Surveyor III Dust Deposits

    Science.gov (United States)

    Metzger, Philip; Hintze, Paul; Trigwell, Steven; Lane, John

    2012-01-01

    The Apollo 12 lunar module (LM) landing near the Surveyor III spacecraft at the end of 1969 has remained the primary experimental verification of the predicted physics of plume ejecta effects from a rocket engine interacting with the surface of the moon. This was made possible by the return of the Surveyor III camera housing by the Apollo 12 astronauts, allowing detailed analysis of the composition of dust deposited by the LM plume. It was soon realized after the initial analysis of the camera housing that the LM plume tended to remove more dust than it had deposited. In the present study, coupons from the camera housing have been reexamined. In addition, plume effects recorded in landing videos from each Apollo mission have been studied for possible clues.

  2. Rocksalt MgS solar blind ultra-violet detectors

    Directory of Open Access Journals (Sweden)

    Ying-Hoi Lai

    2012-03-01

    Full Text Available Studies using in-situ Auger electron spectroscopy and reflection high energy electron diffraction, and ex-situ high resolution X-ray diffraction and electron backscatter diffraction reveal that a MgS thin film grown directly on a GaAs (100 substrate by molecular beam epitaxy adopts its most stable phase, the rocksalt structure, with a lattice constant of 5.20 Å. A Au/MgS/n+-GaAs (100 Schottky-barrier photodiode was fabricated and its room temperature photoresponse was measured to have a sharp fall-off edge at 235 nm with rejection of more than three orders at 400 nm and higher than five orders at 500 nm, promising for various solar-blind UV detection applications.

  3. An examination of Mars' north seasonal polar cap using MGS: Composition and infrared radiation balance

    Science.gov (United States)

    Hansen, Gary B.

    2013-08-01

    A detailed analysis of data from one revolution of the Mars Global Surveyor (MGS) is presented. Approximately 80% of this revolution observes the mid-winter northern seasonal polar cap, which covers the surface to night. The surface composition and temperature are determined through analysis of 6-50 μm infrared spectra from the Thermal Emission Spectrometer (TES). The infrared radiative balance, which is the entire heat balance in the polar night except for small subsurface and atmospheric advection terms, is calculated for the surface and atmospheric column. The primary constituent, CO2 ice, also dominates the infrared spectral properties by variations in its grain size and by admixtures of dust and water ice, which cause large variations in the 20-50 μm emissivity. This is modified by incomplete areal coverage, and clouds or hazes. This quantitative analysis reveals CO2 grain radii ranging from ˜100 μm in isolated areas, to 1-5 mm in more widespread regions. The water ice content varies from none to about one part per thousand by mass, with a clear increase towards the periphery of the polar cap. The dust content is typically a few parts per thousand by mass, but is as much as an order of magnitude less abundant in "cold spot" regions, where the low emissivity of pure CO2 ice is revealed. This is the first quantitative analysis of thermal spectra of the seasonal polar cap and the first to estimate water ice content. Our models show that the cold spots represent cleaner, dust-free ice rather than finer grained ice than the background. Our guess is that the dust in cold spots is hidden in the center of the CO2 frost particles rather than not present. The fringes of the cap have more dust and water ice, and become patchy, with warmer water snow filling the gaps on the night side, and warmer bare soil on the day side. A low optical depth (night side, and appears with smaller optical depth on the day side. The infrared radiative balance at the surface is typically

  4. An investigation of washability characteristics of lignites from Yenicubuk-Gemerek districts by MGS; Yenicubuk gemerek linyit komurlerinin MGS ile yikanabilirliginin arastirilmasi

    Energy Technology Data Exchange (ETDEWEB)

    Aslan, N.; Canbazoglu, M.; Ulusoy, U. [Cumhuriyet Universitesi, Sivas (Turkey). Maden Muhendisligi Bolumu

    1999-07-01

    Washability and ash removal from Gemerek lignite in a multi gravity separator (MGS) were investigated. Experimental studies were carried out on -0.5 mm coal samples containing 37.75% ash in a laboratory C-900 type MGS. Drum speed, shake amplitude, tilt angle, shake frequency, wash water quantity and feed solid ratio were investigated. Optimum operating conditions were determined. 8 refs., 7 figs.

  5. The Cosmology Large Angular Scale Surveyor (CLASS)

    Science.gov (United States)

    Eimer, Joseph; Ali, A.; Amiri, M.; Appel, J. W.; Araujo, D.; Bennett, C. L.; Boone, F.; Chan, M.; Cho, H.; Chuss, D. T.; Colazo, F.; Crowe, E.; Denis, K.; Dünner, R.; Essinger-Hileman, T.; Gothe, D.; Halpern, M.; Harrington, K.; Hilton, G.; Hinshaw, G. F.; Huang, C.; Irwin, K.; Jones, G.; Karakla, J.; Kogut, A. J.; Larson, D.; Limon, M.; Lowry, L.; Marriage, T.; Mehrle, N.; Miller, A. D.; Miller, N.; Moseley, S. H.; Novak, G.; Reintsema, C.; Rostem, K.; Stevenson, T.; Towner, D.; U-Yen, K.; Wagner, E.; Watts, D.; Wollack, E.; Xu, Z.; Zeng, L.

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is an array of telescopes designed to search for the signature of inflation in the polarization of the Cosmic Microwave Background (CMB). By combining the strategy of targeting large scales (>2 deg) with novel front-end polarization modulation and novel detectors at multiple frequencies, CLASS will pioneer a new frontier in ground-based CMB polarization surveys. In this talk, I give an overview of the CLASS instrument, survey, and outlook on setting important new limits on the energy scale of inflation.

  6. The conduction bands of MgO, MgS and HfO2

    NARCIS (Netherlands)

    Boer, P.K. de; Groot, R.A. de

    1998-01-01

    Electronic structure calculations for MgO, MgS and HfO2 are reported. It is shown that the conduction bands of MgO and MgS have predominantly anion character, contrary to the common picture of the conduction band being derived from cation states. In transition metal oxides, unoccupied anion states a

  7. Quantitative studies of volcanic processes on Mars using data from the Mars Global Surveyor

    Science.gov (United States)

    Bishop, Louise Jane

    Volcanic processes on Mars were investigated using topographic profiles derived with the help of IDL software from data collected by the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor Mission (MGS) in 1997-2001 and images obtained by the MGS Mars Orbiter Camera (MOC) and by the earlier Viking mission. Thickness and slope values for lava flows at both Elysium Mons and Alba Patera made it possible to compute flow emplacement times and effusion rates using the flow growth model proposed by C. R. J. Kilburn and R. M. C Lopes in 1990. Geological mapping of the Elysium volcanic region showed that Elysium Mons was emplaced as a result of a single shift in vent position on top of an older volcanic edifice, here termed the Ancient Volcanic Edifice (AVE). This implies that there have been substantial variations in both position and time for the magma supply. Calculations suggest that the flows at Alba Patera were emplaced more quickly than those at Elysium Mons, possibly owing to differences in fissure width and lava composition. There is evidence for both aa and pahoehoe on the summit areas of Elysium Mons and Alba Patera. The presence of aa is consistent with the view that long lava flows on Mars are emplaced quickly. Pahoehoe flows imply slow emplacement, and their inferred presence on Mars provides support for the theory that long terrestrial lavas are often emplaced as sheets of inflated pahoehoe. MOC image analysis indicated that late-stage explosive activity has occurred at several Martian volcanoes where it was previously undetected, contrary to the prevalent view that Martian volcanism evolves from explosive to effusive activity. To resolve the many ambiguities inherent in morphological data and imagery the need remains for ground truthing by experienced observers and detailed geochemical analyses in situ or by means of a sample return mission

  8. Mars Surveyor '98 MVACS Robotic Arm Control System Design Concepts

    Science.gov (United States)

    Bonitz, Robert G.

    1997-01-01

    This paper describes the control system design concepts for the Mars Volatiles and Climate Surveyor (MVACS) Robotic Arm which supports the scientific investigations to be conducted as part of the Mars Surveyor '98 Lander project. Novel solutions are presented to some of the unique problems encountered in this demanding space application with its tight constraints on mass, power, volume, and computing power.

  9. MgS in detached shells around carbon stars. Mining the mass-loss history

    CERN Document Server

    Hony, S

    2004-01-01

    We investigate the dust composition of detached shells around carbon stars, with a focus to understand the origin of the cool magnesium-sulfide (MgS) material around warm carbon stars, which has been detected around several of these objects. We build a radiative transfer model of a carbon star surrounded by an expanding detached shell of dust. The shell contains amorphous carbon grains and MgS grains. We find that a small fraction of MgS dust (2% of the dust mass) can give a significant contribution to the IRAS 25 micron flux. However, the presence of MgS in the detached shell cannot be inferred from the IRAS broadband photometry alone but requires infrared spectroscopy. We apply the model to the detached-shell sources R Scl and U Cam, both exhibiting a cool MgS feature in their ISO/SWS spectra. We use the shell parameters derived for the molecular shell, using the CO submillimetre maps. The models, with MgS grains located in the detached shell, explain the MgS grain temperature, as derived from their ISO spe...

  10. The Cosmology Large Angular Scale Surveyor

    Science.gov (United States)

    Marriage, Tobias; Ali, A.; Amiri, M.; Appel, J. W.; Araujo, D.; Bennett, C. L.; Boone, F.; Chan, M.; Cho, H.; Chuss, D. T.; Colazo, F.; Crowe, E.; Denis, K.; Dünner, R.; Eimer, J.; Essinger-Hileman, T.; Gothe, D.; Halpern, M.; Harrington, K.; Hilton, G.; Hinshaw, G. F.; Huang, C.; Irwin, K.; Jones, G.; Karakla, J.; Kogut, A. J.; Larson, D.; Limon, M.; Lowry, L.; Mehrle, N.; Miller, A. D.; Miller, N.; Moseley, S. H.; Novak, G.; Reintsema, C.; Rostem, K.; Stevenson, T.; Towner, D.; U-Yen, K.; Wagner, E.; Watts, D.; Wollack, E.; Xu, Z.; Zeng, L.

    2014-01-01

    Some of the most compelling inflation models predict a background of primordial gravitational waves (PGW) detectable by their imprint of a curl-like "B-mode" pattern in the polarization of the Cosmic Microwave Background (CMB). The Cosmology Large Angular Scale Surveyor (CLASS) is a novel array of telescopes to measure the B-mode signature of the PGW. By targeting the largest angular scales (>2°) with a multifrequency array, novel polarization modulation and detectors optimized for both control of systematics and sensitivity, CLASS sets itself apart in the field of CMB polarization surveys and opens an exciting new discovery space for the PGW and inflation. This poster presents an overview of the CLASS project.

  11. Beyond Chandra - the X-ray Surveyor

    CERN Document Server

    Weisskopf, Martin C; Tananbaum, Harvey; Vikhlinin, Alexey

    2015-01-01

    Over the past 16 years, NASA's Chandra X-ray Observatory has provided an unparalleled means for exploring the universe with its half-arcsecond angular resolution. Chandra studies have deepened our understanding of galaxy clusters, active galactic nuclei, galaxies, supernova remnants, planets, and solar system objects addressing almost all areas of current interest in astronomy and astrophysics. As we look beyond Chandra, it is clear that comparable or even better angular resolution with greatly increased photon throughput is essential to address even more demanding science questions, such as the formation and subsequent growth of black hole seeds at very high redshift; the emergence of the first galaxy groups; and details of feedback over a large range of scales from galaxies to galaxy clusters. Recently, NASA Marshall Space Flight Center, together with the Smithsonian Astrophysical Observatory, has initiated a concept study for such a mission named the X-ray Surveyor. This study starts with a baseline payloa...

  12. The surveyors' quest for perfect alignment

    CERN Multimedia

    2003-01-01

    Photogrammetry of a CMS endcap and part of the hadronic calorimeter.The structure was covered with targets photographed by digital cameras. Perfect alignment.... Although CERN's surveyors do not claim to achieve it, they are constantly striving for it and deploy all necessary means to come as close as they can. In their highly specialised field of large-scale metrology, the solution lies in geodesy and photogrammetry, both of which are based on increasingly sophisticated instruments and systems. In civil engineering, these techniques are used for non-destructive inspection of bridges, dams and other structures, while industrial applications include dimensional verification and deformation measurement in large mechanical assemblies. The same techniques also come into play for the metrology of research tools such as large telescopes and of course, particle accelerators. Particle physics laboratories are especially demanding customers, and CERN has often asked for the impossible. As a result, the alignment metro...

  13. CERN’s surveyors send sparks flying

    CERN Document Server

    Anaïs Schaeffer

    2013-01-01

    A few weeks ago, we published an article on the three-dimensional laser scanner technique used at CERN to produce 3D images of the LHC tunnels and experiments (see the article here). Photogrammetry is another technique in the CERN surveyors’ arsenal.   The ATLAS wheel during a photogrammetry measurement campaign. The white spots (see red arrows) dotted across the wheel are the retro-reflective "dot" targets. Used in a number of fields including topography, architecture, geology and archaeology, photogrammetry is a stereoscopy technique whereby 2D images taken from different angles can be used to reconstruct a 3D image of an object. Surveyors at CERN have been using this technique for over 15 years as a way of gaining precise information on the shape, size, deformation and position of the LHC detectors and their composite elements. The photogrammetry used at CERN is relatively “light” in terms of the equipment required, w...

  14. Waves in the Martian Atmosphere: Results from MGS Radio Occultations

    Science.gov (United States)

    Flasar, F. M.; Hinson, D. P.; Tyler, G. L.

    1999-09-01

    Temperatures retrieved from Mars Global Surveyor radio occultations have been searched for evidence of waves. Emphasis has been on the initial series of occultations between 29(deg) N and 64(deg) S, obtained during the early martian southern summer, L_s=264(deg-308^deg) . The profiles exhibit an undulatory behavior that is suggestive of vertically propagating waves. Wavelengths ~ 10 km are often dominant, but structure on smaller scales is evident. The undulatory structure is most pronounced between latitudes 29(deg) N and 10(deg) S, usually in regions of ``interesting'' topography, e.g., in the Tharsis region and near the edge of Syrtis Major. Several temperature profiles, particularly within 30(deg) of the equator, exhibit lapse rates that locally become superadiabatic near the 0.4--mbar level or at higher altitudes. This implies that the waves are ``breaking'' and depositing horizontal momentum into the atmosphere. Such a deposition may play an important role in modulating the atmospheric winds, and characterizing the spatial and temporal distribution of these momentum transfers can provide important clues to understanding how the global circulation is maintained.

  15. Forecasting the manpower demand for quantity surveyors in Hong Kong

    Directory of Open Access Journals (Sweden)

    Paul H K Ho

    2013-09-01

    Full Text Available Recently, there has been a massive infrastructure development and an increasing demand for public and private housing, resulting in a shortage of qualified quantity surveyors. This study aims to forecast the demand for qualified quantity surveyors in Hong Kong from 2013 to 2015. Literature review indicates that the demand for quantity surveyors is a function of the gross values of building, civil engineering and maintenance works. The proposed forecasting method consists of two steps. The first step is to estimate the gross values of building, civil engineering and maintenance works by time series methods and the second step is to forecast the manpower demand for quantity surveyors by causal methods. The data for quantity surveyors and construction outputs are based on the ‘manpower survey reports of the building and civil engineering industry’ and the ‘gross value of construction works performed by main contractors’ respectively. The forecasted manpower demand for quantity surveyors in 2013, 2014 and 2015 are 2,480, 2,632 and 2,804 respectively. Due to the low passing rate of the assessment of professional competence (APC and the increasing number of retired qualified members, there will be a serious shortage of qualified quantity surveyors in the coming three years.

  16. Forecasting the manpower demand for quantity surveyors in Hong Kong

    Directory of Open Access Journals (Sweden)

    Paul H K Ho

    2013-09-01

    Full Text Available Recently, there has been a massive infrastructure development and an increasing demand for public and private housing, resulting in a shortage of qualified quantity surveyors. This study aims to forecast the demand for qualified quantity surveyors in Hong Kong from 2013 to 2015. Literature review indicates that the demand for quantity surveyors is a function of the gross values of building, civil engineering and maintenance works. The proposed forecasting method consists of two steps. The first step is to estimate the gross values of building, civil engineering and maintenance works by time series methods and the second step is to forecast the manpower demand for quantity surveyors by causal methods. The data for quantity surveyors and construction outputs are based on the ‘manpower survey reports of the building and civil engineering industry’ and the ‘gross value of construction works performed by main contractors’ respectively. The forecasted manpower demand for quantity surveyors in 2013, 2014 and 2015 are 2,480, 2,632 and 2,804 respectively. Due to the low passing rate of the assessment of professional competence (APC and the increasing number of retired qualified members, there will be a serious shortage of qualified quantity surveyors in the coming three years.

  17. The surveyors get the measure of the LHC

    CERN Multimedia

    2002-01-01

    The first to start work in the LHC tunnel, the surveyors are precisely marking out the positions of the future accelerator's magnets. A total of 7000 reference points will have to be marked out over two years.

  18. an examination of estate surveyors and valuers' perception of flood ...

    African Journals Online (AJOL)

    Osondu

    2013-11-27

    Nov 27, 2013 ... Key words: Estate Surveyors, Perception, Flood risk, Residential ... financial service sector (banking, insurance, etc.) ... 1Department of Estate Management, College of Science .... institutions (Ayida-Otobo, 2009), Lagos State.

  19. Research Ship Southern Surveyor Underway Meteorological Data, Quality Controlled

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Research Ship Southern Surveyor Underway Meteorological Data (delayed ~10 days for quality control) are from the Shipboard Automated Meteorological and Oceanographic...

  20. The Cosmology Large Angular Scale Surveyor

    CERN Document Server

    Harrington, Kathleen; Ali, Aamir; Appel, John W; Bennett, Charles L; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T; Colazo, Felipe; Dahal, Sumit; Denis, Kevin; Dünner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Fluxa, Pedro; Halpern, Mark; Hilton, Gene; Hinshaw, Gary F; Hubmayr, Johannes; Iuliano, Jeffery; Karakla, John; McMahon, Jeff; Miller, Nathan T; Moseley, Samuel H; Palma, Gonzalo; Parker, Lucas; Petroff, Matthew; Pradenas, Bastián; Rostem, Karwan; Sagliocca, Marco; Valle, Deniz; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

    2016-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from inflation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70\\% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad f...

  1. CLASS: The Cosmology Large Angular Scale Surveyor

    CERN Document Server

    Essinger-Hileman, Thomas; Amiri, Mandana; Appel, John W; Araujo, Derek; Bennett, Charles L; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dünner, Rolando; Eimer, Joseph; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Hilton, Gene; Hinshaw, Gary F; Huang, Caroline; Irwin, Kent; Jones, Glenn; Karakla, John; Kogut, Alan J; Larson, David; Limon, Michele; Lowry, Lindsay; Marriage, Tobias; Mehrle, Nicholas; Miller, Amber D; Miller, Nathan; Moseley, Samuel H; Novak, Giles; Reintsema, Carl; Rostem, Karwan; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wagner, Emily; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravita-tional-wave background from inflation in the polarization of the cosmic microwave background (CMB). CLASS is a multi-frequency array of four telescopes operating from a high-altitude site in the Atacama Desert in Chile. CLASS will survey 70\\% of the sky in four frequency bands centered at 38, 93, 148, and 217 GHz, which are chosen to straddle the Galactic-foreground minimum while avoiding strong atmospheric emission lines. This broad frequency coverage ensures that CLASS can distinguish Galactic emission from the CMB. The sky fraction of the CLASS survey will allow the full shape of the primordial B-mode power spectrum to be characterized, including the signal from reionization at low $\\ell$. Its unique combination of large sky coverage, control of systematic errors, and high sensitivity will allow CLASS to measure or place upper limits on the tensor-to-scalar ratio at a level of $r=0.01$ and make a cosmi...

  2. CLASS: The Cosmology Large Angular Scale Surveyor

    Science.gov (United States)

    Essinger-Hileman, Thomas; Ali, Aamir; Amiri, Mandana; Appel, John W.; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Gothe, Dominik; Halpern, Mark; Kogut, Alan J.; Miller, Nathan; Moseley, Samuel; Rostem, Karwan; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wollack, Edward

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is an experiment to measure the signature of a gravitational wave background from inflation in the polarization of the cosmic microwave background (CMB). CLASS is a multi-frequency array of four telescopes operating from a high-altitude site in the Atacama Desert in Chile. CLASS will survey 70% of the sky in four frequency bands centered at 38, 93, 148, and 217 GHz, which are chosen to straddle the Galactic-foreground minimum while avoiding strong atmospheric emission lines. This broad frequency coverage ensures that CLASS can distinguish Galactic emission from the CMB. The sky fraction of the CLASS survey will allow the full shape of the primordial B-mode power spectrum to be characterized, including the signal from reionization at low-length. Its unique combination of large sky coverage, control of systematic errors, and high sensitivity will allow CLASS to measure or place upper limits on the tensor-to-scalar ratio at a level of r = 0:01 and make a cosmic-variance-limited measurement of the optical depth to the surface of last scattering, tau. (c) (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  3. The Cosmology Large Angular Scale Surveyor (CLASS)

    Science.gov (United States)

    Harrington, Kathleen; Marriange, Tobias; Aamir, Ali; Appel, John W.; Bennett, Charles L.; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe; Denis, Kevin; Moseley, Samuel H.; Rostem, Karwan; Wollack, Edward

    2016-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from in ation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, r, down to a level of 0.01 (95% C.L.).

  4. The CAMbridge Emission Line Surveyor (CAMELS)

    CERN Document Server

    Thomas, C N; Maiolino, R; Goldie, D J; Acedo, E de Lera; Wagg, J; Blundell, R; Paine, S; Zeng, L

    2014-01-01

    The CAMbridge Emission Line Surveyor (CAMELS) is a pathfinder program to demonstrate on-chip spectrometry at millimetre wavelengths. CAMELS will observe at frequencies from 103-114.7 GHz, providing 512 channels with a spectral resolution of R = 3000. In this paper we describe the science goals of CAMELS, the current system level design for the instrument and the work we are doing on the detailed designs of the individual components. In addition, we will discuss our efforts to understand the impact that the design and calibration of the filter bank on astronomical performance. The shape of the filter channels, the degree of overlap and the nature of the noise all effect how well the parameters of a spectral line can be recovered. We have developed a new and rigorous method for analysing performance, based on the concept of Fisher information. This can in be turn coupled to a detailed model of the science case, allowing design trade-offs to be properly investigated.

  5. Observing Magnetic and Current Profiles of the Night side and Terminator of Mars through the Mars Global Surveyor Data

    Science.gov (United States)

    Ponce, N.; Fillingim, M. O.; Fogle, A. L.

    2014-12-01

    Mars has no global magnetic field. Changes in the solar wind and interplanetary magnetic field can impact the upper atmosphere and induce currents in the ionosphere of Mars. During aerobraking maneuvers, Mars Global Surveyor (MGS) made over 1000 passes through Mars's ionosphere. During these passes, MGS measured the local magnetic field. From these measurements, we can determine the ionospheric currents. We restrict our analysis to passes where the radial component of the magnetic field is nearly zero. This restriction, along with some assumptions about the gradients in the magnetic field, allows us to estimate the horizontal ionospheric currents. Additionally, we focus on the magnetic field data acquired over regions above negligible crustal magnetic fields in order to simplify the analysis. At a maximum altitude of 250 km, the Mars map was segmented to 30 by 30 degrees east longitude and latitude for analysis. We find that on the night side, where the solar zenith angle (SZA) lies between 130 to 180 degrees, only 4% of the data (out of a total of 52 profiles) is usable for computing currents, that is the radial component of the magnetic field is nearly zero. We also find that near the terminator, where the SZA lies between 50 to 130 degrees, an average of 2% of the magnetic field profiles (out of 1905) are usable to compute currents. This implies that currents are rarely horizontal (as required by our assumptions) in these regions. The currents computed from these profiles can give us insights into how the changing solar wind and interplanetary magnetic field can affect the upper atmosphere of Mars. For example, induced currents can lead to Joule heating of the atmosphere potentially modifying the neutral dynamics.

  6. Surveyor television camera, selected materials and electronic components, Appendix C

    Science.gov (United States)

    Carroll, W. F.

    1972-01-01

    The locations of various parts of the Surveyor camera are presented. Tables were prepared with emphasis on: (1) exterior parts and surfaces that are directly exposed to space, (2) parts that shield others from space radiation, (3) representative or unique materials, and (4) electronic devices that may contain unique or well-characterized materials.

  7. Caspar Wessel (1745-1818). Surveyor and Mathematician

    DEFF Research Database (Denmark)

    Branner, Bodil; Johansen, Nils Voje

    1999-01-01

    This is a biography. It focus on Caspar Wessel's work as surveyor under the auspices of the Royal Danish Academy of Sciences and Letters, in particular on some of his theoretical investigations of geodesy that lead him to use complex numbers to represent directions in a plane at least as early...

  8. Core skills requirement and competencies expected of quantity surveyors: perspectives from quantity surveyors, allied professionals and clients in Nigeria

    Directory of Open Access Journals (Sweden)

    Joshua Oluwasuji Dada

    2015-10-01

    Full Text Available Abstract Deployment of appropriate skills and competencies is crucial and germane to the development and continuous relevance of any profession. In the built environment, the science for selecting the required skills and competencies expected of quantity surveyors and understanding the inherent dependencies between them remains a research issue. The purpose of this study was to determine the skill requirements and competencies expected of quantity surveyors. A structured questionnaire was administered among quantity surveyors, architects, engineers, builders and clients in Nigeria. The respondents were asked to give rating, on a 5 point Likert scale, on usual skills and competencies required of quantity surveyors. A secondary objective of the study was to examine the important skills and competencies and categorized them into core skill, basic skill, core competence, optional competence and special competence. The results of the study indicate the important skills as computer literacy, building engineering, information technology, economics, measurement/quantification and knowledge of civil/heavy engineering works. The results also indicate the important competencies as cost planning and control, estimating, construction procurement system, contract documentation, contract administration and project management. It is emphasized that the findings of the research have considerable implications on the training and practice of quantity surveying in Nigeria.

  9. Core skills requirement and competencies expected of quantity surveyors: perspectives from quantity surveyors, allied professionals and clients in Nigeria

    Directory of Open Access Journals (Sweden)

    Joshua Oluwasuji Dada

    2012-12-01

    Full Text Available AbstractDeployment of appropriate skills and competencies is crucial and germane to the development and continuous relevance of any profession. In the built environment, the science for selecting the required skills and competencies expected of quantity surveyors and understanding the inherent dependencies between them remains a research issue. The purpose of this study was to determine the skill requirements and competencies expected of quantity surveyors. A structured questionnaire was administered among quantity surveyors, architects, engineers, builders and clients in Nigeria. The respondents were asked to give rating, on a 5 point Likert scale, on usual skills and competencies required of quantity surveyors. A secondary objective of the study was to examine the important skills and competencies and categorized them into core skill, basic skill, core competence, optional competence and special competence. The results of the study indicate the important skills as computer literacy, building engineering, information technology, economics, measurement/quantification and knowledge of civil/heavy engineering works. The results also indicate the important competencies as cost planning and control, estimating, construction procurement system, contract documentation, contract administration and project management. It is emphasized that the findings of the research have considerable implications on the training and practice of quantity surveying in Nigeria.

  10. Manned Spacecraft

    Science.gov (United States)

    1989-09-14

    34 spacecraft. Improved were systems of conditioning and regeneration , and the system of soft landing, and there was provided high reliability of hermetic...ceramics, cermets or to cool them. 0 DOC = 89059215 PAGE :5Y (i)MeP ce71uneCKag oqKa 2ObtcoMorfle , epO - fi’loddD ueao tuu0 mnyp~aR U30J13NUU cmep

  11. Spacecraft operations

    CERN Document Server

    Sellmaier, Florian; Schmidhuber, Michael

    2015-01-01

    The book describes the basic concepts of spaceflight operations, for both, human and unmanned missions. The basic subsystems of a space vehicle are explained in dedicated chapters, the relationship of spacecraft design and the very unique space environment are laid out. Flight dynamics are taught as well as ground segment requirements. Mission operations are divided into preparation including management aspects, execution and planning. Deep space missions and space robotic operations are included as special cases. The book is based on a course held at the German Space Operation Center (GSOC).

  12. Neutron Star Science with the X-ray Surveyor

    Science.gov (United States)

    Ozel, Feryal

    2015-10-01

    Probing the interiors and magnetic fields of neutron stars and characterizing their populations in the Galaxy is an important science goal for the next generation X-ray telescopes. I will discuss how the capabilities of the X-ray Surveyor Mission are crucial for making significant advances in these fields and how we can address the open questions with a dataset that will become available with such a mission.

  13. Testing the principle of equivalence with Planck surveyor

    CERN Document Server

    Popa, L A; Mandolesi, N

    2002-01-01

    We consider the effect of the violation of the equivalence principle (VEP) by the massive neutrino component on the Cosmic Microwave Background angular power specrum. We show that in the presence of adiabatic and isocurvature primordial density perturbations the Planck surveyor can place limits on the maximal VEP by the massive neutrino component at the level of 10^ -5, valid in the general relativity, for the case in which the gravity is the single source of VEP. This work has been performed within the framework of the {\\sc Planck}/LFI activities.

  14. Long-Term Cryogenic Propellant Storage for the Titan Orbiter Polar Surveyor (TOPS) Mission

    Science.gov (United States)

    Mustafi, Shuvo; Francis, John; Li, Xiaoyi; DeLee, Hudson; Purves, Lloyd; Willis, Dewey; Nixon, Conor; Mcguinness, Dan; Riall, Sara; Devine, Matt; hide

    2015-01-01

    Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LOX) can dramatically enhance NASAs ability to explore the solar system because of their superior specific impulse (Isp) capability. Although these cryogenic propellants can be challenging to manage and store, they allow significant mass advantages over traditional hypergolic propulsion systems and are therefore technically enabling for many planetary science missions. New cryogenic storage techniques such as subcooling and the use of advanced insulation and low thermal conductivity support structures will allow for the long term storage and use of cryogenic propellants for solar system exploration and hence allow NASA to deliver more payloads to targets of interest, launch on smaller and less expensive launch vehicles, or both. Employing cryogenic propellants will allow NASA to perform missions to planetary destinations that would not be possible with the use of traditional hypergolic propellants. These new cryogenic storage technologies were implemented in a design study for the Titan Orbiter Polar Surveyor (TOPS) mission, with LH2 and LOX as propellants, and the resulting spacecraft design was able to achieve a 43 launch mass reduction over a TOPS mission, that utilized a conventional hypergolic propulsion system with mono-methyl hydrazine (MMH) and nitrogen tetroxide (NTO) propellants. This paper describes the cryogenic propellant storage design for the TOPS mission and demonstrates how these cryogenic propellants are stored passively for a decade-long Titan mission.

  15. CERN's surveyors are pushing back the frontiers of precision

    CERN Multimedia

    2001-01-01

    Aiming at a target on the other side of the Alps, 730 kilometres from CERN, or controlling the positions of thousands of devices to a precision of one tenth of a millimetre, these are just some of the painstaking tasks undertaken by the surveyors in the Positioning Metrology and Surveying Group. These masters of measurement are pushing precision to its very limit.Go down into the LEP tunnel, walk about half a mile and then try to imagine how you could possibly take precise aim at something hundreds of kilometres away without any reference to the surface. Absurd, you might think? Not entirely, for that, in a nutshell, is the geodetic challenge of the Gran Sasso project. Indeed it is just one of the challenges faced by the surveyors in CERN's Positioning Metrology and Surveying Group, whose task it will be to aim a neutrino beam at a detector located in an underground cavern 732 kilometres away at INFN's Gran Sasso laboratory in Italy. The tools for solving such problems are provided by geodetics, the branch of...

  16. The Mars Surveyor '01 Rover and Robotic Arm

    Science.gov (United States)

    Bonitz, Robert G.; Nguyen, Tam T.; Kim, Won S.

    1999-01-01

    The Mars Surveyor 2001 Lander will carry with it both a Robotic Arm and Rover to support various science and technology experiments. The Marie Curie Rover, the twin sister to Sojourner Truth, is expected to explore the surface of Mars in early 2002. Scientific investigations to determine the elemental composition of surface rocks and soil using the Alpha Proton X-Ray Spectrometer (APXS) will be conducted along with several technology experiments including the Mars Experiment on Electrostatic Charging (MEEC) and the Wheel Abrasion Experiment (WAE). The Rover will follow uplinked operational sequences each day, but will be capable of autonomous reactions to the unpredictable features of the Martian environment. The Mars Surveyor 2001 Robotic Arm will perform rover deployment, and support various positioning, digging, and sample acquiring functions for MECA (Mars Environmental Compatibility Assessment) and Mossbauer Spectrometer experiments. The Robotic Arm will also collect its own sensor data for engineering data analysis. The Robotic Arm Camera (RAC) mounted on the forearm of the Robotic Arm will capture various images with a wide range of focal length adjustment during scientific experiments and rover deployment

  17. The X-Ray Surveyor Mission: A Concept Study

    Science.gov (United States)

    Gaskin, Jessica A.; Weisskopf, Martin C.; Vikhlinin, Alexey; Tananbaum, Harvey D.; Bandler, Simon R.; Bautz, Marshall W.; Burrows, David N.; Falcone, Abraham D.; Harrison, Fiona A.; Heilmann, Ralf K.; Heinz, Sebastian; Hopkins, Randall C.; Kilbourne, Caroline A.; Kouveliotou, Chryssa; Kraft, Ralph P.; Kravtsov, Andrey V.; McEntaffer, Randall L.; Natarajan, Priyamvada; O'Dell, Stephen L.; Petre, Robert; Prieskorn, Zachary R.; Ptak, Andrew F.; Ramsey, Brian D.; Reid, Paul B.; Schnell, Andrew R.; Schwartz, Daniel A.; Townsley, Leisa K.

    2015-01-01

    NASA's Chandra X-ray Observatory continues to provide an unparalleled means for exploring the high-energy universe. With its half-arcsecond angular resolution, Chandra studies have deepened our understanding of galaxy clusters, active galactic nuclei, galaxies, supernova remnants, neutron stars, black holes, and solar system objects. As we look beyond Chandra, it is clear that comparable or even better angular resolution with greatly increased photon throughput is essential to address ever more demanding science questions-such as the formation and growth of black hole seeds at very high redshifts; the emergence of the first galaxy groups; and details of feedback over a large range of scales from galaxies to galaxy clusters. Recently, we initiated a concept study for such a mission, dubbed X-ray Surveyor. The X-ray Surveyor strawman payload is comprised of a high-resolution mirror assembly and an instrument set, which may include an X-ray microcalorimeter, a high-definition imager, and a dispersive grating spectrometer and its readout. The mirror assembly will consist of highly nested, thin, grazing-incidence mirrors, for which a number of technical approaches are currently under development-including adjustable X-ray optics, differential deposition, and new polishing techniques applied to a variety of substrates. This study benefits from previous studies of large missions carried out over the past two decades and, in most areas, points to mission requirements no more stringent than those of Chandra.

  18. The Infrared Imaging Surveyor (Iris) Project: Astro-F

    Science.gov (United States)

    Shibai, H.

    IRIS (Infrared Imaging Surveyor) is the first Japanese satellite dedicated solely to infrared astronomy. The telescope has 70-cm aperture, and is cooled down to 6 K with super-fluid helium assisted by two-stage Stirling cycle coolers. On the focal plane, the two instruments, the InfraRed Camera (IRC) and the Far-Infrared Surveyor (FIS), are mounted. IRC is a near- and mid-infrared camera for deep imaging-surveys in the wavelength region from 2 to 25 microns. FIS is a far-infrared instrument for a whole sky survey in the wavelength region from 50 to 200 microns. The diffraction-limited spatial resolution is achieved except in the shortest waveband. The point source sensitivity and the survey coverage are significantly improved compared to previous missions. The primary scientific objective is to investigate birth and evolution of galaxies in the early universe by surveys of young normal galaxies and starburst galaxies. IRIS is thrown by a Japanese M-V rocket into a sun-synchronous orbit, in which the cooled telescope can avoid huge emissions from the Sun and the Earth. The expected holding time of the super-fluid helium is more than one year. After consumption of the helium, the near-infrared observation can be continued by the mechanical coolers

  19. ASTRO-F : Infrared Imaging Surveyor (IRIS) Mission

    Science.gov (United States)

    Onaka, T.

    The ASTRO-F (also known as Infrared Imaging Surveyor: IRIS) is the second infrared satellite mission of the Institute of Space and Astronautical Science, Japan to be launched early 2004 with the M-V rocket and is planned as a second generation infrared sky survey mission. It has a 67-cm aperture telescope and is cooled by 170-liter liquid helium and Stirling-cycle coolers. Two scientific instruments share the focal plane. The infrared camera (IRC) covers 2 to 26 μm range with large two-dimensional arrays in the imaging and low-resolution spectroscopic modes and will perform deep sky surveys of selected areas of the sky with a wide field of view (10' × 10') at unprecedented sensitivity. The far-infrared Surveyor (FIS), consisting of an imaging scanner and a Fourier transform spectrometer, covers 50 to 200 μm range and makes a whole sky survey in four far-infrared bands, which is higher by more than 10 in sensitivity (20 110 mJy), better by several in the spatial resolution (30'' 50''), and longer in the spectral coverage (200 μm) than IRAS. A brief description and the current status of the ASTRO-F mission are presented.

  20. The Digital Cadastral Databse and the Role of the Private Licensed Surveyors in Denmark

    DEFF Research Database (Denmark)

    Enemark, Stig

    2006-01-01

    This article presents the cadastral system and the role of the private licensed surveyors in Denmark as a basis for discussion of its relevance to Ireland......This article presents the cadastral system and the role of the private licensed surveyors in Denmark as a basis for discussion of its relevance to Ireland...

  1. Are Quantity Surveyors Competent to Value for Civil Engineering Works? Evaluating QSs' Competencies and Militating Factors

    Science.gov (United States)

    Olawumi, Timothy Oluwatosin; Ayegun, Olaleke Amos

    2016-01-01

    The role of the quantity surveyor is one that is often unclear amongst the general public. This study discussed the competencies of the quantity surveyor in measuring and managing civil engineering works and also carrying out the financial management for civil engineering construction projects; also outlined the various competencies and skills…

  2. The link between quality and accreditation of residency programs: the surveyors' perceptions.

    Science.gov (United States)

    Dos Santos, Renato Antunes; Snell, Linda; Tenorio Nunes, Maria do Patrocinio

    2017-01-01

    Accreditation of medical residency programs has become globally important. Currently it is moving from the goal of attaining minimal standards to a model of continuous improvement. In some countries, the accreditation system engages peers (physicians) to survey residency programs. The surveyors are sometimes volunteers, usually engaged in multiple clinical and education activities. Few studies have investigated the benefits of residency program evaluation and accreditation from the perspective of the surveyors. As peers they both conduct and receive accreditation surveys, which puts them in a privileged position in that it provides the surveyor with an opportunity to share experiences and knowledge and apply what is learned in their own context. The objective of this study is to obtain the perceptions of these surveyors about the impact of an accreditation system on residency programs. Surveyors participated in semi-structured interviews. A thematic analysis was performed on the interview data, and resulting topics were grouped into five themes: Burden (of documentation and of time needed); Efficiency and efficacy of the accreditation process; Training and experience of surveyors; Being a peer; Professional skills and recognition of surveyors. These categories were organized into two major themes: 'Structure and Process' and 'Human Resources'. The study participants proposed ways to improve efficiency including diminish the burden of documentation to the physicians involved in the process and to increase efforts on training programs and payment for surveyors and program directors. Based on the results we propose a conceptual framework to improve accreditation systems.

  3. A Map-Making for the Planck Surveyor

    CERN Document Server

    Natoli, P; Gheller, C; Vittorio, N

    2001-01-01

    We present a parallel implementation of a map-making algorithm for CMB anisotropy experiments which is both fast and efficient. We show for the first time a Maximum Likelihood, minimum variance map obtained by processing the entire data stream expected from the Planck Surveyor, under the assumption of a symmetric beam profile. Here we restrict ourselves to the case of the 30 GHz channel of the Planck Low Frequency Instrument. The extension to Planck higher frequency channels is straightforward. If the satellite pointing periodicity is good enough to average data that belong to the same sky circle, then the code runs very efficiently on workstations. The serial version of our code also runs on very competitive time-scales the map-making pipeline for current and forthcoming balloon borne experiments.

  4. Cosmology Large Angular Scale Surveyor (CLASS) Focal Plane Development

    CERN Document Server

    Chuss, D T; Amiri, M; Appel, J; Bennett, C L; Colazo, F; Denis, K L; Dünner, R; Essinger-Hileman, T; Eimer, J; Fluxa, P; Gothe, D; Halpern, M; Harrington, K; Hilton, G; Hinshaw, G; Hubmayr, J; Iuliano, J; Marriage, T A; Miller, N; Moseley, S H; Mumby, G; Petroff, M; Reintsema, C; Rostem, K; U-Yen, K; Watts, D; Wagner, E; Wollack, E J; Xu, Z; Zeng, L

    2015-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization of the Cosmic Microwave Background to search for and characterize the polarized signature of inflation. CLASS will operate from the Atacama Desert and observe $\\sim$70% of the sky. A variable-delay polarization modulator (VPM) modulates the polarization at $\\sim$10 Hz to suppress the 1/f noise of the atmosphere and enable the measurement of the large angular scale polarization modes. The measurement of the inflationary signal across angular scales that span both the recombination and reionization features allows a test of the predicted shape of the polarized angular power spectra in addition to a measurement of the energy scale of inflation. CLASS is an array of telescopes covering frequencies of 38, 93, 148, and 217 GHz. These frequencies straddle the foreground minimum and thus allow the extraction of foregrounds from the primordial signal. Each focal plane contains feedhorn-coupled transition-edge sensors that simultaneously d...

  5. Bridging the Gap Between Surveyors and the Geo-Spatial Society

    Science.gov (United States)

    Müller, H.

    2016-06-01

    For many years FIG, the International Association of Surveyors, has been trying to bridge the gap between surveyors and the geospatial society as a whole, with the geospatial industries in particular. Traditionally the surveying profession contributed to the good of society by creating and maintaining highly precise and accurate geospatial data bases, based on an in-depth knowledge of spatial reference frameworks. Furthermore in many countries surveyors may be entitled to make decisions about land divisions and boundaries. By managing information spatially surveyors today develop into the role of geo-data managers, the longer the more. Job assignments in this context include data entry management, data and process quality management, design of formal and informal systems, information management, consultancy, land management, all that in close cooperation with many different stakeholders. Future tasks will include the integration of geospatial information into e-government and e-commerce systems. The list of professional tasks underpins the capabilities of surveyors to contribute to a high quality geospatial data and information management. In that way modern surveyors support the needs of a geo-spatial society. The paper discusses several approaches to define the role of the surveyor within the modern geospatial society.

  6. Anionic lipid binding to the foreign protein MGS provides a tight coupling between phospholipid synthesis and protein overexpression in Escherichia coli.

    Science.gov (United States)

    Ariöz, Candan; Ye, Weihua; Bakali, Amin; Ge, Changrong; Liebau, Jobst; Götzke, Hansjörg; Barth, Andreas; Wieslander, Ake; Mäler, Lena

    2013-08-20

    Certain membrane proteins involved in lipid synthesis can induce formation of new intracellular membranes in Escherichia coli, i.e., intracellular vesicles. Among those, the foreign monotopic glycosyltransferase MGS from Acholeplasma laidlawii triggers such massive lipid synthesis when overexpressed. To examine the mechanism behind the increased lipid synthesis, we investigated the lipid binding properties of MGS in vivo together with the correlation between lipid synthesis and MGS overexpression levels. A good correlation between produced lipid quantities and overexpressed MGS protein was observed when standard LB medium was supplemented with four different lipid precursors that have significant roles in the lipid biosynthesis pathway. Interestingly, this correlation was highest concerning anionic lipid production and at the same time dependent on the selective binding of anionic lipid molecules by MGS. A selective interaction with anionic lipids was also observed in vitro by (31)P NMR binding studies using bicelles prepared with E. coli lipids. The results clearly demonstrate that the discriminative withdrawal of anionic lipids, especially phosphatidylglycerol, from the membrane through MGS binding triggers an in vivo signal for cells to create a "feed-forward" stimulation of lipid synthesis in E. coli. By this mechanism, cells can produce more membrane surface in order to accommodate excessively produced MGS molecules, which results in an interdependent cycle of lipid and MGS protein synthesis.

  7. Simulating spacecraft systems

    CERN Document Server

    Eickhoff, Jens

    2009-01-01

    This book on the application of functional system simulation in spacecraft development covers the entire process from spacecraft design to final verification. It offers the latest research in all relevant topics and includes numerous examples.

  8. CHISL: The Combined High-resolution and Imaging Spectrograph for the LUVOIR Surveyor

    CERN Document Server

    France, Kevin; Hoadley, Keri

    2016-01-01

    NASA is currently carrying out science and technical studies to identify its next astronomy flagship mission, slated to begin development in the 2020s. It has become clear that a Large Ultraviolet/Optical/IR (LUVOIR) Surveyor mission (primary diameter 12 m, 1000 Ang - 2 micron spectroscopic bandpass) can carry out the largest number of NASA's exoplanet and astrophysics science goals over the coming decades. There are technical challenges for several aspects of the LUVOIR Surveyor concept, including component level technology readiness maturation and science instrument concepts for a broadly capable ultraviolet spectrograph. We present the scientific motivation for, and a preliminary design of, a multiplexed ultraviolet spectrograph to support both the exoplanet and astrophysics goals of the LUVOIR Surveyor mission concept, the Combined High-resolution and Imaging Spectrograph for the LUVOIR Surveyor (CHISL). CHISL includes a high-resolution (R 120,000; 1000 - 1700 Ang) point-source spectroscopy channel and a ...

  9. The Far-Infrared Surveyor Mission Study: Paper I, the Genesis

    Science.gov (United States)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; hide

    2017-01-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some preliminary highlights here. We note key areas for technological innovation and improvements necessary to make a Far-Infrared Surveyor mission a reality.

  10. The Far-Infrared Surveyor Mission study: paper I, the genesis

    Science.gov (United States)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; Ennico, K.; Melnick, G. J.; Milam, S.; Narayanan, D.; Pontoppidan, K.; Pope, A.; Roellig, T.; Sandstrom, K.; Su, K. Y. L.; Vieira, J.; Wright, E.; Zmuidzinas, J.; Alato, S.; Carey, S.; Gerin, M.; Helmich, F.; Menten, K.; Scott, D.; Sakon, I.; Vavrek, R.

    2016-07-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some preliminary highlights here. We note key areas for technological innovation and improvements necessary to make a Far-Infrared Surveyor mission a reality.

  11. The Far-Infrared Surveyor Mission Study: Paper I, the Genesis

    CERN Document Server

    Meixner, M; Carter, R; DiPirro, M; Flores, A; Leisawitz, D; Armus, L; Battersby, C; Bergin, E; Bradford, C M; Ennico, K; Melnick, G J; Milam, S; Narayanan, D; Pontoppidan, K; Pope, A; Roellig, T; Sandstrom, K; Su, K Y L; Vieira, J; Wright, E; Zmuidzinas, J; Alato, S; Carey, S; Gerin, M; Helmich, F; Menten, K; Scott, D; Sakon, I; Vavrek, R

    2016-01-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some preliminary highlights here. We note key areas for technological innovation and improvements necessary to make a Far-Infrared Surveyor mission a reality.

  12. Screening for Mutations in Kidney-Related Genes Using SURVEYOR Nuclease for Cleavage at Heteroduplex Mismatches

    OpenAIRE

    Voskarides, Konstantinos; DELTAS, Constantinos

    2009-01-01

    SURVEYOR is a new mismatch-specific plant DNA endonuclease that is very efficient for mutation scanning in heteroduplex DNA. It is much faster, cheaper, more sensitive, and easier to perform than other “traditional” mutation detection methods such as single-strand conformation polymorphism analysis, denaturing high-performance liquid chromatography, heteroduplex analysis, and phage resolvases. This is the first comprehensive report on the use of SURVEYOR for screening genes implicated in a sp...

  13. Schmidt Crater: Using Data from the Mars Global Surveyor

    Science.gov (United States)

    Thomas, Fred

    2001-10-01

    In the Physics Department at Sinclair Community College in Dayton, the most popular general-education course is a three-quarter astronomy sequence. The course is designed to incorporate significant elements of conceptual physics, scientific methods, and quantitative reasoning, along with the content of astronomy. In cooperation with faculty from mathematics and sociology, the author developed new lab activities that engage students in making "practical" plans for the colonization of Mars. The activities are intended to be low-cost, to be suitable for either on-campus or distance-learning environments, and to be fun for both students and instructors. The Schmidt Crater region, an Ohio-sized area near the South Pole of Mars, was selected as a potential site for obtaining large quantities of water. Topographic data for the region was extracted from the 36 CD's of laser altimeter data obtained by the Mars Global Surveyor, and ArcView was used to produce detailed maps. Wide and narrow angle photos of the region from the Mars Orbiter Camera were integrated with the topographic maps. Both the maps and the photographs were therefore made accessible to students who can use free software packages, such as ArcExplorer and Scion Image With access to up-to-date data for this region, students complete a series of "authentic learning tasks" that include calculating water needs for a Martian city, identifying likely water sources, planning transportation methods, and selecting a "homestead" for their own personal use.

  14. The Far-Infrared Surveyor (FIS) for AKARI

    CERN Document Server

    Kawada, Mitsunobu; Barthel, Peter D; Clements, David; Cohen, Martin; Doi, Yasuo; Figueredo, Elysandra; Fujiwara, Mikio; Goto, Tomotsugu; Hasegawa, Sunao; Hibi, Yasunori; Hirao, Takanori; Hiromoto, Norihisa; Jeong, Woong-Seob; Kaneda, Hidehiro; Kawai, Toshihide; Kawamura, Akiko; Kester, Do; Kii, Tsuneo; Kobayashi, Hisato; Kwon, Suk Minn; Lee, Hyung Mok; Makiuti, Sin'itirou; Matsuo, Hiroshi; Matsuura, Shuji; Müller, Thomas G; Murakami, Noriko; Nagata, Hirohisa; Nakagawa, Takao; Narita, Masanao; Noda, Manabu; Oh, Sang Hoon; Okada, Yoko; Okuda, Haruyuki; Oliver, Sebastian; Ootsubo, Takafumi; Pak, Soojong; Park, Yong-Sun; Pearson, Chris P; Rowan-Robinson, Michael; Saito, Toshinobu; Salama, Alberto; Sato, Shinji; Savage, Richard S; Serjeant, Stephen; Shibai, Hiroshi; Shirahata, Mai; Sohn, Jungjoo; Suzuki, Toyoaki; Takagi, Toshinobu; Takahashi, Hidenori; Thomson, Matthew; Usui, Fumihiko; Verdugo, Eva; Watabe, Toyoki; White, Glenn J; Wang, Lingyu; Yamamura, Issei; Yamamuchi, Chisato; Yasuda, Akiko

    2007-01-01

    The Far-Infrared Surveyor (FIS) is one of two focal plane instruments on the AKARI satellite. FIS has four photometric bands at 65, 90, 140, and 160 um, and uses two kinds of array detectors. The FIS arrays and optics are designed to sweep the sky with high spatial resolution and redundancy. The actual scan width is more than eight arcmin, and the pixel pitch is matches the diffraction limit of the telescope. Derived point spread functions (PSFs) from observations of asteroids are similar to the optical model. Significant excesses, however, are clearly seen around tails of the PSFs, whose contributions are about 30% of the total power. All FIS functions are operating well in orbit, and its performance meets the laboratory characterizations, except for the two longer wavelength bands, which are not performing as well as characterized. Furthermore, the FIS has a spectroscopic capability using a Fourier transform spectrometer (FTS). Because the FTS takes advantage of the optics and detectors of the photometer, i...

