Accelerator-Based PIXE and STIM Analysis of Candidate Solar Sail Materials

International Nuclear Information System (INIS)

Hollerman, W.A.; Stanaland, T.L.; Boudreaux, P.; Elberson, L.; Fontenot, J.; Gates, E.; Greco, R.; McBride, M.; Woodward, A.; Edwards, D.

2003-01-01

Solar sailing is a unique form of propulsion where a spacecraft gains momentum from incident photons. A totally reflective sail experiences a pressure of 9.1 μPa at a distance of 1 AU from the Sun. Since sails are not limited by reaction mass, they provide continual acceleration, reduced only by the lifetime of the lightweight film in the space environment and the distance to the Sun. Practical solar sails can expand the number of possible missions, enabling new concepts that are difficult by conventional means. One of the current challenges is to develop strong, lightweight, and radiation resistant sail materials. This paper will discuss initial results from a Particle Induced X-Ray Emission (PIXE) and Scanning Transmission Ion Microscopy (STIM) analysis of candidate solar sail materials

Temperature-Driven Shape Changes of the Near Earth Asteroid Scout Solar Sail

Science.gov (United States)

Stohlman, Olive R.; Loper, Erik R.; Lockett, Tiffany E.

2017-01-01

Near Earth Asteroid Scout (NEA Scout) is a NASA deep space Cubesat, scheduled to launch on the Exploration Mission 1 flight of the Space Launch System. NEA Scout will use a deployable solar sail as its primary propulsion system. The sail is a square membrane supported by rigid metallic tapespring booms, and analysis predicts that these booms will experience substantial thermal warping if they are exposed to direct sunlight in the space environment. NASA has conducted sunspot chamber experiments to confirm the thermal distortion of this class of booms, demonstrating tip displacement of between 20 and 50 centimeters in a 4-meter boom. The distortion behavior of the boom is complex and demonstrates an application for advanced thermal-structural analysis. The needs of the NEA Scout project were supported by changing the solar sail design to keep the booms shaded during use of the solar sail, and an additional experiment in the sunspot chamber is presented in support of this solution.

Multiple NEO Rendezvous Using Solar Sail Propulsion

Science.gov (United States)

Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

2012-01-01

The NASA Marshall Space Flight Center (MSFC) Advanced Concepts Office performed an assessment of the feasibility of using a near-term solar sail propulsion system to enable a single spacecraft to perform serial rendezvous operations at multiple Near Earth Objects (NEOs) within six years of launch on a small-to-moderate launch vehicle. The study baselined the use of the sail technology demonstrated in the mid-2000 s by the NASA In-Space Propulsion Technology Project and is scheduled to be demonstrated in space by 2014 as part of the NASA Technology Demonstration Mission Program. The study ground rules required that the solar sail be the only new technology on the flight; all other spacecraft systems and instruments must have had previous space test and qualification. The resulting mission concept uses an 80-m X 80-m 3-axis stabilized solar sail launched by an Athena-II rocket in 2017 to rendezvous with 1999 AO10, Apophis and 2001 QJ142. In each rendezvous, the spacecraft will perform proximity operations for approximately 30 days. The spacecraft science payload is simple and lightweight; it will consist of only the multispectral imager flown on the Near Earth Asteroid Rendezvous (NEAR) mission to 433 Eros and 253 Mathilde. Most non-sail spacecraft systems are based on the Messenger mission spacecraft. This paper will describe the objectives of the proposed mission, the solar sail technology to be employed, the spacecraft system and subsystems, as well as the overall mission profile.