  15. Cosmology Large Angular Scale Surveyor (CLASS) Focal Plane Development

    Science.gov (United States)

    Chuss, D. T.; Ali, A.; Amiri, M.; Appel, J.; Bennett, C. L.; Colazo, F.; Denis, K. L.; Dunner, R.; Essinger-Hileman, T.; Eimer, J.; Fluxa, P.; Gothe, D.; Halpern, M.; Harrington, K.; Hilton, G.; Hinshaw, G.; Hubmayr, J.; Iuliano, J.; Marriage, T. A.; Miller, N.; Moseley, S. H.; Mumby, G.; Petroff, M.; Reintsema, C.; Rostem, K.; U-yen, K.; Watts, D.; Wagner, E.; Wollack, E. J.; Xu, Z.; Zeng, L.

    2015-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization of the Cosmic Microwave Background to search for and characterize the polarized signature of inflation. CLASS will operate from the Atacama Desert and observe approx.70% of the sky. A variable-delay polarization modulator provides modulation of the polarization at approx.10Hz to suppress the 1/f noise of the atmosphere and enable the measurement of the large angular scale polarization modes. The measurement of the inflationary signal across angular scales that spans both the recombination and reionization features allows a test of the predicted shape of the polarized angular power spectra in addition to a measurement of the energy scale of inflation. CLASS is an array of telescopes covering frequencies of 38, 93, 148, and 217 GHz. These frequencies straddle the foreground minimum and thus allow the extraction of foregrounds from the primordial signal. Each focal plane contains feedhorn-coupled transition-edge sensors that simultaneously detect two orthogonal linear polarizations. The use of single-crystal silicon as the dielectric for the on-chip transmission lines enables both high efficiency and uniformity in fabrication. Integrated band definition has been implemented that both controls the bandpass of the single-mode transmission on the chip and prevents stray light from coupling to the detectors.

  16. The Transient High Energy Sky and Early Universe Surveyor (THESEUS)

    Science.gov (United States)

    Amati, Lorenzo; O'Brien, Paul T.; Götz, Diego

    2016-07-01

    The Transient High Energy Sky and Early Universe Surveyor (THESEUS) is a mission concept under development by a large international collaboration aimed at exploiting gamma-ray bursts for investigating the early Universe. The main scientific objectives of THESEUS include: investigating the star formation rate and metallicity evolution of the ISM and IGM up to redshift 9-10, detecting the first generation (pop III) of stars, studying the sources and physics of re-ionization, detecting the faint end of galaxies luminosity function. These goals will be achieved through a unique combination of instruments allowing GRB detection and arcmin localization over a broad FOV (more than 1sr) and an energy band extending from several MeVs down to 0.3 keV with unprecedented sensitivity, as well as on-board prompt (few minutes) follow-up with a 0.6m class IR telescope with both imaging and spectroscopic capabilities. Such instrumentation will also allow THESEUS to unveil and study the population of soft and sub-energetic GRBs, and, more in general, to perform monitoring and survey of the X-ray sky with unprecedented sensitivity.

  17. Cosmology Large Angular Scale Surveyor (CLASS) Focal Plane Development

    Science.gov (United States)

    Chuss, D. T.; Ali, A.; Amiri, M.; Appel, J.; Bennett, C. L.; Colazo, F.; Denis, K. L.; Dünner, R.; Essinger-Hileman, T.; Eimer, J.; Fluxa, P.; Gothe, D.; Halpern, M.; Harrington, K.; Hilton, G.; Hinshaw, G.; Hubmayr, J.; Iuliano, J.; Marriage, T. A.; Miller, N.; Moseley, S. H.; Mumby, G.; Petroff, M.; Reintsema, C.; Rostem, K.; U-Yen, K.; Watts, D.; Wagner, E.; Wollack, E. J.; Xu, Z.; Zeng, L.

    2016-08-01

    The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization of the Cosmic Microwave Background to search for and characterize the polarized signature of inflation. CLASS will operate from the Atacama Desert and observe ˜ 70 % of the sky. A variable-delay polarization modulator provides modulation of the polarization at ˜ 10 Hz to suppress the 1/ f noise of the atmosphere and enable the measurement of the large angular scale polarization modes. The measurement of the inflationary signal across angular scales that spans both the recombination and reionization features allows a test of the predicted shape of the polarized angular power spectra in addition to a measurement of the energy scale of inflation. CLASS is an array of telescopes covering frequencies of 38, 93, 148, and 217 GHz. These frequencies straddle the foreground minimum and thus allow the extraction of foregrounds from the primordial signal. Each focal plane contains feedhorn-coupled transition-edge sensors that simultaneously detect two orthogonal linear polarizations. The use of single-crystal silicon as the dielectric for the on-chip transmission lines enables both high efficiency and uniformity in fabrication. Integrated band definition has been implemented that both controls the bandpass of the single-mode transmission on the chip and prevents stray light from coupling to the detectors.

  18. Detector architecture of the cosmology large angular scale surveyor

    Science.gov (United States)

    Rostem, K.; Bennett, C. L.; Chuss, D. T.; Costen, N.; Crowe, E.; Denis, K. L.; Eimer, J. R.; Lourie, N.; Essinger-Hileman, T.; Marriage, T. A.; Moseley, S. H.; Stevenson, T. R.; Towner, D. W.; Voellmer, G.; Wollack, E. J.; Zeng, L.

    2012-09-01

    The cosmic microwave background (CMB) provides a powerful tool for testing modern cosmology. In particular, if inflation has occurred, the associated gravitational waves would have imprinted a specific polarized pattern on the CMB. Measurement of this faint polarized signature requires large arrays of polarization-sensitive, background- limited detectors, and an unprecedented control over systematic effects associated with instrument design. To this end, the ground-based Cosmology Large Angular Scale Surveyor (CLASS) employs large-format, feedhorn- coupled, background-limited Transition-Edge Sensor (TES) bolometer arrays operating at 40, 90, and 150 GHz bands. The detector architecture has several enabling technologies. An on-chip symmetric planar orthomode transducer (OMT) is employed that allows for highly symmetric beams and low cross-polarization over a wide bandwidth. Furthermore, the quarter-wave backshort of the OMT is integrated using an innovative indium bump bonding process at the chip level that ensures minimum loss, maximum repeatability and performance uniformity across an array. Care has been taken to reduce stray light and on-chip leakage. In this paper, we report on the architecture and performance of the first prototype detectors for the 40 GHz focal plane.

  19. Optimal Management Of Renewable-Based Mgs An Intelligent Approach Through The Evolutionary Algorithm

    Directory of Open Access Journals (Sweden)

    Mehdi Nafar

    2015-08-01

    Full Text Available Abstract- This article proposes a probabilistic frame built on Scenario fabrication to considerate the uncertainties in the finest action managing of Micro Grids MGs. The MG contains different recoverable energy resources such as Wind Turbine WT Micro Turbine MT Photovoltaic PV Fuel Cell FC and one battery as the storing device. The advised frame is based on scenario generation and Roulette wheel mechanism to produce different circumstances for handling the uncertainties of altered factors. It habits typical spreading role as a probability scattering function of random factors. The uncertainties which are measured in this paper are grid bid alterations cargo request calculating error and PV and WT yield power productions. It is well-intentioned to asset that solving the MG difficult for 24 hours of a day by considering diverse uncertainties and different constraints needs one powerful optimization method that can converge fast when it doesnt fall in local optimal topic. Simultaneously single Group Search Optimization GSO system is presented to vision the total search space globally. The GSO algorithm is instigated from group active of beasts. Also the GSO procedure one change is similarly planned for this algorithm. The planned context and way is applied o one test grid-connected MG as a typical grid.

  20. Screening for mutations in kidney-related genes using SURVEYOR nuclease for cleavage at heteroduplex mismatches.

    Science.gov (United States)

    Voskarides, Konstantinos; Deltas, Constantinos

    2009-07-01

    SURVEYOR is a new mismatch-specific plant DNA endonuclease that is very efficient for mutation scanning in heteroduplex DNA. It is much faster, cheaper, more sensitive, and easier to perform than other "traditional" mutation detection methods such as single-strand conformation polymorphism analysis, denaturing high-performance liquid chromatography, heteroduplex analysis, and phage resolvases. This is the first comprehensive report on the use of SURVEYOR for screening genes implicated in a spectrum of inherited renal diseases. Of the 48.2 kb screened, 44 variations were identified, accounting for one variation per 1.1 kb. The re-sequencing of multiple samples did not reveal any variation that had not been identified by SURVEYOR, attesting to its high fidelity. Additionally, we tested this enzyme against 15 known variants, 14 of which it identified, thus showing a sensitivity of 93%. We showed that the genetic heterogeneity of renal diseases can be easily overcome using this enzyme with a high degree of confidence and no bias for any specific variations. We also showed for the first time that SURVEYOR does not demonstrate any preference regarding mismatch cleavage at specific positions. Disadvantages of using SURVEYOR include enhanced exonucleolytic activity for some polymerase chain reaction products and less than 100% sensitivity. We report that SURVEYOR can be used as a mutation detection method with a high degree of confidence, offering an excellent alternative for low-budget laboratories and for the rapid manipulation of multiple genes.

  1. Molecular beam epitaxy-grown wurtzite MgS thin films for solar-blind ultra-violet detection

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Y. H.; He, Q. L. [Nano Science and Nano Technology Program, The Hong Kong University of Science and Technology, HKSAR, People' s Republic of China (China); Department of Physics and William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, HKSAR, People' s Republic of China (China); Cheung, W. Y.; Lok, S. K.; Wong, K. S.; Sou, I. K. [Department of Physics and William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, HKSAR, People' s Republic of China (China); Ho, S. K. [Faculty of Science and Technology, University of Macau, Macau, People' s Republic of China (China); Tam, K. W. [Department of Electrical and Electronics Engineering, University of Macau, Macau, People' s Republic of China (China)

    2013-04-29

    Molecular beam epitaxy grown MgS on GaAs(111)B substrate was resulted in wurtzite phase, as demonstrated by detailed structural characterizations. Phenomenological arguments were used to account for why wurtzite phase is preferred over zincblende phase or its most stable rocksalt phase. Results of photoresponse and reflectance measurements performed on wurtzite MgS photodiodes suggest a direct bandgap at around 5.1 eV. Their response peaks at 245 nm with quantum efficiency of 9.9% and enjoys rejection of more than three orders at 320 nm and close to five orders at longer wavelengths, proving the photodiodes highly competitive in solar-blind ultraviolet detection.

  2. A New View of the Surface of Mars: High-Resolution Rock Abundance from MGS TES

    Science.gov (United States)

    Nowicki, S.; Christensen, P.

    2001-12-01

    Mars Global Surveyor Thermal Emission Spectrometer data from the most dust-free seasons on Mars were used to calculate the areal percentage of rocks and finer materials such as dust and sand. Rock is defined as a surface material that has a thermal inertia of 1250 J/m2-s1/2-K (30 cal/cm2-s1/2-K) or greater. A surface with a high rock abundance value could be exposed bedrock, blocky debris, well-cemented materials or a combination. Globally, the TES and IRTM data agree well, with no rocks exposed in the large dusty regions such as Tharsis and Arabia, and exposure of rocks in small (a few km) areas where likely eolian or mass-wasting processes actively remove dust from the ancient rocky surface. Analysis of high-resolution TES rock abundance suggests that there are extremely varied surfaces within relatively small regions, and places an upper limit of ~45 % rocks in the rockiest regions. Thermal inertia and rock abundance are correlate to some degree over much of the planet, but the highest thermal inertia surfaces often do not have the highest rock abundances. A global perspective will be presented here, with detailed look at a few high-resolution ares including Ares Vallis/Pathfinder, Valles Marineris, and the proposed landing sites for the 2003 MER landers.

  3. Simulation of the charge collection and signal response of a HPGe double sided strip detector using MGS

    Energy Technology Data Exchange (ETDEWEB)

    Mateu, I., E-mail: isidre.mateu@irap.omp.eu [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France); Medina, P., E-mail: patrice.medina@aero.obs-mip.fr [IPHC, IN2P3 – CNRS/Université Louis Pasteur, 23 rue du Loess, PB28, Strasbourg Cedex 2, F67037 (France); Roques, J.P., E-mail: jean-pierre.roques@irap.omp.eu [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France); Jourdain, E., E-mail: elisabeth.jourdain@irap.omp.eu [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France)

    2014-01-21

    This paper aims to present Multi geometry Simulation (MGS), a software intended for the characterization of the signal response of solid state detectors. Its main feature is the calculation of the pulse shapes induced at the electrodes of the detector by a photon–semiconductor interaction occurring at a specific position inside the detector volume. The program uses numerical methods to simulate the drift of the charge carriers generated by the interaction, as the movement of these particles induces the useful signal for detection to the electrodes. After the description of the tool fundamentals, an example of application is presented where MGS was used for simulating a High Purity Germanium (HPGe) double sided strip detector conceived for hard X-ray astronomy. Simulated and measured pulse shapes are compared for interactions occurring at different depths in the detector volume. The comparison focuses on the difference in time of arrival between the anode and cathode pulses, as this measure allows, together with the X/Y information retrieved from the strips, a 3D determination of the photon interaction point, which is an important feature of the detector. A good matching between simulations and measurements is obtained, with a discrepancy less than 0.5 mm between the measured and the simulated depth of the interaction, for an 11 mm thick detector. -- Highlights: • Description of MGS, a tool for the synthesis of the signal response of solid state detectors. • Validation of the simulator through comparison with measurements on a DSSD prototype. • Discussion on the advantages, drawbacks and possible evolutions of MGS.

  4. Spectroscopy of the X^1Σ^+, A^1Π and B^1Σ^+ Electronic States of MgS

    Science.gov (United States)

    Caron, Nicholas; Tokaryk, Dennis W.; Adam, Allan G.; Linton, Colan

    2016-06-01

    The spectra of some astrophysical sources contain signatures from molecules containing magnesium or sulphur atoms. Therefore, we have extended previous studies of the diatomic molecule MgS, which is a possible candidate for astrophysical detection. Microwave spectra of X^1Σ^+ , the ground electronic state, were reported in 1989 and 1997, and the B^1Σ^+-X^1Σ^+ electronic absorption spectrum in the blue was last studied in 1970. We have investigated the B^1Σ^+-X^1Σ^+ 0-0 spectrum of MgS at high resolution under jet-cooled conditions in a laser-ablation molecular source, and have obtained laser-induced fluorescence spectra from four isotopologues. Dispersed fluorescence from this source identified the low-lying A^1Π state near 4520 wn. We also created MgS in a Broida oven, with the help of a stream of activated nitrogen, and took rotationally resolved dispersed fluorescence spectra of the B^1Σ^+-A^1Π transition with a grating spectrometer by laser excitation of individual rotational levels of the B^1Σ^+ state via the B^1Σ^+-X^1Σ^+ transition. These spectra provide a first observation and analysis of the A^1Π state. S. Takano, S. Yamamoto and S. Saito, Chem. Phys. Lett. 159, 563-566 (1989) K. A. Walker and M. C. L. Gerry, J. Mol. Spectrosc 182, 178-183 (1997) M. Marcano and R. F. Barrow, Trans. Faraday Soc. 66, 2936-2938 (1970)

  5. Spacecraft Spin Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides the capability to correct unbalances of spacecraft by using dynamic measurement techniques and static/coupled measurements to provide products of...

  6. Perancangan Aplikasi Komputer Berbasis Android untuk Survei Kondisi Kapal oleh Owner Surveyor

    Directory of Open Access Journals (Sweden)

    Paul Stevan Haloho

    2017-01-01

    Full Text Available Survei kondisi kapal adalah survei yang dilakukan oleh seorang Owner Surveyor untuk melaporkan kondisi aktual kapal beserta bagian-bagiannya. Proses survei yang dilakukan saat ini masih dilakukan secara manual dimana seorang Owner Surveyor melakukan survei berdasarkan daftar survei yang diterbitkan oleh perusahaan pemilik kapal. Hasil survei kondisi akan disajikan dalam bentuk laporan yang nantinya akan diserahkan kepada pemilik kapal sebagai bahan pertimbangan untuk dilakukannya “repair” dan “maintenance”. Proses survei yang dilakukan saat ini tentu saja kurang efektif untuk dilakukan, mengingat tidak semua Owner Surveyor memiliki pengetahuan dan pengalaman yang sama serta proses pembuatan laporan hasil survei yang sering memakan waktu lama. Penelitian ini bertujuan untuk merancang sebuah aplikasi komputer berbasis android yang dapat membantu seorang Owner Surveyor dalam melakukan proses survei kondisi. Dalam aplikasi ini memuat fasilitas daftar survei, review survei, updating survei, dan menu untuk menambahkan Owner Surveyor. Aplikasi ini telah diujicobakan kepada beberapa responden yang memiliki pengalaman survei kapal dan pihak-pihak yang memiliki latar belakang pendidikan di bidang perkapalan. Pengujian ini dilakukan dalam bentuk kuisioner yang bertujuan untuk mengetahui penilaian para responden terhadap aplikasi ini. Dari hasil kuisioner dapat disimpulkan bahwa aplikasi ini sangat diperlukan dalam mendukung kegiatan survei kondisi kapal.

  7. The Transient High Energy Sky and Early Universe Surveyor

    Science.gov (United States)

    O'Brien, P. T.

    2016-04-01

    The Transient High Energy Sky and Early Universe Surveyor is a mission which will be proposed for the ESA M5 call. THESEUS will address multiple components in the Early Universe ESA Cosmic Vision theme:4.1 Early Universe,4.2 The Universe taking shape, and4.3 The evolving violent Universe.THESEUS aims at vastly increasing the discovery space of the high energy transient phenomena over the entire cosmic history. This is achieved via a unique payload providing an unprecedented combination of: (i) wide and deep sky monitoring in a broad energy band(0.3 keV-20 MeV; (ii) focusing capabilities in the soft X-ray band granting large grasp and high angular resolution; and (iii) on board near-IR capabilities for immediate transient identification and first redshift estimate.The THESEUS payload consists of: (i) the Soft X--ray Imager (SXI), a set of Lobster Eye (0.3--6 keV) telescopes with CCD detectors covering a total FOV of 1 sr; (ii) the X--Gamma-rays spectrometer (XGS), a non-imaging spectrometer (XGS) based on SDD+CsI, covering the same FOV than the Lobster telescope extending the THESEUS energy band up to 20 MeV; and (iii) a 70cm class InfraRed Telescope (IRT) observing up to 2 microns with imaging and moderate spectral capabilities.The main scientific goals of THESEUS are to:(a) Explore the Early Universe (cosmic dawn and reionization era) by unveiling the Gamma--Ray Burst (GRBs) population in the first billion years}, determining when did the first stars form, and investigating the re-ionization epoch, the interstellar medium (ISM) and the intergalactic medium (IGM) at high redshifts.(b) Perform an unprecedented deep survey of the soft X-ray transient Universe in order to fill the present gap in the discovery space of new classes of transient; provide a fundamental step forward in the comprehension of the physics of various classes of Galactic and extra--Galactic transients, and provide real time trigger and accurate locations of transients for follow-up with next

  8. Comparative study of the Martian suprathermal electron depletions based on Mars Global Surveyor, Mars Express, and Mars Atmosphere and Volatile EvolutioN mission observations

    Science.gov (United States)

    Steckiewicz, M.; Garnier, P.; André, N.; Mitchell, D. L.; Andersson, L.; Penou, E.; Beth, A.; Fedorov, A.; Sauvaud, J.-A.; Mazelle, C.; Brain, D. A.; Espley, J. R.; McFadden, J.; Halekas, J. S.; Larson, D. E.; Lillis, R. J.; Luhmann, J. G.; Soobiah, Y.; Jakosky, B. M.

    2017-01-01

    Nightside suprathermal electron depletions have been observed at Mars by three spacecraft to date: Mars Global Surveyor, Mars Express, and the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. This spatial and temporal diversity of measurements allows us to propose here a comprehensive view of the Martian electron depletions through the first multispacecraft study of the phenomenon. We have analyzed data recorded by the three spacecraft from 1999 to 2015 in order to better understand the distribution of the electron depletions and their creation mechanisms. Three simple criteria adapted to each mission have been implemented to identify more than 134,500 electron depletions observed between 125 and 900 km altitude. The geographical distribution maps of the electron depletions detected by the three spacecraft confirm the strong link existing between electron depletions and crustal magnetic field at altitudes greater than 170 km. At these altitudes, the distribution of electron depletions is strongly different in the two hemispheres, with a far greater chance to observe an electron depletion in the Southern Hemisphere, where the strongest crustal magnetic sources are located. However, the unique MAVEN observations reveal that below a transition region near 160-170 km altitude the distribution of electron depletions is the same in both hemispheres, with no particular dependence on crustal magnetic fields. This result supports the suggestion made by previous studies that these low-altitudes events are produced through electron absorption by atmospheric CO2.

  9. Research on Spacecraft Illumination

    Directory of Open Access Journals (Sweden)

    Bo Cai

    2011-07-01

    Full Text Available Illumination analysis of spacecraft is very important. This paper firstly introduces the importance of spacecraft illumination analysis in aerospace fields and points out that illumination conditions will influence the design of shape of spacecraft body and the installation of spacecraft equipments. Then, it discusses two methods for analyzing spacecraft solar-panel shadow and illumination conditions: ray tracing illumination algorithm and polyhedral mesh contour edge projection algorithm and compares their efficiency and feasibility. Shadow area and solar area are computed of every cell on solar panels. We designed solar panel single-axis rotation experiment to validate the proposed algorithm. The experimental results show that contour edge projection algorithm has fine accuracy and costs less time. For detailed illumination information, we apply a practical segment clipping algorithm after some comparisons.

  10. Radio wave phase scintillation and precision Doppler tracking of spacecraft

    Science.gov (United States)

    Armstrong, J. W.

    Phase scintillation caused by propagation through solar wind, ionospheric, and tropospheric irregularities is a noise process for many spacecraft radio science experiments. In precision Doppler tracking observations, scintillation can be the dominant noise process. Scintillation statistics are necessary for experiment planning and in design of signal processing procedures. Here high-precision tracking data taken with operational spacecraft (Mars Observer, Galileo, and Mars Global Surveyor) and ground systems are used to produce temporal statistics of tropospheric and plasma phase scintillation. The variance of Doppler frequency fluctuations is approximately decomposed into two propagation processes. The first, associated with distributed scattering along the sight line in the solar wind, has a smooth spectrum. The second, associated principally with localized tropospheric scattering for X-band experiments, has a marked autocorrelation peak at the two-way light time between the Earth and the spacecraft (thus a cosine-squared modulation of the fluctuation power spectrum). For X-band data taken in the antisolar hemisphere the average noise levels of this process are in good agreement with average tropospheric noise levels determined independently from water vapor radiometer observations and radio interferometic data. The variance of the process having a smooth spectrum is consistent with plasma noise levels determined independently from dual-frequency observations of the Viking spacecraft made at comparable Sun-Earth-spacecraft angles. The observations reported here are used to refine the propagation noise model for Doppler tracking of deep space probes. In particular, they can be used to predict propagation noise levels for high-precision X- and Ka-band tracking observations (e.g., atmosphere/ionosphere/ring occultations, celestial mechanics experiments, and gravitational wave experiments) to be done using the Cassini spacecraft.

  11. Spacecraft dielectric material properties and spacecraft charging

    Science.gov (United States)

    Frederickson, A. R.; Wall, J. A.; Cotts, D. B.; Bouquet, F. L.

    1986-01-01

    The physics of spacecraft charging is reviewed, and criteria for selecting and testing semiinsulating polymers (SIPs) to avoid charging are discussed and illustrated. Chapters are devoted to the required properties of dielectric materials, the charging process, discharge-pulse phenomena, design for minimum pulse size, design to prevent pulses, conduction in polymers, evaluation of SIPs that might prevent spacecraft charging, and the general response of dielectrics to space radiation. SIPs characterized include polyimides, fluorocarbons, thermoplastic polyesters, poly(alkanes), vinyl polymers and acrylates, polymers containing phthalocyanine, polyacene quinones, coordination polymers containing metal ions, conjugated-backbone polymers, and 'metallic' conducting polymers. Tables summarizing the results of SIP radiation tests (such as those performed for the NASA Galileo Project) are included.

  12. Spacecraft momentum control systems

    CERN Document Server

    Leve, Frederick A; Peck, Mason A

    2015-01-01

    The goal of this book is to serve both as a practical technical reference and a resource for gaining a fuller understanding of the state of the art of spacecraft momentum control systems, specifically looking at control moment gyroscopes (CMGs). As a result, the subject matter includes theory, technology, and systems engineering. The authors combine material on system-level architecture of spacecraft that feature momentum-control systems with material about the momentum-control hardware and software. This also encompasses material on the theoretical and algorithmic approaches to the control of space vehicles with CMGs. In essence, CMGs are the attitude-control actuators that make contemporary highly agile spacecraft possible. The rise of commercial Earth imaging, the advances in privately built spacecraft (including small satellites), and the growing popularity of the subject matter in academic circles over the past decade argues that now is the time for an in-depth treatment of the topic. CMGs are augmented ...

  13. Spacecraft Material Outgassing Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This compilation of outgassing data of materials intended for spacecraft use were obtained at the Goddard Space Flight Center (GSFC), utilizing equipment developed...

  14. Spacecraft Power Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project will develop the Spacecraft Power Monitor (SPM) which will use non-intrusive electrical monitoring (NEMO). NEMO transforms the power...

  15. UARS spacecraft recorder

    Science.gov (United States)

    1987-01-01

    The objective was the design, development, and fabrication of UARS spacecraft recorders. The UARS recorder is a tailored configuration of the RCA Standard Tape recorder STR-108. The specifications and requirements are reviewed.

  16. The role of quantity surveyors in public–private partnerships in South Africa

    Directory of Open Access Journals (Sweden)

    Hoffie Cruywagen

    2017-05-01

    Full Text Available Background: Quantity surveyors play an important role in providing cost and contractual advice in the built environment. This article seeks to investigate the current extent of their involvement in public–private partnerships (PPPs in South Africa. Aim: The study intends to establish factors that influence quantity surveyors’ participation in PPPs. Methodology: A mixed-methods research approach was followed by firstly conducting a survey amongst South African quantity surveyors in order to determine their level of participation in PPPs. For triangulation purposes, a case study was also conducted. Results: The results of the research show that, although quantity surveyors have the corresponding skills and competencies required in a PPP project, their current involvement in PPPs in South Africa is limited and that there is a greater role they can play in future. Conclusion: Quantity surveyors are uniquely positioned to play a bigger role in the implementation of PPPs in South Africa.

  17. 120 Years of Education for Mine Surveyors in South Africa A ...

    African Journals Online (AJOL)

    Grobler, Hennie

    identified as the new centre of gravity of mining activities, where in 1903, it was ... 1The NQF level is stated as an approximate value as these qualifications have ..... in the survey department, …after obtaining his mine surveyors certificate, ...

  18. The Far-Infrared Surveyor Mission study: paper I, the genesis

    NARCIS (Netherlands)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; Ennico, K.; Melnick, G. J.; Milam, S.; Narayanan, D.; Pontoppidan, K.; Pope, A.; Roellig, T.; Sandstrom, K.; Su, K. Y. L.; Vieira, J.; Wright, E.; Zmuidzinas, J.; Alato, S.; Carey, S.; Gerin, M.; Helmich, F.; Menten, K.; Scott, D.; Sakon, I.; Vavrek, R.

    2016-01-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some prelimin

  19. The Far-Infrared Surveyor Mission study: paper I, the genesis

    NARCIS (Netherlands)

    Meixner, M.; Cooray, A.; Carter, R.; DiPirro, M.; Flores, A.; Leisawitz, D.; Armus, L.; Battersby, C.; Bergin, E.; Bradford, C. M.; Ennico, K.; Melnick, G. J.; Milam, S.; Narayanan, D.; Pontoppidan, K.; Pope, A.; Roellig, T.; Sandstrom, K.; Su, K. Y. L.; Vieira, J.; Wright, E.; Zmuidzinas, J.; Alato, S.; Carey, S.; Gerin, M.; Helmich, F.; Menten, K.; Scott, D.; Sakon, I.; Vavrek, R.

    2016-01-01

    This paper describes the beginning of the Far-Infrared Surveyor mission study for NASA's Astrophysics Decadal 2020. We describe the scope of the study, and the open process approach of the Science and Technology Definition Team. We are currently developing the science cases and provide some

  20. Identifying and Describing Tutor Archetypes: The Pragmatist, the Architect, and the Surveyor

    Science.gov (United States)

    Harootunian, Jeff A.; Quinn, Robert J.

    2008-01-01

    In this article, the authors identify and anecdotally describe three tutor archetypes: the pragmatist, the architect, and the surveyor. These descriptions, based on observations of remedial mathematics tutors at a land-grant university, shed light on a variety of philosophical beliefs regarding and pedagogical approaches to tutoring. An analysis…

  1. Fossil gastropods from the MGS3 stratigraphic segment in the Salawusu River Valley and their climatic and environmental implications

    Institute of Scientific and Technical Information of China (English)

    LI BaoSheng; YE JianPing; GUO YunHai; CHEN DeNiu; David Dian ZHANG; WEN XiaoHao; QIU ShiFan; OU XianJiao; DU ShuHuan; NIU DongFeng; YANG Yi

    2008-01-01

    Contemporaneous with MIS3, the MGS3 segment of the Milanggouwan stratigraphic section in the Salawusu River Valley, Mu Us Desert, China contains fossil gastropods (terrestrial and freshwater snails) in strata 33LS, 35LS, 37FL and 39LS. Examination of these fossils revealed 11 species belonging to 8 families and 10 genera. They can be classified as: (1) assemblage of Gyraulus and Galba mainly consisting of Gyraulus convexiusculus, Gyraulus sibiricus, Galba pervia and Galba superegra Gredler,etc. (2) assemblage of Vallonia mainly consisting of terrestrial snails, such as Vallonia patens, Pupilla muscorum and Discus paupe, etc. Based on the dating results, and the living habits, living conditions,and geographic distribution of their extant species, we suggest that: the ages of 33LS, 35LS, 37FL, and 39LS are 26000, 29000, 33000 and 38000 a, respectively, corresponding well to the interstadial period in GRIP 4,5, 6 and 10 in terms of chronology and climatic characters; 33LS, 35LS and 39LS represent very warm-humid periods, while 37FL represents a less warm-humid period; the four periods of climatic fluctuations recorded in MGS3 were related to the strong impact of the summer monsoon in East Asia in Mu Us Desert of China during the interstadial of MIS3 on a global climatic background.

  2. Fossil gastropods from the MGS3 stratigraphic segment in the Salawusu River Valley and their climatic and environmental implications

    Institute of Scientific and Technical Information of China (English)

    David; Dian

    2008-01-01

    Contemporaneous with MIS3, the MGS3 segment of the Milanggouwan stratigraphic section in the Salawusu River Valley, Mu Us Desert, China contains fossil gastropods (terrestrial and freshwater snails) in strata 33LS, 35LS, 37FL and 39LS. Examination of these fossils revealed 11 species belonging to 8 families and 10 genera. They can be classified as: (1) assemblage of Gyraulus and Galba mainly consisting of Gyraulus convexiusculus, Gyraulus sibiricus, Galba pervia and Galba superegra Gredler, etc. (2) assemblage of Vallonia mainly consisting of terrestrial snails, such as Vallonia patens, Pupilla muscorum and Discus paupe, etc. Based on the dating results, and the living habits, living conditions, and geographic distribution of their extant species, we suggest that: the ages of 33LS, 35LS, 37FL, and 39LS are 26000, 29000, 33000 and 38000 a, respectively, corresponding well to the interstadial period in GRIP 4, 5, 6 and 10 in terms of chronology and climatic characters; 33LS, 35LS and 39LS represent very warm-humid periods, while 37FL represents a less warm-humid period; the four periods of climatic fluctuations recorded in MGS3 were related to the strong impact of the summer monsoon in East Asia in Mu Us Desert of China during the interstadial of MIS3 on a global climatic background.

  3. An Investigation of the Correlation of Water-Ice and Dust Retrievals Via the MGS TES Data Set

    Science.gov (United States)

    Qu, Z.; Tamppari, L. K.; Smith, M. D.; Bass, Deborah; Hale, A. S.

    2004-01-01

    Water-ice in the Martian atmosphere was first identified in the Mariner 9 Infrared Interferometer Spectrometer (IRIS) spectra. The Viking Imaging Subsystem (VIS) instruments aboard the Viking orbiter also observed water-ice clouds and hazes in the Martian atmosphere. The MGS TES instrument is an infrared inferometer/spectrometer which covers the spectral range 6-50 micron with a selectable sampling resolution of either 5 or 10 per cm. Using the relatively independent and distinct spectral signatures for dust and water-ice, these two retrieved quantities have been retrieved simultaneously. Although the interrelations among the two quantities have been analyzed by Smith et al. and the retrievals are thought to be robust, understanding the impact of each quantity on the other during their retrievals as well as the impact from the surface for retrievals is important for correctly interpreting the science, and therefore requires close examination. An understanding of the correlation or a-correlation between dust and water-ice would aid in understanding the physical processes responsible for the transport of aerosols in the Martian atmosphere. In this presentation, we present an investigation of the correlation between water-ice and dust in the MGS TES data set.

  4. The New Horizons Spacecraft

    Science.gov (United States)

    Fountain, Glen H.; Kusnierkiewicz, David Y.; Hersman, Christopher B.; Herder, Timothy S.; Coughlin, Thomas B.; Gibson, William C.; Clancy, Deborah A.; Deboy, Christopher C.; Hill, T. Adrian; Kinnison, James D.; Mehoke, Douglas S.; Ottman, Geffrey K.; Rogers, Gabe D.; Stern, S. Alan; Stratton, James M.; Vernon, Steven R.; Williams, Stephen P.

    2008-10-01

    The New Horizons spacecraft was launched on 19 January 2006. The spacecraft was designed to provide a platform for seven instruments designated by the science team to collect and return data from Pluto in 2015. The design meets the requirements established by the National Aeronautics and Space Administration (NASA) Announcement of Opportunity AO-OSS-01. The design drew on heritage from previous missions developed at The Johns Hopkins University Applied Physics Laboratory (APL) and other missions such as Ulysses. The trajectory design imposed constraints on mass and structural strength to meet the high launch acceleration consistent with meeting the AO requirement of returning data prior to the year 2020. The spacecraft subsystems were designed to meet tight resource allocations (mass and power) yet provide the necessary control and data handling finesse to support data collection and return when the one-way light time during the Pluto fly-by is 4.5 hours. Missions to the outer regions of the solar system (where the solar irradiance is 1/1000 of the level near the Earth) require a radioisotope thermoelectric generator (RTG) to supply electrical power. One RTG was available for use by New Horizons. To accommodate this constraint, the spacecraft electronics were designed to operate on approximately 200 W. The travel time to Pluto put additional demands on system reliability. Only after a flight time of approximately 10 years would the desired data be collected and returned to Earth. This represents the longest flight duration prior to the return of primary science data for any mission by NASA. The spacecraft system architecture provides sufficient redundancy to meet this requirement with a probability of mission success of greater than 0.85. The spacecraft is now on its way to Pluto, with an arrival date of 14 July 2015. Initial in-flight tests have verified that the spacecraft will meet the design requirements.

  5. Mechanical Design of Spacecraft

    Science.gov (United States)

    1962-01-01

    In the spring of 1962, engineers from the Engineering Mechanics Division of the Jet Propulsion Laboratory gave a series of lectures on spacecraft design at the Engineering Design seminars conducted at the California Institute of Technology. Several of these lectures were subsequently given at Stanford University as part of the Space Technology seminar series sponsored by the Department of Aeronautics and Astronautics. Presented here are notes taken from these lectures. The lectures were conceived with the intent of providing the audience with a glimpse of the activities of a few mechanical engineers who are involved in designing, building, and testing spacecraft. Engineering courses generally consist of heavily idealized problems in order to allow the more efficient teaching of mathematical technique. Students, therefore, receive a somewhat limited exposure to actual engineering problems, which are typified by more unknowns than equations. For this reason it was considered valuable to demonstrate some of the problems faced by spacecraft designers, the processes used to arrive at solutions, and the interactions between the engineer and the remainder of the organization in which he is constrained to operate. These lecture notes are not so much a compilation of sophisticated techniques of analysis as they are a collection of examples of spacecraft hardware and associated problems. They will be of interest not so much to the experienced spacecraft designer as to those who wonder what part the mechanical engineer plays in an effort such as the exploration of space.

  6. Spacecraft Attitude Determination

    DEFF Research Database (Denmark)

    Bak, Thomas

    This thesis describes the development of an attitude determination system for spacecraft based only on magnetic field measurements. The need for such system is motivated by the increased demands for inexpensive, lightweight solutions for small spacecraft. These spacecraft demands full attitude...... determination based on simple, reliable sensors. Meeting these objectives with a single vector magnetometer is difficult and requires temporal fusion of data in order to avoid local observability problems. In order to guaranteed globally nonsingular solutions, quaternions are generally the preferred attitude...... is a detailed study of the influence of approximations in the modeling of the system. The quantitative effects of errors in the process and noise statistics are discussed in detail. The third contribution is the introduction of these methods to the attitude determination on-board the Ørsted satellite...

  7. Revamping Spacecraft Operational Intelligence

    Science.gov (United States)

    Hwang, Victor

    2012-01-01

    The EPOXI flight mission has been testing a new commercial system, Splunk, which employs data mining techniques to organize and present spacecraft telemetry data in a high-level manner. By abstracting away data-source specific details, Splunk unifies arbitrary data formats into one uniform system. This not only reduces the time and effort for retrieving relevant data, but it also increases operational visibility by allowing a spacecraft team to correlate data across many different sources. Splunk's scalable architecture coupled with its graphing modules also provide a solid toolset for generating data visualizations and building real-time applications such as browser-based telemetry displays.

  8. CHISL: the combined high-resolution and imaging spectrograph for the LUVOIR surveyor

    Science.gov (United States)

    France, Kevin; Fleming, Brian; Hoadley, Keri

    2016-07-01

    NASA is currently carrying out science and technical studies to identify its next astronomy flagship mission, slated to begin development in the 2020s. It has become clear that a Large Ultraviolet/Optical/IR (LUVOIR) Surveyor mission (dprimary ≍ 12 m, Δλ ≍ 1000 Å - 2 μm spectroscopic bandpass) can carry out the largest number of NASA's exoplanet and astrophysics science goals over the coming decades. The science grasp of a LUVOIR Surveyor is broad, ranging from the direct detection of potential biomarkers on rocky planets to the flow of matter into and out of galaxies and the history of star-formation across cosmic time. There are technical challenges for several aspects of the LUVOIR Surveyor concept, including component level technology readiness maturation and science instrument concepts for a broadly capable ultraviolet spectrograph. We present the scientific motivation for, and a preliminary design of, a multiplexed ultraviolet spectrograph to support both the exoplanet and astrophysics goals of the LUVOIR Surveyor mission concept, the Combined High-resolution and Imaging Spectrograph for the LUVOIR Surveyor (CHISL). CHISL includes a highresolution (R ≍ 120,000; 1000 - 1700Å) point-source spectroscopy channel and a medium resolution (R >= 14,000 from 1000 - 2000 Å in a single observation and R 24,000 - 35,000 in multiple grating settings) imaging spectroscopy channel. CHISL addresses topics ranging from characterizing the composition and structure of planet-forming disks to the feedback of matter between galaxies and the intergalactic medium. We present the CHISL concept, a small sample of representative science cases, and the primary technological hurdles. Technical challenges include high-efficiency ultraviolet coatings and high-quantum efficiency, large-format, photon counting detectors. We are actively engaged in laboratory and flight characterization efforts for all of these enabling technologies as components on sounding rocket payloads under

  9. Lithospheric Thickness Variations from Gravity and Topography in Areas of High Crustal Remanent Magnetization on Mars

    Science.gov (United States)

    Smrekar, S. E.; Raymond, C. A.

    2001-01-01

    Large regions of intense crustal re- manent magnetization were fortuitously discovered on Mars by the Mars Global Surveyor (MGS) spacecraft. Gravity and topography admittance studies are used to examine lithospheric structure in the areas of intense magnetization. Areas with positively magnetized crust appear to have thinner crust and elastic lithosphere than negatively magnetized crust. Additional information is contained in the original extended abstract.

  10. The New Horizons Spacecraft

    CERN Document Server

    Fountain, Glen H; Hersman, Christopher B; Herder, Timothy S; Coughlin, Thomas B; Gibson, William C; Clancy, Deborah A; DeBoy, Christopher C; Hill, T Adrian; Kinnison, James D; Mehoke, Douglas S; Ottman, Geffrey K; Rogers, Gabe D; Stern, S Alan; Stratton, James M; Vernon, Steven R; Williams, Stephen P

    2007-01-01

    The New Horizons spacecraft was launched on 19 January 2006. The spacecraft was designed to provide a platform for seven instruments that will collect and return data from Pluto in 2015. The design drew on heritage from previous missions developed at The Johns Hopkins University Applied Physics Laboratory (APL) and other missions such as Ulysses. The trajectory design imposed constraints on mass and structural strength to meet the high launch acceleration needed to reach the Pluto system prior to the year 2020. The spacecraft subsystems were designed to meet tight mass and power allocations, yet provide the necessary control and data handling finesse to support data collection and return when the one-way light time during the Pluto flyby is 4.5 hours. Missions to the outer solar system require a radioisotope thermoelectric generator (RTG) to supply electrical power, and a single RTG is used by New Horizons. To accommodate this constraint, the spacecraft electronics were designed to operate on less than 200 W....

  11. Single reusable spacecraft

    Data.gov (United States)

    National Aeronautics and Space Administration — Design of a my single person reusable spacecraft. It can carry one person and it has to be dropped from an aircraft at an altitude of 40,000 - 45,000 feet. Can be...

  12. Solar wind rare gas analysis: Trapped solar wind helium and neon in Surveyor 3 material

    Science.gov (United States)

    Buehler, F.; Eberhardt, P.; Geiss, J.; Schwarzmueller, J.

    1972-01-01

    The He-4 and Ne-20 contents in sections of the Surveyor 3 support strut samples were determined by optical and scanning electron microscopy and are compared to the results of the Apollo solar wind composition (SWC) experiments. The He-4/Ne-20 ratio in the samples from the sunlit side of the strut was approximately 300; the ratios determined in Apollo 12 lunar fines and SWC foil were below 100. The He-4/He-3 ratios were also determined, and the ratio obtained from Surveyor 3 material is higher than those found with Apollo 11 and 12 SWC experiments. The effects of spallation by cosmic rays or solar protons, stripping by cosmic ray or energetic solar alpha particles, recycling of solar wind He and radiogenic Ne, He from terrestrial atmosphere, mass discrimination near the moon, mass dependence of trapping probability, diffusion, and contamination by lunar dust are considered.

  13. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz detector array of bolometric polarimeters

    CERN Document Server

    Appel, John W; Amiri, Mandana; Araujo, Derek; Bennett, Charles L; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Hilton, Gene; Hinshaw, Gary F; Huang, Caroline; Irwin, Kent; Jones, Glenn; Karakla, John; Kogut, Alan J; Larson, David; Limon, Michele; Lowry, Lindsay; Marriage, Tobias; Mehrle, Nicholas; Miller, Amber D; Miller, Nathan; Moseleyb, Samuel H; Novakh, Giles; Reintsemad, Carl; Rostemab, Karwan; Stevensonb, Thomas; Towner, Deborah; U-Yen, Kongpop; Wagner, Emily; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  14. The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz Detector Array of Bolometric Polarimeters

    Science.gov (United States)

    Appel, John W.; Ali, Aamir; Amiri, Mandana; Araujo, Derek; Bennett, Charles L.; Boone, Fletcher; Chan, Manwei; Cho, Hsiao-Mei; Chuss, David T.; Colazo, Felipe; Crowe, Erik; Denis, Kevin; Dunner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Gothe, Dominik; Halpern, Mark; Harrington, Kathleen; Kogut, Alan J..; Miller, Nathan; Moseley, Samuel H.; Stevenson, Thomas; Towner, Deborah; U-Yen, Kongpop; Wollack, Edward

    2014-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) experiment aims to map the polarization of the Cosmic Microwave Background (CMB) at angular scales larger than a few degrees. Operating from Cerro Toco in the Atacama Desert of Chile, it will observe over 65% of the sky at 38, 93, 148, and 217 GHz. In this paper we discuss the design, construction, and characterization of the CLASS 38 GHz detector focal plane, the first ever Q-band bolometric polarimeter array.

  15. Correlates of job satisfaction amongst quantity surveyors in consulting firms in Lagos, Nigeria

    Directory of Open Access Journals (Sweden)

    Henry Ndubuisi Onukwube

    2012-05-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Job satisfaction is the sense of well- being, good feeling and positive mental state that emerge in an incumbent worker when his obtained reward consequent upon his performance is congruent with his equitable reward.The aim of this study is to ascertain the levels of job satisfaction amongst quantity surveyors in consulting firms in Lagos, Nigeria. Biographical and job descriptive index questionnaires (JDI were administered to gather the data. The JDI measures job satisfaction on five facets, namely, pay, promotions, supervision, co-workers and the work itself. A total of 100 questionnaires were collected and used for the study. The survey covered quantity surveyors in consulting firms in Lagos and the respondents were selected using stratified random sampling technique. Data collected were analysed using descriptive statistics, correlation matrix, t-test and one way anova. Findings of the study revealed that the respondents were satisfied with the relationship with co-workers, nature of work and the supervision they receive. Major sources of dissatisfaction are promotion and salaries of the respondents. This finding is a bold step and necessary benchmark for resolving major sources of dissatisfaction among quantity surveyors in consulting firms. The roles of other contextual factors on job satisfaction need to be contemplated for future research.

  16. Correlates of job satisfaction amongst quantity surveyors in consulting firms in Lagos, Nigeria

    Directory of Open Access Journals (Sweden)

    Henry Ndubuisi Onukwube

    2012-05-01

    Full Text Available Job satisfaction is the sense of well- being, good feeling and positive mental state that emerge in an incumbent worker when his obtained reward consequent upon his performance is congruent with his equitable reward.The aim of this study is to ascertain the levels of job satisfaction amongst quantity surveyors in consulting firms in Lagos, Nigeria. Biographical and job descriptive index questionnaires (JDI were administered to gather the data. The JDI measures job satisfaction on five facets, namely, pay, promotions, supervision, co-workers and the work itself. A total of 100 questionnaires were collected and used for the study. The survey covered quantity surveyors in consulting firms in Lagos and the respondents were selected using stratified random sampling technique. Data collected were analysed using descriptive statistics, correlation matrix, t-test and one way anova. Findings of the study revealed that the respondents were satisfied with the relationship with co-workers, nature of work and the supervision they receive. Major sources of dissatisfaction are promotion and salaries of the respondents. This finding is a bold step and necessary benchmark for resolving major sources of dissatisfaction among quantity surveyors in consulting firms. The roles of other contextual factors on job satisfaction need to be contemplated for future research.

  17. Assessment of Cost Management Functions of Quantity Surveyors with Lean Methodology

    Directory of Open Access Journals (Sweden)

    Maroof Opeyemi Anifowose

    2013-11-01

    Full Text Available The Construction industry in Nigeria is made up of a wide variety of activities which include the provision of professional and technical services to clients in the built environment. Despite the provision of these services to a large number of clients worldwide, the construction industry is still awash by the chronic problems of low productivity, insufficient quality, time over-runs, and poor safety, which hinder customer delivered value. The Just-In-Time phenomenon is a characteristic of lean production systems which operate with very little “fat” (e.g. excess inventory extra workers, wasted space.This study aimed at assessing the construction management function of the quantity surveyor in line with the principle of lean methodology (Just-In-Time. This was achieved by exploring the cost management function of the quantity surveyor, to investigate the current practice of cost management by quantity surveying firms. Data for the study were sourced primarily with the use of questionnaire and the subsequent data analysis, which employed the use of descriptive analysis of presenting the data as obtained on tables during the field survey and attempts a rudimentary establishment of patterns using percentages. The study concluded amongst others, that: all activities involved in the cost management function of the quantity surveyor are important, and value adding, corresponding to conversion activities in line with the Just-In-time/lean methodology

  18. Perancangan Aplikasi Komputer Berbasis Android untuk Panduan Pengawasan Pembangunan Kapal Baru oleh Owner Surveyor

    Directory of Open Access Journals (Sweden)

    Joshua Adrian Lasuardi

    2017-01-01

    Full Text Available Kegiatan pengawasan pembangunan kapal baru yang ada saat ini masih dilakukan secara manual dimana seorang owner surveyor melakukan pengawasan mengacu pada form pengawasan. Kegiatan pengawasan yang ada saat ini kurang efektif untuk dilakukan pada proses pembangunan kapal baru, hal ini dikarenakan tidak semua owner surveyor memiliki pengetahuan dan pengalaman yang sama. Tujuan dari tugas akhir ini adalah melakukan observasi sistem pengawasan pembangunan kapal baru yang ada saat ini, merancang aplikasi komputer berbasis android untuk panduan pengawasan pembangunan kapal baru, dan melakukan uji validitas aplikasi tersebut dalam meningkatkan efektivitas pengawasan pembangunan kapal baru. Perancangan aplikasi dilakukan dengan pembuatan mock up aplikasi, desain interface, perancangan database, dan pengkodingan aplikasi tersebut. Aplikasi ini memiliki fitur daftar proses pengawasan, review hasil pengawasan, progress pembangunan kapal, dan menu untuk menambahkan owner surveyor. Uji coba aplikasi ini dilakukan kepada beberapa responden yang memiliki pengalaman pengawasan pembangunan kapal baru dan pihak-pihak yang memiliki latar belakang pendidikan di bidang perkapalan. Dari hasil pengujian menggunakan kuisoner tersebut diperoleh kesimpulan bahwa aplikasi ini perlu diaplikasikan dalam mendukung proses pengawasan pembangunan kapal baru.

  19. The MESSENGER Spacecraft

    Science.gov (United States)

    Leary, James C.; Conde, Richard F.; Dakermanji, George; Engelbrecht, Carl S.; Ercol, Carl J.; Fielhauer, Karl B.; Grant, David G.; Hartka, Theodore J.; Hill, Tracy A.; Jaskulek, Stephen E.; Mirantes, Mary A.; Mosher, Larry E.; Paul, Michael V.; Persons, David F.; Rodberg, Elliot H.; Srinivasan, Dipak K.; Vaughan, Robin M.; Wiley, Samuel R.

    2007-08-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was designed and constructed to withstand the harsh environments associated with achieving and operating in Mercury orbit. The system can be divided into eight subsystems: structures and mechanisms (e.g., the composite core structure, aluminum launch vehicle adapter, and deployables), propulsion (e.g., the state-of-the-art titanium fuel tanks, thruster modules, and associated plumbing), thermal (e.g., the ceramic-cloth sunshade, heaters, and radiators), power (e.g., solar arrays, battery, and controlling electronics), avionics (e.g., the processors, solid-state recorder, and data handling electronics), software (e.g., processor-supported code that performs commanding, data handling, and spacecraft control), guidance and control (e.g., attitude sensors including star cameras and Sun sensors integrated with controllers including reaction wheels), radio frequency telecommunications (e.g., the spacecraft antenna suites and supporting electronics), and payload (e.g., the science instruments and supporting processors). This system architecture went through an extensive (nearly four-year) development and testing effort that provided the team with confidence that all mission goals will be achieved.

  20. Spacecraft Electrostatic Radiation Shielding

    Science.gov (United States)

    2008-01-01

    This project analyzed the feasibility of placing an electrostatic field around a spacecraft to provide a shield against radiation. The concept was originally proposed in the 1960s and tested on a spacecraft by the Soviet Union in the 1970s. Such tests and analyses showed that this concept is not only feasible but operational. The problem though is that most of this work was aimed at protection from 10- to 100-MeV radiation. We now appreciate that the real problem is 1- to 2-GeV radiation. So, the question is one of scaling, in both energy and size. Can electrostatic shielding be made to work at these high energy levels and can it protect an entire vehicle? After significant analysis and consideration, an electrostatic shield configuration was proposed. The selected architecture was a torus, charged to a high negative voltage, surrounding the vehicle, and a set of positively charged spheres. Van de Graaff generators were proposed as the mechanism to move charge from the vehicle to the torus to generate the fields necessary to protect the spacecraft. This design minimized complexity, residual charge, and structural forces and resolved several concerns raised during the internal critical review. But, it still is not clear if such a system is costeffective or feasible, even though several studies have indicated usefulness for radiation protection at energies lower than that of the galactic cosmic rays. Constructing such a system will require power supplies that can generate voltages 10 times that of the state of the art. Of more concern is the difficulty of maintaining the proper net charge on the entire structure and ensuring that its interaction with solar wind will not cause rapid discharge. Yet, if these concerns can be resolved, such a scheme may provide significant radiation shielding to future vehicles, without the excessive weight or complexity of other active shielding techniques.

  1. Analysis of Surveyor 3 television cable after residence on the moon

    Science.gov (United States)

    Gross, F. C.; Park, J. J.

    1972-01-01

    The Apollo 12 astronauts brought the Surveyor III television camera back from the moon in November 1969. Chemical analyses of a portion of television cable revealed changes in the glass fabric sleeve and in the wire insulation as a result of exposure to the lunar environment. Loss of volatile constituents from the glass fabric and a discoloration of the glass occurred. The Teflon layer on the wire showed a slight discoloration and possibly a slight change in its infrared spectrum. Both the polyimide layer and the Teflon layer of the wire insulation showed changes in tensile strength and elongation.

  2. Solar wind modulation of the Martian ionosphere observed by Mars Global Surveyor

    Directory of Open Access Journals (Sweden)

    J.-S. Wang

    2004-06-01

    Full Text Available Electron density profiles in the Martian ionosphere observed by the radio occultation experiment on board Mars Global Surveyor have been analyzed to determine if the densities are influenced by the solar wind. Evidence is presented that the altitude of the maximum ionospheric electron density shows a positive correlation to the energetic proton flux in the solar wind. The solar wind modulation of the Martian ionosphere can be attributed to heating of the neutral atmosphere by the solar wind energetic proton precipitation. The modulation is observed to be most prominent at high solar zenith angles. It is argued that this is consistent with the proposed modulation mechanism.

  3. In Situ Atmospheric Pressure Measurements in the Martian Southern Polar Region: Mars Volatiles and Climate Surveyor Meteorology Package on the Mars Polar Lander

    Science.gov (United States)

    Harri, A.-M.; Polkko, J.; Siili, T.; Crisp, D.

    1998-01-01

    Pressure observations are crucial for the success of the Mars Volatiles and Climate Surveyor (MVACS) Meteorology (MET) package onboard the Mars Polar Lander (MPL), due for launch early next year. The spacecraft is expected to land in December 1999 (L(sub s) = 256 degrees) at a high southern latitude (74 degrees - 78 degrees S). The nominal period of operation is 90 sols but may last up to 210 sols. The MVACS/MET experiment will provide the first in situ observations of atmospheric pressure, temperature, wind, and humidity in the southern hemisphere of Mars and in the polar regions. The martian atmosphere goes through a large-scale atmospheric pressure cycle due to the annual condensation/sublimation of the atmospheric CO2. Pressure also exhibits short period variations associated with dust storms, tides, and other atmospheric events. A series of pressure measurements can hence provide us with information on the large-scale state and dynamics of the atmosphere, including the CO2 and dust cycles as well as local weather phenomena. The measurements can also shed light on the shorter time scale phenomena (e.g., passage of dust devils) and hence be important in contributing to our understanding of mixing and transport of heat, dust, and water vapor.

  4. Surveyor Manual

    DEFF Research Database (Denmark)

    Blyt, Henrik; Hessellund, Regner Bæk

    providing the qualification of ‘building maintenance technician’. Being addressed to people seeking jobs, but also to professionals already working in domains connected to the administration and maintenance of building stock, such as local administration, public and private companies owning buildings, SMEs...

  5. CAS Experiments Onboard Spacecraft Successful

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ The descent module of China's Shenzhou 3 spacecraft returned to Earth on April 1, 2002, one week after the spacecraft was launched at the Jiuquan Satellite Launching Center in Gansu Province. It was the third test flight of a prototype spacecraft expected to carry taikonauts (stemming from the Chinese words for outer space) into space in the near future since the first launch of the Shenzhou (Divine Vessel) series on November 20,1999.

  6. Method of Display Entity Information of VR-forces on MGS Platform%基于MGS平台的VR-Forces实体信息显示方法

    Institute of Scientific and Technical Information of China (English)

    韩晓光; 赵志军; 蔡郁知

    2015-01-01

    在同一模拟系统中同时使用MGS与VR-Forces平台,存在实体信息格式转换问题.为实现在MGS平台中显示VR-Forces中实体信息,分析了VR-Forces平台中实体信息的组织方式,基于XML技术构建了VR-Forces平台与MGS平台间的实体ID编码映射关系,实现了VR-Forces平台中实体经纬度、首向角、敌我关系等属性信息的获取方法,解决了基于MGS开发的模拟仿真训练程序与基于VR-Forces开发的模拟训练程序共存的问题,为后续具有类似功能需求的模拟系统开发提供了技术支持.%To use MGS and VR-Forces in the same simulation system, there is an entity information transform problem. To display VR-Forces entity information on MGS, the entity in heritance structure of VR-Forces is analyzed, building a Mapping Table of entity ID between VR-Forces and MGS platforms on XML technology. To achieve the methods to get latitude,heading,the enemy relationship from VR-Forces, the coexistence problem of MGS and VR-Forces are solved. The technical support for the development of simulation system with the similar function is provided.

  7. Operationally Responsive Spacecraft Subsystem Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Saber Astronautics proposes spacecraft subsystem control software which can autonomously reconfigure avionics for best performance during various mission conditions....

  8. The X-Ray Surveyor mission concept study: forging the path to NASA astrophysics 2020 decadal survey prioritization

    Science.gov (United States)

    Gaskin, Jessica; Özel, Feryal; Vikhlinin, Alexey

    2016-07-01

    The X-Ray Surveyor mission concept is unique among those being studied for prioritization in the NASA Astrophysics 2020 Decadal Survey. The X-Ray Surveyor mission will explore the high-energy Universe; providing essential and complimentary observations to the Astronomy Community. The NASA Astrophysics Roadmap (Enduring Quests, Daring Visions) describes the need for an X-Ray Observatory that is capable of addressing topics such as the origin and growth of the first supermassive black holes, galaxy evolution and growth of the cosmic structure, and the origin and evolution of the stars that make up our Universe. To address these scientifically compelling topics and more, an Observatory that exhibits leaps in capability over that of previous X-Ray Observatories in needed. This paper describes the current status of the X-Ray Surveyor Mission Concept Study and the path forward, which includes scientific investigations, technology development, and community participation.

  9. The X-Ray Surveyor Mission Concept Study: Forging the Path to NASA Astrophysics 2020 Decadal Survey Prioritization

    Science.gov (United States)

    Gaskin, Jessica; Ozel, Feryal; Vikhlinin, Alexey

    2016-01-01

    The X-Ray Surveyor mission concept is unique among those being studied for prioritization in the NASA Astrophysics 2020 Decadal Survey. The X-Ray Surveyor mission will explore the high-energy Universe; providing essential and complimentary observations to the Astronomy Community. The NASA Astrophysics Roadmap (Enduring Quests, Daring Visions) describes the need for an X-Ray Observatory that is capable of addressing topics such as the origin and growth of the first supermassive black holes, galaxy evolution and growth of the cosmic structure, and the origin and evolution of the stars that make up our Universe. To address these scientifically compelling topics and more, an Observatory that exhibits leaps in capability over that of previous X-Ray Observatories in needed. This paper describes the current status of the X-Ray Surveyor Mission Concept Study and the path forward, which includes scientific investigations, technology development, and community participation.

  10. Human Spacecraft Structures Internship

    Science.gov (United States)

    Bhakta, Kush

    2017-01-01

    DSG will be placed in halo orbit around themoon- Platform for international/commercialpartners to explore lunar surface- Testbed for technologies needed toexplore Mars• Habitat module used to house up to 4crew members aboard the DSG- Launched on EM-3- Placed inside SLS fairing Habitat Module - Task Habitat Finite Element Model Re-modeled entire structure in NX2) Used Beam and Shell elements torepresent the pressure vessel structure3) Created a point cloud of centers of massfor mass components- Can now inspect local moments andinertias for thrust ring application8/ Habitat Structure – Docking Analysis Problem: Artificial Gravity may be necessary forastronaut health in deep spaceGoal: develop concepts that show how artificialgravity might be incorporated into a spacecraft inthe near term Orion Window Radiant Heat Testing.

  11. Spacecraft rendezvous and docking

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1999-01-01

    The phenomenons and problems encountered when a rendezvous manoeuvre, and possible docking, of two spacecrafts has to be performed, have been the topic for numerous studies, and, details of a variety of scenarios has been analysed. So far, all solutions that has been brought into realization has...... been based entirely on direct human supervision and control. This paper describes a vision-based system and methodology, that autonomously generates accurate guidance information that may assist a human operator in performing the tasks associated with both the rendezvous and docking navigation...... relative pose information to assist the human operator during the docking phase. The closed loop and operator assistance performance of the system have been assessed using a test bench including human operator, navigation module and high fidelity visualization module. The tests performed verified...

  12. Surveyor nuclease detection of mutations and polymorphisms of mtDNA in children.

    Science.gov (United States)

    Pilch, Jacek; Asman, Marek; Jamroz, Ewa; Kajor, Maciej; Kotrys-Puchalska, Elżbieta; Goss, Małgorzata; Krzak, Maria; Witecka, Joanna; Gmiński, Jan; Sieroń, Aleksander L

    2010-11-01

    Mitochondrial encephalomyopathies are complex disorders with wide range of clinical manifestations. Particularly time-consuming is the identification of mutations in mitochondrial DNA. A group of 20 children with clinical manifestations of mitochondrial encephalomyopathies was selected for molecular studies. The aims were (a) to identify mutations in mtDNA isolated from muscle and (b) to verify detected mutations in DNA isolated from blood, in order to assess the utility of a Surveyor nuclease assay kit for patient screening. The most common changes found were polymorphisms, including a few missense mutations altering the amino acid sequence of mitochondrial proteins. In two boys with MELAS (i.e., mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes), a mutation A→G3243 was detected in the tRNALeu gene of mtDNA isolated from muscle and blood. In one boy, the carrier status of his mother was confirmed, based on molecular analysis of DNA isolated from blood. A method using Surveyor nuclease allows systematic screening for small mutations in mtDNA, using as its source blood of the patients and asymptomatic carriers. The method still requires confirmation studying a larger group. In some patients, the use of this method should precede and might limit indications for traumatic muscle and skin biopsy.

  13. Small Spacecraft for Planetary Science

    Science.gov (United States)

    Baker, John; Castillo-Rogez, Julie; Bousquet, Pierre-W.; Vane, Gregg; Komarek, Tomas; Klesh, Andrew

    2016-07-01

    As planetary science continues to explore new and remote regions of the Solar system with comprehensive and more sophisticated payloads, small spacecraft offer the possibility for focused and more affordable science investigations. These small spacecraft or micro spacecraft (electronics, advanced manufacturing for lightweight structures, and innovative propulsion are making it possible to fly much more capable micro spacecraft for planetary exploration. While micro spacecraft, such as CubeSats, offer significant cost reductions with added capability from advancing technologies, the technical challenges for deep space missions are very different than for missions conducted in low Earth orbit. Micro spacecraft must be able to sustain a broad range of planetary environments (i.e., radiations, temperatures, limited power generation) and offer long-range telecommunication performance on a par with science needs. Other capabilities needed for planetary missions, such as fine attitude control and determination, capable computer and data handling, and navigation are being met by technologies currently under development to be flown on CubeSats within the next five years. This paper will discuss how micro spacecraft offer an attractive alternative to accomplish specific science and technology goals and what relevant technologies are needed for these these types of spacecraft. Acknowledgements: Part of this work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract to NASA. Government sponsorship acknowledged.

  14. Printed Spacecraft Separation System

    Energy Technology Data Exchange (ETDEWEB)

    Holmans, Walter [Planetary Systems Corporation, Silver Springs, MD (United States); Dehoff, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-10-01

    In this project Planetary Systems Corporation proposed utilizing additive manufacturing (3D printing) to manufacture a titanium spacecraft separation system for commercial and US government customers to realize a 90% reduction in the cost and energy. These savings were demonstrated via “printing-in” many of the parts and sub-assemblies into one part, thus greatly reducing the labor associated with design, procurement, assembly and calibration of mechanisms. Planetary Systems Corporation redesigned several of the components of the separation system based on additive manufacturing principles including geometric flexibility and the ability to fabricate complex designs, ability to combine multiple parts of an assembly into a single component, and the ability to optimize design for specific mechanical property targets. Shock absorption was specifically targeted and requirements were established to attenuate damage to the Lightband system from shock of initiation. Planetary Systems Corporation redesigned components based on these requirements and sent the designs to Oak Ridge National Laboratory to be printed. ORNL printed the parts using the Arcam electron beam melting technology based on the desire for the parts to be fabricated from Ti-6Al-4V based on the weight and mechanical performance of the material. A second set of components was fabricated from stainless steel material on the Renishaw laser powder bed technology due to the improved geometric accuracy, surface finish, and wear resistance of the material. Planetary Systems Corporation evaluated these components and determined that 3D printing is potentially a viable method for achieving significant cost and savings metrics.

  15. Analyzing Spacecraft Telecommunication Systems

    Science.gov (United States)

    Kordon, Mark; Hanks, David; Gladden, Roy; Wood, Eric

    2004-01-01

    Multi-Mission Telecom Analysis Tool (MMTAT) is a C-language computer program for analyzing proposed spacecraft telecommunication systems. MMTAT utilizes parameterized input and computational models that can be run on standard desktop computers to perform fast and accurate analyses of telecommunication links. MMTAT is easy to use and can easily be integrated with other software applications and run as part of almost any computational simulation. It is distributed as either a stand-alone application program with a graphical user interface or a linkable library with a well-defined set of application programming interface (API) calls. As a stand-alone program, MMTAT provides both textual and graphical output. The graphs make it possible to understand, quickly and easily, how telecommunication performance varies with variations in input parameters. A delimited text file that can be read by any spreadsheet program is generated at the end of each run. The API in the linkable-library form of MMTAT enables the user to control simulation software and to change parameters during a simulation run. Results can be retrieved either at the end of a run or by use of a function call at any time step.

  16. Knowledge and Attitudes of Nursing Home Staff and Surveyors about the Revised Federal Guidance for Incontinence Care

    Science.gov (United States)

    DuBeau, Catherine E.; Ouslander, Joseph G.; Palmer, Mary H.

    2007-01-01

    Purpose: We assessed nursing home staff and state nursing home surveyors regarding their knowledge and attitudes about urinary incontinence, its management, and the revised federal Tag F315 guidance for urinary incontinence. Design and Methods: We conducted a questionnaire survey of a convenience sample of nursing home staff and state nursing home…

  17. Comparison of T7E1 and surveyor mismatch cleavage assays to detect mutations triggered by engineered nucleases.

    Science.gov (United States)

    Vouillot, Léna; Thélie, Aurore; Pollet, Nicolas

    2015-01-07

    Genome editing using engineered nucleases is used for targeted mutagenesis. But because genome editing does not target all loci with similar efficiencies, the mutation hit-rate at a given locus needs to be evaluated. The analysis of mutants obtained using engineered nucleases requires specific methods for mutation detection, and the enzyme mismatch cleavage method is used commonly for this purpose. This method uses enzymes that cleave heteroduplex DNA at mismatches and extrahelical loops formed by single or multiple nucleotides. Bacteriophage resolvases and single-stranded nucleases are used commonly in the assay but have not been compared side-by-side on mutations obtained by engineered nucleases. We present the first comparison of the sensitivity of T7E1 and Surveyor EMC assays on deletions and point mutations obtained by zinc finger nuclease targeting in frog embryos. We report the mutation detection limits and efficiencies of T7E1 and Surveyor. In addition, we find that T7E1 outperforms the Surveyor nuclease in terms of sensitivity with deletion substrates, whereas Surveyor is better for detecting single nucleotide changes. We conclude that T7E1 is the preferred enzyme to scan mutations triggered by engineered nucleases.

  18. Lybia Montes: A Safe, Ancient Cratered Terrain, Mars Surveyor Landing Site at the Isidis Basin Rim

    Science.gov (United States)

    Haldemann, A. F. C.; Anderson, R. C.; Harbert, W.

    2000-01-01

    The Isidis basin rim may be key to understanding Mars' past with future lander missions: this area enables the mission objective to explore Mars' climatic and geologic history, including the search for liquid water and evidence of prior or extant life in ancient terrains. While two safe candidate landIng sites for Mars Pathfinder were identified in Isidis Planitia, and one is being pursued for the Mars Surveyor 2001 Lander, the region around Isidis Planitia. in contrast to Tharsis for example, has only been lightly studied. The advent of new high resolution data sets provides an opportunity to re-assess the geologic context of this Impact basin and its rim within the Martian geologic sequence as a candidate site for studying Mars' ancient cratered terrain and ancient hydrosphere. This reexamination is warranted by the various hypotheses that Isidis was once filled with ice or water.

  19. PENERAPAN MEDIA MONOPOLY GAMES SMART (MGS UNTUK MENINGKATKAN HASIL BELAJAR SISWA PADA MATERI EKOSISTEM DI KELAS VII MTS AL-WAHDAH SUMBER

    Directory of Open Access Journals (Sweden)

    Sri Ayu

    2015-07-01

    Full Text Available Dalam proses pembelajaran siswa dituntut untuk aktif melaluiaktivitas-aktivitas yang membangun kerja kelompok dan dalam waktu singkatmembuat mereka berfikir tentang materi pelajaran. Keterlibatan siswa secara aktif dalam pembelajaran biologi sangat diperlukan, sehingga apa yang dipelajari akan lebih tertanam dalam pikiran siswa. PenerapanMonopoly Games Smartpada pembelajaranBiologi merupakan salah satu alternatif untuk meningkatkan motivasi dan kreatifitas siswa serta dapat mengurangi kejenuhan belajar siswa, sehingga mendapatkanhasilbelajar siswa yang memuaskan. Adapun yang menjadi tujuan penelitian ini adalah:(1 Untuk mengkaji penerapan media MGS (Monopoly Games Smart pada materi Ekosistem di MTs Al-Wahdah Sumber. (2 Untuk mengkaji hasil belajar siswa pada pembelajaran biologi materi Ekosistem dengan menggunakan media MGS (Monopoly Games Smart di MTs Al-Wahdah Sumber. (3 Untuk mengkaji respon siswa terhadap penggunaan media MGS (Monopoly Games Smart dalam pembelajaran biologi khususnya pada materi Ekosistem di Mts Al-Wahdah Sumber. Penelitian ini dilakukan di MTs Al-Wahdah dengan teknik pengumpulan data yang digunakan adalah instrumen tes (pre-test dan post-test untuk mengukur hasil belajar siswa, observasi untuk mengetahui aktivitas siswa dan angketuntuk mengetahui respon siswa terhadap media pembelajaran. Hasil penelitian menunjukan bahwa (1 berdasarkan hasil analisis observasi, aktivitas siswa meningkat setelah diterapkan media Monopoly Games Smart. (2 Hasil belajar siswa kelas eksperimen menggunakan media pembelajaran Monopoly Games Smart nilai rata-rata pretest sebesar 39, posttest 78 dan n-gain 0,62.. Terbukti dari hasil perhitungan uji T menggunakan SPSS 16 diperoleh nilai Sig. 0,000 < (0,05 yang berarti terdapat peningkatan hasil belajar biologi siswa. (3 berdasarkan hasil analisis angket mengenai respon siswa terhadap penerapan media hampir dari siswa (82% dengan kriteria sangat kuat, menyukai penerapan strategi pembelajaran Monopoly

  20. Spacecraft Cabin Particulate Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We have built and tested an optical extinction monitor for the detection of spacecraft cabin particulates. This sensor sensitive to particle sizes ranging from a few...

  1. Spacecraft Cabin Particulate Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design, build and test an optical extinction monitor for the detection of spacecraft cabin particulates. This monitor will be sensitive to particle...

  2. Spacecraft attitude dynamics and control

    Science.gov (United States)

    Chobotov, Vladimir A.

    This overview of spacecraft dynamics encompasses the fundamentals of kinematics, rigid-body dynamics, linear control theory, orbital environmental effects, and the stability of motion. The theoretical treatment of each issue is complemented by specific references to spacecraft control systems based on spin, dual-spin, three-axis-active, and reaction-wheel methodologies. Also examined are control-moment-gyro, gravity-gradient, and magnetic control systems with attention given to key issues such as nutation damping, separation dynamics of spinning bodies, and tethers. Environmental effects that impinge on the application of spacecraft-attitude dynamics are shown to be important, and consideration is given to gravitation, solar radiation, aerodynamics, and geomagnetics. The publication gives analytical methods for examining the practical implementation of the control techniques as they apply to spacecraft.

  3. Advanced Spacecraft Thermal Modeling Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For spacecraft developers who spend millions to billions of dollars per unit and require 3 to 7 years to deploy, the LoadPath reduced-order (RO) modeling thermal...

  4. Intelligent spacecraft module

    Science.gov (United States)

    Oungrinis, Konstantinos-Alketas; Liapi, Marianthi; Kelesidi, Anna; Gargalis, Leonidas; Telo, Marinela; Ntzoufras, Sotiris; Paschidi, Mariana

    2014-12-01

    The paper presents the development of an on-going research project that focuses on a human-centered design approach to habitable spacecraft modules. It focuses on the technical requirements and proposes approaches on how to achieve a spatial arrangement of the interior that addresses sufficiently the functional, physiological and psychosocial needs of the people living and working in such confined spaces that entail long-term environmental threats to human health and performance. Since the research perspective examines the issue from a qualitative point of view, it is based on establishing specific relationships between the built environment and its users, targeting people's bodily and psychological comfort as a measure toward a successful mission. This research has two basic branches, one examining the context of the system's operation and behavior and the other in the direction of identifying, experimenting and formulating the environment that successfully performs according to the desired context. The latter aspect is researched upon the construction of a scaled-model on which we run series of tests to identify the materiality, the geometry and the electronic infrastructure required. Guided by the principles of sensponsive architecture, the ISM research project explores the application of the necessary spatial arrangement and behavior for a user-centered, functional interior where the appropriate intelligent systems are based upon the existing mechanical and chemical support ones featured on space today, and especially on the ISS. The problem is set according to the characteristics presented at the Mars500 project, regarding the living quarters of six crew-members, along with their hygiene, leisure and eating areas. Transformable design techniques introduce spatial economy, adjustable zoning and increased efficiency within the interior, securing at the same time precise spatial orientation and character at any given time. The sensponsive configuration is

  5. A comparison of NEAR actual spacecraft costs with three parametric cost models

    Science.gov (United States)

    Mosher, Todd J.; Lao, Norman Y.; Davalos, Evelyn T.; Bearden, David A.

    1999-11-01

    Costs for modern (post-1990) U.S.-built small planetary spacecraft have been shown to exhibit significantly different trends from those of larger spacecraft. These differences cannot be accounted for simply by the change in size alone. Some have attributed this departure to NASA's "faster, better, cheaper" design approach embodied by the efficiency of smaller teams, reduced government oversight, increased focus on cost, and short development periods. With the Discovery, Mars Surveyor and New Millennium programs representing the new approach to planetary exploration, it is important to understand these current cost trends and to be able to estimate costs of future proposed missions. To address this issue, The Aerospace Corporation (hereafter referred to as Aerospace) performed a study to compare the actual costs of the Near Earth Asteroid Rendezvous (NEAR) spacecraft bus (instruments were not estimated) using three different cost models; the U.S. Air Force Unmanned Spacecraft Cost Model, Version 7 (USCM-7), the Science Applications International Corporation (SAIC) NASA/Air Force Cost Model 1996 (NAFCOM96) and The Aerospace Corporation's Small Satellite Cost Model 1998 (SSCM98). The NEAR spacecraft was chosen for comparison because it was the first Discovery mission launched, and recently recognized with a Laurel award by Aviation Week and Space Technology as a benchmark for NASA's Discovery program [North, 1997]. It was also selected because the cost data has been released into the public domain [Hemmings, 1996]which makes it easy to discuss in a public forum. This paper summarizes the NEAR program, provides a short synopsis of each of the three cost models, and demonstrates how they were applied for this study.

  6. Thanks to CERN's team of surveyors, the Organization's stand at the Night of Science attracted a large number of visitors : the technology and tools used by the surveyors, such as the Terrameter shown here, attracted many visitors to the CERN stand

    CERN Multimedia

    2004-01-01

    Thanks to CERN's team of surveyors, the Organization's stand at the Night of Science attracted a large number of visitors : the technology and tools used by the surveyors, such as the Terrameter shown here, attracted many visitors to the CERN stand

  7. Holocene millennium-scale climatic variations as recorded by Rb and Sr concentrations for the MGS1 stratigraphical segment of Milanggouwan section in the Salawusu River Valley of Southeast Mu Us Desert%萨拉乌苏河流域MGS1 Rb和Sr记录的全新世千年尺度气候变化

    Institute of Scientific and Technical Information of China (English)

    牛东风; 李保生; 魏建国; 温小浩; 舒培仙; 司月君

    2016-01-01

    萨拉乌苏河流域米浪沟湾剖面全新世地层MGS1层段记录了11个由风成砂与河流相或湖沼相构成的沉积旋回。对该层段63个样品的Rb、Sr数据进行了分析,结果显示由沙丘砂至上覆河湖相Rb和Sr含量由低增高,而Rb/Sr比值的分布则显示出与Rb和Sr含量变化相反的趋势,三者与平均粒径Mz(f)的相关系数都在0.43以上。研究表明MGS1至少经历了11次冷干和11次暖湿的气候波动。米浪沟湾剖面MGS1记录的千年尺度气候波动既是对东亚季风环流演变历史的体现,同时也是对全球气候与环境变化的响应。%The MGS1 stratigraphical segment of Milanggouwan section is located in the Salawusu River Valley of southeast Mu Us Desert. The segment documents 11 sedimentary cycles consisting of aeolian facies and fluvial facies or lacustrine-swamp facies. Totally 63 samples were analyzed for rubidium (Rb) and strontium (Sr) concentrations. The results show that Rb and Sr concentrations increase as the sediments vary from aeolian facies to lacustrine-swamp facies, however, variation of the Rb/Sr ratios shows reversed trends in contrast to that of Rb and Sr concentrations. The line correlation coefficients of Rb and Sr concentrations and Rb/Sr ratios with mean grain size are all above 0.43. All these indicate that the MGS1 stratigraphic segment at least records 11 cold-dry and 11 warm-humid millennium-scale climatic oscillations, which represent the evolution history of East Asian monsoon circulation and show good correspondence to global climatic and environment variations.

  8. Simulating Flexible-Spacecraft Dynamics and Control

    Science.gov (United States)

    Fedor, Joseph

    1987-01-01

    Versatile program applies to many types of spacecraft and dynamical problems. Flexible Spacecraft Dynamics and Control program (FSD) developed to aid in simulation of large class of flexible and rigid spacecraft. Extremely versatile and used in attitude dynamics and control analysis as well as in-orbit support of deployment and control of spacecraft. Applicable to inertially oriented spinning, Earth-oriented, or gravity-gradient-stabilized spacecraft. Written in FORTRAN 77.

  9. Spacecraft Design Thermal Control Subsystem

    Science.gov (United States)

    Miyake, Robert N.

    2003-01-01

    This slide presentation reviews the functions of the thermal control subsystem engineers in the design of spacecraft. The goal of the thermal control subsystem that will be used in a spacecraft is to maintain the temperature of all spacecraft components, subsystems, and all the flight systems within specified limits for all flight modes from launch to the end of the mission. For most thermal control subsystems the mass, power and control and sensing systems must be kept below 10% of the total flight system resources. This means that the thermal control engineer is involved in all other flight systems designs. The two concepts of thermal control, passive and active are reviewed and the use of thermal modeling tools are explained. The testing of the thermal control is also reviewed.

  10. Autonomous Spacecraft Navigation With Pulsars

    CERN Document Server

    Becker, Werner; Jessner, Axel

    2013-01-01

    An external reference system suitable for deep space navigation can be defined by fast spinning and strongly magnetized neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.

  11. Interplanetary spacecraft navigation using pulsars

    CERN Document Server

    Deng, X P; You, X P; Li, M T; Keith, M J; Shannon, R M; Coles, W; Manchester, R N; Zheng, J H; Yu, X Z; Gao, D; Wu, X; Chen, D

    2013-01-01

    We demonstrate how observations of pulsars can be used to help navigate a spacecraft travelling in the solar system. We make use of archival observations of millisecond pulsars from the Parkes radio telescope in order to demonstrate the effectiveness of the method and highlight issues, such as pulsar spin irregularities, which need to be accounted for. We show that observations of four millisecond pulsars every seven days using a realistic X-ray telescope on the spacecraft throughout a journey from Earth to Mars can lead to position determinations better than approx. 20km and velocity measurements with a precision of approx. 0.1m/s.

  12. The MESSIER surveyor: unveiling the ultra-low surface brightness universe

    Science.gov (United States)

    Valls-Gabaud, David; MESSIER Collaboration

    2017-03-01

    The MESSIER surveyor is a small mission designed at exploring the very low surface brightness universe. The satellite will drift-scan the entire sky in 6 filters covering the 200-1000 nm range, reaching unprecedented surface brightness levels of 34 and 37 mag arcsec-2 in the optical and UV, respectively. These levels are required to achieve the two main science goals of the mission: to critically test the ΛCDM paradigm of structure formation through (1) the detection and characterisation of ultra-faint dwarf galaxies, which are predicted to be extremely abundant around normal galaxies, but which remain elusive; and (2) tracing the cosmic web, which feeds dark matter and baryons into galactic haloes, and which may contain the reservoir of missing baryons at low redshifts. A large number of science cases, ranging from stellar mass loss episodes to intracluster light through fluctuations in the cosmological UV-optical background radiation are free by-products of the full-sky maps produced.

  13. Status and path forward for the large ultraviolet/optical/infrared surveyor (LUVOIR) mission concept study

    Science.gov (United States)

    Crooke, Julie A.; Roberge, Aki; Domagal-Goldman, Shawn D.; Mandell, Avi M.; Bolcar, Matthew R.; Rioux, Norman M.; Perez, Mario R.; Smith, Erin C.

    2016-07-01

    In preparation of the 2020 Astrophysics Decadal Survey, National Aeronautics and Space Administration (NASA) has commenced a process for the astronomical community to study several large mission concepts leveraging the lessons learned from past Decadal Surveys. This will enable the Decadal Survey committee to make more informed recommendations to NASA on its astrophysics science and mission priorities with respect to cost and risk. Four astrophysics large mission concepts were identified. Each of them had a Science and Technology Definition Teem (STDT) chartered to produce scientifically compelling, feasible, and executable design reference mission (DRM) concepts to present to the 2020 Decadal Survey. In addition, The Aerospace Corporation will perform an independent cost and technical evaluation (CATE) of each of these mission concept studies in advance of the 2020 Decadal Survey, by interacting with the STDTs to provide detailed technical details on certain areas for which "deep dives" are appropriate. This paper presents the status and path forward for one of the four large mission concepts, namely, the Large UltraViolet, Optical, InfraRed surveyor (LUVOIR).

  14. The Role of County Surveyors and County Drainage Boards in Addressing Water Quality

    Science.gov (United States)

    Dunn, Mike; Mullendore, Nathan; de Jalon, Silvestre Garcia; Prokopy, Linda Stalker

    2016-06-01

    Water quality problems stemming from the Midwestern U.S. agricultural landscape have been widely recognized and documented. The Midwestern state of Indiana contains tens of thousands of miles of regulated drains that represent biotic communities that comprise the headwaters of the state's many rivers and creeks. Traditional management, however, reduces these waterways to their most basic function as conveyances, ignoring their role in the ecosystem as hosts for biotic and abiotic processes that actively regulate the fate and transport of nutrients and farm chemicals. Novel techniques and practices such as the two-stage ditch, denitrifying bioreactor, and constructed wetlands represent promising alternatives to traditional management approaches, yet many of these tools remain underutilized. To date, conservation efforts and research have focused on increasing the voluntary adoption of practices among agricultural producers. Comparatively little attention has been paid to the roles of the drainage professionals responsible for the management of waterways and regulated drains. To address this gap, we draw on survey responses from 39 county surveyors and 85 drainage board members operating in Indiana. By examining the backgrounds, attitudes, and actions of these individuals, we consider their role in advocating and implementing novel conservation practices.

  15. The Cosmology Large Angular Scale Surveyor (CLASS): 40 GHz Optical Design

    Science.gov (United States)

    Eimer, Joseph R.; Bennett, Charles L.; Chuss, David T.; Marriage, Tobias; Wollack, Edward J.; Zeng, Lingzhen

    2012-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) instrument will measure the polarization of the cosmic microwave background at 40, 90, and 150 GHz from Cerro Toco in the Atacama desert of northern Chile. In this paper, we describe the optical design of the 40 GHz telescope system. The telescope is a diffraction limited catadioptric design consisting of a front-end Variable-delay Polarization Modulator (VPM), two ambient temperature mirrors, two cryogenic dielectric lenses, thermal blocking filters, and an array of 36 smooth-wall scalar feedhorn antennas. The feed horns guide the signal to antenna-coupled transition-edge sensor (TES) bolometers. Polarization diplexing and bandpass definition are handled on the same microchip as the TES. The feed horn beams are truncated with 10 dB edge taper by a 4 K Lyot-stop to limit detector loading from stray light and control the edge illumination of the front-end VPM. The field-of-view is 19 deg x 14 deg with a resolution for each beam on the sky of 1.5 deg. FWHM.

  16. Development of x-ray microcalorimeter imaging spectrometers for the X-ray Surveyor mission concept

    Science.gov (United States)

    Bandler, Simon R.; Adams, Joseph S.; Chervenak, James A.; Datesman, Aaron M.; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Richard L.; Kilbourne, Caroline A.; Betancourt-Martinez, Gabriele; Miniussi, Antoine R.; Porter, Frederick S.; Sadleir, John E.; Sakai, Kazuhiro; Smith, Stephen J.; Stevenson, Thomas R.; Wakeham, Nicholas A.; Wassell, Edward J.; Yoon, Wonsik; Becker, Dan; Bennett, Douglas; Doriese, William B.; Fowler, Joseph W.; Gard, Johnathan D.; Hilton, Gene C.; Mates, Benjamin; Morgan, Kelsey M.; Reintsema, Carl D.; Swetz, Daniel; Ullom, Joel N.; Chaudhuri, Saptarshi; Irwin, Kent D.; Lee, Sang-Jun; Vikhlinin, Alexey

    2016-07-01

    Four astrophysics missions are currently being studied by NASA as candidate large missions to be chosen in the 2020 astrophysics decadal survey.1 One of these missions is the "X-Ray Surveyor" (XRS), and possible configurations of this mission are currently under study by a science and technology definition team (STDT). One of the key instruments under study is an X-ray microcalorimeter, and the requirements for such an instrument are currently under discussion. In this paper we review some different detector options that exist for this instrument, and discuss what array formats might be possible. We have developed one design option that utilizes either transition-edge sensor (TES) or magnetically coupled calorimeters (MCC) in pixel array-sizes approaching 100 kilo-pixels. To reduce the number of sensors read out to a plausible scale, we have assumed detector geometries in which a thermal sensor such a TES or MCC can read out a sub-array of 20-25 individual 1" pixels. In this paper we describe the development status of these detectors, and also discuss the different options that exist for reading out the very large number of pixels.

  17. The Cosmology Large Angular Scale Surveyor (CLASS): 40 GHz optical design

    CERN Document Server

    Eimer, Joseph R; Chuss, David T; Marriage, Tobias A; Wollack, Edward J; Zeng, Lingzhen; 10.1117/12.925464

    2012-01-01

    The Cosmology Large Angular Scale Surveyor (CLASS) instrument will measure the polarization of the cosmic microwave background at 40, 90, and 150 GHz from Cerro Toco in the Atacama desert of northern Chile. In this paper, we describe the optical design of the 40 GHz telescope system. The telescope is a diffraction limited catadioptric design consisting of a front-end Variable-delay Polarization Modulator (VPM), two ambient temperature mirrors, two cryogenic dielectric lenses, thermal blocking filters, and an array of 36 smooth-wall scalar feedhorn antennas. The feed horns guide the signal to antenna-coupled transition-edge sensor (TES) bolometers. Polarization diplexing and bandpass definition are handled on the same microchip as the TES. The feed horn beams are truncated with 10 dB edge taper by a 4 K Lyot-stop to limit detector loading from stray light and control the edge illumination of the front-end VPM. The field-of-view is 19deg x 14deg with a resolution for each beam on the sky of 1.5deg FWHM.

  18. Future Japanese X-ray TES Calorimeter Satellite: DIOS (Diffuse Intergalactic Oxygen Surveyor)

    Science.gov (United States)

    Yamada, S.; Ohashi, T.; Ishisaki, Y.; Ezoe, Y.; Miyazaki, N.; Kuwabara, K.; Kuromaru, G.; Suzuki, S.; Mitsuda, K.; Yamasaki, N. Y.; Takei, Y.; Sakai, K.; Nagayoshi, K.; Yamamoto, R.; Hayashi, T.; Muramatsu, H.; Tawara, Y.; Mitsuishi, I.; Babazaki, Y.; Nakamichi, R.; Bandai, A.; Yuasa, T.; Ota, N.

    2016-08-01

    We present the latest update and progress on the future Japanese X-ray satellite mission Diffuse Intergalactic Oxygen Surveyor (DIOS). DIOS is proposed to JAXA as a small satellite mission, and would be launched with an Epsilon rocket. DIOS would carry on the legacy of ASTRO-H, which carries semiconductor-based microcalorimeters and is scheduled to be launched in 2016, in high-resolution X-ray spectroscopy. A 400-pixel array of transition-edge sensors (TESs) would be employed, so DIOS would also provide valuable lessons for the next ESA X-ray mission ATHENA on TES operation and cryogen-free cooling in space. We have been sophisticating the entire design of the satellite to meet the requirement for the Epsilon payload for the next call. The primary goal of the mission is to search for warm-hot intergalactic medium with high-resolution X-ray spectroscopy by detecting redshifted emission lines from OVII and OVIII ions. The results would have significant impacts on our understanding of the nature of "dark baryons," their total amount and spatial distribution, as well as their evolution over cosmological timescales.

  19. The cosmology large angular scale surveyor (CLASS): 40 GHz optical design

    Science.gov (United States)

    Eimer, Joseph R.; Bennett, Charles L.; Chuss, David T.; Marriage, Tobias; Wollack, Edward J.; Zeng, Lingzhen

    2012-09-01

    The Cosmology Large Angular Scale Surveyor (CLASS) instrument will measure the polarization of the cosmic microwave background at 40, 90, and 150 GHz from Cerro Toco in the Atacama desert of northern Chile. In this paper, we describe the optical design of the 40 GHz telescope system. The telescope is a diffraction limited catadioptric design consisting of a front-end Variable-delay Polarization Modulator (VPM), two ambient temperature mirrors, two cryogenic dielectric lenses, thermal blocking filters, and an array of 36 smooth-wall scalar feedhorn antennas. The feed horns guide the signal to antenna-coupled transition-edge sensor (TES) bolometers. Polarization diplexing and bandpass definition are handled on the same microchip as the TES. The feed horn beams are truncated with 10 dB edge taper by a 4 K Lyot-stop to limit detector loading from stray light and control the edge illumination of the front-end VPM. The field-of-view is 19° x 14° with a resolution for each beam on the sky of 1.5° FWHM.

  20. Optimal Reorientation Of Spacecraft Orbit

    Directory of Open Access Journals (Sweden)

    Chelnokov Yuriy Nikolaevich

    2014-06-01

    Full Text Available The problem of optimal reorientation of the spacecraft orbit is considered. For solving the problem we used quaternion equations of motion written in rotating coordinate system. The use of quaternion variables makes this consideration more efficient. The problem of optimal control is solved on the basis of the maximum principle. An example of numerical solution of the problem is given.

  1. Spacecraft Modularity for Serviceable Satellites

    Science.gov (United States)

    Rossetti, Dino; Keer, Beth; Panek, John; Reed, Benjamin; Cepollina, Frank; Ritter, Robert

    2015-01-01

    Satellite servicing has been a proven capability of NASA since the first servicing missions in the 1980s with astronauts on the space shuttle. This capability enabled the on-orbit assembly of the International Space Station (ISS) and saved the Hubble Space Telescope (HST) mission following the discovery of the flawed primary mirror. The effectiveness and scope of servicing opportunities, especially using robotic servicers, is a function of how cooperative a spacecraft is. In this paper, modularity will be presented as a critical design aspect for a spacecraft that is cooperative from a servicing perspective. Different features of modularity are discussed using examples from HST and the Multimission Modular Spacecraft (MMS) program from the 1980s and 1990s. The benefits of modularity will be presented including those directly related to servicing and those outside of servicing including reduced costs and increased flexibility. The new Reconfigurable Operational spacecraft for Science and Exploration (ROSE) concept is introduced as an affordable implementation of modularity that provides cost savings and flexibility. Key aspects of the ROSE architecture are discussed such as the module design and the distributed avionics architecture. The ROSE concept builds on the experience from MMS and due to its modularity, would be highly suitable as a future client for on-orbit servicing.

  2. Propulsion Challenges for Small Spacecraft: 2005

    Institute of Scientific and Technical Information of China (English)

    Vadim Zakirov; LI Luming

    2006-01-01

    Small (<100 kg) spacecrafts are being developed in many countries but their propulsion systems still have many challenges. Although there is demand for small spacecraft propulsion, the number of missions at present is small due to several commercial and technical reasons. Poor performance of existing small spacecraft propulsion systems is one of the main reasons for the small number of missions. Several reasons are given for the poor performance of existing small spacecraft propulsion. Suggested improvements focus on small spacecraft and propulsion hardware mass optimization rather than on specific impulse enhancement. Propellantless propulsion systems are also recommended for small spacecraft interplanetary missions.

  3. Mirko Danijel Bogdanić (1760-1802, Astronomer, Mathematician, Surveyor and Croatian Educator

    Directory of Open Access Journals (Sweden)

    Tatjana Kren

    2010-12-01

    Full Text Available This article provides valuable information about the life and work of Mirko Danijel Bogdanić (Bogdanić Imre Dániel (Virovitica, 1762 – Buda, 1802 who was an astronomer, mathematician, surveyor and the author of a book on world history in Croatian. This article observes his life and work from the historical perspective of the time of Emperor Joseph II in Austria. From 1782 to 1785, Bogdanić studied mathematics, physics and astronomy in Buda and Pešt. He often worked with famous Croatian scientists such as Ivan Paskvić (János Pasquich, Franjo Bruna (Ferenc Bruna, Josip Mitterpacher (József Mitterpacher and others. Particular attention is paid to the period between approximately 1791 and 1796, which he spent in Vienna. At first, he focused on publishing the first volume of his history of the world in Croatian (Dogodjaji svieta (World events, 1792 in which he paid particular attention to astronomy and Croatian astronomical terminology. From 1793 to 1795, he studied astronomy at the University of Vienna. The following period was the most important in his life. He was second, then first assistant at the Buda Observatory (1796–1802 and also (1798–1802 appointed Imperial Assistant Astronomer to the cartographer János Lipszky, charged with conducting precise astronomical observations to determine the geographical coordinates for the geographical map of Hungary (Mappa Generalis Regni Hungariae. His observations, especially of latitudes, were considered excellent. He spent many long, hard hours working in the field under adverse weather conditions, leading to extreme exhaustion, which resulted in serious illness and his premature death.

  4. The Cosmology Large Angular Scale Surveyor (CLASS): In search of the energy scale of inflation

    Science.gov (United States)

    Eimer, Joseph R.

    The hypothesis that the early universe underwent a period of accelerating expansion, called inflation, has become an essential mechanism for explaining the flatness and homogeneity of the universe and explaining the fluctuations found in the cosmic microwave background (CMB). Inflation predicts the existence of primordial gravitational waves that would have produced a unique polarization pattern on the CMB. Measurement of the amplitude of these gravitational waves can be used to infer the energy scale of the potential driving the expansion. Detection of this signal would be a dramatic confirmation of the inflation paradigm and significantly tighten constraints on inflationary models. The Cosmology Large Angular Scale Surveyor (CLASS) is a new ground-based instrument designed to search for the inflationary B-mode signal from the Atacama Desert in northern Chile (elevation ~ 5200 m). The CLASS instrument will observe over 60% of the sky to target the large scale polarization signal (> 10 deg), and consist of four separate telescopes: one observing at 40 GHz, two observing at 90 GHz and one observing at 150 GHz. The detectors for each band will be background limited antenna-coupled transition edge sensor bolometers. A variable-delay polarization modulator (VPM) will be placed as the first optical element in each of the telescopes. The front-end polarization modulator will mitigate many systematic effects and provide a powerful means of distinguishing the instrument response from the input signal. This dissertation contains an overview of the CLASS instrument. Specific emphasis is placed on the connection between the science goals and the instrument architecture. A description of the optical design of the 40 GHz telescope is given, and the application of the VPM technology to the CLASS instrument is described. We end with an overview of the detectors.

  5. Service Oriented Spacecraft Modeling Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The I-Logix team proposes development of the Service Oriented Spacecraft Modeling Environment (SOSME) to allow faster and more effective spacecraft system design...

  6. Quick Spacecraft Thermal Analysis Tool Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For spacecraft design and development teams concerned with cost and schedule, the Quick Spacecraft Thermal Analysis Tool (QuickSTAT) is an innovative software suite...

  7. Meteoroids are Dangerous to Spacecraft

    Science.gov (United States)

    Moorhead, Althea V.

    2017-01-01

    Meteoroids put dents in Shuttle windows much like bouncing gravel puts dents in your car's windshield. However, meteoroids move at such high speeds that they can partly vaporize the surfaces they strike! A dust particle (smaller than a meteoroid) hit the STEREO spacecraft and produced this fountain of smaller particles. When a meteoroid breaks up, its "shrapnel" can also be dangerous. Even when meteoroids don't damage a spacecraft, they can cause problems. Here, a small meteoroid bumped a camera on the Lunar Reconnaissance Orbiter (LRO), causing wiggles in this scan of the lunar surface. Meteoroids and pieces of space junk create rough edges on the outside of the Space Station that can damage space suits. The astronauts' gloves had to be thickened to help prevent them from ripping.

  8. Attitude Fusion Techniques for Spacecraft

    DEFF Research Database (Denmark)

    Bjarnø, Jonas Bækby

    Spacecraft platform instability constitutes one of the most significant limiting factors in hyperacuity pointing and tracking applications, yet the demand for accurate, timely and reliable attitude information is ever increasing. The PhD research project described within this dissertation has...... served to investigate the solution space for augmenting the DTU μASC stellar reference sensor with a miniature Inertial Reference Unit (IRU), thereby obtaining improved bandwidth, accuracy and overall operational robustness of the fused instrument. Present day attitude determination requirements are met...... of the instrument, and affecting operations during agile and complex spacecraft attitude maneuvers. As such, there exists a theoretical foundation for augmenting the high frequency performance of the μASC instrument, by harnessing the complementary nature of optical stellar reference and inertial sensor technology...

  9. Spacecraft Tests of General Relativity

    Science.gov (United States)

    Anderson, John D.

    1997-01-01

    Current spacecraft tests of general relativity depend on coherent radio tracking referred to atomic frequency standards at the ground stations. This paper addresses the possibility of improved tests using essentially the current system, but with the added possibility of a space-borne atomic clock. Outside of the obvious measurement of the gravitational frequency shift of the spacecraft clock, a successor to the suborbital flight of a Scout D rocket in 1976 (GP-A Project), other metric tests would benefit most directly by a possible improved sensitivity for the reduced coherent data. For purposes of illustration, two possible missions are discussed. The first is a highly eccentric Earth orbiter, and the second a solar-conjunction experiment to measure the Shapiro time delay using coherent Doppler data instead of the conventional ranging modulation.

  10. Flywheel energy storage for spacecraft

    Science.gov (United States)

    Gross, S.

    1984-01-01

    Flywheel energy storage systems have been studied to determine their potential for use in spacecraft. This system was found to be superior to alkaline secondary batteries and regenerative fuel cells in most of the areas that are important in spacecraft applications. Of special importance, relative to batteries, are lighter weight, longer cycle and operating life, and high efficiency which minimizes solar array size and the amount of orbital makeup fuel required. In addition, flywheel systems have a long shelf life, give a precise state of charge indication, have modest thermal control needs, are capable of multiple discharges per orbit, have simple ground handling needs, and have the capability of generating extremely high power for short durations.

  11. Spacecraft Tests of General Relativity

    Science.gov (United States)

    Anderson, John D.

    1997-01-01

    Current spacecraft tests of general relativity depend on coherent radio tracking referred to atomic frequency standards at the ground stations. This paper addresses the possibility of improved tests using essentially the current system, but with the added possibility of a space-borne atomic clock. Outside of the obvious measurement of the gravitational frequency shift of the spacecraft clock, a successor to the suborbital flight of a Scout D rocket in 1976 (GP-A Project), other metric tests would benefit most directly by a possible improved sensitivity for the reduced coherent data. For purposes of illustration, two possible missions are discussed. The first is a highly eccentric Earth orbiter, and the second a solar-conjunction experiment to measure the Shapiro time delay using coherent Doppler data instead of the conventional ranging modulation.

  12. Multiple spacecraft Michelson stellar interferometer

    Science.gov (United States)

    Stachnik, R. V.; Arnold, D.; Melroy, P.; Mccormack, E. F.; Gezari, D. Y.

    1984-01-01

    Results of an orbital analysis and performance assessment of SAMSI (Spacecraft Array for Michelson Spatial Interferometry) are presented. The device considered includes two one-meter telescopes in orbits which are identical except for slightly different inclinations; the telescopes achieve separations as large as 10 km and relay starlight to a central station which has a one-meter optical delay line in one interferometer arm. It is shown that a 1000-km altitude, zero mean inclination orbit affords natural scanning of the 10-km baseline with departures from optical pathlength equality which are well within the corrective capacity of the optical delay line. Electric propulsion is completely adequate to provide the required spacecraft motions, principally those needed for repointing. Resolution of 0.00001 arcsec and magnitude limits of 15 to 20 are achievable.