Status of Solar Sail Propulsion Within NASA - Moving Toward Interstellar Travel

Science.gov (United States)

Johnson, Les

2015-01-01

NASA is developing solar sail propulsion for two near-term missions and laying the groundwork for their future use in deep space and interstellar precursor missions. Solar sails use sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like sail made of a lightweight, highly reflective material. This continuous photon pressure provides propellantless thrust, allowing for very high (Delta)V maneuvers on long-duration, deep space exploration. Since reflected light produces thrust, solar sails require no onboard propellant. The Near Earth Asteroid (NEA) Scout mission, managed by MSFC, will use the sail as primary propulsion allowing it to survey and image one or more NEA's of interest for possible future human exploration. Lunar Flashlight, managed by JPL, will search for and map volatiles in permanently shadowed Lunar craters using a solar sail as a gigantic mirror to steer sunlight into the shaded craters. The Lunar Flashlight spacecraft will also use the propulsive solar sail to maneuver into a lunar polar orbit. Both missions use a 6U cubesat architecture, a common an 85 sq m solar sail, and will weigh less than 12 kilograms. Both missions will be launched on the first flight of the Space Launch System in 2018. NEA Scout and Lunar Flashlight will serve as important milestones in the development of solar sail propulsion technology for future, more ambitious missions including the Interstellar Probe - a mission long desired by the space science community which would send a robotic probe beyond the edge of the solar system to a distance of 250 Astronomical Units or more. This paper will summarize the development status of NEA Scout and Lunar Flashlight and describe the next steps required to enable an interstellar solar sail capability.

Dynamics and Control of a Flexible Solar Sail

OpenAIRE

Jiafu Liu; Siyuan Rong; Fan Shen; Naigang Cui

2014-01-01

Solar sail can merely make use of solar radiation pressure (SRP) force as the thrust for space missions. The attitude dynamics is obtained for the highly flexible solar sail with control vanes, sliding masses, and a gimbaled control boom. The vibration equations are derived considering the geometric nonlinearity of the sail structure subjected to the forces generated by the control vanes, solar radiation pressure (SRP), and sliding masses. Then the dynamic models for attitude/vibration contr...

Solar and Drag Sail Propulsion: From Theory to Mission Implementation

Science.gov (United States)

Johnson, Les; Alhorn, Dean; Boudreaux, Mark; Casas, Joe; Stetson, Doug; Young, Roy

2014-01-01

Solar and drag sail technology is entering the mainstream for space propulsion applications within NASA and around the world. Solar sails derive propulsion by reflecting sunlight from a large, mirror- like sail made of a lightweight, reflective material. The continuous sunlight pressure provides efficient primary propulsion, without the expenditure of propellant or any other consumable, allowing for very high V maneuvers and long-duration deep space exploration. Drag sails increase the aerodynamic drag on Low Earth Orbit (LEO) spacecraft, providing a lightweight and relatively inexpensive approach for end-of-life deorbit and reentry. Since NASA began investing in the technology in the late 1990's, significant progress has been made toward their demonstration and implementation in space. NASA's Marshall Space Flight Center (MSFC) managed the development and testing of two different 20-m solar sail systems and rigorously tested them under simulated space conditions in the Glenn Research Center's Space Power Facility at Plum Brook Station, Ohio. One of these systems, developed by L'Garde, Inc., is planned for flight in 2015. Called Sunjammer, the 38m sailcraft will unfurl in deep space and demonstrate solar sail propulsion and navigation as it flies to Earth-Sun L1. In the Flight Center (MSFC) managed the development and testing of two different 20-m solar sail systems and rigorously tested them under simulated space conditions in the Glenn Research Center's Space Power Facility at Plum Brook Station, Ohio. One of these systems, developed by L'Garde, Inc., is planned for flight in 2015. Called Sunjammer, the 38m sailcraft will unfurl in deep space and demonstrate solar sail propulsion and navigation as it flies to Earth-Sun L1. In the interim, NASA MSFC funded the NanoSail-D, a subscale drag sail system designed for small spacecraft applications. The NanoSail-D flew aboard the Fast Affordable Science and Technology SATellite (FASTSAT) in 2010, also developed by MSFC

Near Earth Asteroid Scout: NASA's Solar Sail Mission to a NEA

Science.gov (United States)

Johnson, Les; Lockett, Tiffany

2017-01-01

NASA is developing a solar sail propulsion system for use on the Near Earth Asteroid (NEA) Scout reconnaissance mission and laying the groundwork for their use in future deep space science and exploration missions. Solar sails use sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like sail made of a lightweight, highly reflective material. This continuous photon pressure provides propellantless thrust, allowing for very high Delta V maneuvers on long-duration, deep space exploration. Since reflected light produces thrust, solar sails require no onboard propellant. The Near Earth Asteroid (NEA) Scout mission, funded by NASA's Advanced Exploration Systems Program and managed by NASA MSFC, will use the sail as primary propulsion allowing it to survey and image Asteroid 1991VG and, potentially, other NEA's of interest for possible future human exploration. NEA Scout uses a 6U cubesat (to be provided by NASA's Jet Propulsion Laboratory), an 86 m(exp. 2) solar sail and will weigh less than 12 kilograms. NEA Scout will be launched on the first flight of the Space Launch System in 2018. The solar sail for NEA Scout will be based on the technology developed and flown by the NASA NanoSail-D and The Planetary Society's Lightsail-A. Four approximately 7 m stainless steel booms wrapped on two spools (two overlapping booms per spool) will be motor deployed and pull the sail from its stowed volume. The sail material is an aluminized polyimide approximately 2.5 microns thick. As the technology matures, solar sails will increasingly be used to enable science and exploration missions that are currently impossible or prohibitively expensive using traditional chemical and electric propulsion systems. This paper will summarize the status of the NEA Scout mission and solar sail technology in general.

Flying on Sun Shine: Sailing in Space

International Nuclear Information System (INIS)

Alhorn, Dean

2012-01-01

On January 20th, 2011, NanoSail-D successfully deployed its sail in space. It was the first solar sail vehicle to orbit the earth and the second sail ever unfurled in space. The 10m2 sail, deployment mechanism and electronics were packed into a 3U CubeSat with a volume of about 3500cc. The NanoSail-D mission had two objectives: eject a nanosatellite from a minisatellite; deploy its sail from a highly compacted volume to validate large structure deployment and potential de-orbit technologies. NanoSail-D was jointly developed by NASA's Marshall Space Flight Center and Ames Research Center. The ManTech/NeXolve Corporation provided key sail design support. NanoSail-D is managed by Marshall and jointly sponsored by the Army Space and Missile Defense Command, the Space Test Program, the Von Braun Center for Science and Innovation and Dynetics Inc. The presentation will provide insights into sailcraft advances and potential missions enabled by this emerging in-space propulsion technology.

Dynamics and Control of a Flexible Solar Sail

Directory of Open Access Journals (Sweden)

Jiafu Liu

2014-01-01

Full Text Available Solar sail can merely make use of solar radiation pressure (SRP force as the thrust for space missions. The attitude dynamics is obtained for the highly flexible solar sail with control vanes, sliding masses, and a gimbaled control boom. The vibration equations are derived considering the geometric nonlinearity of the sail structure subjected to the forces generated by the control vanes, solar radiation pressure (SRP, and sliding masses. Then the dynamic models for attitude/vibration controller design and dynamic simulation are obtained, respectively. The linear quadratic regulator (LQR based and optimal proportional-integral (PI based controllers are designed for the coupled attitude/vibration models with constant disturbance torques caused by the center-of-mass (cm/center-of-pressure (cp offset, respectively. It can be concluded from the theoretical analysis and simulation results that the optimal PI based controller performs better than the LQR based controller from the view of eliminating the steady-state errors. The responses with and without the geometrical nonlinearity are performed, and the differences are observed and analyzed. And some suggestions are also presented.