  13. Autonomous spacecraft rendezvous and docking

    Science.gov (United States)

    Tietz, J. C.; Almand, B. J.

    A storyboard display is presented which summarizes work done recently in design and simulation of autonomous video rendezvous and docking systems for spacecraft. This display includes: photographs of the simulation hardware, plots of chase vehicle trajectories from simulations, pictures of the docking aid including image processing interpretations, and drawings of the control system strategy. Viewgraph-style sheets on the display bulletin board summarize the simulation objectives, benefits, special considerations, approach, and results.

  14. Laser Diagnostics for Spacecraft Propulsion

    Science.gov (United States)

    2015-10-13

    AFTC/PA Clearance No. XXXX 8 Ion Engines & Hall Thrusters Operation Ion engines and Hall thrusters are electrostatic propulsion devices • Ion Engines... Hall thrusters are gridless electrostatic thrusters – Propellant ionized by electrons trapped in magnetic field – Ions accelerated by an electric field...Briefing Charts 3. DATES COVERED (From - To) 21 September 2015 – 13 October 2015 4. TITLE AND SUBTITLE Laser Diagnostics for Spacecraft Propulsion 5a

  15. Spacecraft Pointing and Position Control,

    Science.gov (United States)

    1981-11-01

    Automatic Control, Vol. AC-16, No. 6, December 1971. [8] HEIMBOLD, G. Dynamisches Modell eines dreiachsstabilisierten, geostation&- ren Satelliten mit...the error in the star and scanner slit normal orthogonality. This spacecraft attitude also provides intermittent updates for the gyro propagated...attitude determination has been designed and successfully implemented in various earth- orbiting satellites [Ref. 1-4]. It involves a star scanner

  16. Energy Storage Flywheels on Spacecraft

    Science.gov (United States)

    Bartlett, Robert O.; Brown, Gary; Levinthal, Joel; Brodeur, Stephen (Technical Monitor)

    2002-01-01

    With advances in carbon composite material, magnetic bearings, microprocessors, and high-speed power switching devices, work has begun on a space qualifiable Energy Momentum Wheel (EMW). An EMW is a device that can be used on a satellite to store energy, like a chemical battery, and manage angular momentum, like a reaction wheel. These combined functions are achieved by the simultaneous and balanced operation of two or more energy storage flywheels. An energy storage flywheel typically consists of a carbon composite rotor driven by a brushless DC motor/generator. Each rotor has a relatively large angular moment of inertia and is suspended on magnetic bearings to minimize energy loss. The use of flywheel batteries on spacecraft will increase system efficiencies (mass and power), while reducing design-production time and life-cycle cost. This paper will present a discussion of flywheel battery design considerations and a simulation of spacecraft system performance utilizing four flywheel batteries to combine energy storage and momentum management for a typical LEO satellite. A proposed set of control laws and an engineering animation will also be presented. Once flight qualified and demonstrated, space flywheel batteries may alter the architecture of most medium and high-powered spacecraft.

  17. Spacecraft

    Science.gov (United States)

    Clark, John F.; Haggerty, James J.; Woodburn, John H.

    1961-01-01

    In this twentieth century, we are privileged to witness the first steps toward realization of an age-old dream: the exploration of space. Already, in the first few years of the Space Age, man has been able to penetrate the layer of atmosphere which surrounds his planet and to venture briefly into space. Scores of man-made objects have been thrust into space, some of them to roam the solar system forever. Behind each space mission are years of patient research, thousands of man-hours of labor, and large sums of money. Because the sums involved are so enormous, the question is frequently asked, "Is it worth it?" Many people want to know what return this huge investment will bring to mankind. The return on the investment is knowledge. The accumulation of knowledge over the centuries has made possible our advanced way of life. As we unlock more and more of the secrets of the universe through space exploration, we add new volumes to the encyclopedia of man's knowledge. This will be applied to the benefit of mankind. For the practical-minded, there are concrete benefits to our way of life. Although we are still in the Stone Age of space exploration, a number of immediate applications of space technology are already apparent. For instance, imagine the benefits of an absolutely perfect system of predicting the weather. Or, going a step further, even changing the weather. And wouldn't it be fascinating to watch the next Olympic games, telecast from Tokyo, on your TV set? These are just a few of the practical benefits made possible by space technology.

  18. Coffee-can-sized spacecraft

    Science.gov (United States)

    Jones, Ross M.

    1988-01-01

    The current status and potential scientific applications of intelligent 1-5-kg projectiles being developed by SDIO and DARPA for military missions are discussed. The importance of advanced microelectronics for such small spacecraft is stressed, and it is pointed out that both chemical rockets and EM launchers are currently under consideration for these lightweight exoatmospheric projectiles (LEAPs). Long-duration power supply is identified as the primary technological change required if LEAPs are to be used for interplanetary scientific missions, and the design concept of a solar-powered space-based railgun to accelerate LEAPs on such missions is considered.

  19. Advanced antennas for SAR spacecraft

    Science.gov (United States)

    Gail, William B.

    1993-01-01

    Single and multi-frequency antenna concepts were developed to evaluate the feasibility of building large aperture polarimetric synthetic aperture radar (SAR) systems to be launched in low cost vehicles such as the Delta 2. The antennas are 18.9 m long by 2.6 m wide (L-band) and achieve single polarization imaging to an incidence angle of 55 degrees and dual/quad imaging to 42 degrees. When combined with strawman spacecraft designs, both concepts meet the mass and volume constraints imposed by a Delta 2 launch.

  20. Improvement of job satisfaction and organisational commitment through work group identification: an examination of the quantity surveyors in Hong Kong

    Directory of Open Access Journals (Sweden)

    Wai Yee Betty Chiu

    2013-09-01

    Full Text Available Though extant literatures in other sectors indicatethat job satisfaction and organizational commitment are important fordetermining individual and organisational outcomes, limited related researchhas been conducted amongst quantity surveyors in Hong Kong. Given cooperativeworking arrangement in the quantity surveying profession, work groupidentification is regarded as an important antecedent for determining jobsatisfaction and organisational commitment. The aim of this study is to examinewhether work group identification improves job satisfaction and organisationalcommitment. A questionnaire survey is conducted to collect data from quantitysurveyors working in private sector. A total of 71 valid responses are obtainedfrom 509 contacted quantity surveyors in Hong Kong. Bivariate correlation andmultiple regression analyses are performed to find the significance ofrelationships among the variables. Data analysis results support mosthypotheses. Work group identification is found to have significant positiveeffect on job satisfaction, affective and normative commitment. The finding isa bold step for quantity surveying companies to improve their quantity surveyors’job satisfaction and commitment level. The role of other contextual and organisationalfactors on job satisfaction and organisational commitment needs to becomplemented for future research.

  1. A simple, high sensitivity mutation screening using Ampligase mediated T7 endonuclease I and Surveyor nuclease with microfluidic capillary electrophoresis.

    Science.gov (United States)

    Huang, Mo Chao; Cheong, Wai Chye; Lim, Li Shi; Li, Mo-Huang

    2012-03-01

    Mutation and polymorphism detection is of increasing importance for a variety of medical applications, including identification of cancer biomarkers and genotyping for inherited genetic disorders. Among various mutation-screening technologies, enzyme mismatch cleavage (EMC) represents a great potential as an ideal scanning method for its simplicity and high efficiency, where the heteroduplex DNAs are recognized and cleaved into DNA fragments by mismatch-recognizing nucleases. Thereby, the enzymatic cleavage activities of the resolving nucleases play a critical role for the EMC sensitivity. In this study, we utilized the unique features of microfluidic capillary electrophoresis and de novo gene synthesis to explore the enzymatic properties of T7 endonuclease I and Surveyor nuclease for EMC. Homoduplex and HE DNAs with specific mismatches at desired positions were synthesized using PCR (polymerase chain reaction) gene synthesis. The effects of nonspecific cleavage, preference of mismatches, exonuclease activity, incubation time, and DNA loading capability were systematically examined. In addition, the utilization of a thermostable DNA ligase for real-time ligase mediation was investigated. Analysis of the experimental results has led to new insights into the enzymatic cleavage activities of T7 endonuclease I and Surveyor nuclease, and aided in optimizing EMC conditions, which enhance the sensitivity and efficiency in screening of unknown DNA variations.

  2. Hybrid spacecraft attitude control system

    Directory of Open Access Journals (Sweden)

    Renuganth Varatharajoo

    2016-02-01

    Full Text Available The hybrid subsystem design could be an attractive approach for futurespacecraft to cope with their demands. The idea of combining theconventional Attitude Control System and the Electrical Power System ispresented in this article. The Combined Energy and Attitude ControlSystem (CEACS consisting of a double counter rotating flywheel assemblyis investigated for small satellites in this article. Another hybrid systemincorporating the conventional Attitude Control System into the ThermalControl System forming the Combined Attitude and Thermal ControlSystem (CATCS consisting of a "fluid wheel" and permanent magnets isalso investigated for small satellites herein. The governing equationsdescribing both these novel hybrid subsystems are presented and theironboard architectures are numerically tested. Both the investigated novelhybrid spacecraft subsystems comply with the reference missionrequirements.The hybrid subsystem design could be an attractive approach for futurespacecraft to cope with their demands. The idea of combining theconventional Attitude Control System and the Electrical Power System ispresented in this article. The Combined Energy and Attitude ControlSystem (CEACS consisting of a double counter rotating flywheel assemblyis investigated for small satellites in this article. Another hybrid systemincorporating the conventional Attitude Control System into the ThermalControl System forming the Combined Attitude and Thermal ControlSystem (CATCS consisting of a "fluid wheel" and permanent magnets isalso investigated for small satellites herein. The governing equationsdescribing both these novel hybrid subsystems are presented and theironboard architectures are numerically tested. Both the investigated novelhybrid spacecraft subsystems comply with the reference missionrequirements.

  3. Electrolysis Propulsion for Spacecraft Applications

    Science.gov (United States)

    deGroot, Wim A.; Arrington, Lynn A.; McElroy, James F.; Mitlitsky, Fred; Weisberg, Andrew H.; Carter, Preston H., II; Myers, Blake; Reed, Brian D.

    1997-01-01

    Electrolysis propulsion has been recognized over the last several decades as a viable option to meet many satellite and spacecraft propulsion requirements. This technology, however, was never used for in-space missions. In the same time frame, water based fuel cells have flown in a number of missions. These systems have many components similar to electrolysis propulsion systems. Recent advances in component technology include: lightweight tankage, water vapor feed electrolysis, fuel cell technology, and thrust chamber materials for propulsion. Taken together, these developments make propulsion and/or power using electrolysis/fuel cell technology very attractive as separate or integrated systems. A water electrolysis propulsion testbed was constructed and tested in a joint NASA/Hamilton Standard/Lawrence Livermore National Laboratories program to demonstrate these technology developments for propulsion. The results from these testbed experiments using a I-N thruster are presented. A concept to integrate a propulsion system and a fuel cell system into a unitized spacecraft propulsion and power system is outlined.

  4. First Spacecraft Orbit of Mercury

    Science.gov (United States)

    Showstack, Randy

    2011-03-01

    After a 7.9-billion-kilometer flight since its launch on 3 August 2004—which included flybys of Earth, Venus, and Mercury—NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft entered a planned, highly elliptical orbit around the closest planet to our Sun on 17 March. Engineers in the mission operations center at the Johns Hopkins University Applied Physics Laboratory (JHU/APL) in Laurel, Md., which manages the mission for NASA, received radiometric signals indicating a successful orbit insertion at 9:10 P.M. local time. "Tonight we will have orbited the fifth planet in the solar system. This is a major accomplishment," Ed Weiler, NASA assistant administrator for the Science Mission Directorate, said at a 17 March public forum at JHU/APL, noting that spacecraft have previously entered orbit around several other planets. "You only go into orbit for the first time around Mercury once in human history, and that is what was accomplished tonight."

  5. Rapid Spacecraft Development: Results and Lessons Learned

    Science.gov (United States)

    Watson, William A.

    2002-01-01

    The Rapid Spacecraft Development Office (RSDO) at NASA's Goddard Space Flight Center is responsible for the management and direction of a dynamic and versatile program for the definition, competition, and acquisition of multiple indefinite delivery and indefinite quantity contracts - resulting in a catalog of spacecraft buses. Five spacecraft delivery orders have been placed by the RSDO and one spacecraft has been launched. Numerous concept and design studies have been performed, most with the intent of leading to a future spacecraft acquisition. A collection of results and lessons learned is recorded to highlight management techniques, methods and processes employed in the conduct of spacecraft acquisition. Topics include working relationships under fixed price delivery orders, price and value, risk management, contingency reserves, and information restrictions.

  6. Computer simulation of spacecraft/environment interaction.

    Science.gov (United States)

    Krupnikov, K K; Makletsov, A A; Mileev, V N; Novikov, L S; Sinolits, V V

    1999-10-01

    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991 1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language.

  7. Computer simulation of spacecraft/environment interaction

    CERN Document Server

    Krupnikov, K K; Mileev, V N; Novikov, L S; Sinolits, V V

    1999-01-01

    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991-1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language.

  8. Formation Flying Spacecraft Concept for Heliophysics Applications

    Science.gov (United States)

    Novo-Gradac, Anne-Marie; Davila, Joseph; Yang, Guangning; Lu, Wei; Shah, Neerav; Li, Steven X.

    2016-05-01

    A number of space-based heliophysics instruments would benefit from formation flying spacecraft. An occulter or a focusing optic such as a photon sieve could be mounted on a separate spacecraft rather than at the end of a boom. This would enable science measurements to be made on smaller, less expensive spacecraft. To accomplish this goal, the relative position of the spacecraft must be monitored and controlled to high precision. We describe two separate optical sensing systems that monitor relative position of the spacecraft to the level required for a photon sieve mission concept wherein the photon sieve is mounted on one spacecraft while the imaging detector is mounted on another. The first system employs a novel time of flight measurement of a laser beam that includes imbedded optical data packets. The contents of the returning data packet can be compared to the departing data packet to provide an extremely high resolution distance measurement. Employing three such systems allows measurement of pitch and yaw in addition to longitudinal separation. The second optical system monitors lateral motion. A mildy divergent laser beam is transmitted from one spacecraft to a sensor array on the second spacecraft. Monitoring the position of the brightest portion of the beam on the sensor array provides a direct measurement of lateral relative motion. Employing at least two such systems enables monitoring roll of the spacecraft as well as centration. We will also discuss low force thruster systems required for high precision station keeping.

  9. ESA's billion star surveyor - Flight operations experience from Gaia's first 1.5 Years

    Science.gov (United States)

    Milligan, D.; Rudolph, A.; Whitehead, G.; Loureiro, T.; Serpell, E.; di Marco, F.; Marie, J.; Ecale, E.

    2016-10-01

    This paper details the initial in-flight mission operations experience from ESA's ultra-precise Gaia spacecraft. Tasked with mapping the positions and movements of 1 billion stars to unprecedented precision (to the 10 s of micro-arc-second level, comparable to the width of a coin on the Moon as viewed from Earth). ESA's Science cornerstone mission is expected to also discover and chart 100,000's of new objects including near Earth Asteroids, exoplanets, brown dwarfs and Quasars. After a flawless launch 19 Dec 2013, Gaia was brought the circa 1.5 million kms into L2 via a sequence of technically demanding orbit transfer manoeuvres using onboard thrusters in thrust vectoring mode. Starting in parallel to this, and lasting 6 months, the full spacecraft was commissioned and brought gradually up to the highest operational mode. A number of problems were detected and tackled during commissioning and early routine phase operations. An apparent dimming of the on-board laser and imaged stars, was tracked down to water ice building up inside the telescope enclosure. Also apparent was more straylight than expected. Elsewhere, a micro-propulsion thruster developed unexpected performance levels and a back-up chemical thruster suffered a failed latch valve. These issues, like several others, were dealt with and solved in a series of review meetings, in-orbit special operations and newly developed procedures and on-board software changes. After commissioning Gaia was working so well that it was producing approximately 45% more science data than originally foreseen, primarily since it was able to see stars fainter than required. The mission operations concept was quickly adapted to partially automate ground operations and increase ground station time to allow the full scientific potential of Gaia to be realised.

  10. NEAR Shoemaker spacecraft mission operations

    Science.gov (United States)

    Holdridge, Mark E.

    2002-01-01

    On 12 February 2001, Near Earth Asteroid Rendezvous (NEAR) Shoemaker became the first spacecraft to land on a small body, 433 Eros. Prior to that historic event, NEAR was the first-ever orbital mission about an asteroid. The mission presented general challenges associated with other planetary space missions as well as challenges unique to an inaugural mission around a small body. The NEAR team performed this operations feat with processes and tools developed during the 4-year-long cruise to Eros. Adding to the success of this historic mission was the cooperation among the NEAR science, navigation, guidance and control, mission design, and software teams. With clearly defined team roles, overlaps in responsibilities were minimized, as were the associated costs. This article discusses the processes and systems developed at APL that enabled the success of NEAR mission operations.

  11. Spacecraft Water Exposure Guidelines (SWEGs)

    Science.gov (United States)

    James, John T.

    2008-01-01

    As the protection of crew health is a primary focus of the National Aeronautics and Space Administration, the Space and Life Sciences Directorate (SLSD) is vigilant in setting potable water limits for spaceflight that are health protective. Additional it is important that exposure limits not be set so stringently that water purification systems are unnecessarily over designed. With these considerations in mind, NASA has partnered with the National Research Council on Toxicology (NRCCOT) to develop spacecraft water exposure guidelines (SWEGs) for application in spaceflight systems. Based on documented guidance (NRC, 2000) NASA has established 28 SWEGs for chemical components that are particularly relevant to water systems on the International Space Station, the Shuttle and looking forward to Constellation.

  12. DHPLC/SURVEYOR nuclease: a sensitive, rapid and affordable method to analyze BRCA1 and BRCA2 mutations in breast cancer families.

    Science.gov (United States)

    Pilato, Brunella; De Summa, Simona; Danza, Katia; Papadimitriou, Stavros; Zaccagna, Paolo; Paradiso, Angelo; Tommasi, Stefania

    2012-09-01

    Hereditary breast cancer accounts for about 10% of all breast cancers and BRCA1 and BRCA2 genes have been identified as validated susceptibility genes for this pathology. Testing for BRCA gene mutations is usually based on a pre-screening approach, such as the partial denaturation DHPLC method, and capillary direct sequencing. However, this approach is time consuming due to the large size of BRCA1 and BRCA2 genes. Recently, a new low cost and time saving DHPLC protocol has been developed to analyze gene mutations by using SURVEYOR(®) Nuclease digestion and DHPLC analysis. A subset of 90 patients, enrolled in the Genetic Counseling Program of the National Cancer Centre of Bari (Italy), was performed to validate this approach. Previous retrospective analysis showed that 9/90 patients (10%) were mutated in BRCA1 and BRCA2 genes and these data were confirmed by the present approach. DNA samples underwent touchdown PCR and, subsequently, SURVEYOR(®) nuclease digestion. BRCA1 and BRCA2 amplicons were divided into groups depending on amplicon size to allow multiamplicon digestion. The product of this reaction were analyzed on Transgenomic WAVE Nucleic Acid High Sensitivity Fragment Analysis System. The operator who performed the DHPLC surveyor approach did not know the sequencing results at that time. The SURVEYOR(®) Nuclease DHPLC approach was able to detect all alterations with a sensitivity of 95%. Furthermore, in order to save time and reagents, a multiamplicon setting preparation was validated.

  13. Spacecraft electronics design for radiation tolerance

    Science.gov (United States)

    Rasmussen, Robert D.

    1988-01-01

    Current design practices are described and future trends in spacecraft electronics which are likely to alter traditional approaches are discussed. A summary of radiation effects and radiation tolerance requirements typically levied on spacecraft designs is provided. Methods of dealing with radiation and testability issues are considered.

  14. Wet oxidation of a spacecraft model waste

    Science.gov (United States)

    Johnson, C. C.; Wydeven, T.

    1985-01-01

    Wet oxidation was used to oxidize a spacecraft model waste under different oxidation conditions. The variables studied were pressure, temperature, duration of oxidation, and the use of one homogeneous and three heterogeneous catalysts. Emphasis is placed on the final oxidation state of carbon and nitrogen since these are the two major components of the spacecraft model waste and two important plant nutrients.

  15. Evaluation of Cast Re-Orientation on a Dental Surveyor Using Three Tripod Techniques: A Survey and In Vitro Study.

    Science.gov (United States)

    Sayed, Mohammed E; Busaily, Idris A; Nahari, Rana J; Hakami, Ruaa O; Maashi, Sami M; Ramireddy, Naveen R

    2017-01-18

    To survey different educational levels (i.e., students, interns, technicians, and prosthodontic faculty) with regard to their opinions, attitudes, and adoption of three selected tripod techniques. The study will also investigate the accuracy of these techniques to reposition casts on the dental surveyor in anterio-posterior (AP) and lateral directions at both technique and educational levels. Tripod points, scored lines, and cemented post tripod techniques were used in this study. Three Kennedy class II modification I stone casts, duplicated from a standard cast, were assigned to each of the tripod techniques. The tilt angles of all casts were set on the dental surveyor to 10° (control angle) in AP and lateral directions using a digital angle gauge with an accuracy of 0.2°. The casts were tripoded accordingly. A total of 243 participants were involved in this study. Participants were first asked to remount the three casts on three different dental surveyors using the tripod technique noted on each cast. Questionnaires were then given to each participant in an individual interview setting; this assured a 100% response rate. The angle differences were calculated. All data were coded and entered into an Excel Spreadsheet file. Statistical analyses were performed using a paired Chi-square, Wilcoxon Matched-pairs, ANOVA, and Tukey post hoc tests at 5% level of significance. No significant difference was found between the educational levels relative to the responses to technique demands, sensitivity, and time required for reorientation (p = 0.08202, 0.8108, 0.6874, respectively); however, the majority of respondents reported low technique demands, low sensitivity, and time saving for technique C in comparison to techniques A and B. Significant differences were noted among the educational levels in response to preference and adoption questions (p = 0.0035 and 0.0015, respectively). The highest percentage of faculty chose technique A for inclusion into the academic

  16. TTEthernet for Integrated Spacecraft Networks

    Science.gov (United States)

    Loveless, Andrew

    2015-01-01

    Aerospace projects have traditionally employed federated avionics architectures, in which each computer system is designed to perform one specific function (e.g. navigation). There are obvious downsides to this approach, including excessive weight (from so much computing hardware), and inefficient processor utilization (since modern processors are capable of performing multiple tasks). There has therefore been a push for integrated modular avionics (IMA), in which common computing platforms can be leveraged for different purposes. This consolidation of multiple vehicle functions to shared computing platforms can significantly reduce spacecraft cost, weight, and design complexity. However, the application of IMA principles introduces significant challenges, as the data network must accommodate traffic of mixed criticality and performance levels - potentially all related to the same shared computer hardware. Because individual network technologies are rarely so competent, the development of truly integrated network architectures often proves unreasonable. Several different types of networks are utilized - each suited to support a specific vehicle function. Critical functions are typically driven by precise timing loops, requiring networks with strict guarantees regarding message latency (i.e. determinism) and fault-tolerance. Alternatively, non-critical systems generally employ data networks prioritizing flexibility and high performance over reliable operation. Switched Ethernet has seen widespread success filling this role in terrestrial applications. Its high speed, flexibility, and the availability of inexpensive commercial off-the-shelf (COTS) components make it desirable for inclusion in spacecraft platforms. Basic Ethernet configurations have been incorporated into several preexisting aerospace projects, including both the Space Shuttle and International Space Station (ISS). However, classical switched Ethernet cannot provide the high level of network

  17. Spacecraft command and control using expert systems

    Science.gov (United States)

    Norcross, Scott; Grieser, William H.

    1994-11-01

    This paper describes a product called the Intelligent Mission Toolkit (IMT), which was created to meet the changing demands of the spacecraft command and control market. IMT is a command and control system built upon an expert system. Its primary functions are to send commands to the spacecraft and process telemetry data received from the spacecraft. It also controls the ground equipment used to support the system, such as encryption gear, and telemetry front-end equipment. Add-on modules allow IMT to control antennas and antenna interface equipment. The design philosophy for IMT is to utilize available commercial products wherever possible. IMT utilizes Gensym's G2 Real-time Expert System as the core of the system. G2 is responsible for overall system control, spacecraft commanding control, and spacecraft telemetry analysis and display. Other commercial products incorporated into IMT include the SYBASE relational database management system and Loral Test and Integration Systems' System 500 for telemetry front-end processing.

  18. Spacecraft Power Source Installation at Launch Complex

    Science.gov (United States)

    Lytal, Paul; Hoffman, Pamela

    2010-01-01

    For certain space missions, an assembly must be integrated onto the spacecraft as late as possible in the launch vehicle processing flow. 12This late integration can be driven for a variety of reasons including thermal or hazardous materials constraints. This paper discusses the process of integrating an assembly onto a spacecraft as late as one week prior to the opening of the launch window. Consideration is given to achieving sufficient access for hardware integration, methods of remotely securing hardware to the spacecraft, maintaining spacecraft cleanliness throughout the integration process, and electrically integrating the component to the spacecraft. Specific examples are taken from the remote mechanical, electrical, and fluid cooling system integration of the power source onto the Mars Science Laboratory (MSL) Rover at the Atlas V Vertical Integration Facility (VIF) at Cape Canaveral Air Force Station, Florida.

  19. Spacecraft Dynamics and Control Program at AFRPL

    Science.gov (United States)

    Das, A.; Slimak, L. K. S.; Schloegel, W. T.

    1986-01-01

    A number of future DOD and NASA spacecraft such as the space based radar will be not only an order of magnitude larger in dimension than the current spacecraft, but will exhibit extreme structural flexibility with very low structural vibration frequencies. Another class of spacecraft (such as the space defense platforms) will combine large physical size with extremely precise pointing requirement. Such problems require a total departure from the traditional methods of modeling and control system design of spacecraft where structural flexibility is treated as a secondary effect. With these problems in mind, the Air Force Rocket Propulsion Laboratory (AFRPL) initiated research to develop dynamics and control technology so as to enable the future large space structures (LSS). AFRPL's effort in this area can be subdivided into the following three overlapping areas: (1) ground experiments, (2) spacecraft modeling and control, and (3) sensors and actuators. Both the in-house and contractual efforts of the AFRPL in LSS are summarized.

  20. Dynamics and control of underactuated multibody spacecraft

    Science.gov (United States)

    Cho, Sangbum

    In this dissertation, we develop equations of motion for a class of multibody spacecraft consisting of a rigid base body and multiple rigid appendages connected to the base body. There has been much prior research on this topic; however, much of this research is not appropriate for nonlinear control design purposes. The motion of a multibody spacecraft is described by the position and attitude of a base body in an inertial frame and by the relative position and attitude of the attached bodies with respect to the base body; these latter quantities define the shape of the multibody spacecraft. Our aim is to develop equations of motion that reveal important nonlinear coupling effects between the translation, rotation and shape dynamics, but are simple enough for control design purposes. A rotation matrix is used to represent the attitude of the spacecraft. This allows us to avoid complexity related to the use of parameter representations such as Euler angles. Hamilton's variational principle gives three sets of nonlinear equations of motion. The latter part of this dissertation presents results of control problems for several underactuated multibody spacecraft examples. These include spacecraft with an unactuated internal sliding mass, spacecraft with unactuated fuel slosh dynamics, tethered spacecraft with attachment point actuation and the triaxial attitude control testbed with two proof mass actuation devices. These examples illustrate important features related to the dynamics and control of various underactuated multibody spacecraft. Differences in geometries of the spacecraft and gravitational assumptions require adoption of different types of control schemes. We use the multibody equations in this dissertation to formulate control equations for the models and to construct feedback controllers that achieves asymptotic stability (or convergence) to the desired (relative) equilibrium manifolds. Computer simulations demonstrate the effectiveness of the controllers.

  1. Control of particle-spacecraft interactions in a LEO near-spacecraft environment

    Science.gov (United States)

    Conger, J. C.; Hastings, D. E.

    1993-01-01

    Spacecraft may actively modify their environment by the release of particulate contamination. Particles may also enter the near-spacecraft environment when spacecraft enter clouds of dust or debris in space. This contamination may seriously hamper the function of systems on board the craft. Particulate contamination in the vicinity of a spacecraft may interfere substantially with electromagnetic observations in the infrared, visible and ultraviolet regions of the spectrum. Particles may also accumulate on surfaces such as radiators, and degrade their performance. A computational model is developed to observe the behavior of particulate contamination in the spacecraft environment. This model self-consistently monitors the forces and charge on the particle.

  2. Martian Meteorology: Determination of Large Scale Weather Patterns from Surface Measurements

    Science.gov (United States)

    Murphy, James R.; Haberle, Robert M.; Bridger, Alison F. C.

    1998-01-01

    We employed numerical modelling of the martian atmosphere, and our expertise in understanding martian atmospheric processes, to better understand the coupling between lower and upper atmosphere processes. One practical application of this work has been our involvement with the ongoing atmospheric aerobraking which the Mars Global Surveyor (MGS) spacecraft is currently undergoing at Mars. Dr. Murphy is currently a member of the Mars Global Surveyor (MGS) Aerobraking Atmospheric Advisory Group (AAG). He was asked to participate in this activity based upon his knowledge of martian atmospheric dynamical processes. Aerobraking is a process whereby a spacecraft, in an elliptical orbit, passes through the upper layers of the atmosphere (in this instance Mars). This passage through the atmosphere 'drags'upon the spacecraft, gradually reducing its orbital velocity. This has the effect, over time, of converting the elliptical orbit to a circular orbit, which is the desired mapping orbit for MGS. Carrying out aerobraking eliminates the need for carrying large amounts of fuel on the spacecraft to execute an engine burn to achieve the desired orbit. Eliminating the mass of the fuel reduces the cost of launch. Damage to one of MGS's solar panels shortly after launch has resulted in a less aggressive extended in time aerobraking phase which will not end until March, 1999. Phase I extended from Sept. 1997 through March 1998. During this time period, Dr. Murphy participated almost daily in the AAG meetings, and beginning in December 1997 lead the meeting several times per week. The leader of each of the daily AAG meetings took the results of that meeting (current state of the atmosphere, identification of any time trends or spatial patterns in upper atmosphere densities, etc.) forward to the Aerobraking Planning Group (APG) meeting, at which time the decision was made to not change MGS orbit, to lower the orbit to reach higher densities (greater 'drag'), or raise the orbit to avoid

  3. Submarines, spacecraft and exhaled breath.

    Science.gov (United States)

    Pleil, Joachim D; Hansel, Armin

    2012-03-01

    Foreword The International Association of Breath Research (IABR) meetings are an eclectic gathering of researchers in the medical, environmental and instrumentation fields; our focus is on human health as assessed by the measurement and interpretation of trace chemicals in human exhaled breath. What may have escaped our notice is a complementary field of research that explores the creation and maintenance of artificial atmospheres practised by the submarine air monitoring and air purification (SAMAP) community. SAMAP is comprised of manufacturers, researchers and medical professionals dealing with the engineering and instrumentation to support human life in submarines and spacecraft (including shuttlecraft and manned rockets, high-altitude aircraft, and the International Space Station (ISS)). Here, the immediate concerns are short-term survival and long-term health in fairly confined environments where one cannot simply 'open the window' for fresh air. As such, one of the main concerns is air monitoring and the main sources of contamination are CO(2) and other constituents of human exhaled breath. Since the inaugural meeting in 1994 in Adelaide, Australia, SAMAP meetings have been held every two or three years alternating between the North American and European continents. The meetings are organized by Dr Wally Mazurek (a member of IABR) of the Defense Systems Technology Organization (DSTO) of Australia, and individual meetings are co-hosted by the navies of the countries in which they are held. An overriding focus at SAMAP is life support (oxygen availability and carbon dioxide removal). Certainly, other air constituents are also important; for example, the closed environment of a submarine or the ISS can build up contaminants from consumer products, cooking, refrigeration, accidental fires, propulsion and atmosphere maintenance. However, the most immediate concern is sustaining human metabolism: removing exhaled CO(2) and replacing metabolized O(2). Another

  4. A Ross-Stirling spacecraft refrigerator

    Science.gov (United States)

    Walker, G.; Scott, M.; Zylstra, S.

    A spacecraft refrigerator was investigated capable of providing cooling for storage of food and biological samples in the temperature range 0-20 F with cooling capacity in the range of 1 to 2 kW, operating for long periods with great reliability. The system operated on the Stirling refrigeration cycle using the spacecraft life-support gases as the working fluid. A prototype spacecraft Stirling refrigerator was designed, built, and tested with air as the working fluid. The system performance was satisfactory, meeting the requirements specified above. Potential applications for the prototype unit are mentioned.

  5. Autonomy Architectures for a Constellation of Spacecraft

    Science.gov (United States)

    Barrett, Anthony

    2000-01-01

    Until the past few years, missions typically involved fairly large expensive spacecraft. Such missions have primarily favored using older proven technologies over more recently developed ones, and humans controlled spacecraft by manually generating detailed command sequences with low-level tools and then transmitting the sequences for subsequent execution on a spacecraft controller. This approach toward controlling a spacecraft has worked spectacularly on previous missions, but it has limitations deriving from communications restrictions - scheduling time to communicate with a particular spacecraft involves competing with other projects due to the limited number of deep space network antennae. This implies that a spacecraft can spend a long time just waiting whenever a command sequence fails. This is one reason why the New Millennium program has an objective to migrate parts of mission control tasks onboard a spacecraft to reduce wait time by making spacecraft more robust. The migrated software is called a "remote agent" and has 4 components: a mission manager to generate the high level goals, a planner/scheduler to turn goals into activities while reasoning about future expected situations, an executive/diagnostics engine to initiate and maintain activities while interpreting sensed events by reasoning about past and present situations, and a conventional real-time subsystem to interface with the spacecraft to implement an activity's primitive actions. In addition to needing remote planning and execution for isolated spacecraft, a trend toward multiple-spacecraft missions points to the need for remote distributed planning and execution. The past few years have seen missions with growing numbers of probes. Pathfinder has its rover (Sojourner), Cassini has its lander (Huygens), and the New Millenium Deep Space 3 (DS3) proposal involves a constellation of 3 spacecraft for interferometric mapping. This trend is expected to continue to progressively larger fleets. For

  6. Odor Control in Spacecraft Waste Management Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft and lunar bases generate a variety of wastes containing water, including food wastes, feces, and brines. Disposal of these wastes, as well as recovery of...

  7. A Sustainable Spacecraft Component Database Solution Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Numerous spacecraft component databases have been developed to support NASA, DoD, and contractor design centers and design tools. Despite the clear utility of...

  8. High Efficiency Synchronous Rectification in Spacecraft

    Science.gov (United States)

    Krauhamer, S.; Das, R.; Vorperian, V.; White, J.; Bennett, J.; Rogers, D.

    1993-01-01

    This paper examines the implementaion of MOSFETs as synchronous rectifiers which results in a substantial improvement in power processing efficency and therefore may result in significant reduction of spacecraft mass and volum for the same payload.

  9. A Framework for Designing Optimal Spacecraft Formations

    Science.gov (United States)

    2002-09-01

    3 1. Reference Frame ..................................................................................6 B. SOLVING OPTIMAL CONTROL PROBLEMS ........................................7...spacecraft state. Depending on the model, there may be additional variables in the state, but there will be a minimum of these six. B. SOLVING OPTIMAL CONTROL PROBLEMS Until

  10. Participation of women in spacecraft science teams

    Science.gov (United States)

    Rathbun, Julie

    2017-06-01

    There is an ongoing discussion about the participation of women in science and particularly astronomy. Demographic data from NASA's robotic planetary spacecraft missions show women scientists to be consistently under-represented.

  11. Spacecraft (Mobile Satellite) configuration design study

    Science.gov (United States)

    1985-01-01

    The relative costs to procure and operate a two-satellite mobile satellite system designed to operate either in the UHF band of the L Band, and with several antenna diameter options in each frequency band was investigated. As configured, the size of the spacecraft is limited to the current RCA Series 4000 Geosynchronous Communications Spacecraft bus, which spans the range from 4000 to 5800 pounds in the transfer orbit. The Series 4000 bus forms the basis around which the Mobile Satellite transponder and associated antennas were appended. Although the resultant configuration has little outward resemblance to the present Series 4000 microwave communications spacecraft, the structure, attitude control, thermal, power, and command and control subsystems of the Series 4000 spacecraft are all adapted to support the Mobile Satellite mission.

  12. Chaos in attitude dynamics of spacecraft

    CERN Document Server

    Liu, Yanzhu

    2013-01-01

    Attitude dynamics is the theoretical basis of attitude control of spacecrafts in aerospace engineering. With the development of nonlinear dynamics, chaos in spacecraft attitude dynamics has drawn great attention since the 1990's. The problem of the predictability and controllability of the chaotic attitude motion of a spacecraft has a practical significance in astronautic science. This book aims to summarize basic concepts, main approaches, and recent progress in this area. It focuses on the research work of the author and other Chinese scientists in this field, providing new methods and viewpoints in the investigation of spacecraft attitude motion, as well as new mathematical models, with definite engineering backgrounds, for further analysis. Professor Yanzhu Liu was the Director of the Institute of Engineering Mechanics, Shanghai Jiao Tong University, China. Dr. Liqun Chen is a Professor at the Department of Mechanics, Shanghai University, China.

  13. Mirage Fire Sensor for Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft fires create exception risks to crew members. There is usually no place to escape. Even small amounts of hardware damage can compromise a mission. The...

  14. Passive Wireless Sensors for Spacecraft Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — New classes of sensors are needed on spacecraft that can be interrogated remotely using RF signals and respond with the sensor's identity as well as the...

  15. High Efficiency Synchronous Rectification in Spacecraft

    Science.gov (United States)

    Krauhamer, S.; Das, R.; Vorperian, V.; White, J.; Bennett, J.; Rogers, D.

    1993-01-01

    This paper examines the implementaion of MOSFETs as synchronous rectifiers which results in a substantial improvement in power processing efficency and therefore may result in significant reduction of spacecraft mass and volum for the same payload.

  16. Fermi FT2 Spacecraft Pointing Files

    Data.gov (United States)

    National Aeronautics and Space Administration — This utility permits you to download the most current version of the spacecraft (FT2) file predicting the LAT's pointing for a given mission week. The FT2 file is a...

  17. Global 4-D trajectory optimization for spacecraft

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Global 4-D trajectory(x,y,z,t)is optimized for a spacecraft,which is launched from the Earth to fly around the Sun,just as star-drift of 1437 asteroids in the solar system.The spacecraft trajectory is controlled by low thrust.The performance index of optimal trajectory is to maximize the rendezvous times with the intermediate asteroids,and also maximize the final mass.This paper provides a combined algorithm of global 4-D trajectory optimization.The algorithm is composed of dynamic programming and two-point-boundary algorithm based on optimal control theory.The best 4-D trajectory is obtained:the spacecraft flies passing 55 asteroids,and rendezvous with(following or passing again)asteroids for 454 days,and finally rendezvous with the asteroid 2005SN25 on the day 60521(MJD),the final mass of the spacecraft is 836.53 kg.

  18. Power requirements for commercial communications spacecraft

    Science.gov (United States)

    Billerbeck, W. J.

    1985-01-01

    Historical data on commercial spacecraft power systems are presented and their power requirements to the growth of satellite communications channel usage are related. Some approaches for estimating future power requirements of this class of spacecraft through the year 2000 are proposed. The key technology drivers in satellite power systems are addressed. Several technological trends in such systems are described, focusing on the most useful areas for research and development of major subsystems, including solar arrays, energy storage, and power electronics equipment.

  19. Nondestructive Evaluation of Aircraft and Spacecraft Wiring

    Science.gov (United States)

    White, John E.; Tucholski, Edward J.; Green, Robert E., Jr.

    2004-01-01

    Spacecraft, and especially aircraft, often fry well past their original design lives and, therefore, the need to develop nondestructive evaluation procedures for inspection of vital structures in these craft is extremely important. One of the more recent problems is the degradation of wiring and wiring insulation. The present paper describes several nondestructive characterization methods which afford the possibility to detect wiring and insulation degradation in-situ prior to major problems with the safety of aircraft and spacecraft.

  20. Vibration and acoustic testing of spacecraft

    Science.gov (United States)

    Scharton, T. D.

    2002-01-01

    Spacecraft are subjected to a variety of dynamics environments, which may include: quasi-static, vibration and acoustic loads at launch: pyrotechnic shocks generated by separation mechanisms; on orbit jitter; and sometimes, planetary landing loads. There is a trend in the aerospace industry to rely more on structural analyses and less on testing to simulate these environments, because dynamics testing of spacecraft is time consuming, risky and expensive.

  1. Attitude Estimation in Fractionated Spacecraft Cluster Systems

    Science.gov (United States)

    Hadaegh, Fred Y.; Blackmore, James C.

    2011-01-01

    An attitude estimation was examined in fractioned free-flying spacecraft. Instead of a single, monolithic spacecraft, a fractionated free-flying spacecraft uses multiple spacecraft modules. These modules are connected only through wireless communication links and, potentially, wireless power links. The key advantage of this concept is the ability to respond to uncertainty. For example, if a single spacecraft module in the cluster fails, a new one can be launched at a lower cost and risk than would be incurred with onorbit servicing or replacement of the monolithic spacecraft. In order to create such a system, however, it is essential to know what the navigation capabilities of the fractionated system are as a function of the capabilities of the individual modules, and to have an algorithm that can perform estimation of the attitudes and relative positions of the modules with fractionated sensing capabilities. Looking specifically at fractionated attitude estimation with startrackers and optical relative attitude sensors, a set of mathematical tools has been developed that specify the set of sensors necessary to ensure that the attitude of the entire cluster ( cluster attitude ) can be observed. Also developed was a navigation filter that can estimate the cluster attitude if these conditions are satisfied. Each module in the cluster may have either a startracker, a relative attitude sensor, or both. An extended Kalman filter can be used to estimate the attitude of all modules. A range of estimation performances can be achieved depending on the sensors used and the topology of the sensing network.

  2. Simultaneous mutation detection of three homoeologous genes in wheat by High Resolution Melting analysis and Mutation Surveyor®

    Directory of Open Access Journals (Sweden)

    Vincent Kate

    2009-12-01

    Full Text Available Abstract Background TILLING (Targeting Induced Local Lesions IN Genomes is a powerful tool for reverse genetics, combining traditional chemical mutagenesis with high-throughput PCR-based mutation detection to discover induced mutations that alter protein function. The most popular mutation detection method for TILLING is a mismatch cleavage assay using the endonuclease CelI. For this method, locus-specific PCR is essential. Most wheat genes are present as three similar sequences with high homology in exons and low homology in introns. Locus-specific primers can usually be designed in introns. However, it is sometimes difficult to design locus-specific PCR primers in a conserved region with high homology among the three homoeologous genes, or in a gene lacking introns, or if information on introns is not available. Here we describe a mutation detection method which combines High Resolution Melting (HRM analysis of mixed PCR amplicons containing three homoeologous gene fragments and sequence analysis using Mutation Surveyor® software, aimed at simultaneous detection of mutations in three homoeologous genes. Results We demonstrate that High Resolution Melting (HRM analysis can be used in mutation scans in mixed PCR amplicons containing three homoeologous gene fragments. Combining HRM scanning with sequence analysis using Mutation Surveyor® is sensitive enough to detect a single nucleotide mutation in the heterozygous state in a mixed PCR amplicon containing three homoeoloci. The method was tested and validated in an EMS (ethylmethane sulfonate-treated wheat TILLING population, screening mutations in the carboxyl terminal domain of the Starch Synthase II (SSII gene. Selected identified mutations of interest can be further analysed by cloning to confirm the mutation and determine the genomic origin of the mutation. Conclusion Polyploidy is common in plants. Conserved regions of a gene often represent functional domains and have high sequence

  3. The cart before the horse: Mariner spacecraft and launch vehicles

    Science.gov (United States)

    1984-01-01

    Evolution of unmanned space exploration (Pioneer, Ranger, Surveyor, and Prospector) up to 1960, and the problems in the design and use of the Atlas Centaur launch vehicle were discussed. The Mariner Program was developed from the experience gained from the previous unmanned flights.

  4. Marine bird specimen, marine bird sighting, and other data from the NOAA Ship SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 24 July 1979 to 19 November 1982 (NODC Accession 8300058)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird specimen, marine bird sighting, and other data were collected from the NOAA Ship SURVEYOR from 24 July 1979 to 19 November 1982. Data were collected by...

  5. Temperature profiles from expendable bathythermograph (XBT) casts from NOAA Ship SURVEYOR in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 1976-09-27 to 1976-10-22 (NCEI Accession 7601473)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from NOAA Ship SURVEYOR in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the National Ocean...

  6. Delayed XBT data from the Southern Surveyor, collected by Commonwealth Scientific Industrial Research Organization (CSIRO), and submitted to the Global Temperature-Salinity Profile Program (GTSPP), date range from 02/07/2009 - 03/14/2009 (NODC Accession 0059379)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected in the Pacific Ocean aboard the Southern Surveyor from 07 February to 14 March 2009. Data were submitted by the CommonWealth Scientific...

  7. Temperature profiles from expendable bathythermograph (XBT) casts from the NOAA Ship SURVEYOR in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 14 November 1986 to 23 November 1986 (NODC Accession 8600384)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — XBT data were collected from the NOAA Ship SURVEYOR in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the National...

  8. Marine animal sighting and census data from the NOAA Ship SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 11 May 1982 to 19 March 1983 (NODC Accession 8400150)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine animal sighting and census data were collected from the NOAA Ship SURVEYOR from 11 May 1982 to 19 March 1983. Data were collected by the Envirosphere Co. as...

  9. Marine toxic substance and other data from bottle casts from the NOAA Ship SURVEYOR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 13 August 1980 to 21 February 1981 (NODC Accession 8100531)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine toxic substance and other data were collected from bottle casts from the NOAA Ship SURVEYOR from 13 August 1980 to 21 February 1981. Data were collected by...

  10. Physical, meteorological, and other data from surface sensors and CTD casts from the SURVEYOR and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 23 February 1981 to 30 April 1983 (NODC Accession 8300167)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts from the SURVEYOR and other platforms from 23 February 1981 to 30 April...

  11. Zooplankton and other data from net casts in Prince William Sound from NOAA Ship SURVEYOR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1975-10-03 to 1975-10-10 (NCEI Accession 7601873)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton and other data were collected from net casts in Prince William Sound from the SURVEYOR from 03 October 1975 to 10 October 1975. Data were collected by...

  12. Zooplankton and other data from net casts in the Gulf of Alaska from the SURVEYOR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 30 September 1975 to 24 October 1975 (NODC Accession 7601809)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton and other data were collected from net casts in the Gulf of Alaska from the SURVEYOR from 30 September 1975 to 24 October 1975. Data were collected by...

  13. Zooplankton and other data from net casts from NOAA Ship SURVEYOR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1977-06-28 to 1977-07-04 (NCEI Accession 7900066)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton and other data were collected from net casts from NOAA Ship SURVEYOR from 28 June 1977 to 04 July 1977. Data were collected by the University of Alaska,...

  14. Zooplankton and other data from net casts from NOAA Ship SURVEYOR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1976-03-17 to 1976-04-26 (NCEI Accession 7601628)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton and other data were collected from net casts from NOAA Ship SURVEYOR from 17 March 1976 to 26 April 1976. Data were collected by the University of Alaska...

  15. Physical, meteorological, and other data from surface sensors and CTD casts from SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 16 August 1977 to 15 September 1977 (NODC Accession 7800013)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts from the SURVEYOR. Data were collected by the Pacific Marine Environmental...

  16. Physical, meteorological, and other data from surface sensors, bottle casts, and CTD casts from SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 15 April 1976 to 26 April 1976 (NODC Accession 7601823)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors, bottle casts, and CTD casts from the SURVEYOR. Data were collected by the University of...

  17. Temperature, salinity and other measurements found in dataset CTD taken from the SOUTHERN SURVEYOR (VLHJ) in the Coastal S Pacific, Equatorial Pacific and other locations from 2003 to 2006 (NODC Accession 0043461)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity, chemical, and other data were collected using CTD casts from the SOUTHERN SURVEYOR in the Iceland Sea and North / South Pacific Ocean. Data...

  18. Temperature and salinity profiles from surface sensors and CTD casts in the Gulf of Alaska from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 21 September 1975 to 22 September 1975 (NODC Accession 7601224)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature and salinity profiles were collected from surface sensors and CTD casts in the Gulf of Alaska from the SURVEYOR. Data were collected by the Pacific...

  19. Physical and other data from surface sensors and CTD casts in the Gulf of Alaska from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 05 June 1975 to 12 June 1975 (NODC Accession 7601225)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical and other data were collected from surface sensors and CTD casts in the Gulf of Alaska from the SURVEYOR. Data were collected by the Pacific Marine...

  20. Marine animal sighting and census data from NOAA Ship SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 17 May 1975 to 13 October 1977 (NODC Accession 8000349)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine animal sighting and census data were collected from the NOAA Ship SURVEYOR from 17 May 1975 to 13 October 1977. Data were collected by the U.S. National...

  1. Marine bird sighting and other data from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 01 September 1976 to 02 September 1976 (NODC Accession 7800704)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from the SURVEYOR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP). Data were...

  2. Physical, meteorological, and other data from surface sensors and CTD casts from the NOAA Ship SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 15 August 1980 to 05 September 1980 (NODC Accession 8200116)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts from the NOAA Ship SURVEYOR from 15 August 1980 to 05 September 1980. Data...

  3. Oceanographic profile data collected aboard Atlantic Surveyor as part of project OPR-D302-KR-12 in the North Atlantic Ocean from 2012-07-05 to 2012-09-05 (NCEI Accession 0130622)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0130622 includes physical and profile data collected aboard the Atlantic Surveyor during project OPR-D302-KR-12 in the North Atlantic Ocean from...

  4. Marine mammal specimen and other data from the NOAA Ship SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 22 July 1975 to 28 August 1979 (NODC Accession 8100349)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected from the NOAA Ship SURVEYOR from 22 July 1975 to 28 August 1979. Data were collected by the University of...

  5. Marine mammal specimen and other data from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 10 February 1977 to 19 November 1977 (NODC Accession 7900320)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected from the SURVEYOR and other platforms from 10 February 1977 to 19 November 1977. Data were collected by the...

  6. Marine mammal specimen and other data from the SURVEYOR and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 20 March 1977 to 02 November 1977 (NODC Accession 7900319)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected from the SURVEYOR and other platforms from 20 March 1977 to 02 November 1977. Data were collected by the Alaska...

  7. Marine bird sighting and other data from the NOAA Ship SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 16 August 1980 to 05 September 1980 (NODC Accession 8100473)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine bird sighting and other data were collected from the NOAA Ship SURVEYOR from 16 August 1980 to 05 September 1980. Data were collected by the University of...