Near Earth Asteroid Solar Sail Engineering Development Unit Test Program

Science.gov (United States)

Lockett, Tiffany Russell; Few, Alexander; Wilson, Richard

2017-01-01

The Near Earth Asteroid (NEA) Scout project is a 30x20x10cm (6U) cubesat reconnaissance mission to investigate a near Earth asteroid utilizing an 86m2 solar sail as the primary propulsion system. This will be the largest solar sail NASA will launch to date. NEA Scout is a secondary payload currently manifested on the maiden voyage of the Space Launch System in 2018. In development of the solar sail subsystem, design challenges were identified and investigated for packaging within a 6U form factor and deployment in cis-lunar space. Analysis furthered understanding of thermal, stress, and dynamics of the stowed system and matured an integrated sail membrane model for deployed flight dynamics. This paper will address design, fabrication, and lessons learned from the NEA Scout solar sail subsystem engineering development unit. From optical properties of the sail material to folding and spooling the single 86m2 sail, the team has developed a robust deployment system for the solar sail. This paper will also address expected and received test results from ascent vent, random vibration, and deployment tests.

Validation of Solar Sail Simulations for the NASA Solar Sail Demonstration Project

Science.gov (United States)

Braafladt, Alexander C.; Artusio-Glimpse, Alexandra B.; Heaton, Andrew F.

2014-01-01

NASA's Solar Sail Demonstration project partner L'Garde is currently assembling a flight-like sail assembly for a series of ground demonstration tests beginning in 2015. For future missions of this sail that might validate solar sail technology, it is necessary to have an accurate sail thrust model. One of the primary requirements of a proposed potential technology validation mission will be to demonstrate solar sail thrust over a set time period, which for this project is nominally 30 days. This requirement would be met by comparing a L'Garde-developed trajectory simulation to the as-flown trajectory. The current sail simulation baseline for L'Garde is a Systems Tool Kit (STK) plug-in that includes a custom-designed model of the L'Garde sail. The STK simulation has been verified for a flat plate model by comparing it to the NASA-developed Solar Sail Spaceflight Simulation Software (S5). S5 matched STK with a high degree of accuracy and the results of the validation indicate that the L'Garde STK model is accurate enough to meet the potential future mission requirements. Additionally, since the L'Garde sail deviates considerably from a flat plate, a force model for a non-flat sail provided by L'Garde sail was also tested and compared to a flat plate model in S5. This result will be used in the future as a basis of comparison to the non-flat sail model being developed for STK.

Laboratory Facility for Simulating Solar Wind Sails

International Nuclear Information System (INIS)

Funaki, Ikkoh; Ueno, Kazuma; Oshio, Yuya; Ayabe, Tomohiro; Horisawa, Hideyuki; Yamakawa, Hiroshi

2008-01-01

Magnetic sail (MagSail) is a deep space propulsion system, in which an artificial magnetic cavity captures the energy of the solar wind to propel a spacecraft in the direction leaving the sun. For a scale-model experiment of the plasma flow of MagSail, we employed a magnetoplasmadynamic arcjet as a solar wind simulator. It is observed that a plasma flow from the solar wind simulator reaches a quasi-steady state of about 0.8 ms duration after a transient phase when initiating the discharge. During this initial phase of the discharge, a blast-wave was observed to develop radially in a vacuum chamber. When a solenoidal coil (MagSail scale model) is immersed into the quasi-steady flow where the velocity is 45 km/s, and the number density is 10 19 m-3, a bow shock as well as a magnetic cavity were formed in front of the coil. As a result of the interaction between the plasma flow and the magnetic cavity, the momentum of the simulated solar wind is decreased, and it is found from the thrust measurement that the solar wind momentum is transferred to the coil simulating MagSail.

Advances in solar sailing

CERN Document Server

Third International Symposium on Solar Sailing

2014-01-01

Hosted by the Advanced Space Concepts Laboratory within the department of Mechanical and Aerospace Engineering of the University of Strathclyde, the third International Symposium on Solar Sailing was held in McCance Building at 16 Richmond Street, Glasgow, between 11 and 13 June 2013. The symposium attracted over 90 delegates from19 different counties, bringing together international experts from across the globe to discuss funded solar sail flight programs alongside on-going technology development and testing programs. The symposium also provided a forum for the discussion of enabling technologies, new application concepts, materials and structural concepts, space environmental effects, dynamics, navigation, control, and much more. This volume contains the unabridged symposium proceedings, in the gathered experts own words. As symposium chair, I thank our partners at Scottish Enterprise and L’Garde, Inc., the symposium’s gold sponsor, for their support in realising this symposium.

Deorbiting Upper-Stages in LEO at EOM using Solar Sails

Directory of Open Access Journals (Sweden)

Alexandru IONEL

2017-06-01

Full Text Available This paper analyzes the possibility of deorbiting a launch vehicle upper-stage at end-of-mission from low Earth orbit through the use of a solar sail. Different solar sail sizes are taken into account. The analysis is made via a MATLAB numerical simulation, integrating with the ode45 solver the accelerations arising from geopotential, atmospheric drag and solar radiation pressure. Direct solar pressure and drag augmentation effect are analyzed and a state of the art study in the solar sail research field is performed for a better grasp of the feasibility of the device implementation.

The Physics and Technology of Solar Sail Spacecraft.

Science.gov (United States)

Dwivedi, B. N.; McInnes, C. R.

1991-01-01

Various aspects of the solar sail spacecraft such as solar sailing, solar sail design, navigation with solar sails, solar sail mission applications and future prospects for solar sailing are described. Several possible student projects are suggested. (KR)

Comprehensive Solar Sail Simulation, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Solar sails as a propulsive device have several potential applications: providing access to previously inaccessible orbits, longer mission times, and increased...

Invited article: Electric solar wind sail: toward test missions.

Science.gov (United States)

Janhunen, P; Toivanen, P K; Polkko, J; Merikallio, S; Salminen, P; Haeggström, E; Seppänen, H; Kurppa, R; Ukkonen, J; Kiprich, S; Thornell, G; Kratz, H; Richter, L; Krömer, O; Rosta, R; Noorma, M; Envall, J; Lätt, S; Mengali, G; Quarta, A A; Koivisto, H; Tarvainen, O; Kalvas, T; Kauppinen, J; Nuottajärvi, A; Obraztsov, A

2010-11-01

The electric solar wind sail (E-sail) is a space propulsion concept that uses the natural solar wind dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.e., the potential structure of the tethers, can be millions of times larger than the physical area of the thin tethers wires, which offsets the fact that the dynamic pressure of the solar wind is very weak. Indeed, according to the most recent published estimates, an E-sail of 1 N thrust and 100 kg mass could be built in the rather near future, providing a revolutionary level of propulsive performance (specific acceleration) for travel in the solar system. Here we give a review of the ongoing technical development work of the E-sail, covering tether construction, overall mechanical design alternatives, guidance and navigation strategies, and dynamical and orbital simulations.

Solarelastic Stability of Solar Sail Structures

Data.gov (United States)

National Aeronautics and Space Administration — In order to avoid an unintended failure in proposed Solar Sail spacecraft due to solarelastic interactions it is important to develop an analytical framework for...

Near Earth Asteroid Scout Solar Sail Engineering Development Unit Test Suite

Science.gov (United States)

Lockett, Tiffany Russell; Few, Alexander; Wilson, Richard

2017-01-01

The Near Earth Asteroid (NEA) Scout project is a 6U reconnaissance mission to investigate a near Earth asteroid utilizing an 86m(sub 2) solar sail as the primary propulsion system. This will be the largest solar sail NASA has launched to date. NEA Scout is currently manifested on the maiden voyage of the Space Launch System in 2018. In development of the solar sail subsystem, design challenges were identified and investigated for packaging within a 6U form factor and deployment in cis-lunar space. Analysis was able to capture understanding of thermal, stress, and dynamics of the stowed system as well as mature an integrated sail membrane model for deployed flight dynamics. Full scale system testing on the ground is the optimal way to demonstrate system robustness, repeatability, and overall performance on a compressed flight schedule. To physically test the system, the team developed a flight sized engineering development unit with design features as close to flight as possible. The test suite included ascent vent, random vibration, functional deployments, thermal vacuum, and full sail deployments. All of these tests contributed towards development of the final flight unit. This paper will address several of the design challenges and lessons learned from the NEA Scout solar sail subsystem engineering development unit. Testing on the component level all the way to the integrated subsystem level. From optical properties of the sail material to fold and spooling the single sail, the team has developed a robust deployment system for the solar sail. The team completed several deployments of the sail system in preparation for flight at half scale (4m) and full scale (6.8m): boom only, half scale sail deployment, and full scale sail deployment. This paper will also address expected and received test results from ascent vent, random vibration, and deployment tests.