  8. Large-Scale Spacecraft Fire Safety Tests

    Science.gov (United States)

    Urban, David; Ruff, Gary A.; Ferkul, Paul V.; Olson, Sandra; Fernandez-Pello, A. Carlos; T'ien, James S.; Torero, Jose L.; Cowlard, Adam J.; Rouvreau, Sebastien; Minster, Olivier; Toth, Balazs; Legros, Guillaume; Eigenbrod, Christian; Smirnov, Nickolay; Fujita, Osamu; Jomaas, Grunde

    2014-01-01

    An international collaborative program is underway to address open issues in spacecraft fire safety. Because of limited access to long-term low-gravity conditions and the small volume generally allotted for these experiments, there have been relatively few experiments that directly study spacecraft fire safety under low-gravity conditions. Furthermore, none of these experiments have studied sample sizes and environment conditions typical of those expected in a spacecraft fire. The major constraint has been the size of the sample, with prior experiments limited to samples of the order of 10 cm in length and width or smaller. This lack of experimental data forces spacecraft designers to base their designs and safety precautions on 1-g understanding of flame spread, fire detection, and suppression. However, low-gravity combustion research has demonstrated substantial differences in flame behavior in low-gravity. This, combined with the differences caused by the confined spacecraft environment, necessitates practical scale spacecraft fire safety research to mitigate risks for future space missions. To address this issue, a large-scale spacecraft fire experiment is under development by NASA and an international team of investigators. This poster presents the objectives, status, and concept of this collaborative international project (Saffire). The project plan is to conduct fire safety experiments on three sequential flights of an unmanned ISS re-supply spacecraft (the Orbital Cygnus vehicle) after they have completed their delivery of cargo to the ISS and have begun their return journeys to earth. On two flights (Saffire-1 and Saffire-3), the experiment will consist of a flame spread test involving a meter-scale sample ignited in the pressurized volume of the spacecraft and allowed to burn to completion while measurements are made. On one of the flights (Saffire-2), 9 smaller (5 x 30 cm) samples will be tested to evaluate NASAs material flammability screening tests

  9. Interference of Co-Amplified Nuclear Mitochondrial DNA Sequences on the Determination of Human mtDNA Heteroplasmy by Using the SURVEYOR Nuclease and the WAVE HS System

    OpenAIRE

    Hsiu-Chuan Yen; Shiue-Li Li; Wei-Chien Hsu; Petrus Tang

    2014-01-01

    High-sensitivity and high-throughput mutation detection techniques are useful for screening the homoplasmy or heteroplasmy status of mitochondrial DNA (mtDNA), but might be susceptible to interference from nuclear mitochondrial DNA sequences (NUMTs) co-amplified during polymerase chain reaction (PCR). In this study, we first evaluated the platform of SURVEYOR Nuclease digestion of heteroduplexed DNA followed by the detection of cleaved DNA by using the WAVE HS System (SN/WAVE-HS) for detectin...

  10. REQUIREMENTS FOR IMAGE QUALITY OF EMERGENCY SPACECRAFTS

    Directory of Open Access Journals (Sweden)

    A. I. Altukhov

    2015-05-01

    Full Text Available The paper deals with the method for formation of quality requirements to the images of emergency spacecrafts. The images are obtained by means of remote sensing of near-earth space orbital deployment in the visible range. of electromagnetic radiation. The method is based on a joint taking into account conditions of space survey, characteristics of surveillance equipment, main design features of the observed spacecrafts and orbital inspection tasks. Method. Quality score is the predicted linear resolution image that gives the possibility to create a complete view of pictorial properties of the space image obtained by electro-optical system from the observing satellite. Formulation of requirements to the numerical value of this indicator is proposed to perform based on the properties of remote sensing system, forming images in the conditions of outer space, and the properties of the observed emergency spacecraft: dimensions, platform construction of the satellite, on-board equipment placement. For method implementation the authors have developed a predictive model of requirements to a linear resolution for images of emergency spacecrafts, making it possible to select the intervals of space shooting and get the satellite images required for quality interpretation. Main results. To verify the proposed model functionality we have carried out calculations of the numerical values for the linear resolution of the image, ensuring the successful task of determining the gross structural damage of the spacecrafts and identifying changes in their spatial orientation. As input data were used with dimensions and geometric primitives corresponding to the shape of deemed inspected spacecrafts: Resurs-P", "Canopus-B", "Electro-L". Numerical values of the linear resolution images have been obtained, ensuring the successful task solution for determining the gross structural damage of spacecrafts.

  11. A Novel Spacecraft Charge Monitor for LEO

    Science.gov (United States)

    Goembel, Luke

    2004-01-01

    Five years ago we introduced a new method for measuring spacecraft chassis floating potential relative to the space plasma (absolute spacecraft potential) in low Earth orbit. The method, based on a straightforward interpretation of photoelectron spectra, shows promise for numerous applications, but has not yet been tried. In the interest of testing the method, and ultimately supplying another tool for measuring absolute spacecraft charge, we are producing a flight prototype Spacecraft Charge Monitor (SCM) with support from NASA's Small Business Innovation Research (SBIR) program. Although insight into the technique came from data collected in space over two decades ago, very little data are available. The data indicate that it may be possible to determine spacecraft floating potential to within 0.1 volt each with the SCM second under certain conditions. It is debatable that spacecraft floating potential has ever been measured with such accuracy. The compact, easily deployed SCM also offers the advantage of long-term stability in calibration. Accurate floating potential determinations from the SCM could be used to correct biases in space plasma measurements and evaluate charge mitigation and/or sensing devices. Although this paper focuses on the device's use in low Earth orbit (LEO), the device may also be able to measure spacecraft charge at higher altitudes, in the solar wind, and in orbits around other planets. The flight prototype SCM we are producing for delivery to NASA in the third quarter of 2004 will measure floating potential from 0 to -150 volts with 0.1 volt precision, weigh approximately 600-700 grams, consume approximately 2 watts, and will measure approximately 8 x 10 x 17 cm.

  12. Feedhorn-coupled Bolometer Detectors at 40 GHz Implemented on the Cosmology Large Angular Scale Surveyor (CLASS)

    Science.gov (United States)

    Chuss, David T.; Ali, A.; Appel, J. W.; Bennett, C. L.; Colazo, F.; Crowe, E.; Denis, K.; Eimer, J.; Essinger-Hileman, T.; Marriage, T.; Moseley, S. H.; Rostem, K.; Stevenson, T.; Towner, D.; U-Yen, K.; Wollack, E.; Zeng, L.

    2014-01-01

    We have designed, produced, and tested 40 GHz feedhorn-coupled transition-edge sensor (TES) detectors using microstrip circuits on monocrystalline silicon dielectric substrates. Symmetric planar orthomode transducers (OMTs) couple two independent orthogonal linear polarization modes from feedhorns onto planar transmission lines over a broad (60 %) bandwidth. The 33-43 GHz band is defined by a combination of on-chip planar filtering and effective integrated shielding of stray light (blue leaks). The integrated stray light control is achieved over a frequency range of > 10:1. The monocrystalline silicon substrate provides a highly uniform dielectric constant that results in reliable circuit uniformity and performance. In addition, the monocrystalline silicon enables high efficiency due to its extremely low loss. The efficiency of the devices, including all integrated filtering, has been measured to be ~90 % for each polarization. The Cosmology Large Angular Scale Surveyor (CLASS) cosmic microwave background B-mode experiment is employing a 36-element focal plane of these detectors, along with similar detectors at higher frequencies, to map a large fraction of the sky.

  13. Spacecraft Attitude Maneuver Planning Using Genetic Algorithms

    Science.gov (United States)

    Kornfeld, Richard P.

    2004-01-01

    A key enabling technology that leads to greater spacecraft autonomy is the capability to autonomously and optimally slew the spacecraft from and to different attitudes while operating under a number of celestial and dynamic constraints. The task of finding an attitude trajectory that meets all the constraints is a formidable one, in particular for orbiting or fly-by spacecraft where the constraints and initial and final conditions are of time-varying nature. This approach for attitude path planning makes full use of a priori constraint knowledge and is computationally tractable enough to be executed onboard a spacecraft. The approach is based on incorporating the constraints into a cost function and using a Genetic Algorithm to iteratively search for and optimize the solution. This results in a directed random search that explores a large part of the solution space while maintaining the knowledge of good solutions from iteration to iteration. A solution obtained this way may be used as is or as an initial solution to initialize additional deterministic optimization algorithms. A number of representative case examples for time-fixed and time-varying conditions yielded search times that are typically on the order of minutes, thus demonstrating the viability of this method. This approach is applicable to all deep space and planet Earth missions requiring greater spacecraft autonomy, and greatly facilitates navigation and science observation planning.

  14. Spacecraft Alignment Determination and Control for Dual Spacecraft Precision Formation Flying

    Science.gov (United States)

    Calhoun, Philip C.; Novo-Gradac, Anne-Marie; Shah, Neerav

    2017-01-01

    Many proposed formation flying missions seek to advance the state of the art in spacecraft science imaging by utilizing precision dual spacecraft formation flying to enable a virtual space telescope. Using precision dual spacecraft alignment, very long focal lengths can be achieved by locating the optics on one spacecraft and the detector on the other. Proposed science missions include astrophysics concepts with spacecraft separations from 1000 km to 25,000 km, such as the Milli-Arc-Second Structure Imager (MASSIM) and the New Worlds Observer, and Heliophysics concepts for solar coronagraphs and X-ray imaging with smaller separations (50m 500m). All of these proposed missions require advances in guidance, navigation, and control (GNC) for precision formation flying. In particular, very precise astrometric alignment control and estimation is required for precise inertial pointing of the virtual space telescope to enable science imaging orders of magnitude better than can be achieved with conventional single spacecraft instruments. This work develops design architectures, algorithms, and performance analysis of proposed GNC systems for precision dual spacecraft astrometric alignment. These systems employ a variety of GNC sensors and actuators, including laser-based alignment and ranging systems, optical imaging sensors (e.g. guide star telescope), inertial measurement units (IMU), as well as micro-thruster and precision stabilized platforms. A comprehensive GNC performance analysis is given for Heliophysics dual spacecraft PFF imaging mission concept.

  15. Attitude coordination for spacecraft formation with multiple communication delays

    Directory of Open Access Journals (Sweden)

    Guo Yaohua

    2015-04-01

    Full Text Available Communication delays are inherently present in information exchange between spacecraft and have an effect on the control performance of spacecraft formation. In this work, attitude coordination control of spacecraft formation is addressed, which is in the presence of multiple communication delays between spacecraft. Virtual system-based approach is utilized in case that a constant reference attitude is available to only a part of the spacecraft. The feedback from the virtual systems to the spacecraft formation is introduced to maintain the formation. Using backstepping control method, input torque of each spacecraft is designed such that the attitude of each spacecraft converges asymptotically to the states of its corresponding virtual system. Furthermore, the backstepping technique and the Lyapunov–Krasovskii method contribute to the control law design when the reference attitude is time-varying and can be obtained by each spacecraft. Finally, effectiveness of the proposed methodology is illustrated by the numerical simulations of a spacecraft formation.

  16. Guidance and control of swarms of spacecraft

    Science.gov (United States)

    Morgan, Daniel James

    There has been considerable interest in formation flying spacecraft due to their potential to perform certain tasks at a cheaper cost than monolithic spacecraft. Formation flying enables the use of smaller, cheaper spacecraft that distribute the risk of the mission. Recently, the ideas of formation flying have been extended to spacecraft swarms made up of hundreds to thousands of 100-gram-class spacecraft known as femtosatellites. The large number of spacecraft and limited capabilities of each individual spacecraft present a significant challenge in guidance, navigation, and control. This dissertation deals with the guidance and control algorithms required to enable the flight of spacecraft swarms. The algorithms developed in this dissertation are focused on achieving two main goals: swarm keeping and swarm reconfiguration. The objectives of swarm keeping are to maintain bounded relative distances between spacecraft, prevent collisions between spacecraft, and minimize the propellant used by each spacecraft. Swarm reconfiguration requires the transfer of the swarm to a specific shape. Like with swarm keeping, minimizing the propellant used and preventing collisions are the main objectives. Additionally, the algorithms required for swarm keeping and swarm reconfiguration should be decentralized with respect to communication and computation so that they can be implemented on femtosats, which have limited hardware capabilities. The algorithms developed in this dissertation are concerned with swarms located in low Earth orbit. In these orbits, Earth oblateness and atmospheric drag have a significant effect on the relative motion of the swarm. The complicated dynamic environment of low Earth orbits further complicates the swarm-keeping and swarm-reconfiguration problems. To better develop and test these algorithms, a nonlinear, relative dynamic model with J2 and drag perturbations is developed. This model is used throughout this dissertation to validate the algorithms

  17. Developing Sustainable Spacecraft Water Management Systems

    Science.gov (United States)

    Thomas, Evan A.; Klaus, David M.

    2009-01-01

    It is well recognized that water handling systems used in a spacecraft are prone to failure caused by biofouling and mineral scaling, which can clog mechanical systems and degrade the performance of capillary-based technologies. Long duration spaceflight applications, such as extended stays at a Lunar Outpost or during a Mars transit mission, will increasingly benefit from hardware that is generally more robust and operationally sustainable overtime. This paper presents potential design and testing considerations for improving the reliability of water handling technologies for exploration spacecraft. Our application of interest is to devise a spacecraft wastewater management system wherein fouling can be accommodated by design attributes of the management hardware, rather than implementing some means of preventing its occurrence.

  18. Dawn Spacecraft Reaction Control System Flight Experience

    Science.gov (United States)

    Mizukami, Masashi; Nakazono, Barry

    2014-01-01

    The NASA Dawn spacecraft mission is studying conditions and processes of the solar system's earliest epoch by investigating two protoplanets remaining intact since their formations, Ceres and Vesta. Launch was in 2007. Ion propulsion is used to fly to and enter orbit around Vesta, depart Vesta and fly to Ceres, and enter orbit around Ceres. A conventional blowdown hydrazine reaction control system (RCS) is used to provide external torques for attitude control. Reaction wheel assemblies were intended to provide attitude control in most cases. However, the spacecraft experienced one, then two apparent failures of reaction wheels. Also, similar thrusters experienced degradation in a long life application on another spacecraft. Those factors led to RCS being operated in ways completely different than anticipated prior to launch. Numerous mitigations and developments needed to be implemented. The Vesta mission was fully successful. Even with the compromises necessary due to those anomalies, the Ceres mission is also projected to be feasible.

  19. Controllability and observability for flexible spacecraft

    Science.gov (United States)

    Hughes, P. C.; Skelton, R. E.

    1979-01-01

    Current interest in extended sensing and actuation for the control of flexible spacecraft has led to the use of modern multivariable control theory and the associated concepts of controllability and observability. This paper shows how to evaluate these properties on a mode-by-mode basis for flexible spacecraft control analysis. Relatively simple criteria are derived which indicate the degree of controllability (observability) of each mode in simple literal terms. These criteria provide physical insight and practical guidance on the type, number, and positioning of sensors and actuators. The results are interpreted for force and torque actuators, and for attitude and deformation measurements. To illustrate these ideas, sample controllability and observability 'surfaces' are presented for the Purdue generic flexible spacecraft model.

  20. Embedded Thermal Control for Spacecraft Subsystems Miniaturization

    Science.gov (United States)

    Didion, Jeffrey R.

    2014-01-01

    Optimization of spacecraft size, weight and power (SWaP) resources is an explicit technical priority at Goddard Space Flight Center. Embedded Thermal Control Subsystems are a promising technology with many cross cutting NSAA, DoD and commercial applications: 1.) CubeSatSmallSat spacecraft architecture, 2.) high performance computing, 3.) On-board spacecraft electronics, 4.) Power electronics and RF arrays. The Embedded Thermal Control Subsystem technology development efforts focus on component, board and enclosure level devices that will ultimately include intelligent capabilities. The presentation will discuss electric, capillary and hybrid based hardware research and development efforts at Goddard Space Flight Center. The Embedded Thermal Control Subsystem development program consists of interrelated sub-initiatives, e.g., chip component level thermal control devices, self-sensing thermal management, advanced manufactured structures. This presentation includes technical status and progress on each of these investigations. Future sub-initiatives, technical milestones and program goals will be presented.

  1. Autonomous Spacecraft Communication Interface for Load Planning

    Science.gov (United States)

    Dever, Timothy P.; May, Ryan D.; Morris, Paul H.

    2014-01-01

    Ground-based controllers can remain in continuous communication with spacecraft in low Earth orbit (LEO) with near-instantaneous communication speeds. This permits near real-time control of all of the core spacecraft systems by ground personnel. However, as NASA missions move beyond LEO, light-time communication delay issues, such as time lag and low bandwidth, will prohibit this type of operation. As missions become more distant, autonomous control of manned spacecraft will be required. The focus of this paper is the power subsystem. For present missions, controllers on the ground develop a complete schedule of power usage for all spacecraft components. This paper presents work currently underway at NASA to develop an architecture for an autonomous spacecraft, and focuses on the development of communication between the Mission Manager and the Autonomous Power Controller. These two systems must work together in order to plan future load use and respond to unanticipated plan deviations. Using a nominal spacecraft architecture and prototype versions of these two key components, a number of simulations are run under a variety of operational conditions, enabling development of content and format of the messages necessary to achieve the desired goals. The goals include negotiation of a load schedule that meets the global requirements (contained in the Mission Manager) and local power system requirements (contained in the Autonomous Power Controller), and communication of off-plan disturbances that arise while executing a negotiated plan. The message content is developed in two steps: first, a set of rapid-prototyping "paper" simulations are preformed; then the resultant optimized messages are codified for computer communication for use in automated testing.

  2. Spacecraft Attitude Control in Hamiltonian Framework

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2000-01-01

    The objective of this paper is to give a design scheme for attitude control algorithms of a generic spacecraft. Along with the system model formulated in the Hamilton's canonical form the algorithm uses information about a required potential energy and a dissipative term. The control action...... is the sum of the gradient of the potential energy and the dissipative force. It is shown that this control law makes the system uniformly asymptotically stable to the desired reference point. Three problems were addressed in the paper: spacecraft stabilization in the inertial frame, libration damping...

  3. Operational Philosophy Concerning Manned Spacecraft Cabin Leaks

    Science.gov (United States)

    DeSimpelaere, Edward

    2011-01-01

    The last thirty years have seen the Space Shuttle as the prime United States spacecraft for manned spaceflight missions. Many lessons have been learned about spacecraft design and operation throughout these years. Over the next few decades, a large increase of manned spaceflight in the commercial sector is expected. This will result in the exposure of commercial crews and passengers to many of the same risks crews of the Space Shuttle have encountered. One of the more dire situations that can be encountered is the loss of pressure in the habitable volume of the spacecraft during on orbit operations. This is referred to as a cabin leak. This paper seeks to establish a general cabin leak response philosophy with the intent of educating future spacecraft designers and operators. After establishing a relative definition for a cabin leak, the paper covers general descriptions of detection equipment, detection methods, and general operational methods for management of a cabin leak. Subsequently, all these items are addressed from the perspective of the Space Shuttle Program, as this will be of the most value to future spacecraft due to similar operating profiles. Emphasis here is placed upon why and how these methods and philosophies have evolved to meet the Space Shuttle s needs. This includes the core ideas of: considerations of maintaining higher cabin pressures vs. lower cabin pressures, the pros and cons of a system designed to feed the leak with gas from pressurized tanks vs. using pressure suits to protect against lower cabin pressures, timeline and consumables constraints, re-entry considerations with leaks of unknown origin, and the impact the International Space Station (ISS) has had to the standard Space Shuttle cabin leak response philosophy. This last item in itself includes: procedural management differences, hardware considerations, additional capabilities due to the presence of the ISS and its resource, and ISS docking/undocking considerations with a

  4. Science Benefits of Onboard Spacecraft Navigation

    Science.gov (United States)

    Cangahuala, Al; Bhaskaran, Shyam; Owen, Bill

    2012-01-01

    Primitive bodies (asteroids and comets), which have remained relatively unaltered since their formation, are important targets for scientific missions that seek to understand the evolution of the solar system. Often the first step is to fly by these bodies with robotic spacecraft. The key to maximizing data returns from these flybys is to determine the spacecraft trajectory relative to the target body-in short, navigate the spacecraft- with sufficient accuracy so that the target is guaranteed to be in the instruments' field of view. The most powerful navigation data in these scenarios are images taken by the spacecraft of the target against a known star field (onboard astrometry). Traditionally, the relative trajectory of the spacecraft must be estimated hours to days in advance using images collected by the spacecraft. This is because of (1)!the long round-trip light times between the spacecraft and the Earth and (2)!the time needed to downlink and process navigation data on the ground, make decisions based on the result, and build and uplink instrument pointing sequences from the results. The light time and processing time compromise navigation accuracy considerably, because there is not enough time to use more accurate data collected closer to the target-such data are more accurate because the angular capability of the onboard astrometry is essentially constant as the distance to the target decreases, resulting in better "plane-of- sky" knowledge of the target. Excellent examples of these timing limitations are high-speed comet encounters. Comets are difficult to observe up close; their orbits often limit scientists to brief, rapid flybys, and their coma further restricts viewers from seeing the nucleus in any detail, unless they can view the nucleus at close range. Comet nuclei details are typically discernable for much shorter durations than the roundtrip light time to Earth, so robotic spacecraft must be able to perform onboard navigation. This onboard

  5. Ray-tracing critical-angle transmission gratings for the X-ray Surveyor and Explorer-size missions

    Science.gov (United States)

    Günther, Hans M.; Bautz, Marshall W.; Heilmann, Ralf K.; Huenemoerder, David P.; Marshall, Herman L.; Nowak, Michael A.; Schulz, Norbert S.

    2016-07-01

    We study a critical angle transmission (CAT) grating spectrograph that delivers a spectral resolution significantly above any X-ray spectrograph ever own. This new technology will allow us to resolve kinematic components in absorption and emission lines of galactic and extragalactic matter down to unprecedented dispersion levels. We perform ray-trace simulations to characterize the performance of the spectrograph in the context of an X-ray Surveyor or Arcus like layout (two mission concepts currently under study). Our newly developed ray-trace code is a tool suite to simulate the performance of X-ray observatories. The simulator code is written in Python, because the use of a high-level scripting language allows modifications of the simulated instrument design in very few lines of code. This is especially important in the early phase of mission development, when the performances of different configurations are contrasted. To reduce the run-time and allow for simulations of a few million photons in a few minutes on a desktop computer, the simulator code uses tabulated input (from theoretical models or laboratory measurements of samples) for grating efficiencies and mirror reflectivities. We find that the grating facet alignment tolerances to maintain at least 90% of resolving power that the spectrometer has with perfect alignment are (i) translation parallel to the optical axis below 0.5 mm, (ii) rotation around the optical axis or the groove direction below a few arcminutes, and (iii) constancy of the grating period to 1:105. Translations along and rotations around the remaining axes can be significantly larger than this without impacting the performance.

  6. Characterization of overwintering sites of the invasive brown marmorated stink bug in natural landscapes using human surveyors and detector canines.

    Directory of Open Access Journals (Sweden)

    Doo-Hyung Lee

    Full Text Available Halyomorpha halys is an invasive species from Asia causing major economic losses in agricultural production in the mid-Atlantic region of the United States. Unlike other crop pests, H. halys is also well-known for nuisance problems in urban, suburban, and rural areas, as massive numbers of adults often invade human-made structures to overwinter inside protected environments. Research efforts have focused on populations in human-made structures while overwintering ecology of H. halys in natural landscapes is virtually unknown. We explored forested landscapes in the mid-Atlantic region to locate and characterize natural overwintering structures used by H. halys. We also evaluated the use of detector canines to locate overwintering H. halys to enhance the accuracy and efficiency of surveys. From these studies, we indentified shared characteristics of overwintering sites used by H. halys in natural landscapes. Overwintering H. halys were recovered from dry crevices in dead, standing trees with thick bark, particularly oak (Quercus spp. and locust (Robinia spp.; these characteristics were shared by 11.8% of all dead trees in surveyed landscapes. For trees with favorable characteristics, we sampled ∼20% of the total above-ground tree area and recovered 5.9 adults per tree from the trees with H. halys present. Two detector canines were successfully trained to recognize and detect the odor of adult H. halys yielding >84% accuracy in laboratory and semi-field trials. Detector canines also found overwintering H. halys under field conditions. In particular, overwintering H. halys were recovered only from dead trees that yielded positive indications from the canines and shared key tree characteristics established by human surveyors. The identified characteristics of natural overwintering sites of H. halys will serve as baseline information to establish crop economic risk levels posed by overwintering populations, and accordingly develop sustainable

  7. Surveyor Nuclease: a new strategy for a rapid identification of heteroplasmic mitochondrial DNA mutations in patients with respiratory chain defects.

    Science.gov (United States)

    Bannwarth, Sylvie; Procaccio, Vincent; Paquis-Flucklinger, Veronique

    2005-06-01

    Molecular analysis of mitochondrial DNA (mtDNA) is a critical step in diagnosis and genetic counseling of respiratory chain defects. No fast method is currently available for the identification of unknown mtDNA point mutations. We have developed a new strategy based on complete mtDNA PCR amplification followed by digestion with a mismatch-specific DNA endonuclease, Surveyor Nuclease. This enzyme, a member of the CEL nuclease family of plant DNA endonucleases, cleaves double-strand DNA at any mismatch site including base substitutions and small insertions/deletions. After digestion, cleavage products are separated and analyzed by agarose gel electrophoresis. The size of the digestion products indicates the location of the mutation, which is then confirmed and characterized by sequencing. Although this method allows the analysis of 2 kb mtDNA amplicons and the detection of multiple mutations within the same fragment, it does not lead to the identification of homoplasmic base substitutions. Homoplasmic pathogenic mutations have been described. Nevertheless, most homoplasmic base substitutions are neutral polymorphisms while deleterious mutations are typically heteroplasmic. Here, we report that this method can be used to detect mtDNA mutations such as m.3243A>G tRNA(Leu) and m.14709T>C tRNA(Glu) even when they are present at levels as low as 3% in DNA samples derived from patients with respiratory chain defects. Then, we tested five patients suffering from a mitochondrial respiratory chain defect and we identified a variant (m.16189T>C) in two of them, which was previously associated with susceptibility to diabetes and cardiomyopathy. In conclusion, this method can be effectively used to rapidly and completely screen the entire human mitochondrial genome for heteroplasmic mutations and in this context represents an important advance for the diagnosis of mitochondrial diseases.

  8. How Spacecraft Fly Spaceflight Without Formulae

    CERN Document Server

    Swinerd, Graham

    2009-01-01

    About half a century ago a small satellite, Sputnik 1, was launched. The satellite did very little other than to transmit a radio signal to announce its presence in orbit. However, this humble beginning heralded the dawn of the Space Age. Today literally thousands of robotic spacecraft have been launched, many of which have flown to far-flung regions of the Solar System carrying with them the human spirit of scientific discovery and exploration. Numerous other satellites have been launched in orbit around the Earth providing services that support our technological society on the ground. How Spacecraft Fly: Spaceflight Without Formulae by Graham Swinerd focuses on how these spacecraft work. The book opens with a historical perspective of how we have come to understand our Solar System and the Universe. It then progresses through orbital flight, rocket science, the hostile environment within which spacecraft operate, and how they are designed. The concluding chapters give a glimpse of what the 21st century may ...

  9. Fault Detection and Isolation for Spacecraft

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Wisniewski, Rafal

    2002-01-01

    This article realizes nonlinear Fault Detection and Isolation for actuators, given there is no measurement of the states in the actuators. The Fault Detection and Isolation of the actuators is instead based on angular velocity measurement of the spacecraft and knowledge about the dynamics...

  10. Underactuated Spacecraft Control with Disturbance Compensation

    Science.gov (United States)

    2015-08-31

    ASSIGNED DISTRIBUTION STATEMENT. //SIGNED// //SIGNED// FREDERICK LEVE PAUL HAUSGEN, Ph.D. Program Manager Technical Advisor, Space Based...ABSTRACT This research focuses on the development and application of three methods for the underactuated spacecraft attitude problem . The first method...achieved by conventional control schemes. A Linear Quadratic (LQ) approach was first applied due to its robustness, its optimal control properties

  11. Spacecraft Attitude Control in Hamiltonian Framework

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2000-01-01

    The objective of this paper is to give a design scheme for attitude control algorithms of a generic spacecraft. Along with the system model formulated in the Hamilton's canonical form the algorithm uses information about a required potential energy and a dissipative term. The control action...

  12. Software for Engineering Simulations of a Spacecraft

    Science.gov (United States)

    Shireman, Kirk; McSwain, Gene; McCormick, Bernell; Fardelos, Panayiotis

    2005-01-01

    Spacecraft Engineering Simulation II (SES II) is a C-language computer program for simulating diverse aspects of operation of a spacecraft characterized by either three or six degrees of freedom. A functional model in SES can include a trajectory flight plan; a submodel of a flight computer running navigational and flight-control software; and submodels of the environment, the dynamics of the spacecraft, and sensor inputs and outputs. SES II features a modular, object-oriented programming style. SES II supports event-based simulations, which, in turn, create an easily adaptable simulation environment in which many different types of trajectories can be simulated by use of the same software. The simulation output consists largely of flight data. SES II can be used to perform optimization and Monte Carlo dispersion simulations. It can also be used to perform simulations for multiple spacecraft. In addition to its generic simulation capabilities, SES offers special capabilities for space-shuttle simulations: for this purpose, it incorporates submodels of the space-shuttle dynamics and a C-language version of the guidance, navigation, and control components of the space-shuttle flight software.

  13. Handling Qualities Implications for Crewed Spacecraft Operations

    Science.gov (United States)

    Bailey, Randall E.; Jackson, E. Bruce; Arthur, J. J.

    2012-01-01

    Abstract Handling qualities embody those qualities or characteristics of an aircraft that govern the ease and precision with which a pilot is able to perform the tasks required in support of an aircraft role. These same qualities are as critical, if not more so, in the operation of spacecraft. A research, development, test, and evaluation process was put into effect to identify, understand, and interpret the engineering and human factors principles which govern the pilot-vehicle dynamic system as they pertain to space exploration missions and tasks. Toward this objective, piloted simulations were conducted at the NASA Langley Research Center and Ames Research Center for earth-orbit proximity operations and docking and lunar landing. These works provide broad guidelines for the design of spacecraft to exhibit excellent handling characteristics. In particular, this work demonstrates how handling qualities include much more than just stability and control characteristics of a spacecraft or aircraft. Handling qualities are affected by all aspects of the pilot-vehicle dynamic system, including the motion, visual and aural cues of the vehicle response as the pilot performs the required operation or task. A holistic approach to spacecraft design, including the use of manual control, automatic control, and pilot intervention/supervision is described. The handling qualities implications of design decisions are demonstrated using these pilot-in-the-loop evaluations of docking operations and lunar landings.

  14. Spacecraft 3D Augmented Reality Mobile App

    Science.gov (United States)

    Hussey, Kevin J.; Doronila, Paul R.; Kumanchik, Brian E.; Chan, Evan G.; Ellison, Douglas J.; Boeck, Andrea; Moore, Justin M.

    2013-01-01

    The Spacecraft 3D application allows users to learn about and interact with iconic NASA missions in a new and immersive way using common mobile devices. Using Augmented Reality (AR) techniques to project 3D renditions of the mission spacecraft into real-world surroundings, users can interact with and learn about Curiosity, GRAIL, Cassini, and Voyager. Additional updates on future missions, animations, and information will be ongoing. Using a printed AR Target and camera on a mobile device, users can get up close with these robotic explorers, see how some move, and learn about these engineering feats, which are used to expand knowledge and understanding about space. The software receives input from the mobile device's camera to recognize the presence of an AR marker in the camera's field of view. It then displays a 3D rendition of the selected spacecraft in the user's physical surroundings, on the mobile device's screen, while it tracks the device's movement in relation to the physical position of the spacecraft's 3D image on the AR marker.

  15. Large Scale Experiments on Spacecraft Fire Safety

    DEFF Research Database (Denmark)

    Urban, David L.; Ruff, Gary A.; Minster, Olivier

    2012-01-01

    Full scale fire testing complemented by computer modelling has provided significant knowhow about the risk, prevention and suppression of fire in terrestrial systems (cars, ships, planes, buildings, mines, and tunnels). In comparison, no such testing has been carried out for manned spacecraft due...

  16. Asymmetric Electrostatic Radiation Shielding for Spacecraft

    Science.gov (United States)

    Metzger, Philip T.; Youngquist, Robert C.; Lane, John E.

    2005-01-01

    A paper describes the types, sources, and adverse effects of energetic-particle radiation in interplanetary space, and explores a concept of using asymmetric electrostatic shielding to reduce the amount of such radiation impinging on spacecraft. Typically, such shielding would include a system of multiple inflatable, electrically conductive spheres deployed in clusters in the vicinity of a spacecraft on lightweight structures that would maintain the spheres in a predetermined multipole geometry. High-voltage generators would maintain the spheres at potential differences chosen in conjunction with the multipole geometry so that the resulting multipole field would gradually divert approaching energetic atomic nuclei from a central region occupied by the spacecraft. The spheres nearest the center would be the most positive, so as to repel the positively charged impinging nuclei from the center. At the same time, the monopole potential of the overall spacecraft-and-shielding system would be made negative so as to repel thermal electrons. The paper presents results of computational simulations of energetic-particle trajectories and shield efficiency for a trial system of 21 spheres arranged in three clusters in an overall linear quadrupole configuration. Further development would be necessary to make this shielding concept practical.

  17. Spacecraft potential control for Double Star

    Directory of Open Access Journals (Sweden)

    K. Torkar

    2005-11-01

    Full Text Available The spacecraft potential of Double Star TC-1 is positive in large parts of the orbits due to the photo-effect from solar EUV irradiation. These positive potentials typically disturb low energy plasma measurements on board. The potential can be reduced, and thereby the particle measurements improved, by emitting a positive ion beam. This method has successfully been applied on several other spacecraft and it has also been chosen for TC-1. The instrument TC-1/ASPOC is a derivative of the Cluster/ASPOC instruments, from which it has inherited many features. The paper describes the adaptations and further developments made for the ion emitters and the electronics. The instrument performs very well and can support higher beam currents than on Cluster. The expected significant improvement of the low energy particle measurements on board was indeed observed. The modifications of the electron distributions are analysed for a one-time interval when the spacecraft was located in the magnetosheath. The change in the potential due to the ion beam was determined, and first studies of the 3-D electron distributions in response to the spacecraft potential control have been performed, which indicate that the method works as expected.

  18. Standardization activity for the spacecraft onboard interfaces

    Science.gov (United States)

    Smith, J. F.; Plummer, C.; Plancke, P.

    2003-01-01

    The Consultative Committee for Space Data Systems (CCSDS) is an international organization of national space agencies that is organized to promote theinterchange of space related information. CCSDS is branching out to provide new standards to enhanced reuse of spacecraft equipment and software onboard of a spacecraft. This effort is know as Spacecraft Onboard Interface (SOIF). SOIF expects that these standards will be well used within the space community, and that they will be based on the well-known Internet protocols. This paper will provide a description of the SOIF work by reviewing this work with three orthogonal views. The Services View describes the data communications services that are provided to the users. The Interoperability view provides a description to users on how to use SOIF to interchange between different spacecraft data busses. And finally, the Protocol view, describes the protocols and services that are to be implemented in order to provide the users with the advantages of the SOIF architecture. This paper will give the reader an excellent introduction to the work of the international SOIF team.

  19. AIM: Ames Imaging Module Spacecraft Camera

    Science.gov (United States)

    Thompson, Sarah

    2015-01-01

    The AIM camera is a small, lightweight, low power, low cost imaging system developed at NASA Ames. Though it has imaging capabilities similar to those of $1M plus spacecraft cameras, it does so on a fraction of the mass, power and cost budget.

  20. Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior

    Science.gov (United States)

    Klem, B.; Swann, D.

    2011-09-01

    Anomalous behavior of on-orbit spacecraft can often be detected using passive, remote sensors which measure electro-optical signatures that vary in time and spectral content. Analysts responsible for assessing spacecraft operational status and detecting detrimental anomalies using non-resolved imaging sensors are often presented with various sensing and identification issues. Modeling and measuring spacecraft self emission and reflected radiant intensity when the radiation patterns exhibit a time varying reflective glint superimposed on an underlying diffuse signal contribute to assessment of spacecraft behavior in two ways: (1) providing information on body component orientation and attitude; and, (2) detecting changes in surface material properties due to the space environment. Simple convex and cube-shaped spacecraft, designed to operate without protruding solar panel appendages, may require an enhanced level of preflight characterization to support interpretation of the various physical effects observed during on-orbit monitoring. This paper describes selected portions of the signature database generated using streamlined signature modeling and simulations of basic geometry shapes apparent to non-imaging sensors. With this database, summarization of key observable features for such shapes as spheres, cylinders, flat plates, cones, and cubes in specific spectral bands that include the visible, mid wave, and long wave infrared provide the analyst with input to the decision process algorithms contained in the overall sensing and identification architectures. The models typically utilize baseline materials such as Kapton, paints, aluminum surface end plates, and radiators, along with solar cell representations covering the cylindrical and side portions of the spacecraft. Multiple space and ground-based sensors are assumed to be located at key locations to describe the comprehensive multi-viewing aspect scenarios that can result in significant specular reflection

  1. Low-Temperature Spacecraft: Challenges/Opportunities

    Science.gov (United States)

    Dickman, J. E.; Patterson, R. L.; Overton, E.; Hammoud, A. N.; Gerber, S. S.

    2001-01-01

    Imagine sending a spacecraft into deep space that operates at the ambient temperature of its environment rather than hundreds of degrees Kelvin warmer. The average temperature of a spacecraft warmed only by the sun drops from 279 K near the Earth's orbit to 90 K near the orbit of Saturn, and to 44 K near Pluto's orbit. At present, deep space probes struggle to maintain an operating temperature near 300 K for the onboard electronics. To warm the electronics without consuming vast amounts of electrical energy, radioisotope heater units (RHUs) are used in vast numbers. Unfortunately, since RHU are always 'on', an active thermal management system is required to reject the excess heat. A spacecraft designed to operate at cryogenic temperatures and shielded from the sun by a large communication dish or solar cell array could be less complex, lighter, and cheaper than current deep space probes. Before a complete low-temperature spacecraft becomes a reality, there are several challenges to be met. Reliable cryogenic power electronics is one of the major challenges. The Low-Temperature Power Electronics Research Group at NASA Glenn Research Center (GRC) has demonstrated the ability of some commercial off the shelf power electronic components to operate at temperatures approaching that of liquid nitrogen (77 K). Below 77 K, there exists an opportunity for the development of reliable semiconductor power switching technologies other than bulk silicon CMOS. This paper will report on the results of NASA GRC's Low-Temperature Power Electronics Program and discuss the challenges to (opportunities for) the creation of a low-temperature spacecraft.

  2. Building the future of WaferSat spacecraft for relativistic spacecraft

    Science.gov (United States)

    Brashears, Travis; Lubin, Philip; Rupert, Nic; Stanton, Eric; Mehta, Amal; Knowles, Patrick; Hughes, Gary B.

    2016-09-01

    Recently, there has been a dramatic change in the way space missions are viewed. Large spacecraft with massive propellant-filled launch stages have dominated the space industry since the 1960's, but low-mass CubeSats and low-cost rockets have enabled a new approach to space exploration. In recent work, we have built upon the idea of extremely low mass (sub 1 kg), propellant-less spacecraft that are accelerated by photon propulsion from dedicated directed-energy facilities. Advanced photonics on a chip with hybridized electronics can be used to implement a laser-based communication system on board a sub 1U spacecraft that we call a WaferSat. WaferSat spacecraft are equipped with reflective sails suitable for propulsion by directed-energy beams. This low-mass spacecraft design does not require onboard propellant, creating significant new opportunities for deep space exploration at a very low cost. In this paper, we describe the design of a prototype WaferSat spacecraft, constructed on a printed circuit board. The prototype is envisioned as a step toward a design that could be launched on an early mission into Low Earth Orbit (LEO), as a key milestone in the roadmap to interstellar flight. In addition to laser communication, the WaferSat prototype includes subsystems for power source, attitude control, digital image acquisition, and inter-system communications.

  3. The Evolution of the Surveyor Fan and Channel System, Gulf of Alaska based on Core-Log-Seismic Integration at IODP Site U1417

    Science.gov (United States)

    Morey, S.; Gulick, S. P. S.; Walton, M. A. L.; Swartz, J. M.; Worthington, L. L.; Reece, R.; Somchat, K.; Wagner, P. F.; Jaeger, J. M.; Mix, A. C.

    2015-12-01

    The transition to quasi-periodic ~100-kyr glacial cycles during the mid-Pleistocene transition (MPT, ~1.2 Ma) saw an acceleration of sediment delivery from the St. Elias orogen. Eroded sediment from the St. Elias Mountains is transferred to the deep sea via glacially carved shelf troughs and eventually to the Aleutian Trench via the Surveyor Channel and Fan system. By analyzing the submarine sediments in this Fan, we can evaluate the source-to-sink relationship between the erosion of an orogen and deep-sea deposition and inform our understanding of the impact of climate on local tectonics. Our work seeks to update depositional models of the unique sedimentary sequences, architecture, and origins of the glacially-fed Surveyor Fan using well-log-seismic correlation and new data from Integrated Ocean Drilling Program (IODP) Expedition 341. Exp. 341 results question proposed ages of major fan stratigraphic packages, necessitating this update. We created an integrated velocity model using discrete core-based p-wave velocities acquired at site U1417 from 100-152m, down-hole sonic log velocities from 152m-476m, and then projected the trend of the sonic log velocity from 476m to the base of the borehole. Previous work has interpreted the Sequence I/II boundary (~300 mbsf at U1417) to correspond with the start of the Surveyor Fan and the onset of tidewater glaciation in the late Miocene and the Sequence II/III boundary (~160 mbsf at U1417) to coincide with the intensification of glaciation and subsequent increase in sediment flux at the MPT. Our updated velocity model places these major sequence boundaries at the correct depths in borehole site U1417. We can use the revised velocity model to correlate lithologic, biostratigraphic, paleomagnetic, and logging data from the borehole/cores to seismic data, allowing for construction of a temporal model for the evolution of the Surveyor fan. We can then examine the relationship between glacial-interglacial cycle duration and

  4. The Aerial Regional-Scale Environmental Surveyor (ARES): New Mars Science to Reduce Human Risk and Prepare for the Human Exploration

    Science.gov (United States)

    Levine, Joel S.; Croom, Mark A.; Wright, Henry S.; Killough, B. D.; Edwards, W. C.

    2012-01-01

    Obtaining critical measurements for eventual human Mars missions while expanding upon recent Mars scientific discoveries and deriving new scientific knowledge from a unique near surface vantage point is the focus of the Aerial Regional-scale Environmental Surveyor (ARES) exploration mission. The key element of ARES is an instrumented,rocket-powered, well-tested robotic airplane platform, that will fly between one to two kilometers above the surface while traversing hundreds of kilometers to collect and transmit previously unobtainable high spatial measurements relevant to the NASA Mars Exploration Program and the exploration of Mars by humans.

  5. Lunar Module 5 mated with Spacecraft Lunar Module Adapter (SLA)

    Science.gov (United States)

    1969-01-01

    Interior view of the Kennedy Space Center's (KSC) Manned Spacecraft Operations Building showing Lunar Module 5 mated to its Spacecraft Lunar Module Adapter (SLA). LM-5 is scheduled to be flown on the Apollo 11 lunar landing mission.

  6. High-Performance Fire Detector for Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The danger from fire aboard spacecraft is immediate with only moments for detection and suppression. Spacecraft are unique high-value systems where the cost of...

  7. The Behavior of Warm Molecules in Planet-forming Disks and CHESS: a Pathfinder UV Spectrograph for the LUVOIR Surveyor

    Science.gov (United States)

    Hoadley, Keri; France, Kevin

    2017-01-01

    Understanding the evolution of gas over the lifetime of protoplanetary disks provides us with important clues about how planet formation mechanisms drive the diversity of exoplanetary systems observed to date. In the first part of my talk, I will discuss how we use emission line observations of molecular hydrogen (H2) in the far-ultraviolet (far-UV) with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope to study the warm molecular regions (a disks. We compare the observations with analytic disk models that produce synthetic H2 profiles, and we statistically determine the disk representations that best replicate the data. I will discuss the results of our comparisons and how the modeled radial distributions of H2 in the disk help provide important constraints on the effective density of gas left in the inner disk of protoplanetary disks at various disk evolutionary stages. Finally, I will talk about follow-up studies that look to connect the warm, UV-pumped molecular populations of the inner disk to thermally-excited molecules observed in similar regions of the disk in the near- to mid-IR.In the second part of my talk, I will discuss the observational requirements in the UV and IR band passes to gain further insights into the behavior of the warm, gaseous protoplanetary disk, focusing specifically on a spectrograph concept for the next-generation LUVOIR Surveyor. I will discuss a testbed instrument, the Colorado High-resolution Echelle Stellar Spectrograph (CHESS), built as a demonstration of one component of the LUVOIR spectrograph and new technological improvements to UV optical components for the next generation of near- to far-UV astrophysical observatories. CHESS is a far-UV sounding rocket experiment designed to probe the warm and cool atoms and molecules near sites of recent star formation in the local interstellar medium. I will talk about the science goals, design, research and development (R&D) components, and calibration of the CHESS

  8. Soft x-ray transmission grating spectrometer for X-ray Surveyor and smaller missions with high resolving power

    Science.gov (United States)

    Heilmann, Ralf K.; Bruccoleri, Alexander; Schattenburg, Mark; Kolodziejczak, jeffery; Gaskin, Jessica; O'Dell, Stephen L.

    2017-01-01

    A number of high priority subjects in astrophysics are addressed by a state-of-the-art soft x-ray grating spectrometer, e.g. the role of Active Galactic Nuclei in galaxy and star formation, characterization of the WHIM and the “missing baryon” problem, characterization of halos around the Milky Way and nearby galaxies, and stellar coronae and surrounding winds and disks. An Explorer-scale, large-area (A > 1,000 cm2), high resolving power (R > 3,000) soft x-ray grating spectrometer is highly feasible based on Critical-Angle Transmission (CAT) grating technology, even for telescopes with angular resolution of 5-10 arcsec. Significantly higher performance could be provided by a CAT grating spectrometer on an X-ray-Surveyor-type mission (A > 4,000 cm2, R > 5,000). CAT gratings combine advantages of blazed reflection gratings (high efficiency, use of higher orders) with those of transmission gratings (low mass, relaxed alignment tolerances and temperature requirements, transparent at higher energies) with minimal mission resource requirements. Blazing is achieved through grazing-incidence reflection off the smooth silicon grating bar sidewalls. Silicon is well matched to the soft x-ray band, and 30% absolute diffraction efficiency has been acheived with clear paths for further improvement. CAT gratings with sidewalls made of high-Z elements allow extension of blazing to higher energies and larger dispersion angles, enabling higher resolving power at shorter wavelengths. X-ray data from CAT gratings coated with a thin layer of platinum using atomic layer deposition demonstrate efficient blazing to higher energies and much larger blaze angles than possible with silicon alone. Measurements of the resolving power of a breadboard CAT grating spectrometer consisting of a Wolter-I slumped-glass focusing optic from GSFC and CAT gratings, taken at the MSFC Stray Light Facility, have demonstrated resolving power > 10,000. Thus currently fabricated CAT gratings are compatible

  9. NASA STD-4005: The LEO Spacecraft Charging Design Standard

    Science.gov (United States)

    Ferguson, Dale C.

    2006-01-01

    Power systems with voltages higher than about 55 volts may charge in Low Earth Orbit (LEO) enough to cause destructive arcing. The NASA STD-4005 LEO Spacecraft Charging Design Standard will help spacecraft designers prevent arcing and other deleterious effects on LEO spacecraft. The Appendices, an Information Handbook based on the popular LEO Spacecraft Charging Design Guidelines by Ferguson and Hillard, serve as a useful explanation and accompaniment to the Standard.

  10. Gravity Gradient Tensor Eigendecomposition for Spacecraft Positioning

    CERN Document Server

    Chen, Pei; Han, Chao

    2016-01-01

    In this Note, a new approach to spacecraft positioning based on GGT inversion is presented. The gravity gradient tensor is initially measured in the gradiometer reference frame (GRF) and then transformed to the Earth-Centered Earth-Fixed (ECEF) frame via attitude information as well as Earth rotation parameters. Matrix Eigen-Decomposition is introduced to directly translate GGT into position based on the fact that the eigenvalues and eigenvectors of GGT are simplespecific functions of spherical coordinates of the observation position. without the need of an initial position. Unlike the strategy of inertial navigation aiding, no prediction or first guess of the spacecraft position is needed. The method makes use of the J2 gravity model, and is suitable for space navigation where higher frequency terrain contributions to the GGT signals can be neglected.

  11. Evaluation of Ultrafiltration for Spacecraft Water Reuse

    Science.gov (United States)

    Pickering, Karen D.; Wiesner, Mark R.

    2001-01-01

    Ultrafiltration is examined for use as the first stage of a primary treatment process for spacecraft wastewater. It is hypothesized that ultrafiltration can effectively serve as pretreatment for a reverse osmosis system, removing the majority of organic material in a spacecraft wastewater. However, it is believed that the interaction between the membrane material and the surfactant found in the wastewater will have a significant impact on the fouling of the ultrafiltration membrane. In this study, five different ultrafiltration membrane materials are examined for the filtration of wastewater typical of that expected to be produced onboard the International Space Station. Membranes are used in an unstirred batch cell. Flux, organic carbon rejection, and recovery from fouling are measured. The results of this evaluation will be used to select the most promising membranes for further study.

  12. Fundamentals of spacecraft attitude determination and control

    CERN Document Server

    Markley, F Landis

    2014-01-01

    This book explores topics that are central to the field of spacecraft attitude determination and control. The authors provide rigorous theoretical derivations of significant algorithms accompanied by a generous amount of qualitative discussions of the subject matter. The book documents the development of the important concepts and methods in a manner accessible to practicing engineers, graduate-level engineering students and applied mathematicians. It includes detailed examples from actual mission designs to help ease the transition from theory to practice, and also provides prototype algorithms that are readily available on the author’s website. Subject matter includes both theoretical derivations and practical implementation of spacecraft attitude determination and control systems. It provides detailed derivations for attitude kinematics and dynamics, and provides detailed description of the most widely used attitude parameterization, the quaternion. This title also provides a thorough treatise of attitu...

  13. Orion Spacecraft MMOD Protection Design and Assessment

    Science.gov (United States)

    Bohl, William; Miller, Joshua; Deighton, Kevin; Foreman, Cory; Yasensky, John; Christiansen, Eric; Hyde, James; Nahra, Henry

    2009-01-01

    The Orion spacecraft will replace the Space Shuttle Orbiter for American and international partner access to the International Space Station by 2015 and, afterwards, for access to the moon for initial sorties and later for extend outpost visits as part of the Constellation Exploration Initiative. This work describes some of the efforts being undertaken to ensure that Orion design will meet or exceed the stringent MicroMeteoroid and Orbital Debris (MMOD) requirements set out by NASA when exposed to the environments encountered with these missions. This paper will provide a brief overview of the approaches being used to provide MMOD protection to the Orion vehicle and to assess the spacecraft for compliance to the Constellation Program s MMOD requirements.

  14. Formation Flying Control of Multiple Spacecraft

    Science.gov (United States)

    Hadaegh, F. Y.; Lau, Kenneth; Wang, P. K. C.

    1997-01-01

    The problem of coordination and control of multiple spacecraft (MS) moving in formation is considered. Here, each MS is modeled by a rigid body with fixed center of mass. First, various schemes for generating the desired formation patterns are discussed, Then, explicit control laws for formation-keeping and relative attitude alignment based on nearest neighbor-tracking are derived. The necessary data which must be communicated between the MS to achieve effective control are examined. The time-domain behavior of the feedback-controlled MS formation for typical low-Earth orbits is studied both analytically and via computer simulation. The paper concludes with a discussion of the implementation of the derived control laws, and the integration of the MS formation coordination and control system with a proposed inter-spacecraft communication/computing network.

  15. The Anomalous Acceleration of the Pioneer Spacecrafts

    CERN Document Server

    de Diego, Jose A

    2008-01-01

    Radiometric data from the Pioneer 10 and 11 spacecrafts have revealed an unexplained constant acceleration of a_A = (8.74 +/- 1.33) x 10^(-10) m s^(-2) towards the Sun, also known as the Pioneer anomaly. Different groups have analyzed the Pioneer data and have got the same results, which rules out computer programming and handling errors. Attempts to explain this phenomenon arguing intrinsic causes on-board the spacecrafts failed or have lead to inconclusive results. Therefore, the Pioneer anomalous acceleration has motivated the interest of researchers to find out explanations that could bring insight upon the forces acting in the outer Solar Systems or a hint to discover new natural laws.

  16. Close-Range Photogrammetry & Next Generation Spacecraft

    Science.gov (United States)

    Pappa, Richard S.

    2002-01-01

    NASA is focusing renewed attention on the topic of large, ultra-lightweight space structures, also known as 'gossamer' spacecraft. Nearly all of the details of the giant spacecraft are still to be worked out. But it's already clear that one of the most challenging aspects will be developing techniques to align and control these systems after they are deployed in space. A critical part of this process is creating new ground test methods to measure gossamer structures under stationary, deploying and vibrating conditions for validation of corresponding analytical predictions. In addressing this problem, I considered, first of all, the possibility of simply using conventional displacement or vibration sensor that could provide spatial measurements. Next, I turned my attention to photogrammetry, a method of determining the spatial coordinates of objects using photographs. The success of this research and development has convinced me that photogrammetry is the most suitable method to solve the gossamer measurement problem.

  17. Titan Airship Surveyor

    Science.gov (United States)

    Kerzhanovich, V.; Yavrouian, A.; Cutts, J.; Colozza, A.; Fairbrother, D.

    2001-01-01

    Saturn's moon Titan is considered to be one of the prime candidates for studying prebiotic materials - the substances that precede the formation of life but have disappeared from the Earth as a result of the evolution of life. A unique combination of a dense, predominantly nitrogen, atmosphere (more than four times that of the Earth), low gravity (six times less than on the Earth) and small temperature variations makes Titan the almost ideal planet for studies with lighter-than-air aerial platforms (aerobots). Moreover, since methane clouds and photochemical haze obscure the surface, low-altitude aerial platforms are the only practical means that can provide global mapping of the Titan surface at visible and infrared wavelengths. One major challenge in Titan exploration is the extremely cold atmosphere (approx. 90 K). However, current material technology the capability to operate aerobots at these very low temperatures. A second challenge is the remoteness from the Sun (10 AU) that makes the nuclear (radioisotopic) energy the only practical source of power. A third challenge is remoteness from the Earth (approx. 10 AU, two-way light-time approx. 160 min) which imposes restrictions on data rates and makes impractical any meaningful real-time control. A small-size airship (approx. 25 cu m) can carry a payload approximately 100 kg. A Stirling engine coupled to a radioisotope heat source would be the prime choice for producing both mechanical and electrical power for sensing, control, and communications. The cold atmospheric temperature makes Stirling machines especially effective. With the radioisotope power source the airship may fly with speed approximately 5 m/s for a year or more providing an excellent platform for in situ atmosphere measurements and a high-resolution remote sensing with unlimited access on a global scale. In a station-keeping mode the airship can be used for in situ studies on the surface by winching down an instrument package. Floating above the surface allows relatively simple means for flight control. Mission requirements and possible methods of navigation, control, data acquisition, and communications are discussed. The presentation describes also the state-of-the art and current progress in aerial deployed aerobots.

  18. GPS for land surveyors

    CERN Document Server

    Van Sickle, Jan

    2008-01-01

    The GPS SignalGlobal Positioning System (GPS) Signal StructureTwo ObservablesPseudorangingCarrier Phase RangingBiases and SolutionsThe Error BudgetDifferencingThe FrameworkTechnological ForerunnersVery Long Baseline InterferometryTransitNavstar GPSGPS Segment OrganizationGPS ConstellationThe Control SegmentReceivers and MethodsCommon Features of GPS ReceiversChoosing a GPS ReceiverSome GPS Surveying MethodsCoordinatesA Few Pertinent Ideas About Geodetic Datums for GPSState Plane CoordinatesHeightsGPS Surveying TechniquesStatic GPS SurveyingReal-Time Kinematic (RTK) and Differential GPS (DGPS)T

  19. Nonlinear Robust Control for Spacecraft Attitude

    Directory of Open Access Journals (Sweden)

    Wang Lina

    2013-07-01

    Full Text Available Nonlinear robust control of the spacecraft attitude with the existence of external disturbances is considered. A robust attitude controller is designed based on the passivity approach the quaternion representation, which introduces the suppression vector of external disturbance into the control law and does not need angular velocity measurement. Stability conditions of the robust attitude controller are given. And the numerical simulation results show the effectiveness of the attitude controller.

  20. Spacecraft Dynamic Characteristics While Deploying Flexible Beams

    Institute of Scientific and Technical Information of China (English)

    程绪铎; 李俊峰; 樊勇; 王照林

    2002-01-01

    The attitude dynamic equations of a spacecraft while deploying two flexible beams and the beam equations were developed from momentum theory. The dynamic equations were solved numerically using the Runge-Kutta method to calculate the vibration amplitudes of the flexible beams and the attitude angular velocity. The results show that the vibration amplitudes increase as the beam length increases or as the initial attitude angular velocity increases. The results also show that the vibration amplitudes decrease as the deployment velocity increases.

  1. Spacecraft Reed-Solomon downlink module

    Science.gov (United States)

    Luong, Huy H. (Inventor); Donaldson, James A. (Inventor); Wood, Steven H. (Inventor)

    1998-01-01

    Apparatus and method for providing downlink frames to be transmitted from a spacecraft to a ground station. Each downlink frame includes a synchronization pattern and a transfer frame. The apparatus may comprise a monolithic Reed-Solomon downlink (RSDL) encoding chip coupled to data buffers for storing transfer frames. The RSKL chip includes a timing device, a bus interface, a timing and control unit, a synchronization pattern unit, and a Reed-Solomon encoding unit, and a bus arbiter.

  2. Additive Manufacturing: Ensuring Quality for Spacecraft Applications

    Science.gov (United States)

    Swanson, Theodore; Stephenson, Timothy

    2014-01-01

    Reliable manufacturing requires that material properties and fabrication processes be well defined in order to insure that the manufactured parts meet specified requirements. While this issue is now relatively straightforward for traditional processes such as subtractive manufacturing and injection molding, this capability is still evolving for AM products. Hence, one of the principal challenges within AM is in qualifying and verifying source material properties and process control. This issue is particularly critical for applications in harsh environments and demanding applications, such as spacecraft.

  3. Artificial Intelligence and Spacecraft Power Systems

    Science.gov (United States)

    Dugel-Whitehead, Norma R.

    1997-01-01

    This talk will present the work which has been done at NASA Marshall Space Flight Center involving the use of Artificial Intelligence to control the power system in a spacecraft. The presentation will include a brief history of power system automation, and some basic definitions of the types of artificial intelligence which have been investigated at MSFC for power system automation. A video tape of one of our autonomous power systems using co-operating expert systems, and advanced hardware will be presented.

  4. Research of solid state recorder for spacecraft

    OpenAIRE

    Shirakura, Masashi; Ichikawa, Satoshi; Sasada, Takeshi; Ohashi, Eiji; 白倉 政志; 市川 愉; 笹田 武志; 大橋 永嗣

    2006-01-01

    This research is to develop advanced, small, light-weight and low power consumption Solid State Recorder (SSR) on spacecraft utilizing the newest commercial semi-conductor memory device. We have manufactured, tested and evaluated next generation solid state recorder, researched high-efficient Error Detection And Correction code (EDAC). And also experimented and analyzed mission data of SSR on Mission Demonstration Satellite-1 (MDS-1) on orbit.

  5. Research of solid state recorder on spacecraft

    OpenAIRE

    Ichikawa, Satoshi; Shirakura, Masashi; Sasada, Takeshi; 市川 愉; 白倉 政志; 笹田 武志

    2004-01-01

    This research is to develop advanced, small, light-weight and low power consumption solid state recorder (SSR) on spacecraft utilizing the newest commercial semi-conductor memory device. Next generation solid state recorder has been manufactured, tested and evaluated, high-efficient error detection and correction code (EDAC) have been researched, and also mission data of SSR on Mission Demonstration Satellite-1 (MDS-1) on orbit has been experimented and analyzed.

  6. TAU as Tao. [interstellar spacecraft performance

    Science.gov (United States)

    Lyman, P. T.; Reid, M. S.

    1989-01-01

    This paper discusses the feasibility of building and launching a truly deep-space spacecraft mission that will penetrate near interstellar space to a depth of one thousand astronomical units (TAU) within a flight time of 50 years. Particular attention is given to the mission profile and to its communications system, power system, and propulsion system. Results of experimental studies indicate that, with advanced technology, reasonable trip times can be achieved and adequate science information can be brought to earth.

  7. Schema for Spacecraft-Command Dictionary

    Science.gov (United States)

    Laubach, Sharon; Garcia, Celina; Maxwell, Scott; Wright, Jesse

    2008-01-01

    An Extensible Markup Language (XML) schema was developed as a means of defining and describing a structure for capturing spacecraft command- definition and tracking information in a single location in a form readable by both engineers and software used to generate software for flight and ground systems. A structure defined within this schema is then used as the basis for creating an XML file that contains command definitions.

  8. THE FUTURE OF SPACECRAFT NUCLEAR PROPULSION

    OpenAIRE

    Jansen, Frank

    2014-01-01

    This paper summarizes the advantages of space nuclear power and propulsion systems. It describes the actual status of international power level dependent spacecraft nuclear propulsion missions, especially the high power EU-Russian MEGAHIT study including the Russian Megawatt-Class Nuclear Power Propulsion System, the NASA GRC project and the low and medium power EU DiPoP study. Space nuclear propulsion based mission scenarios of these studies are sketched as well.

  9. The Future of Spacecraft Nuclear Propulsion

    Science.gov (United States)

    Jansen, F.

    2014-06-01

    This paper summarizes the advantages of space nuclear power and propulsion systems. It describes the actual status of international power level dependent spacecraft nuclear propulsion missions, especially the high power EU-Russian MEGAHIT study including the Russian Megawatt-Class Nuclear Power Propulsion System, the NASA GRC project and the low and medium power EU DiPoP study. Space nuclear propulsion based mission scenarios of these studies are sketched as well.

  10. Artificial Intelligence and Spacecraft Power Systems

    Science.gov (United States)

    Dugel-Whitehead, Norma R.

    1997-01-01

    This talk will present the work which has been done at NASA Marshall Space Flight Center involving the use of Artificial Intelligence to control the power system in a spacecraft. The presentation will include a brief history of power system automation, and some basic definitions of the types of artificial intelligence which have been investigated at MSFC for power system automation. A video tape of one of our autonomous power systems using co-operating expert systems, and advanced hardware will be presented.

  11. Stabilization of rotational motion with application to spacecraft attitude control

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2000-01-01

    on a Riemannian manifold. The Lyapnov stability theory is adapted and reformulated to fit to the new framework of Riemannian manifolds. Toillustrate the results a spacecraft attitude control problem is considered. Firstly, a global canonical representation for the spacecraft motion is found, then three spacecraft...

  12. A Neutral Plasma Source for Active Spacecraft Charge Control.

    Science.gov (United States)

    1985-08-01

    potentials are generally negative since electrons have higher mobilities as compared to ions. Overall spacecraft frame charging enhances surface contamination...Cuchanski, M., Kremer, P. C., "Surface Micro-Discharges on Spacecraft Dielectrics", Paper 111-7, Proceedings of the Spacecraft Charging Techonology

  13. Wireless Intra-Spacecraft Communication: The Benefits and the Challenges

    Science.gov (United States)

    Zheng, Will H.; Armstrong, John T.

    2010-01-01

    In this paper we present a systematic study of how intra-spacecraft wireless communication can be adopted to various subsystems of the spacecraft including C&DH (Command & Data Handling), Telecom, Power, Propulsion, and Payloads, and the interconnects between them. We discuss the advantages of intra-spacecraft wireless communication and the disadvantages and challenges and a proposal to address them.

  14. Time Delay Interferometry with Moving Spacecraft Arrays

    CERN Document Server

    Tinto, M; Armstrong, J W; Tinto, Massimo; Estabrook, Frank B.; Armstrong, adn J.W.

    2004-01-01

    Space-borne interferometric gravitational wave detectors, sensitive in the low-frequency (millihertz) band, will fly in the next decade. In these detectors the spacecraft-to-spacecraft light-travel-times will necessarily be unequal, time-varying, and (due to aberration) have different time delays on up- and down-links. Reduction of data from moving interferometric laser arrays in solar orbit will in fact encounter non-symmetric up- and downlink light time differences that are about 100 times larger than has previously been recognized. The time-delay interferometry (TDI) technique uses knowledge of these delays to cancel the otherwise dominant laser phase noise and yields a variety of data combinations sensitive to gravitational waves. Under the assumption that the (different) up- and downlink time delays are constant, we derive the TDI expressions for those combinations that rely only on four inter-spacecraft phase measurements. We then turn to the general problem that encompasses time-dependence of the light...

  15. Spacecraft charging requirements and engineering issues

    Science.gov (United States)

    Garrett, Henry B.; Whittlesey, Albert C.

    2006-01-01

    An effort is currently underway to recast and combine two NASA guidelines for mitigating the effects of spacecraft charging and electrostatic discharge on spacecraft. The task has the goal of taking the existing NASA guidelines for preventing surface electrostatic charging, NASA-TP-2361 (Purvis et al., 1984), and internal electrostatic charging, NASAHDBK 4002 (Whittlesey, 1999), and bringing them up to date with recent laboratory and onorbit findings. This paper will describe the status of those on-going efforts to combine and update the two guidelines. Reasons for the upgrades will be presented, including new subject material for which there is now a greater understanding or a greater need which changes satellite design procedures, or both. There will be an emphasis on the proposed contents and on the differences and similarities between surface and internal charging mitigation techniques. In addition, the mitigation requirements that can be derived from the combined handbook will be discussed with emphasis on how they might affect the engineering design and testing of future spacecraft.

  16. Spacecraft charging requirements and engineering issues

    Science.gov (United States)

    Garrett, Henry B.; Whittlesey, Albert C.

    2006-01-01

    An effort is currently underway to recast and combine two NASA guidelines for mitigating the effects of spacecraft charging and electrostatic discharge on spacecraft. The task has the goal of taking the existing NASA guidelines for preventing surface electrostatic charging, NASA-TP-2361 (Purvis et al., 1984), and internal electrostatic charging, NASAHDBK 4002 (Whittlesey, 1999), and bringing them up to date with recent laboratory and onorbit findings. This paper will describe the status of those on-going efforts to combine and update the two guidelines. Reasons for the upgrades will be presented, including new subject material for which there is now a greater understanding or a greater need which changes satellite design procedures, or both. There will be an emphasis on the proposed contents and on the differences and similarities between surface and internal charging mitigation techniques. In addition, the mitigation requirements that can be derived from the combined handbook will be discussed with emphasis on how they might affect the engineering design and testing of future spacecraft.

  17. Space Weathering Experiments on Spacecraft Materials

    Science.gov (United States)

    Engelhart, D. P.; Cooper, R.; Cowardin, H.; Maxwell, J.; Plis, E.; Ferguson, D.; Barton, D.; Schiefer, S.; Hoffmann, R.

    2017-01-01

    A project to investigate space environment effects on specific materials with interest to remote sensing was initiated in 2016. The goal of the project is to better characterize changes in the optical properties of polymers found in multi-layered spacecraft insulation (MLI) induced by electron bombardment. Previous analysis shows that chemical bonds break and potentially reform when exposed to high energy electrons like those seen in orbit. These chemical changes have been shown to alter a material's optical reflectance, among other material properties. This paper presents the initial experimental results of MLI materials exposed to various fluences of high energy electrons, designed to simulate a portion of the geosynchronous Earth orbit (GEO) space environment. It is shown that the spectral reflectance of some of the tested materials changes as a function of electron dose. These results provide an experimental benchmark for analysis of aging effects on satellite systems which can be used to improve remote sensing and space situational awareness. They also provide preliminary analysis on those materials that are most likely to comprise the high area-to-mass ratio (HAMR) population of space debris in the geosynchronous orbit environment. Finally, the results presented in this paper serve as a proof of concept for simulated environmental aging of spacecraft polymers that should lead to more experiments using a larger subset of spacecraft materials.

  18. Internet Distribution of Spacecraft Telemetry Data

    Science.gov (United States)

    Specht, Ted; Noble, David

    2006-01-01

    Remote Access Multi-mission Processing and Analysis Ground Environment (RAMPAGE) is a Java-language server computer program that enables near-real-time display of spacecraft telemetry data on any authorized client computer that has access to the Internet and is equipped with Web-browser software. In addition to providing a variety of displays of the latest available telemetry data, RAMPAGE can deliver notification of an alarm by electronic mail. Subscribers can then use RAMPAGE displays to determine the state of the spacecraft and formulate a response to the alarm, if necessary. A user can query spacecraft mission data in either binary or comma-separated-value format by use of a Web form or a Practical Extraction and Reporting Language (PERL) script to automate the query process. RAMPAGE runs on Linux and Solaris server computers in the Ground Data System (GDS) of NASA's Jet Propulsion Laboratory and includes components designed specifically to make it compatible with legacy GDS software. The client/server architecture of RAMPAGE and the use of the Java programming language make it possible to utilize a variety of competitive server and client computers, thereby also helping to minimize costs.

  19. Stability analysis of spacecraft power systems

    Science.gov (United States)

    Halpin, S. M.; Grigsby, L. L.; Sheble, G. B.; Nelms, R. M.

    1990-01-01

    The problems in applying standard electric utility models, analyses, and algorithms to the study of the stability of spacecraft power conditioning and distribution systems are discussed. Both single-phase and three-phase systems are considered. Of particular concern are the load and generator models that are used in terrestrial power system studies, as well as the standard assumptions of load and topological balance that lead to the use of the positive sequence network. The standard assumptions regarding relative speeds of subsystem dynamic responses that are made in the classical transient stability algorithm, which forms the backbone of utility-based studies, are examined. The applicability of these assumptions to a spacecraft power system stability study is discussed in detail. In addition to the classical indirect method, the applicability of Liapunov's direct methods to the stability determination of spacecraft power systems is discussed. It is pointed out that while the proposed method uses a solution process similar to the classical algorithm, the models used for the sources, loads, and networks are, in general, more accurate. Some preliminary results are given for a linear-graph, state-variable-based modeling approach to the study of the stability of space-based power distribution networks.

  20. Determination of Realistic Fire Scenarios in Spacecraft

    Science.gov (United States)

    Dietrich, Daniel L.; Ruff, Gary A.; Urban, David

    2013-01-01

    This paper expands on previous work that examined how large a fire a crew member could successfully survive and extinguish in the confines of a spacecraft. The hazards to the crew and equipment during an accidental fire include excessive pressure rise resulting in a catastrophic rupture of the vehicle skin, excessive temperatures that burn or incapacitate the crew (due to hyperthermia), carbon dioxide build-up or accumulation of other combustion products (e.g. carbon monoxide). The previous work introduced a simplified model that treated the fire primarily as a source of heat and combustion products and sink for oxygen prescribed (input to the model) based on terrestrial standards. The model further treated the spacecraft as a closed system with no capability to vent to the vacuum of space. The model in the present work extends this analysis to more realistically treat the pressure relief system(s) of the spacecraft, include more combustion products (e.g. HF) in the analysis and attempt to predict the fire spread and limiting fire size (based on knowledge of terrestrial fires and the known characteristics of microgravity fires) rather than prescribe them in the analysis. Including the characteristics of vehicle pressure relief systems has a dramatic mitigating effect by eliminating vehicle overpressure for all but very large fires and reducing average gas-phase temperatures.

  1. Heliocentric phasing performance of electric sail spacecraft

    Science.gov (United States)

    Mengali, Giovanni; Quarta, Alessandro A.; Aliasi, Generoso

    2016-10-01

    We investigate the heliocentric in-orbit repositioning problem of a spacecraft propelled by an Electric Solar Wind Sail. Given an initial circular parking orbit, we look for the heliocentric trajectory that minimizes the time required for the spacecraft to change its azimuthal position, along the initial orbit, of a (prescribed) phasing angle. The in-orbit repositioning problem can be solved using either a drift ahead or a drift behind maneuver and, in general, the flight times for the two cases are different for a given value of the phasing angle. However, there exists a critical azimuthal position, whose value is numerically found, which univocally establishes whether a drift ahead or behind trajectory is superior in terms of flight time it requires for the maneuver to be completed. We solve the optimization problem using an indirect approach for different values of both the spacecraft maximum propulsive acceleration and the phasing angle, and the solution is then specialized to a repositioning problem along the Earth's heliocentric orbit. Finally, we use the simulation results to obtain a first order estimate of the minimum flight times for a scientific mission towards triangular Lagrangian points of the Sun-[Earth+Moon] system.

  2. Spacecraft formation flying: Dynamics, control and navigation

    Science.gov (United States)

    Alfriend, Kyle Terry; Vadali, Srinivas Rao; Gurfil, Pini; How, Jonathan; Breger, Louis S.

    2009-12-01

    Space agencies are now realizing that much of what has previously been achieved using hugely complex and costly single platform projects - large unmanned and manned satellites (including the present International Space Station) - can be replaced by a number of smaller satellites networked together. The key challenge of this approach, namely ensuring the proper formation flying of multiple craft, is the topic of this second volume in Elsevier's Astrodynamics Series, Spacecraft Formation Flying: Dynamics, control and navigation. In this unique text, authors Alfriend et al. provide a coherent discussion of spacecraft relative motion, both in the unperturbed and perturbed settings, explain the main control approaches for regulating relative satellite dynamics, using both impulsive and continuous maneuvers, and present the main constituents required for relative navigation. The early chapters provide a foundation upon which later discussions are built, making this a complete, standalone offering. Intended for graduate students, professors and academic researchers in the fields of aerospace and mechanical engineering, mathematics, astronomy and astrophysics, Spacecraft Formation Flying is a technical yet accessible, forward-thinking guide to this critical area of astrodynamics.

  3. Ontological Modeling for Integrated Spacecraft Analysis

    Science.gov (United States)

    Wicks, Erica

    2011-01-01

    Current spacecraft work as a cooperative group of a number of subsystems. Each of these requiresmodeling software for development, testing, and prediction. It is the goal of my team to create anoverarching software architecture called the Integrated Spacecraft Analysis (ISCA) to aid in deploying the discrete subsystems' models. Such a plan has been attempted in the past, and has failed due to the excessive scope of the project. Our goal in this version of ISCA is to use new resources to reduce the scope of the project, including using ontological models to help link the internal interfaces of subsystems' models with the ISCA architecture.I have created an ontology of functions specific to the modeling system of the navigation system of a spacecraft. The resulting ontology not only links, at an architectural level, language specificinstantiations of the modeling system's code, but also is web-viewable and can act as a documentation standard. This ontology is proof of the concept that ontological modeling can aid in the integration necessary for ISCA to work, and can act as the prototype for future ISCA ontologies.

  4. Stochastic Analysis of Orbital Lifetimes of Spacecraft

    Science.gov (United States)

    Sasamoto, Washito; Goodliff, Kandyce; Cornelius, David

    2008-01-01

    A document discusses (1) a Monte-Carlo-based methodology for probabilistic prediction and analysis of orbital lifetimes of spacecraft and (2) Orbital Lifetime Monte Carlo (OLMC)--a Fortran computer program, consisting of a previously developed long-term orbit-propagator integrated with a Monte Carlo engine. OLMC enables modeling of variances of key physical parameters that affect orbital lifetimes through the use of probability distributions. These parameters include altitude, speed, and flight-path angle at insertion into orbit; solar flux; and launch delays. The products of OLMC are predicted lifetimes (durations above specified minimum altitudes) for the number of user-specified cases. Histograms generated from such predictions can be used to determine the probabilities that spacecraft will satisfy lifetime requirements. The document discusses uncertainties that affect modeling of orbital lifetimes. Issues of repeatability, smoothness of distributions, and code run time are considered for the purpose of establishing values of code-specific parameters and number of Monte Carlo runs. Results from test cases are interpreted as demonstrating that solar-flux predictions are primary sources of variations in predicted lifetimes. Therefore, it is concluded, multiple sets of predictions should be utilized to fully characterize the lifetime range of a spacecraft.

  5. Space Environments and Spacecraft Effects Organization Concept

    Science.gov (United States)

    Edwards, David L.; Burns, Howard D.; Miller, Sharon K.; Porter, Ron; Schneider, Todd A.; Spann, James F.; Xapsos, Michael

    2012-01-01

    The National Aeronautics and Space Administration (NASA) is embarking on a course to expand human presence beyond Low Earth Orbit (LEO) while also expanding its mission to explore the solar system. Destinations such as Near Earth Asteroids (NEA), Mars and its moons, and the outer planets are but a few of the mission targets. Each new destination presents an opportunity to increase our knowledge of the solar system and the unique environments for each mission target. NASA has multiple technical and science discipline areas specializing in specific space environments disciplines that will help serve to enable these missions. To complement these existing discipline areas, a concept is presented focusing on the development of a space environments and spacecraft effects (SENSE) organization. This SENSE organization includes disciplines such as space climate, space weather, natural and induced space environments, effects on spacecraft materials and systems and the transition of research information into application. This space environment and spacecraft effects organization will be composed of Technical Working Groups (TWG). These technical working groups will survey customers and users, generate products, and provide knowledge supporting four functional areas: design environments, engineering effects, operational support, and programmatic support. The four functional areas align with phases in the program mission lifecycle and are briefly described below. Design environments are used primarily in the mission concept and design phases of a program. Engineering effects focuses on the material, component, sub-system and system-level selection and the testing to verify design and operational performance. Operational support provides products based on real time or near real time space weather to mission operators to aid in real time and near-term decision-making. The programmatic support function maintains an interface with the numerous programs within NASA, other federal

  6. Multi-Spacecraft Turbulence Analysis Methods

    Science.gov (United States)

    Horbury, Tim S.; Osman, Kareem T.

    Turbulence is ubiquitous in space plasmas, from the solar wind to supernova remnants, and on scales from the electron gyroradius to interstellar separations. Turbulence is responsible for transporting energy across space and between scales and plays a key role in plasma heating, particle acceleration and thermalisation downstream of shocks. Just as with other plasma processes such as shocks or reconnection, turbulence results in complex, structured and time-varying behaviour which is hard to measure with a single spacecraft. However, turbulence is a particularly hard phenomenon to study because it is usually broadband in nature: it covers many scales simultaneously. One must therefore use techniques to extract information on multiple scales in order to quantify plasma turbulence and its effects. The Cluster orbit takes the spacecraft through turbulent regions with a range of characteristics: the solar wind, magnetosheath, cusp and magnetosphere. In each, the nature of the turbulence (strongly driven or fully evolved; dominated by kinetic effects or largely on fluid scales), as well as characteristics of the medium (thermalised or not; high or low plasma sub- or super-Alfvenic) mean that particular techniques are better suited to the analysis of Cluster data in different locations. In this chapter, we consider a range of methods and how they are best applied to these different regions. Perhaps the most studied turbulent space plasma environment is the solar wind, see Bruno and Carbone [2005]; Goldstein et al. [2005] for recent reviews. This is the case for a number of reasons: it is scientifically important for cosmic ray and solar energetic particle scattering and propagation, for example. However, perhaps the most significant motivations for studying solar wind turbulence are pragmatic: large volumes of high quality measurements are available; the stability of the solar wind on the scales of hours makes it possible to identify statistically stationary intervals to

  7. The research and practice of spacecraft software engineering

    Science.gov (United States)

    Chen, Chengxin; Wang, Jinghua; Xu, Xiaoguang

    2017-06-01

    In order to ensure the safety and reliability of spacecraft software products, it is necessary to execute engineering management. Firstly, the paper introduces the problems of unsystematic planning, uncertain classified management and uncontinuous improved mechanism in domestic and foreign spacecraft software engineering management. Then, it proposes a solution for software engineering management based on system-integrated ideology in the perspective of spacecraft system. Finally, a application result of spacecraft is given as an example. The research can provides a reference for executing spacecraft software engineering management and improving software product quality.

  8. A Survey of Recent APL Spacecraft Power Systems

    OpenAIRE

    1987-01-01

    During the last 25 years APL has designed and built more than 50 small spacecraft, many being unique designs. The Power Systems of these spacecraft take many forms but almost all use a solar cell array and a Nickel-Cadmium battery. An overview of seven spacecraft power systems is presented. Four of the spacecraft are gravity gradient stabilized in a near-polar Low Earth Orbit (LEO). The remaining three spacecraft are spin stabilized, two with near-equatorial orbits. Both dissipative and nondi...

  9. Influence of Natural Environments in Spacecraft Design, Development, and Operation

    Science.gov (United States)

    Edwards, Dave

    2013-01-01

    Spacecraft are growing in complexity and sensitivity to environmental effects. The spacecraft engineer must understand and take these effects into account in building reliable, survivable, and affordable spacecraft. Too much protections, however, means unnecessary expense while too little will potentially lead to early mission loss. The ability to balance cost and risk necessitates an understanding of how the environment impacts the spacecraft and is a critical factor in its design. This presentation is intended to address both the space environment and its effects with the intent of introducing the influence of the environment on spacecraft performance.

  10. Potential Spacecraft-to-Spacecraft Radio Observations with EJSM: Wave of the Future? (Invited)

    Science.gov (United States)

    Marouf, E. A.; Tortora, P.; Asmar, S. W.; Folkner, W. M.; Hinson, D.; Iess, L.; Linscott, I. R.; Lorenz, R. D.; Mueller-Wodarg, I. C.

    2010-12-01

    Future active radio observations of planetary and satellite atmospheres and surfaces could significantly benefit form the presence of two or more spacecraft in orbit around a target object. Traditionally, radio occultation and bistatic surface scattering experiments have been conducted using a single spacecraft operating in the Downlink (DL) configuration, with the spacecraft transmitting and at least one Earth-based station receiving. The configuration has the advantage of using powerful ground-based receivers for down-conversion, digitization, and digital recording of large bandwidth data for later off-line processing and analysis. It has the disadvantage of an available free-space signal-to-noise ratio (SNR) limited by the relatively small carrier power (10-20 W) a spacecraft can practically transmit. Recent technological advances in designing small-mass and small-power spacecraft-based digital receivers capable of on-board signal processing could open the door for significant performance improvement compared with the DL configuration. For example, with two spacecraft in orbit instead of one, the smaller distance D between the two spacecraft compared with the distance to Earth can boost achievable free-space SNR by one to three orders of magnitude, depending on D. In addition, richer variability in observation geometry can be captured using spacecraft-to-spacecraft (SC-to-SC) radio occultations and surface scattering. By their nature, traditional DL occultations are confined to the morning and evening terminators. Availability of on-board processing capability also opens the door for conducting Uplink (UL) occultation and bistatic observations, where very large power (> 20 kW) can be transmitted from an Earth-based station, potentially boasting achievable free-space SNR by orders of magnitude, comparable to the SC-to-SC case and much higher than the DL case. The Europa Jupiter System Mission (EJSM) will likely be the first planetary mission to benefit from the

  11. Evidence for collisionless magnetic reconnection at Mars

    Science.gov (United States)

    Eastwood, J. P.; Brain, D. A.; Halekas, J. S.; Drake, J. F.; Phan, T. D.; Øieroset, M.; Mitchell, D. L.; Lin, R. P.; Acuña, M.

    2008-01-01

    Using data from Mars Global Surveyor (MGS) in combination with Particle-In-Cell (PIC) simulations of reconnection, we present the first direct evidence of collisionless magnetic reconnection at Mars. The evidence indicates that the spacecraft passed through the diffusion region where reconnection is initiated and observed the magnetic field signatures of differential electron and ion motion - the Hall magnetic field - that uniquely indicate the reconnection process. These are the first such in-situ reconnection observations at an astronomical body other than the Earth. Reconnection may be the source of Mars' recently discovered auroral activity and the changing boundaries of the closed regions of crustal magnetic field.

  12. Cluster PEACE observations of electrons of spacecraft origin

    Directory of Open Access Journals (Sweden)

    S. Szita

    Full Text Available The two PEACE (Plasma Electron And Current Experiment sensors on board each Cluster spacecraft sample the electron velocity distribution across the full 4 solid angle and the energy range 0.7 eV to 26 keV with a time resolution of 4 s. We present high energy and angular resolution 3D observations of electrons of spacecraft origin in the various environments encountered by the Cluster constellation, including a lunar eclipse interval where the spacecraft potential was reduced but remained positive, and periods of ASPOC (Active Spacecraft POtential Control operation which reduced the spacecraft potential. We demonstrate how the spacecraft potential may be found from a gradient change in the PEACE low energy spectrum, and show how the observed spacecraft electrons are confined by the spacecraft potential. We identify an intense component of the spacecraft electrons with energies equivalent to the spacecraft potential, the arrival direction of which is seen to change when ASPOC is switched on. Another spacecraft electron component, observed in the sunward direction, is reduced in the eclipse but unaffected by ASPOC, and we believe this component is produced in the analyser by solar UV. We find that PEACE anodes with a look direction along the spacecraft surfaces are more susceptible to spacecraft electron contamination than those which look perpendicular to the surface, which justifies the decision to mount PEACE with its field-of-view radially outward rather than tangentially.

    Key words. Magnetosheric physics (general or miscellaneous Space plasma physics (spacecraft sheaths, wakes, charging

  13. Spacecraft fabrication and test MODIL. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Saito, T.T.

    1994-05-01

    This report covers the period from October 1992 through the close of the project. FY 92 closed out with the successful briefing to industry and with many potential and important initiatives in the spacecraft arena. Due to the funding uncertainties, we were directed to proceed as if our funding would be approximately the same as FY 92 ($2M), but not to make any major new commitments. However, the MODIL`s FY 93 funding was reduced to $810K and we were directed to concentrate on the cryocooler area. The cryocooler effort completed its demonstration project. The final meetings with the cryocooler fabricators were very encouraging as we witnessed the enthusiastic reception of technology to help them reduce fabrication uncertainties. Support of the USAF Phillips Laboratory cryocooler program was continued including kick-off meetings for the Prototype Spacecraft Cryocooler (PSC). Under Phillips Laboratory support, Gill Cruz visited British Aerospace and Lucas Aerospace in the United Kingdom to assess their manufacturing capabilities. In the Automated Spacecraft & Assembly Project (ASAP), contracts were pursued for the analysis by four Brilliant Eyes prime contractors to provide a proprietary snap shot of their current status of Integrated Product Development. In the materials and structure thrust the final analysis was completed of the samples made under the contract (``Partial Automation of Matched Metal Net Shape Molding of Continuous Fiber Composites``) to SPARTA. The Precision Technologies thrust funded the Jet Propulsion Laboratory to prepare a plan to develop a Computer Aided Alignment capability to significantly reduce the time for alignment and even possibly provide real time and remote alignment capability of systems in flight.

  14. Introducing GV : The Spacecraft Geometry Visualizer

    Science.gov (United States)

    Throop, Henry B.; Stern, S. A.; Parker, J. W.; Gladstone, G. R.; Weaver, H. A.

    2009-12-01

    GV (Geometry Visualizer) is a web-based program for planning spacecraft observations. GV is the primary planning tool used by the New Horizons science team to plan the encounter with Pluto. GV creates accurate 3D images and movies showing the position of planets, satellites, and stars as seen from an observer on a spacecraft or other body. NAIF SPICE routines are used throughout for accurate calculations of all geometry. GV includes 3D geometry rendering of all planetary bodies, lon/lat grids, ground tracks, albedo maps, stellar magnitudes, types and positions from HD and Tycho-2 catalogs, and spacecraft FOVs. It generates still images, animations, and geometric data tables. GV is accessed through an easy-to-use and flexible web interface. The web-based interface allows for uniform use from any computer and assures that all users are accessing up-to-date versions of the code and kernel libraries. Compared with existing planning tools, GV is often simpler, faster, lower-cost, and more flexible. GV was developed at SwRI to support the New Horizons mission to Pluto. It has been subsequently expanded to support multiple other missions in flight or under development, including Cassini, Messenger, Rosetta, LRO, and Juno. The system can be used to plan Earth-based observations such as occultations to high precision, and was used by the public to help plan 'Kodak Moment' observations of the Pluto system from New Horizons. Potential users of GV may contact the author for more information. Development of GV has been funded by the New Horizons, Rosetta, and LRO missions.

  15. Future trends in spacecraft design and qualification

    Science.gov (United States)

    Venneri, Samuel L.; Hanks, Brantley R.; Pinson, Larry D.

    1986-01-01

    Material and structures issues that must be resolved in order to develop the technology data base needed to design and qualify the next generation of large flexible spacecraft are discussed. This invoves the development of new ground test and analysis methods and the conduct of appropriate instrumented in-space flight experiments for final verification. A review of present understanding of material behavior in the space environment and identification of future needs is presented. The dynamic verification and subsequent qualification of a spacecraft structure currently rely heavily on ground-based tests, coupled with the verified analysis model. Future space structures, such as large antennas, Space Station and other large platforms, will be of sizes difficult to test using current ground test methods. In addition to size, other complex factors, such as low natural frequencies, lightweight construction and many structural joints, will also contribute significant problems to the test and qualification process in an Earth-gravity environment. These large spacecraft will also require new technology for controlling the configuration and dynamic deformations of the structures. Future trend in large flexible structures will also involve long-life design missions (10 to 20 years). In low earth orbit (LEO), materials will be subjected to repeated thermal cycles, ultraviolet radiation, atomic oxygen and vacuum. For high orbits such as geo-synchronous earth orbit (GEO), the materials will also be subjected to large doses of high energy electrons and protons. Understanding degradation and material stability over long-mission time periods will confront the designer with many issues that are unresolved today.

  16. Microgravity Flammability Experiments for Spacecraft Fire Safety

    DEFF Research Database (Denmark)

    Legros, Guillaume; Minster, Olivier; Tóth, Balazs;

    2012-01-01

    -supply vehicle like the ATV or Orbital’s Cygnus, a series of supporting experiments are being planned and conducted by the team members. In order to answer the appropriate scientific and engineering problems relevant for spacecraft fire safety, a canonical scenario that can improve the understanding of flame...... spread, and thus also the modeling thereof, in realistic conditions is described. Some of the parameters governing the flame spread are also identified and their scaling against the dimensions of the test specimen is briefly questioned. Then several of the current and scheduled efforts are presented...

  17. Status of the JWST sunshield and spacecraft

    Science.gov (United States)

    Arenberg, J.; Flynn, J.; Cohen, A.; Lynch, R.; Cooper, J.

    2016-07-01

    This paper reports on the development, manufacture and integration of the James Webb Space Telescope's sunshield and spacecraft. Both of these JWST elements have completed design and development testing. This paper will review basic architecture and roles of these systems. Also to be presented is the current state of manufacture, assembly integration and test. This paper will conclude with a look at the road ahead for each subsystem prior to integration with the integrated telescope and instrument elements at Northrop Grumman's Space Park facility in late 2017.

  18. Impulsive orbit control for spacecraft around asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 崔平远; 栾恩杰

    2003-01-01

    An impulse feedback control law to change the mean orbit elements of spacecraft around asteroid is presented. First, the mean orbit elements are transferred to the osculating orbit elements at the burning time.Then, the feedback control law based on Gauss' s perturbation equations of motion is given. And the impulse control for targeting from the higher circulation orbit to the specified periapsis is developed. Finally, the numerical simulation is performed and the simulation results show that the presented impulse control law is effective.

  19. Large Scale Experiments on Spacecraft Fire Safety

    DEFF Research Database (Denmark)

    Urban, David L.; Ruff, Gary A.; Minster, Olivier

    2012-01-01

    ) to be conducted on an ISS resupply vehicle, such as the Automated Transfer Vehicle (ATV) or Orbital Cygnus after it leaves the ISS and before it enters the atmosphere. A computer modelling effort will complement the experimental effort. Although the experiment will need to meet rigorous safety requirements...... validation. This unprecedented opportunity will expand the understanding of the fundamentals of fire behaviour in spacecraft. The experiment is being developed by an international topical team that is collaboratively defining the experiment requirements and performing supporting analysis, experimentation...

  20. Magnetically suspended momentum wheels for spacecraft stabilization

    Science.gov (United States)

    Henrikson, C. H.; Lyman, J.; Studer, P. A.

    1974-01-01

    Magnetic bearings for spacecraft momentum wheels offer the promise of low friction and unlimited life. This paper describes how magnetic bearings work and their advantages and disadvantages. The present status of magnetic bearings is described and examples are shown of the various and widely-different magnetically suspended momentum wheels that have been built to date. These include wheels whose bearings exhibit high stiffness and wheels with zero-power suspensions. The future of magnetically suspended momentum wheels is discussed including the possibility of wheels with neither spokes nor shaft.

  1. Multi-spacecraft observations of quasiperiodic emissions

    Science.gov (United States)

    Nemec, Frantisek; Pickett, Jolene S.; Hospodarsky, George; Santolik, Ondrej; Bezdekova, Barbora; Hayosh, Mykhaylo; Parrot, Michel; Kurth, William; Kletzing, Craig

    2016-04-01

    Whistler mode electromagnetic waves observed in the inner magnetosphere at frequencies of a few kilohertz sometimes exhibit a nearly periodic modulation of the wave intensity. The modulation periods may range from several tens of seconds up to a few minutes, and such emissions are usually called quasiperiodic (QP) emissions. The origin of these events is still unclear, but it seems that their generation might be related to compressional ULF magnetic field pulsations which periodically modulate resonance conditions in the source region. From an observational point of view, single-point measurements are quite insufficient, as they do not allow us to distinguish between spatial and temporal variations of the emissions. Multipoint observations of these events are, on the other hand, rather rare. We present several QP wave events observed simultaneously by several different spacecraft (Cluster, Van Allen Probes, THEMIS, DEMETER). We demonstrate that although the quasiperiodic modulation is observed over a huge spatial region, individual spacecraft do not see the QP elements at exactly the same times. Moreover, when an event is observed simultaneously on the dawnside and on the duskside, the modulation period observed on the duskside is about twice larger than the modulation period observed on the dawnside. We present a qualitative explanation of these phenomena.

  2. Merits of flywheels for spacecraft energy storage

    Science.gov (United States)

    Gross, S.

    1984-01-01

    Flywheel energy storage systems which have a very good potential for use in spacecraft are discussed. This system can be superior to alkaline secondary batteries and regenerable fuel cells in most of the areas that are important in spacecraft applications. Of special importance, relative to batteries, are lighter weight, longer cycle and operating life, and high efficiency which minimizes solar array size and the amount of orbital makeup fuel required. Flywheel systems have a long shelf life, give a precise state of charge indication, have modest thermal control needs, are capable of multiple discharges per orbit, have simple ground handling needs, and have characteristics which would be useful for military applications. The major disadvantages of flywheel energy storage systems are that: power is not available during the launch phase without special provisions; and in flight failure of units may force shutdown of good counter rotating units, amplifying the effects of failure and limiting power distribution system options; no inherent emergency power capability unless specifically designed for, and a high level of complexity compared with batteries. The potential advantages of the flywheel energy storage system far outweigh the disadvantages.

  3. Spacecraft design project: High latitude communications satellite

    Science.gov (United States)

    Josefson, Carl; Myers, Jack; Cloutier, Mike; Paluszek, Steve; Michael, Gerry; Hunter, Dan; Sakoda, Dan; Walters, Wes; Johnson, Dennis; Bauer, Terry

    1989-01-01

    The spacecraft design project was part of AE-4871, Advanced Spacecraft Design. The project was intended to provide experience in the design of all major components of a satellite. Each member of the class was given primary responsibility for a subsystem or design support function. Support was requested from the Naval Research Laboratory to augment the Naval Postgraduate School faculty. Analysis and design of each subsystem was done to the extent possible within the constraints of an eleven week quarter and the design facilities (hardware and software) available. The project team chose to evaluate the design of a high latitude communications satellite as representative of the design issues and tradeoffs necessary for a wide range of satellites. The High-Latitude Communications Satellite (HILACS) will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites, i.e., the area above approximately 60 N latitude. HILACS will also provide a communications link to stations below 60 N via a relay Net Control Station (NCS), which is located with access to both the HILACS and geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specified coverage.

  4. Electrodeless plasma thrusters for spacecraft: A review

    Science.gov (United States)

    Bathgate, S. N.; Bilek, M. M. M.; McKenzie, D. R.

    2017-08-01

    The physics of electrodeless electric thrusters that use directed plasma to propel spacecraft without employing electrodes subject to plasma erosion is reviewed. Electrodeless plasma thrusters are potentially more durable than presently deployed thrusters that use electrodes such as gridded ion, Hall thrusters, arcjets and resistojets. Like other plasma thrusters, electrodeless thrusters have the advantage of reduced fuel mass compared to chemical thrusters that produce the same thrust. The status of electrodeless plasma thrusters that could be used in communications satellites and in spacecraft for interplanetary missions is examined. Electrodeless thrusters under development or planned for deployment include devices that use a rotating magnetic field; devices that use a rotating electric field; pulsed inductive devices that exploit the Lorentz force on an induced current loop in a plasma; devices that use radiofrequency fields to heat plasmas and have magnetic nozzles to accelerate the hot plasma and other devices that exploit the Lorentz force. Using metrics of specific impulse and thrust efficiency, we find that the most promising designs are those that use Lorentz forces directly to expel plasma and those that use magnetic nozzles to accelerate plasma.

  5. Processing Images of Craters for Spacecraft Navigation

    Science.gov (United States)

    Cheng, Yang; Johnson, Andrew E.; Matthies, Larry H.

    2009-01-01

    A crater-detection algorithm has been conceived to enable automation of what, heretofore, have been manual processes for utilizing images of craters on a celestial body as landmarks for navigating a spacecraft flying near or landing on that body. The images are acquired by an electronic camera aboard the spacecraft, then digitized, then processed by the algorithm, which consists mainly of the following steps: 1. Edges in an image detected and placed in a database. 2. Crater rim edges are selected from the edge database. 3. Edges that belong to the same crater are grouped together. 4. An ellipse is fitted to each group of crater edges. 5. Ellipses are refined directly in the image domain to reduce errors introduced in the detection of edges and fitting of ellipses. 6. The quality of each detected crater is evaluated. It is planned to utilize this algorithm as the basis of a computer program for automated, real-time, onboard processing of crater-image data. Experimental studies have led to the conclusion that this algorithm is capable of a detection rate >93 percent, a false-alarm rate <5 percent, a geometric error <0.5 pixel, and a position error <0.3 pixel.

  6. Spacecraft Dynamic Characterization by Strain Energies Method

    Science.gov (United States)

    Bretagne, J.-M.; Fragnito, M.; Massier, S.

    2002-01-01

    In the last years the significant increase in satellite broadcasting demand, with the wide band communication dawn, has given a great impulse to the telecommunication satellite market. The big demand is translated from operators (such as SES/Astra, Eutelsat, Intelsat, Inmarsat, EuroSkyWay etc.) in an increase of orders of telecom satellite to the world industrials. The largest part of these telecom satellite orders consists of Geostationary platforms which grow more and more in mass (over 5 tons) due to an ever longer demanded lifetime (up to 20 years), and become more complex due to the need of implementing an ever larger number of repeaters, antenna reflectors and feeds, etc... In this frame, the mechanical design and verification of these large spacecraft become difficult and ambitious at the same time, driven by the dry mass limitation objective. By the Finite Element Method (FEM), and on the basis of the telecom satellite heritage of a world leader constructor such as Alcatel Space Industries it is nowadays possible to model these spacecraft in a realistic and confident way in order to identify the main global dynamic aspects such as mode shapes, mass participation and/or dynamic responses. But on the other hand, one of the main aims consists in identifying soon in a program the most critical aspects of the system behavior in the launch dynamic environment, such as possible dynamic coupling between the different subsystems and secondary structures of the spacecraft (large deployable reflectors, thrusters, etc.). To this aim a numerical method has been developed in the frame of the Alcatel SPACEBUS family program, using MSC/Nastran capabilities and it is presented in this paper. The method is based on Spacecraft sub-structuring and strain energy calculation. The method mainly consists of two steps : 1) subsystem modal strain energy ratio (with respect to the global strain energy); 2) subsystem strain energy calculation for each mode according to the base driven

  7. Three spacecraft observe Jupiter's glowing polar regions

    Science.gov (United States)

    1996-09-01

    The aurorae on Jupiter are like the Aurorae Borealis and Australis on the Earth, although visible only by ultraviolet light. They flicker in a similar way in response to variations in the solar wind of charged particles blowing from the Sun. While Galileo monitored the changing environment of particles and magnetism in Jupiter's vicinity, IUE recorded surprisingly large and rapid variations in the overall strength of the auroral activity. IUE's main 45-centimetre telescope did not supply images,but broke up the ultraviolet rays into spectra, like invisible rainbows, from which astrophysicists could deduce chemical compositions, motions and temperatures in the cosmic objects under examination. In the case of Jupiter's aurorae, the strongest emission came from activated hydrogen atoms at a wavelength of 1216 angstroms. The Hubble Space Telescope's contributions to the International Jupiter Watch included images showing variations in the form of the aurorae, and "close-up" spectra of parts of the auroral ovals. Astronomers will compare the flickering aurorae on Jupiter with concurrent monitoring of the Sun and the solar wind by the ESA-NASA SOHO spacecraft and several satellites of the Interagency Solar-Terrestrial Programme. It is notable that changes in auroral intensity by a factor of two or three occurred during the 1996 observational period, even though the Sun was in an exceptionally quiet phase, with very few sunspots. In principle, a watch on Jupiter's aurorae could become a valuable means of checking the long-range effects of solar activity, which also has important consequences for the Earth. The situation at Jupiter is quite different from the Earth's, with the moons strongly influencing the planet's space environment. But with Hubble busy with other work, any such Jupiter-monitoring programme will have to await a new ultraviolet space observatory. IUE observed Jupiter intensively in 1979-80 in conjunction with the visits of NASA's Voyager spacecraft, and

  8. Attitude stabilization of a rigid spacecraft using two control torques: A nonlinear control approach based on the spacecraft attitude dynamics

    Science.gov (United States)

    Krishnan, Hariharan; Reyhanoglu, Mahmut; McClamroch, Harris

    1994-06-01

    The attitude stabilization problem of a rigid spacecraft using control torques supplied by gas jet actuators about only two of its principal axes is considered. If the uncontrolled principal axis of the spacecraft is not an axis of symmetry, then the complete spacecraft dynamics are small time locally controllable. However, the spacecraft cannot be asymptotically stabilized to any equilibrium attitude using time-invariant continuous feedback. A discontinuous stabilizing feedback control strategy is constructed which stabilizes the spacecraft to any equilibrium attitude. If the uncontrolled principal axis of the spacecraft is an axis of symmetry, the complete spacecraft dynamics are not even assessible. However, the spacecraft dynamics are strongly accessible and small time locally controllable in a reduced sense. The reduced spacecraft dynamics cannot be asymptotically stabilized to any equilibrium attitude using time-invariant continuous feedback, but again a discontinuous stabilizing feedback control strategy is constructed. In both cases, the discontinuous feedback controllers are constructed by switching between several feedback functions which are selected to accomplish a sequence of spacecraft maneuvers. The results of the paper show that although standard nonlinear control techniques are not applicable, it is possible to construct a nonlinear discontinuous control law based on the dynamics of the particular physical system.

  9. Attitude dynamics and control of spacecraft using geomagnetic Lorentz force

    CERN Document Server

    Abdel-Aziz, Yehia A

    2014-01-01

    The attitude stabilization of a charged rigid spacecraft in Low Earth Orbit (LEO) using torques due to Lorentz force in pitch and roll directions is considered. A spacecraft that generates an electrostatic charge on its surface in the Earth magnetic field will be subject to perturbations from Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft's orientation. We assume that the spacecraft is moving in the Earth's magnetic field in an elliptical orbit under the effects of the gravitational, geomagnetic and Lorentz torques. The magnetic field of the Earth is modeled as a non-tilted dipole. A model incorporating all Lorentz torques as a function of orbital elements has been developed on the basis of electric and magnetic fields. The stability of the spacecraft orientation is investigated both analytically and numerically. The existence and stability of equilibrium positions is investigated for different values of the charge to...

  10. Spacecraft Dynamics Should be Considered in Kalman Filter Attitude Estimation

    Science.gov (United States)

    Yang, Yaguang; Zhou, Zhiqiang

    2016-01-01

    Kalman filter based spacecraft attitude estimation has been used in some high-profile missions and has been widely discussed in literature. While some models in spacecraft attitude estimation include spacecraft dynamics, most do not. To our best knowledge, there is no comparison on which model is a better choice. In this paper, we discuss the reasons why spacecraft dynamics should be considered in the Kalman filter based spacecraft attitude estimation problem. We also propose a reduced quaternion spacecraft dynamics model which admits additive noise. Geometry of the reduced quaternion model and the additive noise are discussed. This treatment is more elegant in mathematics and easier in computation. We use some simulation example to verify our claims.

  11. Stabilization of rotational motion with application to spacecraft attitude control

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2001-01-01

    on a Riemannian manifold. The Lyapnov stability theory is adapted and reformulated to fit to the new framework of Riemannian manifolds. Toillustrate the results a spacecraft attitude control problem is considered. Firstly, a global canonical representation for the spacecraft motion is found, then three spacecraft...... control problems are addressed: stabilization in the inertial frame, magnetic libration damping for the gravity gradient stabilization and a slew maneuver with obstacle avoidance...

  12. The Mars Analysis Correction Data Assimilation (MACDA) Dataset V1.0

    Science.gov (United States)

    Montabone, L.; Marsh, K.; Lewis, S. R.; Read, P. L.; Smith, M. D.; Holmes, J.; Spiga, A.; Lowe, D.; Pamment, A.

    2014-06-01

    The Mars Analysis Correction Data Assimilation (MACDA) dataset version 1.0 contains the reanalysis of fundamental atmospheric and surface variables for the planet Mars covering a period of about three Martian years (a Martian year is about 1.88 terrestrial years). This has been produced by data assimilation of observations from NASA's Mars Global Surveyor (MGS) spacecraft during its science mapping phase (February 1999-August 2004). In particular, we have used retrieved thermal profiles and total dust optical depths from the Thermal Emission Spectrometer (TES) on board MGS. Data have been assimilated into a Mars global climate model (MGCM) using the Analysis Correction scheme developed at the UK Meteorological Office. The MGCM used is the UK spectral version of the Laboratoire de Météorologie Dynamique (LMD, Paris, France) MGCM. MACDA is a joint project of the University of Oxford and The Open University in the UK.

  13. Application of advanced electronics to a future spacecraft computer design

    Science.gov (United States)

    Carney, P. C.

    1980-01-01

    Advancements in hardware and software technology are summarized with specific emphasis on spacecraft computer capabilities. Available state of the art technology is reviewed and candidate architectures are defined.

  14. Concurrent engineering: Spacecraft and mission operations system design

    Science.gov (United States)

    Landshof, J. A.; Harvey, R. J.; Marshall, M. H.

    1994-01-01

    Despite our awareness of the mission design process, spacecraft historically have been designed and developed by one team and then turned over as a system to the Mission Operations organization to operate on-orbit. By applying concurrent engineering techniques and envisioning operability as an essential characteristic of spacecraft design, tradeoffs can be made in the overall mission design to minimize mission lifetime cost. Lessons learned from previous spacecraft missions will be described, as well as the implementation of concurrent mission operations and spacecraft engineering for the Near Earth Asteroid Rendezvous (NEAR) program.

  15. A New Feature Points Reconstruction Method in Spacecraft Vision Navigation

    Directory of Open Access Journals (Sweden)

    Bing Hua

    2015-01-01

    Full Text Available The important applications of monocular vision navigation in aerospace are spacecraft ground calibration tests and spacecraft relative navigation. Regardless of the attitude calibration for ground turntable or the relative navigation between two spacecraft, it usually requires four noncollinear feature points to achieve attitude estimation. In this paper, a vision navigation system based on the least feature points is designed to deal with fault or unidentifiable feature points. An iterative algorithm based on the feature point reconstruction is proposed for the system. Simulation results show that the attitude calculation of the designed vision navigation system could converge quickly, which improves the robustness of the vision navigation of spacecraft.

  16. Electromagnetic fields produced by simulated spacecraft discharges

    Science.gov (United States)

    Nonevicz, J. E.; Adamo, R. C.; Beers, B. L.; Delmer, T. N.

    1980-01-01

    The initial phase of a broader, more complete program for the characterization of electrical breakdowns on spacecraft insulating materials is described which consisted of the development of a discharge simulator and characterization facility and the performance of a limited number of discharge measurements to verify the operation of the laboratory setup and to provide preliminary discharge transient field data. A preliminary model of the electromagnetic characteristics of the discharge was developed. It is based upon the "blow off" current model of discharges, with the underlying assumption of a propagating discharge. The laboratory test facility and discharge characterization instrumentation are discussed and the general results of the "quick look" tests are described on quartz solar reflectors aluminized Kapton and silver coated Teflon are described.

  17. Life in the spacecraft and planetary station.

    Science.gov (United States)

    Adamovich, B A; Nefyodov, Y G; Ushakov, A S; Chizhov, S V

    1968-01-01

    Further exploration of outer space and the solar system, performance of interplanetary flights and establishment of planetary stations necessitate extensive physiological studies and development of reliable life-support systems. When developing the systems, particular attention should be paid to the concept and testing of new processes which can provide a highly efficient regeneration of vitally important materials and decrease the weight of expendables. Of great significance is the establishment of optimal parameters of the environment for long-term manned spaceflights and selection of facilities securing them. The development of new life-support systems should be based on a thorough study of the particular environment, proper selection and physiological and hygienical evaluation of their components. Long duration space missions can be planned from studies on the effects of space flight factors upon the human body to reveal its variability limits under peculiar conditions of the spacecraft or planetary station.

  18. Human factors issues for interstellar spacecraft

    Science.gov (United States)

    Cohen, Marc M.; Brody, Adam R.

    1991-01-01

    Developments in research on space human factors are reviewed in the context of a self-sustaining interstellar spacecraft based on the notion of traveling space settlements. Assumptions about interstellar travel are set forth addressing costs, mission durations, and the need for multigenerational space colonies. The model of human motivation by Maslow (1970) is examined and directly related to the design of space habitat architecture. Human-factors technology issues encompass the human-machine interface, crew selection and training, and the development of spaceship infrastructure during transtellar flight. A scenario for feasible instellar travel is based on a speed of 0.5c, a timeframe of about 100 yr, and an expandable multigenerational crew of about 100 members. Crew training is identified as a critical human-factors issue requiring the development of perceptual and cognitive aids such as expert systems and virtual reality.

  19. A Microwave Thruster for Spacecraft Propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Chiravalle, Vincent P [Los Alamos National Laboratory

    2012-07-23

    This presentation describes how a microwave thruster can be used for spacecraft propulsion. A microwave thruster is part of a larger class of electric propulsion devices that have higher specific impulse and lower thrust than conventional chemical rocket engines. Examples of electric propulsion devices are given in this presentation and it is shown how these devices have been used to accomplish two recent space missions. The microwave thruster is then described and it is explained how the thrust and specific impulse of the thruster can be measured. Calculations of the gas temperature and plasma properties in the microwave thruster are discussed. In addition a potential mission for the microwave thruster involving the orbit raising of a space station is explored.

  20. Understanding natural language for spacecraft sequencing

    Science.gov (United States)

    Katz, Boris; Brooks, Robert N., Jr.

    1987-01-01

    The paper describes a natural language understanding system, START, that translates English text into a knowledge base. The understanding and the generating modules of START share a Grammar which is built upon reversible transformations. Users can retrieve information by querying the knowledge base in English; the system then produces an English response. START can be easily adapted to many different domains. One such domain is spacecraft sequencing. A high-level overview of sequencing as it is practiced at JPL is presented in the paper, and three areas within this activity are identified for potential application of the START system. Examples are given of an actual dialog with START based on simulated data for the Mars Observer mission.

  1. Spacecraft fleet to comet Halley - an introduction

    Energy Technology Data Exchange (ETDEWEB)

    Tsurutani, B.T.

    1985-01-01

    Questions related to the formation and the characteristics of comets are discussed, and it is suggested that an evolutionary link exists between comets, prebiotic organic synthesis, and the origin of life as it is known. Fundamental questions about the solar wind interaction with comets, are considered, giving attention to the ionization mechanisms in the different cometary regions, the presence of field-aligned currents, and the cometary plasma tail. It is pointed out that some of the questions will soon be answered when the NASA-ESA International Cometary Explorer (ICE) goes through the tail of Giacobini-Zinner in September 1985, and when a five spacecraft fleet arrives at comet Halley in March 1986. 14 references.

  2. A pulsed cathodic arc spacecraft propulsion system

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, P R C; Bilek, M M M; Tarrant, R N; McKenzie, D R [School of Physics, University of Sydney, NSW 2006 Australia (Australia)

    2009-11-15

    We investigate the use of a centre-triggered cathodic arc as a spacecraft propulsion system that uses an inert solid as a source of plasma. The cathodic vacuum arc produces almost fully ionized plasma with a high exhaust velocity (>10{sup 4} m s{sup -1}), giving a specific impulse competitive with other plasma or ion thrusters. A centre trigger design is employed that enables efficient use of cathode material and a high pulse-to-pulse repeatability. We compare three anode geometries, two pulse current profiles and two pulse durations for their effects on impulse generation, energy and cathode material usage efficiency. Impulse measurement is achieved through the use of a free-swinging pendulum target constructed from a polymer material. Measurements show that impulse is accurately controlled by varying cathode current. The cylindrical anode gave the highest energy efficiency. Cathode usage is optimized by choosing a sawtooth current profile. There is no requirement for an exhaust charge neutralization system.

  3. Meteor Shower Forecasting for Spacecraft Operations

    Science.gov (United States)

    Moorhead, Althea V.; Cooke, William J.; Campbell-Brown, Margaret D.

    2017-01-01

    Although sporadic meteoroids are a much greater hazard to spacecraft than shower meteoroids in general, meteor showers can significantly increase the risk of damage over short time periods. Because showers are brief, it is sometimes possible to mitigate the risk operationally, which requires accurate predictions of shower activity. NASA's Meteoroid Environment Office generates an annual meteor shower forecast that describes the variations in the near-Earth meteoroid flux produced by meteor showers, which presents the shower flux both in absolute terms and relative to the sporadic ux. The shower forecast incorporates model predictions of annual variations in shower activity and quotes fluxes to several limiting particle kinetic energies. In this work, we describe our forecasting methods, compare them to actual observations, and highlight recent improvements to the temporal pro les based on flux measurements from the Canadian Meteor Orbit Radar (CMOR).

  4. Meteoroid-Induced Anomalies on Spacecraft

    Science.gov (United States)

    Cooke, William J.

    2015-01-01

    Many programs/projects use a simple meteoroid environment based on Grun's 1985 paper or the old NASA space station spec in their design and risk assessments. These models, which are omni directional and mono-­velocity, bear little resemblance to the actual meteoroid environment, which is sun-fixed, very directional, and which has a complex speed distribution varying by source and particle size. As a result, the simple meteoroid models lead to estimates that underestimate the spacecraft/vehicle risk by a factor of 2 or more. In addition, programs often over-emphasize the risk posed by meteor showers, which typically account for less than ten percent of the meteoroid risk over the vehicle lifetime. Fueled by popular media, the emphasis on meteor showers (the risks from which can usually be mitigated operationally) can lead to ambivalence to the real risk driver, which is the sporadic background.

  5. Rechargeable metal hydrides for spacecraft application

    Science.gov (United States)

    Perry, J. L.

    1988-01-01

    Storing hydrogen on board the Space Station presents both safety and logistics problems. Conventional storage using pressurized bottles requires large masses, pressures, and volumes to handle the hydrogen to be used in experiments in the U.S. Laboratory Module and residual hydrogen generated by the ECLSS. Rechargeable metal hydrides may be competitive with conventional storage techniques. The basic theory of hydride behavior is presented and the engineering properties of LaNi5 are discussed to gain a clear understanding of the potential of metal hydrides for handling spacecraft hydrogen resources. Applications to Space Station and the safety of metal hydrides are presented and compared to conventional hydride storage. This comparison indicates that metal hydrides may be safer and require lower pressures, less volume, and less mass to store an equivalent mass of hydrogen.

  6. Infrared Photometry of GEO Spacecraft with WISE

    Science.gov (United States)

    Lee, C.; Seitzer, P.; Cutri, R.; Grillmair, C.; Schildknecht, T.

    2016-09-01

    NASA launched the Wide-field Infrared Survey Explorer (WISE) into orbit on December 2009 with a mission to scan the entire sky in the infrared in four wavelength bands of 3.4, 4.6, 12, and 22 microns. WISE acquired data in the four bands for 10 months until the solid hydrogen cryogen was depleted and then proceeded to operate in the two shorter wavelength bands for an additional four months in a Post-Cryo phase. In its trove of data, WISE captured many streaks that were artificial satellites in orbit around Earth. We have examined a subset of equatorial WISE images with |declination| 30 degrees in order to minimize contamination of the satellite streaks by stars in the galactic plane. At least one streak of the length appropriate for a GEO station-keeping satellite appears in over 10% of these images. In bands 1 through 3 (for images 1016x1016 in size), the streaks are approximately 100 pixels in length, and in band 4 (for images 508x508 in size), the streaks are approximately 50 pixels in length. Most, but not all, of these spacecraft appear in all 4 wavelength bands. Since WISE is in a Sun-synchronous orbit pointed approximately radially away from the Earth at all times, all observations of GEO objects were obtained at a solar phase angle of approximately 90 degrees. We report on the color distributions of these detections and interpret the colors and compare the spacecraft colors with colors of other astronomical objects such as stars, galaxies, and asteroids that have appeared in previously published works on WISE data.

  7. Maneuvering of flexible spacecraft with application to SCOLE. [Spacecraft Control Laboratory Experiment

    Science.gov (United States)

    Meirovitch, L.; Quinn, R. D.; Norris, M. A.

    1985-01-01

    This paper is concerned with the derivation of the equations of motion for the Spacecraft Control Laboratory Experiment (SCOLE). For future reference, the equations of motion of a similar structure orbiting the earth are also derived. The structure is assumed to undergo large rigid-body maneuvers and small elastic deformations. A perturbation approach is presented where the quantities defining the rigid-body maneuver are assumed to be relatively large, with the elastic deformations and deviations from the rigid-body maneuver being relatively small. The perturbation equations have the form of linear, non-self-adjoint equations with time-dependent coefficients. An active control technique can then be formulated to permit maneuvering of the spacecraft and simultaneously suppressing the elastic vibration.

  8. Generalized Analysis Tools for Multi-Spacecraft Missions

    Science.gov (United States)

    Chanteur, G. M.

    2011-12-01

    Analysis tools for multi-spacecraft missions like CLUSTER or MMS have been designed since the end of the 90's to estimate gradients of fields or to characterize discontinuities crossed by a cluster of spacecraft. Different approaches have been presented and discussed in the book "Analysis Methods for Multi-Spacecraft Data" published as Scientific Report 001 of the International Space Science Institute in Bern, Switzerland (G. Paschmann and P. Daly Eds., 1998). On one hand the approach using methods of least squares has the advantage to apply to any number of spacecraft [1] but is not convenient to perform analytical computation especially when considering the error analysis. On the other hand the barycentric approach is powerful as it provides simple analytical formulas involving the reciprocal vectors of the tetrahedron [2] but appears limited to clusters of four spacecraft. Moreover the barycentric approach allows to derive theoretical formulas for errors affecting the estimators built from the reciprocal vectors [2,3,4]. Following a first generalization of reciprocal vectors proposed by Vogt et al [4] and despite the present lack of projects with more than four spacecraft we present generalized reciprocal vectors for a cluster made of any number of spacecraft : each spacecraft is given a positive or nul weight. The non-coplanarity of at least four spacecraft with strictly positive weights is a necessary and sufficient condition for this analysis to be enabled. Weights given to spacecraft allow to minimize the influence of some spacecraft if its location or the quality of its data are not appropriate, or simply to extract subsets of spacecraft from the cluster. Estimators presented in [2] are generalized within this new frame except for the error analysis which is still under investigation. References [1] Harvey, C. C.: Spatial Gradients and the Volumetric Tensor, in: Analysis Methods for Multi-Spacecraft Data, G. Paschmann and P. Daly (eds.), pp. 307-322, ISSI

  9. Gas flow analysis during thermal vacuum test of a spacecraft. [self contamination of IMP spacecraft

    Science.gov (United States)

    Scialdone, J. J.

    1974-01-01

    The self-contamination of the IMP-H spacecraft, while it was undergoing thermal and solar vacuum tests, has been investigated in conjunction with the outgassing evaluation and detection of molecular flow anomalies occurring in the test chamber. The pressures indicated by two tubulated ionization gauges were used to calculate flow kinetics in the vacuum chamber. The fluxes of emitted molecules and chamber wall reflected molecules were monitored during the entire test. Representative equations and graphs are presented. Test results indicate that from 3 to 9 of every 100 emitted molecules returned to the spacecraft surface; that self-contamination by noncondensable gases was more severe than that by condensable gases; and that outgassing of the spacecraft was approximately 1.18 x 0.01 g/s after 10 hours and 1.18 x 0.001 after 90 hours of vacuum exposure. Testing deficiencies have been identified, and the type and location of instruments required to measure the outgassing, the degree of contamination, and return flow are discussed.

  10. Spacecraft Component Adaptive Layout Environment (SCALE): An efficient optimization tool

    Science.gov (United States)

    Fakoor, Mahdi; Ghoreishi, Seyed Mohammad Navid; Sabaghzadeh, Hossein

    2016-11-01

    For finding the optimum layout of spacecraft subsystems, important factors such as the center of gravity, moments of inertia, thermal distribution, natural frequencies, etc. should be taken into account. This large number of effective parameters makes the optimum layout process of spacecraft subsystems complex and time consuming. In this paper, an automatic tool, based on multi-objective optimization methods, is proposed for a three dimensional layout of spacecraft subsystems. In this regard, an efficient Spacecraft Component Adaptive Layout Environment (SCALE) is produced by integration of some modeling, FEM, and optimization software. SCALE automatically provides optimal solutions for a three dimensional layout of spacecraft subsystems with considering important constraints such as center of gravity, moment of inertia, thermal distribution, natural frequencies and structural strength. In order to show the superiority and efficiency of SCALE, layout of a telecommunication spacecraft and a remote sensing spacecraft are performed. The results show that, the objective functions values for obtained layouts by using SCALE are in a much better condition than traditional one i.e. Reference Baseline Solution (RBS) which is proposed by the engineering system team. This indicates the good performance and ability of SCALE for finding the optimal layout of spacecraft subsystems.

  11. Astronaut Scott Carpenter inserted into Aurora 7 spacecraft

    Science.gov (United States)

    1962-01-01

    Astronaut M. Scott Carpenter, pilot of the Mercury-Atlas 7 space flight, is inserted into Aurora 7 spacecraft during the prelaunch countdown. Carpenter is assisted into the spacecraft by Astronaut John Glenn and Gunter Vendt, McDonnell Douglas pad capsule test conducter.

  12. Spacecraft attitude determination using the earth's magnetic field

    Science.gov (United States)

    Simpson, David G.

    1989-01-01

    A method is presented by which the attitude of a low-Earth orbiting spacecraft may be determined using a vector magnetometer, a digital Sun sensor, and a mathematical model of the Earth's magnetic field. The method is currently being implemented for the Solar Maximum Mission spacecraft (as a backup for the failing star trackers) as a way to determine roll gyro drift.

  13. Distributed parameter modelling of flexible spacecraft: Where's the beef?

    Science.gov (United States)

    Hyland, D. C.

    1994-01-01

    This presentation discusses various misgivings concerning the directions and productivity of Distributed Parameter System (DPS) theory as applied to spacecraft vibration control. We try to show the need for greater cross-fertilization between DPS theorists and spacecraft control designers. We recommend a shift in research directions toward exploration of asymptotic frequency response characteristics of critical importance to control designers.

  14. Propellant-free Spacecraft Relative Maneuvering via Atmospheric Differential Drag

    Science.gov (United States)

    2015-07-06

    vectorized form Rp Pearson correlation coefficient Re Earth mean radius S Spacecraft cross-wind section area for chaser and target spacecraft...Gaidash, S. P., Ivanov, K. G., and Kanonidi, Kh. D., “Unusually High Geomagnetic Activity in 2003,” Cosmic Research, Vol. 42, No. 6, 2004, pp. 541-550

  15. A Comparison of Learning Technologies for Teaching Spacecraft Software Development

    Science.gov (United States)

    Straub, Jeremy

    2014-01-01

    The development of software for spacecraft represents a particular challenge and is, in many ways, a worst case scenario from a design perspective. Spacecraft software must be "bulletproof" and operate for extended periods of time without user intervention. If the software fails, it cannot be manually serviced. Software failure may…

  16. Attitude dynamics and control of spacecraft using geomagnetic Lorentz force

    Science.gov (United States)

    Abdel-Aziz, Yehia A.; Shoaib, Muhammad

    2015-01-01

    Attitude stabilization of a charged rigid spacecraft in Low Earth Orbit using torques due to Lorentz force in pitch and roll directions is considered. A spacecraft that generates an electrostatic charge on its surface in the Earth's magnetic field will be subject to perturbations from the Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft's orientation. We assume that the spacecraft is moving in the Earth's magnetic field in an elliptical orbit under the effects of gravitational, geomagnetic and Lorentz torques. The magnetic field of the Earth is modeled as a non-tilted dipole. A model incorporating all Lorentz torques as a function of orbital elements has been developed on the basis of electric and magnetic fields. The stability of the spacecraft orientation is investigated both analytically and numerically. The existence and stability of equilibrium positions is investigated for different values of the charge to mass ratio (α*). Stable orbits are identified for various values of α*. The main parameters for stabilization of the spacecraft are α* and the difference between the components of the moment of inertia for the spacecraft.

  17. Low-Impact Mating System for Docking Spacecraft

    Science.gov (United States)

    Lewis, James L.; Robertson, Brandan; Carroll, Monty B.; Le, Thang; Morales, Ray

    2008-01-01

    A document describes a low-impact mating system suitable for both docking (mating of two free-flying spacecraft) and berthing (in which a robot arm in one spacecraft positions an object for mating with either spacecraft). The low-impact mating system is fully androgynous: it mates with a copy of itself, i.e., all spacecraft and other objects to be mated are to be equipped with identical copies of the system. This aspect of the design helps to minimize the number of unique parts and to standardize and facilitate mating operations. The system includes a closed-loop feedback control subsystem that actively accommodates misalignments between mating spacecraft, thereby attenuating spacecraft dynamics and mitigating the need for precise advance positioning of the spacecraft. The operational characteristics of the mating system can be easily configured in software, during operation, to enable mating of spacecraft having various masses, center-of-gravity offsets, and closing velocities. The system design provides multi-fault tolerance for critical operations: for example, to ensure unmating at a critical time, a redundant unlatching mechanism and two independent pyrotechnic release subsystems are included.

  18. Rockets and spacecraft: Sine qua non of space science

    Science.gov (United States)

    1980-01-01

    The evolution of the national launch vehicle stable is presented along with lists of launch vehicles used in NASA programs. A partial list of spacecraft used throughout the world is also given. Scientific spacecraft costs are presented along with an historial overview of project development and funding in NASA.

  19. A Comparison of Learning Technologies for Teaching Spacecraft Software Development

    Science.gov (United States)

    Straub, Jeremy

    2014-01-01

    The development of software for spacecraft represents a particular challenge and is, in many ways, a worst case scenario from a design perspective. Spacecraft software must be "bulletproof" and operate for extended periods of time without user intervention. If the software fails, it cannot be manually serviced. Software failure may…

  20. Precise Relative Positioning of Formation Flying Spacecraft using GPS

    NARCIS (Netherlands)

    Kroes, R.

    2006-01-01

    Spacecraft formation flying is considered as a key technology for advanced space missions. Compared to large individual spacecraft, the distribution of sensor systems amongst multiple platforms offers improved flexibility, shorter times to mission, and the prospect of being more cost effective. Besi

  1. Spacecraft design project: Low Earth orbit communications satellite

    Science.gov (United States)

    Moroney, Dave; Lashbrook, Dave; Mckibben, Barry; Gardener, Nigel; Rivers, Thane; Nottingham, Greg; Golden, Bill; Barfield, Bill; Bruening, Joe; Wood, Dave

    1991-01-01

    This is the final product of the spacecraft design project completed to fulfill the academic requirements of the Spacecraft Design and Integration 2 course (AE-4871) taught at the U.S. Naval Postgraduate School. The Spacecraft Design and Integration 2 course is intended to provide students detailed design experience in selection and design of both satellite system and subsystem components, and their location and integration into a final spacecraft configuration. The design team pursued a design to support a Low Earth Orbiting (LEO) communications system (GLOBALSTAR) currently under development by the Loral Cellular Systems Corporation. Each of the 14 team members was assigned both primary and secondary duties in program management or system design. Hardware selection, spacecraft component design, analysis, and integration were accomplished within the constraints imposed by the 11 week academic schedule and the available design facilities.

  2. Vibration Control of Flexible Spacecraft Using Adaptive Controller

    Directory of Open Access Journals (Sweden)

    V.I. George

    2012-01-01

    Full Text Available The aim is to develop vibration control of flexible spacecraft by adaptive controller. A case study will be carried out which simulates planar motion of flexible spacecraft as a coupled hybrid dynamics of rigid body motion and the flexible arm vibration. The notch filter and adaptive vibration controller, which updates filter and controller parameters continuously from the sensor measurement, are implemented in the real time control. The least mean square algorithm using the adaptive notch filter is applied to the flexible spacecraft. This study will show that the adaptive vibration controller successfully stabilizes the uncertain and it will accurately control the vibration of flexible spacecraft. The Least mean square  algorithm is applied in flexible spacecraft to attenuate the vibration. The simulation studies are carried out in a Matlab/Simulink environment.

  3. Asteroid Deflection Using a Spacecraft in Restricted Keplerian Motion

    CERN Document Server

    Ketema, Yohannes

    2016-01-01

    A method for asteroid deflection that makes use of a spacecraft moving back and forth on a segment of an appropriate Keplerian orbit about the asteroid is described and evaluated. It is shown that, on average, the spacecraft describing such a trajectory can exert a significantly larger force on the asteroid than e.g. a stationary gravity tractor, thereby reducing the time needed to effect a desired velocity change for the asteroid. Furthermore, the current method does not require canted thrusters on the spacecraft (unlike a stationary gravity tractor), markedly reducing the amount of fuel needed to create a given change in the asteroid velocity. In addition, the method allows for the simultaneous use of several spacecraft, further strengthening the overall tugging effect on the asteroid, and distributing the thrust requirement among the spacecraft.

  4. Differential spacecraft charging on the geostationary operational environmental satellites

    Science.gov (United States)

    Farthing, W. H.; Brown, J. P.; Bryant, W. C.

    1982-01-01

    Subsystems aboard the Geostationary Operational Environmental Satellites 4 and 5 showed instances of anomalous changes in state corresponding to false commands. Evidence linking the anomalous changes to geomagnetic activity, and presumably static discharges generated by spacecraft differential charging induced by substorm particle injection events is presented. The anomalies are shown to be correlated with individual substorms as monitored by stations of the North American Magnetometer Chain. The relative frequency of the anomalies is shown to be a function of geomagnetic activity. Finally a least squares fit to the time delay between substorm initiation and spacecraft anomaly as a function of spacecraft local time is shown to be consistent with injected electron populations with energy in the range 10 keV to 15 keV, in agreement with present understanding of the spacecraft charging mechanism. The spacecraft elements responsible for the differential charging were not satisfactorily identified. That question is currently under investigation.

  5. A Survey of Research on Service-Spacecraft Orbit Design

    Institute of Scientific and Technical Information of China (English)

    LI Yue; ZHANG Jian-xin; ZHANG Qiang; WEI Xiao-peng

    2013-01-01

    On-orbit service spacecraft orbit problem has been addressed for decades. The research of on-orbit service spacecraft orbit can be roughly divided into orbit design and orbit optimization. The paper mainly focuses on the orbit design problem. We simply summarize of the previous works, and point out the main content of the on-orbit service spacecraft orbit design. We classify current on-orbit service spacecraft orbit design problem into parking-orbit design, maneuvering-orbit design and servicing-orbit design. Then, we give a detail description of the three specific orbits, and put forward our own ideas on the existed achievements. The paper will provide a meaningful reference for the on-orbit service spacecraft orbital design research.

  6. Formation design and nonlinear control of spacecraft formation flying

    Science.gov (United States)

    Wong, Hong

    The fundamental control challenges associated with Spacecraft Formation Flying (SFF) can be classified into two categories: (i) trajectory design and (ii) trajectory tracking. In this research, we address these challenges for several different operating environments. The first part of this research focuses on providing a trajectory generation and an adaptive control design methodology to facilitate SFF missions near the Sun-Earth L2 Lagrange point. Specifically, we create a spacecraft formation by placing a leader spacecraft on a desired Halo orbit and a follower spacecraft on a desired quasi-periodic orbit surrounding the Halo orbit. We develop the nonlinear dynamics of the leader spacecraft and the follower spacecraft relative to the leader spacecraft, wherein the leader spacecraft is assumed to be on a desired Halo orbit trajectory. Finally, we design formation maintenance controllers such that the leader and follower spacecraft track desired trajectories. In particular, we design a set of adaptive position tracking controllers for the leader and follower spacecraft in the presence of unknown spacecraft mass. The proposed control laws are simulated for the case of the leader and follower spacecraft pair and are shown to yield asymptotic convergence of the position tracking errors. The second part of this research focuses on providing nonlinear trajectory tracking control designs for SFF missions near Earth. First, we address output feedback tracking control problems for the coupled translation and attitude motion of a leader and a follower spacecraft. It is assumed that the translation and angular velocity measurements of the two spacecraft are not available for feedback. Second, we address a periodic trajectory tracking problem arising in spacecraft formation flying. In particular, the nonlinear position dynamics of a follower spacecraft relative to a leader spacecraft are utilized to develop a learning controller which learns a periodic, unknown model

  7. Quaternion normalization in spacecraft attitude determination

    Science.gov (United States)

    Deutschmann, J.; Markley, F. L.; Bar-Itzhack, Itzhack Y.

    1993-01-01

    Attitude determination of spacecraft usually utilizes vector measurements such as Sun, center of Earth, star, and magnetic field direction to update the quaternion which determines the spacecraft orientation with respect to some reference coordinates in the three dimensional space. These measurements are usually processed by an extended Kalman filter (EKF) which yields an estimate of the attitude quaternion. Two EKF versions for quaternion estimation were presented in the literature; namely, the multiplicative EKF (MEKF) and the additive EKF (AEKF). In the multiplicative EKF, it is assumed that the error between the correct quaternion and its a-priori estimate is, by itself, a quaternion that represents the rotation necessary to bring the attitude which corresponds to the a-priori estimate of the quaternion into coincidence with the correct attitude. The EKF basically estimates this quotient quaternion and then the updated quaternion estimate is obtained by the product of the a-priori quaternion estimate and the estimate of the difference quaternion. In the additive EKF, it is assumed that the error between the a-priori quaternion estimate and the correct one is an algebraic difference between two four-tuple elements and thus the EKF is set to estimate this difference. The updated quaternion is then computed by adding the estimate of the difference to the a-priori quaternion estimate. If the quaternion estimate converges to the correct quaternion, then, naturally, the quaternion estimate has unity norm. This fact was utilized in the past to obtain superior filter performance by applying normalization to the filter measurement update of the quaternion. It was observed for the AEKF that when the attitude changed very slowly between measurements, normalization merely resulted in a faster convergence; however, when the attitude changed considerably between measurements, without filter tuning or normalization, the quaternion estimate diverged. However, when the

  8. A Technology Program that Rescues Spacecraft

    Science.gov (United States)

    Deutsch, Leslie J.; Lesh, J. R.

    2004-03-01

    There has never been a long-duration deep space mission that did not have unexpected problems during operations. JPL's Interplanetary Network Directorate (IND) Technology Program was created to develop new and improved methods of communication, navigation, and operations. A side benefit of the program is that it maintains a cadre of human talent and experimental systems that can be brought to bear on unexpected problems that may occur during mission operations. Solutions fall into four categories: applying new technology during operations to enhance science performance, developing new operational strategies, providing domain experts to help find solutions, and providing special facilities to trouble-shoot problems. These are illustrated here using five specific examples of spacecraft anomalies that have been solved using, at least in part, expertise or facilities from the IND Technology Program: Mariner 10, Voyager, Galileo, SOHO, and Cassini/Huygens. In this era of careful cost management, and emphasis on returns-on-investment, it is important to recognize this crucial additional benefit from such technology program investments.

  9. A corrector for spacecraft calculated electron moments

    Directory of Open Access Journals (Sweden)

    J. Geach

    2005-03-01

    Full Text Available We present the application of a numerical method to correct electron moments calculated on-board spacecraft from the effects of potential broadening and energy range truncation. Assuming a shape for the natural distribution of the ambient plasma and employing the scalar approximation, the on-board moments can be represented as non-linear integral functions of the underlying distribution. We have implemented an algorithm which inverts this system successfully over a wide range of parameters for an assumed underlying drifting Maxwellian distribution. The outputs of the solver are the corrected electron plasma temperature Te, density Ne and velocity vector Ve. We also make an estimation of the temperature anisotropy A of the distribution. We present corrected moment data from Cluster's PEACE experiment for a range of plasma environments and make comparisons with electron and ion data from other Cluster instruments, as well as the equivalent ground-based calculations using full 3-D distribution PEACE telemetry.

  10. Parameter Studies for the VISTA Spacecraft Concept

    Energy Technology Data Exchange (ETDEWEB)

    Orth, C D

    2000-11-21

    The baseline design for the VISTA spacecraft concept employs a diode-pumped solid-state laser (DPSSL) driver. This type of driver is now under development at LLNL and elsewhere as an extension of the mature solid-state (glass) laser technology developed for terrestrial applications of inertial confinement fusion (ICF). A DPSSL is repratable up to at least 30 Hz, and has an efficiency soon to be experimentally verified of at least 10%. By using a detailed systems code including the essential physics of a DPSSL, we have run parameter studies for the baseline roundtrip (RT) to Mars with a 100-ton payload. We describe the results of these studies as a function of the optimized (minimum) RT flight duration. We also demonstrate why DT fuel gives the best performance, although DD, D3He, or even antimatter can be used, and why DT-ignited DD is probably the fuel most preferred. We also describe the overall power flow, showing where the fusion energy is ultimately utilized, and estimate the variation in performance to the planets dictated by variations in target gain and other parameters.

  11. Underactuated spacecraft formation reconfiguration with collision avoidance

    Science.gov (United States)

    Huang, Xu; Yan, Ye; Zhou, Yang

    2017-02-01

    Underactuated collision-free controllers are proposed in this paper for multiple spacecraft formation reconfiguration in circular orbits with the loss of either the radial or in-track thrust. A nonlinear dynamical model of underactuated formation flying is introduced, which is then linearized about circular orbits for controllability and feasibility analyses on underactuated formation reconfiguration. By using the inherent dynamics coupling of system states, reduced-order sliding mode controllers are then designed for either case to indirectly stabilize the system trajectories to the desired formations. In consideration of the collision-avoidance requirement, the artificial potential function method is then employed to design novel underactuated collision-avoidance maneuvers. Rigorous proof substantiates the capabilities of such maneuvers in preventing collisions even in the absence of radial or in-track thrust. Furthermore, a Lyapunov-based analysis ensures the asymptotic stability of the overall closed-loop system. Numerical simulations are performed in a J2-perturbed environment to verify the validity of the proposed underactuated control schemes for collision-free reconfiguration.

  12. Software-Reconfigurable Processors for Spacecraft

    Science.gov (United States)

    Farrington, Allen; Gray, Andrew; Bell, Bryan; Stanton, Valerie; Chong, Yong; Peters, Kenneth; Lee, Clement; Srinivasan, Jeffrey

    2005-01-01

    A report presents an overview of an architecture for a software-reconfigurable network data processor for a spacecraft engaged in scientific exploration. When executed on suitable electronic hardware, the software performs the functions of a physical layer (in effect, acts as a software radio in that it performs modulation, demodulation, pulse-shaping, error correction, coding, and decoding), a data-link layer, a network layer, a transport layer, and application-layer processing of scientific data. The software-reconfigurable network processor is undergoing development to enable rapid prototyping and rapid implementation of communication, navigation, and scientific signal-processing functions; to provide a long-lived communication infrastructure; and to provide greatly improved scientific-instrumentation and scientific-data-processing functions by enabling science-driven in-flight reconfiguration of computing resources devoted to these functions. This development is an extension of terrestrial radio and network developments (e.g., in the cellular-telephone industry) implemented in software running on such hardware as field-programmable gate arrays, digital signal processors, traditional digital circuits, and mixed-signal application-specific integrated circuits (ASICs).

  13. VCO PLL Frequency Synthesizers for Spacecraft Transponders

    Science.gov (United States)

    Smith, Scott; Mysoor, Narayan; Lux, James; Cook, Brian

    2007-01-01

    Two documents discuss a breadboard version of advanced transponders that, when fully developed, would be installed on future spacecraft to fly in deep space. These transponders will be required to be capable of operation on any deepspace- communications uplink frequency channel between 7,145 and 7,235 MHz, and any downlink frequency channel between 8,400 and 8,500 MHz. The document focuses on the design and operation of frequency synthesizers for the receiver and transmitter. Heretofore, frequency synthesizers in deep-space transponders have been based on dielectric resonator oscillators (DROs), which do not have the wide tuning bandwidth necessary to tune over all channels in the uplink or downlink frequency bands. To satisfy the requirement for tuning bandwidth, the present frequency synthesizers are based on voltage-controlled-oscillator (VCO) phase-locked loops (PLLs) implemented by use of monolithic microwave integrated circuits (MMICs) implemented using inGaP heterojunction bipolar transistor (HBT) technology. MMIC VCO PLL frequency synthesizers similar to the present ones have been used in commercial and military applications but, until now, have exhibited too much phase noise for use in deep-space transponders. The present frequency synthesizers contain advanced MMIC VCOs, which use HBT technology and have lower levels of flicker (1/f) phase noise. When these MMIC VCOs are used with high-speed MMIC frequency dividers, it becomes possible to obtain the required combination of frequency agility and low phase noise.

  14. An AFDX Network for Spacecraft Data Handling

    Science.gov (United States)

    Deredempt, Marie-Helene; Kollias, Vangelis; Sun, Zhili; Canamares, Ernest; Ricco, Philippe

    2014-08-01

    In aeronautical domain, ARINC-664 Part 7 specification (AFDX) [4] provides the enabling technology for interfacing equipment in Integrated Modular Avionics (IMA) architectures. The complementary part of AFDX for a complete interoperability - Time and Space Partitioning (ARINC 653) concepts [1]- was already studied as part of space domain ESA roadmap (i.e. IMA4Space project)Standardized IMA based architecture is already considered in aeronautical domain as more flexible, reliable and secure. Integration and validation become simple, using a common set of tools and data base and could be done by part on different means with the same definition (hardware and software test benches, flight control or alarm test benches, simulator and flight test installation).In some area, requirements in terms of data processing are quite similar in space domain and the concept could be applicable to take benefit of the technology itself and of the panel of hardware and software solutions and tools available on the market. The Mission project (Methodology and assessment for the applicability of ARINC-664 (AFDX) in Satellite/Spacecraft on-board communicatION networks), as an FP7 initiative for bringing terrestrial SME research into the space domain started to evaluate the applicability of the standard in space domain.

  15. Kalman Filter for Spinning Spacecraft Attitude Estimation

    Science.gov (United States)

    Markley, F. Landis; Sedlak, Joseph E.

    2008-01-01

    This paper presents a Kalman filter using a seven-component attitude state vector comprising the angular momentum components in an inertial reference frame, the angular momentum components in the body frame, and a rotation angle. The relatively slow variation of these parameters makes this parameterization advantageous for spinning spacecraft attitude estimation. The filter accounts for the constraint that the magnitude of the angular momentum vector is the same in the inertial and body frames by employing a reduced six-component error state. Four variants of the filter, defined by different choices for the reduced error state, are tested against a quaternion-based filter using simulated data for the THEMIS mission. Three of these variants choose three of the components of the error state to be the infinitesimal attitude error angles, facilitating the computation of measurement sensitivity matrices and causing the usual 3x3 attitude covariance matrix to be a submatrix of the 6x6 covariance of the error state. These variants differ in their choice for the other three components of the error state. The variant employing the infinitesimal attitude error angles and the angular momentum components in an inertial reference frame as the error state shows the best combination of robustness and efficiency in the simulations. Attitude estimation results using THEMIS flight data are also presented.

  16. Thermal Management Architecture for Future Responsive Spacecraft

    Science.gov (United States)

    Bugby, D.; Zimbeck, W.; Kroliczek, E.

    2009-03-01

    This paper describes a novel thermal design architecture that enables satellites to be conceived, configured, launched, and operationally deployed very quickly. The architecture has been given the acronym SMARTS for Satellite Modular and Reconfigurable Thermal System and it involves four basic design rules: modest radiator oversizing, maximum external insulation, internal isothermalization and radiator heat flow modulation. The SMARTS philosophy is being developed in support of the DoD Operationally Responsive Space (ORS) initiative which seeks to drastically improve small satellite adaptability, deployability, and design flexibility. To illustrate the benefits of the philosophy for a prototypical multi-paneled small satellite, the paper describes a SMARTS thermal control system implementation that uses: panel-to-panel heat conduction, intra-panel heat pipe isothermalization, radiator heat flow modulation via a thermoelectric cooler (TEC) cold-biased loop heat pipe (LHP) and maximum external multi-layer insulation (MLI). Analyses are presented that compare the traditional "cold-biasing plus heater power" passive thermal design approach to the SMARTS approach. Plans for a 3-panel SMARTS thermal test bed are described. Ultimately, the goal is to incorporate SMARTS into the design of future ORS satellites, but it is also possible that some aspects of SMARTS technology could be used to improve the responsiveness of future NASA spacecraft. [22 CFR 125.4(b)(13) applicable

  17. Improved Spacecraft Materials for Radiation Shielding

    Science.gov (United States)

    Wilson, J. W.; Shinn, J. L.; Singleterry, R. C.; Tai, H.; Thibeault, S. A.; Simonsen, L. C.; Cucinotta, F. A.; Miller, J.

    1999-01-01

    In the execution of this proposal, we will first examine current and developing spacecraft materials and evaluate their ability to attenuate adverse biological mutational events in mammalian cell systems and reduce the rate of cancer induction in mice harderian glands as a measure of their protective qualities. The HZETRN code system will be used to generate a database on GCR attenuation in each material. If a third year of funding is granted, the most promising and mission-specific materials will be used to study the impact on mission cost for a typical Mars mission scenario as was planned in our original two year proposal at the original funding level. The most promising candidate materials will be further tested as to their transmission characteristics in Fe and Si ion beams to evaluate the accuracy of the HZETRN transmission factors. Materials deemed critical to mission success may also require testing as well as materials developed by industry for their radiation protective qualities (e.g., Physical Sciences Inc.) A study will be made of designing polymeric materials and composite materials with improved radiation shielding properties as well as the possible improvement of mission-specific materials.

  18. Dust impact signals on the wind spacecraft

    Science.gov (United States)

    Kellogg, P. J.; Goetz, K.; Monson, S. J.

    2016-02-01

    We analyze waveforms recorded by the Time Domain Sampler of the WAVES experiment on Wind which are similar to impulsive waveforms observed by the S/WAVES experiment on STEREO. These have been interpreted as dust impacts by Meyer-Vernet et al. and M. L. Kaiser and K. Goetz and extensively analyzed by Zaslavsky et al. The mechanism for coupling the emission to the antennas to produce an electrical signal is still not well understood, however. One suggested mechanism for coupling of the impact to the antenna is that the spacecraft body changes potential with respect to the surrounding plasma but the antennas do not (the body mechanism). Another class of mechanisms, with several forms, is that the charge of the emitted cloud interacts with the antennas. The Wind data show that both are operating. The time domain shapes of the dust pulses are highly variable but we have little understanding of what provides these shapes. One feature of the STEREO data has been interpreted as impacts from high velocity nanoparticles entrained by the solar wind. We have not found evidence for fast nanodust in the Wind data. An appreciable fraction of the impacts observed on Wind is consistent with interstellar dust. The impact rates do not follow a Poisson distribution, expected for random independent events, and this is interpreted as bunching. We have not succeeded in relating this bunching to known meteor showers, and they do not repeat from 1 year to the next. The data suggest bunching by fields in the heliosphere.

  19. Dielectric Heaters for Testing Spacecraft Nuclear Reactors

    Science.gov (United States)

    Sims, William Herbert; Bitteker, Leo; Godfroy, Thomas

    2006-01-01

    A document proposes the development of radio-frequency-(RF)-driven dielectric heaters for non-nuclear thermal testing of the cores of nuclear-fission reactors for spacecraft. Like the electrical-resistance heaters used heretofore for such testing, the dielectric heaters would be inserted in the reactors in place of nuclear fuel rods. A typical heater according to the proposal would consist of a rod of lossy dielectric material sized and shaped like a fuel rod and containing an electrically conductive rod along its center line. Exploiting the dielectric loss mechanism that is usually considered a nuisance in other applications, an RF signal, typically at a frequency .50 MHz and an amplitude between 2 and 5 kV, would be applied to the central conductor to heat the dielectric material. The main advantage of the proposal is that the wiring needed for the RF dielectric heating would be simpler and easier to fabricate than is the wiring needed for resistance heating. In some applications, it might be possible to eliminate all heater wiring and, instead, beam the RF heating power into the dielectric rods from external antennas.

  20. Vibration and Acoustic Testing for Mars Micromission Spacecraft

    Science.gov (United States)

    Kern, Dennis L.; Scharton, Terry D.

    1999-01-01

    The objective of the Mars Micromission program being managed by the Jet Propulsion Laboratory (JPL) for NASA is to develop a common spacecraft that can carry telecommunications equipment and a variety of science payloads for exploration of Mars. The spacecraft will be capable of carrying robot landers and rovers, cameras, probes, balloons, gliders or aircraft, and telecommunications equipment to Mars at much lower cost than recent NASA Mars missions. The lightweight spacecraft (about 220 Kg mass) will be launched in a cooperative venture with CNES as a TWIN auxiliary payload on the Ariane 5 launch vehicle. Two or more Mars Micromission launches are planned for each Mars launch opportunity, which occur every 26 months. The Mars launch window for the first mission is November 1, 2002 through April 2003, which is planned to be a Mars airplane technology demonstration mission to coincide with the 100 year anniversary of the Kittyhawk flight. Several subsequent launches will create a telecommunications network orbiting Mars, which will provide for continuous communication with lenders and rovers on the Martian surface. Dedicated science payload flights to Mars are slated to start in 2005. This new cheaper and faster approach to Mars exploration calls for innovative approaches to the qualification of the Mars Micromission spacecraft for the Ariane 5 launch vibration and acoustic environments. JPL has in recent years implemented new approaches to spacecraft testing that may be effectively applied to the Mars Micromission. These include 1) force limited vibration testing, 2) combined loads, vibration and modal testing, and 3) direct acoustic testing. JPL has performed nearly 200 force limited vibration tests in the past 9 years; several of the tests were on spacecraft and large instruments, including the Cassini and Deep Space One spacecraft. Force limiting, which measures and limits the spacecraft base reaction force using triaxial force gages sandwiched between the

  1. A Low Cost Spacecraft Architecture for Robotic Lunar Exploration Projects

    Science.gov (United States)

    Lemke, Lawrence G.; Gonzales, Andrew A.

    2006-01-01

    A program of frequent, capable, but affordable lunar robotic missions prior to return of humans to the moon can contribute to the Vision for Space Exploration (VSE) NASA is tasked to execute. The Lunar Reconnaissance Orbiter (LRO) and its secondary payload are scheduled to orbit the moon, and impact it, respectively, in 2008. It is expected that the sequence of missions occurring for approximately the decade after 2008 will place an increasing emphasis on soft landed payloads. These missions are requited to explore intrinsic characteristics of the moon, such as hydrogen distribution in the regolith, and levitated dust, to demonstrate the ability to access and process in-situ resources, and to demonstrate functions critical to supporting human presence, such as automated precision navigation and landing. Additional factors governing the design of spacecraft to accomplish this diverse set of objectives are: operating within a relatively modest funding profile, the need tb visit multiple sites (both polar and equatorial) repeatedly, and to use the current generation of launch vehicles. In the US, this implies use of the Evolved Expendable Launch Vehicles, or EELVs, although this design philosophy may be extended to launch vehicles of other nations, as well. Many of these factors are seemingly inconsistent with each other. For example, the cost of a spacecraft usually increases with mass; therefore the desire to fly frequent, modestly priced spacecraft seems to imply small spacecraft (autonomous navigation and soft landing) also usually increases cost. A strategy for spacecraft design that meets these conflicting requirements is presented. Taken together, spacecraft structure and propulsion subsystems constitute the majority of spacecraft mass; saving development and integration cost on these elements is critical to controlling cost. Therefore, a low cost, modular design for spacecraft structure and propulsion subsystems is presented which may be easily scaled up or

  2. Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods

    Directory of Open Access Journals (Sweden)

    S. E. Haaland

    2004-04-01

    Full Text Available In this paper, we use Cluster data from one magnetopause event on 5 July 2001 to compare predictions from various methods for determination of the velocity, orientation, and thickness of the magnetopause current layer. We employ established as well as new multi-spacecraft techniques, in which time differences between the crossings by the four spacecraft, along with the duration of each crossing, are used to calculate magnetopause speed, normal vector, and width. The timing is based on data from either the Cluster Magnetic Field Experiment (FGM or the Electric Field Experiment (EFW instruments. The multi-spacecraft results are compared with those derived from various single-spacecraft techniques, including minimum-variance analysis of the magnetic field and deHoffmann-Teller, as well as Minimum-Faraday-Residue analysis of plasma velocities and magnetic fields measured during the crossings. In order to improve the overall consistency between multi- and single-spacecraft results, we have also explored the use of hybrid techniques, in which timing information from the four spacecraft is combined with certain limited results from single-spacecraft methods, the remaining results being left for consistency checks. The results show good agreement between magnetopause orientations derived from appropriately chosen single-spacecraft techniques and those obtained from multi-spacecraft timing. The agreement between magnetopause speeds derived from single- and multi-spacecraft methods is quantitatively somewhat less good but it is evident that the speed can change substantially from one crossing to the next within an event. The magnetopause thickness varied substantially from one crossing to the next, within an event. It ranged from 5 to 10 ion gyroradii. The density profile was sharper than the magnetic profile: most of the density change occured in the earthward half of the magnetopause.

    Key words. Magnetospheric physics (magnetopause, cusp and

  3. Time Frequency Analysis of Spacecraft Propellant Tank Spinning Slosh

    Science.gov (United States)

    Green, Steven T.; Burkey, Russell C.; Sudermann, James

    2010-01-01

    Many spacecraft are designed to spin about an axis along the flight path as a means of stabilizing the attitude of the spacecraft via gyroscopic stiffness. Because of the assembly requirements of the spacecraft and the launch vehicle, these spacecraft often spin about an axis corresponding to a minor moment of inertia. In such a case, any perturbation of the spin axis will cause sloshing motions in the liquid propellant tanks that will eventually dissipate enough kinetic energy to cause the spin axis nutation (wobble) to grow further. This spinning slosh and resultant nutation growth is a primary design problem of spinning spacecraft and one that is not easily solved by analysis or simulation only. Testing remains the surest way to address spacecraft nutation growth. This paper describes a test method and data analysis technique that reveal the resonant frequency and damping behavior of liquid motions in a spinning tank. Slosh resonant frequency and damping characteristics are necessary inputs to any accurate numerical dynamic simulation of the spacecraft.

  4. Applying a cloud computing approach to storage architectures for spacecraft

    Science.gov (United States)

    Baldor, Sue A.; Quiroz, Carlos; Wood, Paul

    As sensor technologies, processor speeds, and memory densities increase, spacecraft command, control, processing, and data storage systems have grown in complexity to take advantage of these improvements and expand the possible missions of spacecraft. Spacecraft systems engineers are increasingly looking for novel ways to address this growth in complexity and mitigate associated risks. Looking to conventional computing, many solutions have been executed to solve both the problem of complexity and heterogeneity in systems. In particular, the cloud-based paradigm provides a solution for distributing applications and storage capabilities across multiple platforms. In this paper, we propose utilizing a cloud-like architecture to provide a scalable mechanism for providing mass storage in spacecraft networks that can be reused on multiple spacecraft systems. By presenting a consistent interface to applications and devices that request data to be stored, complex systems designed by multiple organizations may be more readily integrated. Behind the abstraction, the cloud storage capability would manage wear-leveling, power consumption, and other attributes related to the physical memory devices, critical components in any mass storage solution for spacecraft. Our approach employs SpaceWire networks and SpaceWire-capable devices, although the concept could easily be extended to non-heterogeneous networks consisting of multiple spacecraft and potentially the ground segment.

  5. The dynamics and control of large flexible asymmetric spacecraft

    Science.gov (United States)

    Humphries, T. T.

    1991-02-01

    This thesis develops the equations of motion for a large flexible asymmetric Earth observation satellite and finds the characteristics of its motion under the influence of control forces. The mathematical model of the structure is produced using analytical methods. The equations of motion are formed using an expanded momentum technique which accounts for translational motion of the spacecraft hub and employs orthogonality relations between appendage and vehicle modes. The controllability and observability conditions of the full spacecraft motions using force and torque actuators are defined. A three axis reaction wheel control system is implemented for both slewing the spacecraft and controlling its resulting motions. From minor slew results it is shown that the lowest frequency elastic mode of the spacecraft is more important than higher frequency modes, when considering the effects of elastic motion on instrument pointing from the hub. Minor slews of the spacecraft configurations considered produce elastic deflections resulting in rotational attitude motions large enough to contravene pointing accuracy requirements of instruments aboard the spacecraft hub. Active vibration damping is required to reduce these hub motions to acceptable bounds in sufficiently small time. A comparison between hub mounted collocated and hub/appendage mounted non-collocated control systems verifies that provided the non-collocated system is stable, it can more effectively damp elastic modes whilst maintaining adequate damping of rigid modes. Analysis undertaken shows that the reaction wheel controller could be replaced by a thruster control system which decouples the modes of the spacecraft motion, enabling them to be individually damped.

  6. Does spacecraft potential depend on the ambient electron density?

    Science.gov (United States)

    Lai, S. T.; Martinez-Sanchez, M.; Cahoy, K.; Thomsen, M. F.; Shprits, Y.; Lohmeyer, W. Q.; Wong, F.

    2014-12-01

    In a Maxwellian space plasma model, the onset of spacecraft charging at geosynchronous altitudes is due to the ambient electron, ambient ions, and secondary electrons. By using current balance, one can show that the onset of spacecraft charging depends not on the ambient electron density but instead on the critical temperature of the ambient electrons. If the ambient plasma deviates significantly from equilibrium, a non-Maxwellian electron distribution results. For a kappa distribution, the onset of spacecraft charging remains independent of ambient electron density. However, for double Maxwellian distributions, the densities do have a role in the onset of spacecraft charging. For a dielectric spacecraft in sunlight, the trapping of photoelectrons on the sunlit side enhances the local electron density. Using the coordinated environmental satellite data from the Los Alamos National Laboratory geosynchronous satellites, we have obtained results that confirm that the observed spacecraft potential is independent of the ambient electron density during eclipse and that in sunlight charging the low-energy population around the sunlit side of the spacecraft is enhanced by photoelectrons trapped inside the potential barrier.

  7. Fourth-order gravity gradient torque of spacecraft orbiting asteroids

    CERN Document Server

    Wang, Yue; Xu, Shijie

    2014-01-01

    The dynamical behavior of spacecraft around asteroids is a key element in design of such missions. An asteroid's irregular shape, non-spherical mass distribution and its rotational sate make the dynamics of spacecraft quite complex. This paper focuses on the gravity gradient torque of spacecraft around non-spherical asteroids. The gravity field of the asteroid is approximated as a 2nd degree and order-gravity field with harmonic coefficients C20 and C22. By introducing the spacecraft's higher-order inertia integrals, a full fourth-order gravity gradient torque model of the spacecraft is established through the gravitational potential derivatives. Our full fourth-order model is more precise than previous fourth-order model due to the consideration of higher-order inertia integrals of the spacecraft. Some interesting conclusions about the gravity gradient torque model are reached. Then a numerical simulation is carried out to verify our model. In the numerical simulation, a special spacecraft consisted of 36 po...

  8. An Educational Multimedia Presentation on the Introduction to Spacecraft Charging

    Science.gov (United States)

    Lin, E.; dePayrebrune, M.

    2004-01-01

    Over the last few decades, significant knowledge has been gained in how to protect spacecraft from charging; however, the continuing technical advancement in the design and build of satellites requires on-going effort in the study of spacecraft charging. A situation that we have encountered is that not all satellite designers and builders are familiar with the problem of spacecraft charging. The design of a satellite involves many talented people with diverse backgrounds, ranging from manufacturing and assembly to engineering and program management. The complex design and build of a satellite system requires people with highly specialized skills such that cross-specialization is often not achievable. As a result, designers and builders of satellites are not usually familiar with the problems outside their specialization. This is also true for spacecraft charging. Not everyone is familiar with the definition of spacecraft charging and the damage that spacecraft charging can cause. Understanding the problem is an important first step in getting everyone involved in addressing the appropriate spacecraft charging issues during the satellite design and build phases. To address this important first step, an educational multimedia presentation has been created to inform the general engineering community about the basics of spacecraft charging. The content of this educational presentation is based on relevant published technical papers. The presentation was developed using Macromedia Flash. This software produces a more dynamic learning environment than a typical slide show , resulting in a more effective learning experience. The end result is that the viewer will have learned about the basics of spacecraft charging. This presentation is available to the public through our website, www.dplscience.com, free of charge. Viewers are encouraged to pass this presentation to colleagues within their own work environment. This paper describes the content of the multimedia

  9. LCOGT Network observations of spacecraft target comets

    Science.gov (United States)

    Lister, Tim; Knight, Matthew M.; Snodgrass, Colin; Samarasinha, Nalin H.

    2015-01-01

    Las Cumbres Observatory Global Telescope (LCOGT) network currently has 12 telescopes at 6 locations in the northern and southern hemispheres with expansion plans for more. This network is versatile and can respond rapidly to target of opportunity events and also perform long term monitoring of slowly changing astronomical phenomena.We have been using the LCOGT Network to perform photometric monitoring of comet 67P/Churyumov-Gerasimenko to support the ESA Rosetta comet mission and of C/2013 A1 (Siding Spring) as part of the ground-based observation teams for these important comets. This broadband photometry will allow a vital link between the detailed in-situ measurements made by the spacecraft and the global properties of the coma, at a time when the comet is only visible for short periods from single sites. The science we can extract includes the rotational state of the nucleus, characterization of the nucleus' activity, gas and dust properties in the coma (e.g., outflow velocities), chemical origin of gas species in the coma, and temporal behavior of the coma structure when the comet is close to the sun. Comet Siding Spring is a dynamically new comet on its first approach to the Sun that will pass close to Mars, so we can directly sample the composition of an original unaltered remnant of the protoplanetary disc. We will also be making use of specialized comet filters available at LCOGT's 2-m Faulkes Telescope North (FTN) to obtain a unique data set on comet C/2013 A1 (Siding Spring), as part of a large worldwide campaign. As one of only two robotic telescope equipped with cometary narrowband filters in the Northern hemisphere and having the largest aperture plus a high quality site, FTN can provide critical regular monitoring that cannot be achieved by any other single facility in the campaign.

  10. Spacecraft Environment May Reduce Resistance To Infection

    Science.gov (United States)

    Pierson, Duane L.; Ott, C. Mark; Castro, V. A.; Leal, Melanie; Mehta, Satish K.

    2006-01-01

    Living and working in a spacecraft exposes the crew to a unique environment. This environment includes microgravity, increased radiation, chemical and biological contamination, and a variety of stressors. Disturbances in this balance are often manifested by diminished immunity in astronauts/cosmonauts. Reactivation of Epstein- Barr virus (EBV), cytomegalovirus (CMV), and varicella-zoster virus (VZV) has been used as an indicator of immune status. Reactivation of EBV and VZV were detected and quantified in saliva. CMV was measured in urine. The DNA was extracted using a Qiagen Inc. kit and viral DNA was detected by real time polymerase chain reaction (PCR) based assay with Taqman 7700 (PE Biosystems). Patterns of Epstein-Barr virus (EBV) reactivation in 32 astronauts and 18 healthy age-matched control subjects were characterized by quantifying EBV shedding. Saliva samples were collected before, during, and after 10 space shuttle missions of 5 to 14 d duration. Of 1398 saliva specimens from 32 astronauts, 314 (23%) were positive for EBV DNA. Examination by flight phase showed that 29% of the saliva specimens collected from 28 astronauts before flight were positive for EBV DNA, as were 16% of those collected from 25 astronauts during flight and 16% of those collected after flight from 23 astronauts. The mean number of EBV copies/mL from samples taken during the flights was 417, ten-fold greater (p EBV DNA with a frequency of 3.7% and mean EBV copies of 40 per mL of saliva. Ten days before flight and on landing day, titers of antibody to EBV viral capsid antigen were significantly (p EBV-specific antibody were consistent with EBV reactivation before, during, and after space flight. Similarly, CMV and VZV reactivation increased in response to space flight conditions. Data indicates that space flight is a unique stress environment that may produce stress-induced changes in the host-microbe relationship resulting in increased risk of infection.

  11. Spacecraft Water Monitoring: Adapting to an Era of Emerging Scientific Challenges

    Science.gov (United States)

    McCoy, J. Torin

    2009-01-01

    This viewgraph presentation reviews spacecraft water monitoring, and the scientific challenges associated with spacecraft water quality. The contents include: 1) Spacecraft Water 101; 2) Paradigm Shift; and 3) Technology Needs.

  12. Fifty-one years of Los Alamos Spacecraft

    Energy Technology Data Exchange (ETDEWEB)

    Fenimore, Edward E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-09-04

    From 1963 to 2014, the Los Alamos National Laboratory was involved in at least 233 spacecraft. There are probably only one or two institutions in the world that have been involved in so many spacecraft. Los Alamos space exploration started with the Vela satellites for nuclear test detection, but soon expanded to ionospheric research (mostly barium releases), radioisotope thermoelectric generators, solar physics, solar wind, magnetospheres, astrophysics, national security, planetary physics, earth resources, radio propagation in the ionosphere, and cubesats. Here, we present a list of the spacecraft, their purpose, and their launch dates for use during RocketFest

  13. Spacecraft redesign to reduce microphonic response of a VCO component

    Science.gov (United States)

    Strain, J. C.; Mittal, S.

    1988-01-01

    Reaction wheel vibration was found to induce out of specification sidebands on the carrier frequencies of some spacecraft components containing mechanical voltage control oscillators (VCOs). Concurrent investigations were performed to redesign the VCOs to reduce their response to the wheel vibration, and to design a reaction wheel isolation system to reduce the vibration input to the affected components. Component level tests indicated that both efforts provided viable solutions. The redesigned VCO will be incorporated into future spacecraft in the series, while affected spacecraft already in production will be retrofitted with the reaction wheel isolation system.

  14. Cooper-Harper Experience Report for Spacecraft Handling Qualities Applications

    Science.gov (United States)

    Bailey, Randall E.; Jackson, E. Bruce; Bilimoria, Karl D.; Mueller, Eric R.; Frost, Chad R.; Alderete, Thomas S.

    2009-01-01

    A synopsis of experience from the fixed-wing and rotary-wing aircraft communities in handling qualities development and the use of the Cooper-Harper pilot rating scale is presented as background for spacecraft handling qualities research, development, test, and evaluation (RDT&E). In addition, handling qualities experiences and lessons-learned from previous United States (US) spacecraft developments are reviewed. This report is intended to provide a central location for references, best practices, and lessons-learned to guide current and future spacecraft handling qualities RDT&E.

  15. Trajectory Design for the Phobos and Deimos & Mars Environment Spacecraft

    Science.gov (United States)

    Genova, Anthony L.; Korsmeyer, David J.; Loucks, Michel E.; Yang, Fan Yang; Lee, Pascal

    2016-01-01

    The presented trajectory design and analysis was performed for the Phobos and Deimos & Mars Environment (PADME) mission concept as part of a NASA proposal submission managed by NASA Ames Research Center in the 2014-2015 timeframe. The PADME spacecraft would be a derivative of the successfully flown Lunar Atmosphere & Dust Environment Explorer (LADEE) spacecraft. While LADEE was designed to enter low-lunar orbit, the PADME spacecraft would instead enter an elliptical Mars orbit of 2-week period. This Mars orbit would pass by Phobos near periapsis on successive orbits and then raise periapsis to yield close approaches of Deimos every orbit thereafter.

  16. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the SOUTHERN SURVEYOR in the Bass Strait, Coral Sea and others from 2008011 to 2010-10-31 (NODC Accession 0115181)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115181 includes chemical, meteorological, physical and underway - surface data collected from SOUTHERN SURVEYOR in the Bass Strait, Coral Sea, Great...

  17. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the SOUTHERN SURVEYOR in the Coral Sea, Indian Ocean and others from 2012-04-11 to 2012-07-25 (NODC Accession 0115295)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115295 includes chemical, meteorological, physical and underway - surface data collected from SOUTHERN SURVEYOR in the Coral Sea, Indian Ocean, South...

  18. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the SOUTHERN SURVEYOR in the Coral Sea, Great Australian Bight and others from 2011-04-06 to 2011-11-26 (NODC Accession 0115708)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0115708 includes chemical, meteorological, physical and underway - surface data collected from SOUTHERN SURVEYOR in the Coral Sea, Great Australian...

  19. Physical, meteorological, and other data from surface sensors, bottle casts, and CTD casts in the Gulf of Alaska from the SURVEYOR and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 22 July 1976 to 02 October 1976 (NODC Accession 7800045)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors, bottle casts, and CTD casts in the Gulf of Alaska from the SURVEYOR and other...

  20. Phytoplankton and other data from net and bottle casts in the North Pacific Ocean from NOAA Ship SURVEYOR as part of Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1976-03-15 to 1976-04-26 (NODC Accession 7700779)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Phytoplankton and other data were collected from net and bottle casts in the North Pacific Ocean from NOAA Ship SURVEYOR from 15 March 1976 to 26 April 1976. Data...

  1. Physical, meteorological, and other data from surface sensors, bottle casts, and CTD casts in the Gulf of Alaska from NOAA Ship SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1975-10-28 to 1975-11-17 (NODC Accession 7601830)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors, bottle casts, and CTD casts in the Gulf of Alaska from NOAA Ship SURVEYOR. Data were...

  2. Physical, meteorological, and other data from surface sensors, bottle casts, and CTD casts in the Bering Sea from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 18 March 1977 to 04 April 1977 (NODC Accession 7800309)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors, bottle casts, and CTD casts in the Bering Sea from the SURVEYOR. Data were collected by...

  3. Physical, meteorological, and other data from surface sensors and CTD casts in the Gulf of Alaska from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 22 July 1977 to 05 August 1977 (NODC Accession 7700854)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Gulf of Alaska from the SURVEYOR. Data were collected by the...

  4. Physical, meteorological, and other data from surface sensors, bottle casts, and CTD casts in the Bering Sea from the SURVEYOR as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 17 April 1977 to 01 May 1977 (NODC Accession 7800310)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors, bottle casts, and CTD casts in the Bering Sea from the SURVEYOR. Data were collected by...

  5. Dissolved inorganic carbon, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the SOUTHERN SURVEYOR in the North Pacific Ocean and South Pacific Ocean from 2009-02-03 to 2009-03-24 (NODC Accession 0108082)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108082 includes chemical, discrete sample, physical and profile data collected from SOUTHERN SURVEYOR in the North Pacific Ocean and South Pacific...

  6. Marine mammal specimen and other data from the Gulf of Alaska from NOAA Ship SURVEYOR and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 1978-04-06 to 1978-09-12 (NODC Accession 8000004)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected in the Gulf of Alaska from NOAA Ship SURVEYOR and other platforms from 06 April 1978 to 12 September 1978. Data...

  7. Marine mammal specimen and other data from the Beaufort Sea and other locations from the SURVEYOR and other platforms as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 25 January 1977 to 17 November 1977 (NODC Accession 7900339)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marine mammal specimen and other data were collected in the Beaufort Sea from the SURVEYOR and other platforms from 25 January 1977 to 17 November 1977. Data were...

  8. RFP to work on formation flying capabilities for spacecrafts for the GRACE project

    DEFF Research Database (Denmark)

    Riis, Troels; Thuesen, Gøsta; Kilsgaard, Søren

    1999-01-01

    The National Aeronautics and Space Agency of USA, NASA, are working on formation flying capabilities for spacecrafts, GRACE Project. IAU and JPL are developing the inter spacecraft attitude link to be used on the two spacecrafts.......The National Aeronautics and Space Agency of USA, NASA, are working on formation flying capabilities for spacecrafts, GRACE Project. IAU and JPL are developing the inter spacecraft attitude link to be used on the two spacecrafts....

  9. Surface Brightness Correction for Compact Extended Sources Observed by the AKARI Far-Infrared Surveyor (FIS) in the Slow-Scan Mode

    CERN Document Server

    Ueta, Toshiya; Takita, Satoshi; Izumiura, Hideyuki; Shirahata, Mai; Fullard, Andrew; Yamamura, Issei; Matsuura, Shuji

    2016-01-01

    We present a general surface brightness correction method for compact extended sources imaged in the slow-scan pointed observation mode of the Far-Infrared Surveyor (FIS) aboard the AKARI Infrared Astronomical Satellite. Our method recovers correct surface brightness distribution maps by re-scaling archived raw FIS maps using the surface-brightness-dependent inverse FIS response function. The flux of a target source is then automatically corrected for as the simple sum of surface brightnesses within the adopted contour encircling the perimeter of the target (i.e., contour photometry). This correction method is contrasted to the previous aperture photometry method for point sources, which directly corrects for the target flux with a flux-dependent scaling law. The new surface brightness correction scheme is applicable to objects of any shape from unresolved point sources to resolved extended objects, as long as the target is not deemed diffuse, i.e., the total extent of the target source does not exceed too mu...

  10. Development Status of Adjustable X-ray Optics with 0.5 Arcsec Imaging for the X-ray Surveyor Mission Concept

    Science.gov (United States)

    Reid, Paul B.; Allured, Ryan; ben-Ami, Sagi; Cotroneo, Vincenzo; Schwartz, Daniel A.; Tananbaum, Harvey; Vikhlinin, Alexey; Trolier-McKinstry, Susan; Wallace, Margeaux L.; Jackson, Tom

    2016-04-01

    The X-ray Surveyor mission concept is designed as a successor to the Chandra X-ray Observatory. As currently envisioned, it will have as much as 30-50 times the collecting area of Chandra with the same 0.5 arcsec imaging resolution. This combination of telescope area and imaging resolution, along with a detector suite for imaging and dispersive and non-dispersive imaging spectroscopy, will enable a wide range of astrophysical observations. These observations will include studies of the growth of large scale structure, early black holes and the growth of SMBHs, and high resolution spectroscopy with arcsec resolution, among many others. We describe the development of adjustable grazing incidence X-ray optics, a potential technology for the high resolution, thin, lightweight mirrors. We discuss recent advancements including the demonstration of deterministic figure correction via the use of the adjusters, the successful demonstration of integrating control electronics directly on the actuator cells to enable row-column addressing, and discuss the feasibility of on-orbit piezoelectric performance and figure monitoring via integrated semiconductor strain gauges. We also present the telescope point design and progress in determining the telescope thermal sensitivities and achieving alignment and mounting requirements.

  11. Applicability of ISO 16697 Data to Spacecraft Fire Fighting Strategies

    Science.gov (United States)

    Hirsch, David B.; Beeson, Harold D.

    2012-01-01

    Presentation Agenda: (1) Selected variables affecting oxygen consumption during spacecraft fires, (2) General overview of ISO 16697, (3) Estimated amounts of material consumed during combustion in typical ISS enclosures, (4) Discussion on potential applications.

  12. Distributed Control Architectures for Precision Spacecraft Formations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — LaunchPoint Technologies, Inc. (LaunchPoint) proposes to develop synthesis methods and design architectures for distributed control systems in precision spacecraft...

  13. A multi-spacecraft formation approach to space debris surveillance

    Science.gov (United States)

    Felicetti, Leonard; Emami, M. Reza

    2016-10-01

    This paper proposes a new mission concept devoted to the identification and tracking of space debris through observations made by multiple spacecraft. Specifically, a formation of spacecraft has been designed taking into account the characteristics and requirements of the utilized optical sensors as well as the constraints imposed by sun illumination and visibility conditions. The debris observations are then shared among the team of spacecraft, and processed onboard of a "hosting leader" to estimate the debris motion by means of Kalman filtering techniques. The primary contribution of this paper resides on the application of a distributed coordination architecture, which provides an autonomous and robust ability to dynamically form spacecraft teams once the target has been detected, and to dynamically build a processing network for the orbit determination of space debris. The team performance, in terms of accuracy, readiness and number of the detected objects, is discussed through numerical simulations.

  14. A Data Abstraction Architecture for Spacecraft Autonomy Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft generate huge amounts of data. A significant challenge for both human operators and autonomous control systems is ensuring that the right data (and...

  15. Passive Devices for Advanced Fluid Management aboard Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Acute challenges are faced by the designers of fluid systems for spacecraft because of the persistently unfamiliar and unforgiving low-g environment. For example,...

  16. Wireless Data and Power Transfer on Small Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Achieving low-cost space missions implies lowering all phases of mission development, including spacecraft design, assembly, integration and test. The concept of the...

  17. Diagnosing Faults in Electrical Power Systems of Spacecraft and Aircraft

    Data.gov (United States)

    National Aeronautics and Space Administration — Electrical power systems play a critical role in spacecraft and aircraft, and they exhibit a rich variety of failure modes. This paper discusses electrical power...

  18. Hard-real-time resource management for autonomous spacecraft

    Science.gov (United States)

    Gat, E.

    2000-01-01

    This paper describes tickets, a computational mechanism for hard-real-time autonomous resource management. Autonomous spacecraftcontrol can be considered abstractly as a computational process whose outputs are spacecraft commands.

  19. Spacecraft Thermal Control System Not Requiring Power Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The thermal management of spacecraft would be enhanced by dynamic control over surface emissivity in the mid-infrared. In this SBIR program, Triton Systems proposes...

  20. Triple3 Redundant Spacecraft Subsystems (T3RSS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Redefine Technologies, along with researchers at the University of Colorado, will use three redundancy methods to decrease the susceptibility of a spacecraft, on a...

  1. Autonomous Supervisory Engine for Multi-Spacecraft Formation Flying Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of this project is to develop an onboard, autonomous Multi-spacecraft Supervisory Engine (MSE) for formation-flying guidance, navigation and control...

  2. Advanced Portable Fine Water Mist Fire Extinguisher for Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fine water mist (FWM) is a promising replacement technology for fire suppression on the next generation of manned spacecraft. It offers advantages in performance,...

  3. Spacecraft design project: High temperature superconducting infrared imaging satellite

    Science.gov (United States)

    1991-01-01

    The High Temperature Superconductor Infrared Imaging Satellite (HTSCIRIS) is designed to perform the space based infrared imaging and surveillance mission. The design of the satellite follows the black box approach. The payload is a stand alone unit, with the spacecraft bus designed to meet the requirements of the payload as listed in the statement of work. Specifications influencing the design of the spacecraft bus were originated by the Naval Research Lab. A description of the following systems is included: spacecraft configuration, orbital dynamics, radio frequency communication subsystem, electrical power system, propulsion, attitude control system, thermal control, and structural design. The issues of testing and cost analysis are also addressed. This design project was part of the course Advanced Spacecraft Design taught at the Naval Postgraduate School.

  4. Charge Dissipating Transparent Conformal Coatings for Spacecraft Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The space environment poses significant challenges to spacecraft electronics in the form of electrostatic discharge (ESD) as a result of exposure to highly charged...

  5. High Throughput Hall Thruster for Small Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek Co. Inc. proposes to develop a high throughput, nominal 100 W Hall Effect Thruster (HET). This HET will be sized for small spacecraft (< 180 kg), including...

  6. Indonesian Islands as seen from Gemini 11 spacecraft

    Science.gov (United States)

    1966-01-01

    Indonesian Islands (partial cloud cover): Sumatra, Java, Bali, Borneo, Sumbawa, as photographed from the Gemini 11 spacecraft during its 26th revolution of the earth, at an altitude of 570 nautical miles.

  7. Novel Metal Organic Framework Synthesis for Spacecraft Oxygen Capture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek and University of Utah propose to develop novel metal organic framework (MOF) material to efficiently capture oxygen in spacecraft cabin environment. The...

  8. Aerogel Insulation for the Thermal Protection of Venus Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — One of NASA's primary goals for the next decade is the design, development and launch of a spacecraft aimed at the in-situ exploration of the deep atmosphere and...

  9. High Throughput Hall Thruster for Small Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek is developing a high throughput nominal 100-W Hall Effect Thruster. This device is well sized for spacecraft ranging in size from several tens of kilograms to...

  10. Aerogel Insulation for the Thermal Protection of Venus Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — One of NASA's primary goals for the next decade is the design, development and launch of a spacecraft aimed at the in-situ exploration of the deep atmosphere and...

  11. Modeling Vacuum Arcs On Spacecraft Solar Panel Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft charging and subsequent vacuum arcing poses a significant threat to satellites in LEO and GEO plasma conditions. Localized arc discharges can cause a...

  12. Best Geosynchronous Earth Orbit Daytime Spacecraft Charging Index

    Science.gov (United States)

    Ferguson, D.; Hilmer, R. V.; Davis, V. A.

    2016-12-01

    Recently, the debate on what is the best daytime Geosynchronous Earth Orbit spacecraft charging index has beenreopened. In this paper, the conclusions of one of the recent papers on the subject are verified by comparing Nascap-2k results with charging and fluxes measured on the Spacecraft Charging at the High Altitudes, Intelsat, DefenseSatellite Communications System, and Los Alamos National Laboratory Geosynchronous Earth Orbit satellites. Inaddition, a refined measure of charging is presented as the total thermal electron flux above a certainminimumenergythat is well above the second crossover point in secondary electron emission. The use of this type of index is justified bycorrelations between Nascap-2k simulation results and total fluxes above a range of energies. The best minimumenergy to use is determined for spacecraft of different design and surface materials. Finally, the optimumGeosynchronous Earth Orbit daytime spacecraft charging index is obtained, and its use for predicting and resolvingspacecraft anomalies in real time is justified.

  13. Spacecraft Water Regeneration by Catalytic Wet Air Oxidation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to develop advanced catalysts for a volatile removal assembly used to purify spacecraft water. The innovation of the proposed...

  14. Trace Contaminant Monitor for Air in Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A need exists for analyzers that can measure trace contaminants in air on board spacecraft. Toxic gas buildup can endanger the crew particularly during long...

  15. Micro GC's for Contaminant Monitoring in Spacecraft Air Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this proposal is to create new gas chromatographs (GCs) for contaminant monitoring in spacecraft air that do not require any reagents or special...

  16. A Self-Regulating Freezable Heat Exchanger for Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A spacecraft thermal control system must keep the cabin (both air and its structure if manned) and electronic equipment within a narrow temperature range even though...

  17. Fractionated spacecraft: The new sprout in distributed space systems

    NARCIS (Netherlands)

    Guo, J.; Maessen, D.C.; Gill, E.K.A.

    2009-01-01

    This paper provides a survey of current state-of-the-art technologies of fractionated spacecraft, a new architecture for distributed space systems. The survey covers six aspects: architecture, networking, wireless communication, wireless power transfer, distributed computing, and planned missions

  18. Autonomous Spacecraft Navigation Based on Pulsar Timing Information

    CERN Document Server

    Bernhardt, Mike Georg; Prinz, Tobias; Breithuth, Ferdinand Maximilian; Walter, Ulrich

    2011-01-01

    We discuss the possibility of an autonomous navigation system for spacecraft that is based on pulsar timing data. Pulsars are rapidly rotating neutron stars that are observable as variable celestial sources of electromagnetic radiation. Their periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board the spacecraft with predicted pulse arrivals at some reference location, the spacecraft position can be determined autonomously with accuracies on the order of 5 kilometres. For a spacecraft at a distance of 10 astronomical units from Earth (e.g., Earth-Saturn), this means an improvement by a factor of 8 compared to conventional methods. Therefore this new technology is an alternative to standard navigation based on radio tracking by ground stations, without the disadvantages of uncertainty in...

  19. The Impact of Autonomy Technology on Spacecraft Software Architecture

    Science.gov (United States)

    Gamble, E. B., Jr.

    1998-01-01

    Autonomy technology for high-level, closed-loop control of spacecraft offers considerable benefits to space-flight projects. Those benefits can enable whole new classes of missions; however, they are not without cost.

  20. Investigation of Correction Method of the Spacecraft Low Altitude Ranging

    CERN Document Server

    Liu, Jing-Lei; Wu, Shi-Tong; Huang, Wei

    2015-01-01

    gamma ray altitude control system is an important equipment for deep space exploration and sample return mission, its main purpose is a low altitude measurement of the spacecraft based on Compton Effect at the moment when it lands on extraterrestrial celestial or sampling returns to the Earth land, and an ignition altitude correction of the spacecraft retrograde landing rocket at different landing speeds. This paper presents an ignition altitude correction method of the spacecraft at different landing speeds, based on the number of particles gamma ray reflected field gradient graded. Through the establishment of a theoretical model, its algorithm feasibility is proved by a mathematical derivation and verified by an experiment, and also the adaptability of the algorithm under different parameters is described. The method provides a certain value for landing control of the deep space exploration spacecraft landing the planet surface.

  1. Navigation of the EPOXI Spacecraft to Comet Hartley 2

    Science.gov (United States)

    Bhaskaran, Shyam; Abrahamson, Matt; Chesley, Steven; Chung, Min-Kun; Halsell, Allen; Haw, Robert; Helfrich, Cliff; Jefferson, David; Kennedy, Brian; McElrath, Tim; Owen, William; Rush, Brian; Smith, Jonathon; Wang, Tseng-Chan; Yen, Chen-Wan

    2011-01-01

    On November 4, 2010, the EPOXI spacecraft flew by the comet Hartley 2, marking the fourth time that a NASA spacecraft successfully captured high resolution images of a cometary nucleus. EPOXI is the extended mission of the Deep Impact mission, which delivered an impactor on comet Tempel-1 on July 4, 2005. EPOXI officially started in September 2007 and eventually took over 3 years of flight time and had 3 Earth gravity assists to achieve the proper encounter conditions. In the process, the mission was redesigned to accommodate a new comet as the target and changes in the trajectory to achieve better imaging conditions at encounter. Challenges in navigation of the spacecraft included precision targeting of several Earth flybys and the comet encounter, uncertainties in determining the ephemeris of the comet relative to the spacecraft, and the high accuracy trajectory knowledge needed to image the comet during the encounter. This paper presents an overview of the navigation process used for the mission.

  2. A Self-Regulating Freezable Heat Exchanger for Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A spacecraft thermal control system must keep the vehicle, avionics and atmosphere (if crewed) within a defined temperature range. Since water is non-toxic and good...

  3. Nuclear-powered Hysat spacecraft: comparative design study

    Energy Technology Data Exchange (ETDEWEB)

    Raab, B.

    1975-08-01

    The study shows that the all-nuclear spacecraft can have a substantial weight advantage over a hybrid (nuclear/solar) or all-solar spacecraft, owing to a further reduction in power requirement, and to the elimination of such equipment as the sensor gimbal and rotating joint assemblies. Because the need for a sun-oriented section is eliminated, the all-nuclear spacecraft can be designed as a monolithic structure, with the sensor and other payload firmly secured in a fixed position on the structure. This enhances attitude stability while minimizing structural weight and eliminating the need for flexible fluid lines. Sensor motion can be produced, varied, and controlled within the limits specified by the study contractors by moving the entire spacecraft in the prescribed pattern. A simple attitude control system using available hardware suffices to meet all requirements.

  4. High-Performance Contaminant Monitor for Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Vision for Space Exploration demands increasing reliance on real-time trace gas monitors onboard spacecraft. Present grab samples and badges will be inadequate...

  5. Revamping Spacecraft Operational Intelligence with Splunk

    Science.gov (United States)

    Hwang, Victor

    2012-01-01

    So what is Splunk? Instead of giving the technical details, which you can find online, I'll tell you what it did for me. Splunk slapped everything into one place, with one uniform format, and gave me the ability to forget about all these annoying details of where it is, how to parse it, and all that. Instead, I only need to interact with Splunk to find the data I need. This sounds simple and obvious, but it's surprising what you can do once you all of your data is indexed in one place. By having your data organized, querying becomes much easier. Let's say that I want to search telemetry for a sensor_name gtemp_1 h and to return all data that is at most five minutes old. And because Splunk can hook into a real ]time stream, this data will always be up-to-date. Extending the previous example, I can now aggregate all types of data into one view based in time. In this picture, I've got transaction logs, telemetry, and downlinked files all in one page, organized by time. Even though the raw data looks completely than this, I've defined interfaces that transform it into this uniform format. This gives me a more complete picture for the question what was the spacecraft doing at this particular time? And because querying data is simple, I can start with a big block of data and whiddle it down to what I need, rather than hunting around for the individual pieces of data that I need. When we have all the data we need, we can begin widdling down the data with Splunk's Unix-like search syntax. These three examples highlights my trial-and-error attempts to find large temperature changes. I begin by showing the first 5 temperatures, only to find that they're sorted chronologically, rather than from highest temperatures to lowest temperatures. The next line shows sorting temperatures by their values, but I find that that fs not really what I want either. I want to know the delta temperatures between readings. Looking through Splunk's user manual, I find the delta function, which

  6. NASA Spacecraft Fault Management Workshop Results

    Science.gov (United States)

    Newhouse, Marilyn; McDougal, John; Barley, Bryan; Fesq, Lorraine; Stephens, Karen

    2010-01-01

    tools that have not kept pace with the increasing complexity of mission requirements and spacecraft systems. This paper summarizes the findings and recommendations from that workshop, as well as opportunities identified for future investment in tools, processes, and products to facilitate the development of space flight fault management capabilities.

  7. Dynamics and control of Lorentz-augmented spacecraft relative motion

    CERN Document Server

    Yan, Ye; Yang, Yueneng

    2017-01-01

    This book develops a dynamical model of the orbital motion of Lorentz spacecraft in both unperturbed and J2-perturbed environments. It explicitly discusses three kinds of typical space missions involving relative orbital control: spacecraft hovering, rendezvous, and formation flying. Subsequently, it puts forward designs for both open-loop and closed-loop control schemes propelled or augmented by the geomagnetic Lorentz force. These control schemes are entirely novel and represent a significantly departure from previous approaches.

  8. Computer memory power control for the Galileo spacecraft

    Science.gov (United States)

    Detwiler, R. C.

    1983-01-01

    The developmental history, major design drives, and final topology of the computer memory power system on the Galileo spacecraft are described. A unique method of generating memory backup power directly from the fault current drawn during a spacecraft power overload or fault condition allows this system to provide continuous memory power. This concept provides a unique solution to the problem of volatile memory loss without the use of a battery of other large energy storage elements usually associated with uninterrupted power supply designs.

  9. Radio Ranging System for Guidance of Approaching Spacecraft

    Science.gov (United States)

    Manikonda, Vikram; vanDoom, Eric

    2008-01-01

    A radio communication and ranging system has been proposed for determining the relative position and orientations of two approaching spacecraft to provide guidance for docking maneuvers. On Earth, the system could be used similarly for guiding approaching aircraft and for automated positioning of large, heavy objects. In principle, the basic idea is to (1) measure distances between radio transceivers on the two spacecraft and (2) compute the relative position and orientations from the measured distances.

  10. Titan IV - An integrated spacecraft/booster view

    Science.gov (United States)

    Albrecht, Samuel W.

    1992-03-01

    The Titan IV launch vehicle is briefly described focusing on the integration process which starts with spacecraft environmental and mechanical interface requirements definition and progresses through physical mating of the spacecraft and launch vehicle, launch countdown, launch, and orbit insertion. An approach to payload integration is presented where teamwork between the government and contractor organizations provides the framework necessary for the efficient incorporation of mission unique requirements.

  11. Spacecraft Re-Entry Impact Point Targeting Using Aerodynamic Drag

    Science.gov (United States)

    Omar, Sanny R.; Bevilacqua, Riccardo

    2017-01-01

    The ability to re-enter the atmosphere at a desired location is important for spacecraft containing components that may survive re-entry. While impact point targeting has traditionally been initiated through impulsive burns with chemical thrusters on large vehicles such as the Space Shuttle, and the Soyuz and Apollo capsules, many small spacecraft do not host thrusters and require an alternative means of impact point targeting to ensure that falling debris do not cause harm to persons or property. This paper discusses the use of solely aerodynamic drag force to perform this targeting. It is shown that by deploying and retracting a drag device to vary the ballistic coefficient of the spacecraft, any desired longitude and latitude on the ground can be targeted provided that the maneuvering begins early enough and the latitude is less than the inclination of the orbit. An analytical solution based on perturbations from a numerically propagated trajectory is developed to map the initial state and ballistic coefficient profile of a spacecraft to its impact point. This allows the ballistic coefficient profile necessary to reach a given target point to be rapidly calculated, making it feasible to generate the guidance for the decay trajectory onboard the spacecraft. The ability to target an impact point using aerodynamic drag will enhance the capabilities of small spacecraft and will enable larger space vehicles containing thrusters to save fuel by more effectively leveraging the available aerodynamic drag.

  12. The use of molecular adsorbers for spacecraft contamination control

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, S.; Chen, P. [NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Triolo, J.; Carosso, N. [Swales and Associates, Inc., 5050 Powder Mill Road, Beltsville, Maryland 20705 (United States)

    1996-03-01

    In recent years, the technologies associated with contamination control in space environments have grown increasingly more sophisticated, due to the ever expanding need for improving and enhancing optical and thermal control systems for spacecraft. The presence of contaminants in optical and thermal control systems can cause serious degradation of performance and/or impact the lifetime of a spacecraft. It has been a goal of the global contamination community to develop new and more effective means for controlling contamination for spacecraft. This paper describes an innovative method for controlling molecular contaminants in space environments, via the utilization of Molecular Adsorbers. It has been found that the incorporation of appropriate molecular adsorbing materials within spacecraft volumes will decrease the overall contamination level within the cavity, thereby decreasing the potential for contaminants to migrate to more critical areas. In addition, it has been found that the placement of a Molecular Adsorber at a vent location actually serves as a molecular {open_quote}{open_quote}trap{close_quote}{close_quote} for the contaminants that would have otherwise been vented into the external spacecraft environment. This paper summarizes the theory, basic design, planned applications and significant results already obtained during the investigation of using Molecular Adsorbers for spacecraft contamination control purposes. {copyright} {ital 1996 American Institute of Physics.}

  13. Mesh Network Architecture for Enabling Inter-Spacecraft Communication

    Science.gov (United States)

    Becker, Christopher; Merrill, Garrick

    2017-01-01

    To enable communication between spacecraft operating in a formation or small constellation, a mesh network architecture was developed and tested using a time division multiple access (TDMA) communication scheme. The network is designed to allow for the exchange of telemetry and other data between spacecraft to enable collaboration between small spacecraft. The system uses a peer-to-peer topology with no central router, so that it does not have a single point of failure. The mesh network is dynamically configurable to allow for addition and subtraction of new spacecraft into the communication network. Flight testing was performed using an unmanned aerial system (UAS) formation acting as a spacecraft analogue and providing a stressing environment to prove mesh network performance. The mesh network was primarily devised to provide low latency, high frequency communication but is flexible and can also be configured to provide higher bandwidth for applications desiring high data throughput. The network includes a relay functionality that extends the maximum range between spacecraft in the network by relaying data from node to node. The mesh network control is implemented completely in software making it hardware agnostic, thereby allowing it to function with a wide variety of existing radios and computing platforms..

  14. Bounding Extreme Spacecraft Charging in the Lunar Environment

    Science.gov (United States)

    Minow, Joseph I.; Parker, Linda N.

    2008-01-01

    Robotic and manned spacecraft from the Apollo era demonstrated that the lunar surface in daylight will charge to positive potentials of a few tens of volts because the photoelectron current dominates the charging process. In contrast, potentials of the lunar surface in darkness which were predicted to be on the order of a hundred volts negative in the Apollo era have been shown more recently to reach values of a few hundred volts negative with extremes on the order of a few kilovolts. The recent measurements of night time lunar surface potentials are based on electron beams in the Lunar Prospector Electron Reflectometer data sets interpreted as evidence for secondary electrons generated on the lunar surface accelerated through a plasma sheath from a negatively charged lunar surface. The spacecraft potential was not evaluated in these observations and therefore represents a lower limit to the magnitude of the lunar negative surface potential. This paper will describe a method for obtaining bounds on the magnitude of lunar surface potentials from spacecraft measurements in low lunar orbit based on estimates of the spacecraft potential. We first use Nascap-2k surface charging analyses to evaluate potentials of spacecraft in low lunar orbit and then include the potential drops between the ambient space environment and the spacecraft to the potential drop between the lunar surface and the ambient space environment to estimate the lunar surface potential from the satellite measurements.

  15. The interaction of relativistic spacecrafts with the interstellar medium

    CERN Document Server

    Hoang, Thiem; Burkhart, Blakesley; Loeb, Abraham

    2016-01-01

    The Breakthrough Starshot initiative aims to launch a gram-scale spacecraft to a speed of $v\\sim 0.2$c, capable of reaching the nearest star system, $\\alpha$ Centauri, in about 20 years. However, a critical challenge for the initiative is the damage to the spacecraft by interstellar gas and dust during the journey. In this paper, we quantify the interaction of a relativistic spacecraft with gas and dust in the interstellar medium. For gas bombardment, we find that damage by track formation due to heavy elements is an important effect. We find that gas bombardment can potentially damage the surface of the spacecraft to a depth of $\\sim 0.1$ mm for quartz material after traversing a gas column of $N_{\\rm H}\\sim 2\\times 10^{18}\\rm cm^{-2}$ along the path to $\\alpha$ Centauri, whereas the effect is much weaker for graphite material. The effect of dust bombardment erodes the spacecraft surface and produces numerous craters due to explosive evaporation of surface atoms. For a spacecraft speed $v=0.2c$, we find that...

  16. ESA unveils its big XMM spacecraft

    Science.gov (United States)

    1998-02-01

    XMM, the X-ray Multi-Mirror mission, is due do be lanched in 1999. It is a European conception with innovative telescopes. XMM will revolutionize the study of X-rays coming from the Universe, by harvesting far more X-rays per hour than any previous mission. Its enormous capacity will enable astronomers to analyse many strong sources of cosmic X-rays very quickly, and to discover and characterize many faint sources previously beyond their reach. As the most popular and competitive branch of space astronomy, X-ray astronomy reveals special places in the Universe where very high temperatures or violent forces generate energetic radiation. These sources include black holes, exploding stars, paris of stars orbiting very close together, and the central region of clusters of galaxies. XMM's optical monitor, viewing the scenes by visible light, will help in the interpretations. The combination of X-ray telescopes and optical monitoring should be well-suited to tracking down gamma-ray bursters - extraordinary explosions in space that mystify the astronomers. Full descriptions of the X-ray sources will depend on precise spectral analysis of the relative intensities of X-rays of different energies, including the signatures of identifiable chemical elements. Such spectral analysis is XMM's task, using instruments of the highest quality fed by the remarkable telescopes. As seen at ESTEC today, the spacecraft stands upside down. Its front end, where the mirror modules of the X-ray telescopes pass through the satellite's service module, is closest to the ground. At the top is the section containing detectors at the focus of the X-ray telescopes. Surmounting the assembly, a pair of cones will carry heat away from the detectors. XMM's appearance is, though, dominated by the long tube that spans the telescope's focal length, and by the black thermal blanket that will protect the spacecraft from unequal heating on the sunny and shaded sides. A miracle of telescope engineering « You

  17. Assessment of Capabilities for First-Principles Simulation of Spacecraft Electric Propulsion Systems and Plasma Spacecraft Environment

    Science.gov (United States)

    2016-04-29

    other provision of law , no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a...Briefing Charts 3. DATES COVERED (From - To) 05 April 2016 – 29 April 2016 4. TITLE AND SUBTITLE Assessment of Capabilities for First- Principles ...Simulation of Spacecraft Electric Propulsion Systems and Plasma Spacecraft Environment 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  18. Enabling Advanced Automation in Spacecraft Operations with the Spacecraft Emergency Response System

    Science.gov (United States)

    Breed, Julie; Fox, Jeffrey A.; Powers, Edward I. (Technical Monitor)

    2001-01-01

    True autonomy is the Holy Grail of spacecraft mission operations. The goal of launching a satellite and letting it manage itself throughout its useful life is a worthy one. With true autonomy, the cost of mission operations would be reduced to a negligible amount. Under full autonomy, any problems (no matter the severity or type) that may arise with the spacecraft would be handled without any human intervention via some combination of smart sensors, on-board intelligence, and/or smart automated ground system. Until the day that complete autonomy is practical and affordable to deploy, incremental steps of deploying ever-increasing levels of automation (computerization of once manual tasks) on the ground and on the spacecraft are gradually decreasing the cost of mission operations. For example, NASA's Goddard Space Flight Center (NASA-GSFC) has been flying spacecraft with low cost operations for several years. NASA-GSFC's SMEX (Small Explorer) and MIDEX (Middle Explorer) missions have effectively deployed significant amounts of automation to enable the missions to fly predominately in 'light-out' mode. Under light-out operations the ground system is run without human intervention. Various tools perform many of the tasks previously performed by the human operators. One of the major issues in reducing human staff in favor of automation is the perceived increased in risk of losing data, or even losing a spacecraft, because of anomalous conditions that may occur when there is no one in the control center. When things go wrong, missions deploying advanced automation need to be sure that anomalous conditions are detected and that key personal are notified in a timely manner so that on-call team members can react to those conditions. To ensure the health and safety of its lights-out missions, NASA-GSFC's Advanced Automation and Autonomy branch (Code 588) developed the Spacecraft Emergency Response System (SERS). The SERS is a Web-based collaborative environment that enables

  19. Topology Optimization of Spacecraft Transfer Compartment

    Directory of Open Access Journals (Sweden)

    A. A. Borovikov

    2016-01-01

    Full Text Available IntroductionThe subject of this research is topology optimization of the adapter of a spacecraft transfer compartment. The finite element topology optimization [1] is widely used for simple structure elements [6, 7]. It is argued that using this method in conjunction with additive technology (3D - printing it is possible to create construction designs with the best weight characteristics. However, the paper shows that when applying this method to a complex construction design the optimization results are highly sensitive to optimization algorithm parameters. The goal of this research is to study parameters of the topology optimization algorithm and the influence of their variations on results.1.      Problem formulation   A commercial software Altair HyperWorks/OptiStruct (student’s license performed numerical calculations. The paper presents a detailed description of the finite element model.The main features of the proposed model are as follows:-          Simplicity with non-complicated geometry;-          Building a finite element model in terms of computing time minimization;-          Using the lumped mass elements to simulate the impacts of the conjugates on the adapter;-          A limit of material strength, decreased by an order of magnitude, to eliminate stress concentrators;-          The gravitational load applied corresponds to the loads for the Angara-A5 launcher [8]. 2.      Method of solutionA brief description of the SIMP-method realized in the Altair HyperWorks/OptiStruct software is given.3.      ResultsPerformed numerical calculations, and shown the influence of variations of algorithm parameters (DISCRETE, MATINIT, MINDIM, MAXDIM on construction design as well as the parameters SINGLE and SPLIT used to reveal restrictions on manufacturing.Shown that, depending on variations of parameters, an adapter construction strives to «truss» or «shell» type. Described

  20. Message Mode Operations for Spacecraft: A Proposal for Operating Spacecraft During Cruise and Mitigating the Network Loading Crunch

    Science.gov (United States)

    Greenberg, Ed; MacMedan, Marv; Kazz, Greg; Kallemeyn, Pieter

    2000-01-01

    The NASA Deep Space Network (DSN) is a world-class spacecraft tracking facility with stations located in Spain, Australia and USA, servicing Deep Space Missions of many space agencies. The current system of scheduling spacecraft during cruise for multiple 8 hour tracking sessions per week currently leads to an overcommitted DSN. Studies indicate that future projected mission demands upon the Network will only make the loading problem worse. Therefore, a more efficient scheduling of DSN resources is necessary in order to support the additional network loading envisioned in the next few years: The number of missions is projected to increase from 25 in 1998 to 34 by 2001. In fact given the challenge of the NASA administrator, Dan Goldin, of launching 12 spacecraft per year, the DSN would be tracking approximately 90 spacecraft by 2010. Currently a large amount of antenna time and network resources are subscribed by a project in order to have their mission supported during the cruise phase. The recently completed Mars Pathfinder mission was tracked 3 times a week (8 hours/day) during the majority of its cruise to Mars. This paper proposes an innovative approach called Message Mode Operations (MMO) for mitigating the Network loading problem while continuing to meet the tracking, reporting, time management, and scheduling requirements of these missions during Cruise while occupying very short tracking times. MMO satisfies these requirements by providing the following services: Spacecraft Health and Welfare Monitoring Service Command Delivery Service Adaptive Spacecraft Scheduling Service Orbit Determination Service Time Calibration Service Utilizing more efficient engineering telemetry summarization and filtering techniques on-board the spacecraft and collapsing the navigation requirements for Doppler and Range into shorter tracks, we believe spacecraft can be adequately serviced using short 10 to 30 minute tracking sessions. This claim assumes that certain changes would