Drift-free solar sail formations in elliptical Sun-synchronous orbits

Science.gov (United States)

Parsay, Khashayar; Schaub, Hanspeter

2017-10-01

To study the spatial and temporal variations of plasma in the highly dynamic environment of the magnetosphere, multiple spacecraft must fly in a formation. The objective for this study is to investigate the feasibility of solar sail formation flying in the Earth-centered, Sun-synchronous orbit regime. The focus of this effort is to enable formation flying for a group of solar sails that maintain a nominally fixed Sun-pointing attitude during formation flight, solely for the purpose of precessing their orbit apse lines Sun-synchronously. A fixed-attitude solar sail formation is motivated by the difficulties in the simultaneous control of orbit and attitude in flying solar sails. First, the secular rates of the orbital elements resulting from the effects of solar radiation pressure (SRP) are determined using averaging theory for a Sun-pointing attitude sail. These averaged rates are used to analytically derive the first-order necessary conditions for a drift-free solar sail formation in Sun-synchronous orbits, assuming a fixed Sun-pointing orientation for each sail in formation. The validity of the first-order necessary conditions are illustrated by designing quasi-periodic relative motions. Next, nonlinear programming is applied to design truly drift-free two-craft solar sail formations. Lastly, analytic expressions are derived to determine the long-term dynamics and sensitivity of the formation with respect to constant attitude errors, uncertainty in orbital elements, and uncertainty in a sail's characteristic acceleration.

Reduction of Martian Sample Return Mission Launch Mass with Solar Sail Propulsion

Science.gov (United States)

Russell, Tiffany E.; Heaton, Andrew; Thomas, Scott; Thomas, Dan; Young, Roy; Baysinger, Mike; Capizzo, Pete; Fabisinski, Leo; Hornsby, Linda; Maples, Dauphne;

Exploring the Heliogyro’s Superior Orbital Control Capabilities for Solar Sail Halo Orbits

NARCIS (Netherlands)

Heiligers, M.J.; Guerrant, D.; Lawrence, D

2017-01-01

Solar sailing is an elegant form of space propulsion that reflects solar photons off a large membrane to produce thrust. Different sail configurations exist, including a traditional fixed polygonal flat sail and a heliogyro, which divides the membrane into a number of long, slender blades. The

Deployment Technology of a Heliogyro Solar Sail for Long Duration Propulsion

Science.gov (United States)

Peerawan, Wiwattananon; Bryant, Robert G.; Edmonson, William W.; Moore, William B.; Bell, Jared M.

2015-01-01

Interplanetary, multi-mission, station-keeping capabilities will require that a spacecraft employ a highly efficient propulsion-navigation system. The majority of space propulsion systems are fuel-based and require the vehicle to carry and consume fuel as part of the mission. Once the fuel is consumed, the mission is set, thereby limiting the potential capability. Alternatively, a method that derives its acceleration and direction from solar photon pressure using a solar sail would eliminate the requirement of onboard fuel to meet mission objectives. MacNeal theorized that the heliogyro-configured solar sail architecture would be lighter, less complex, cheaper, and less risky to deploy a large sail area versus a masted sail. As sail size increases, the masted sail requires longer booms resulting in increased mass, and chaotic uncontrollable deployment. With a heliogyro, the sail membrane is stowed as a roll of thin film forming a blade when deployed that can extend up to kilometers. Thus, a benefit of using a heliogyro-configured solar sail propulsion technology is the mission scalability as compared to masted versions, which are size constrained. Studies have shown that interplanetary travel is achievable by the heliogyro solar sail concept. Heliogyro solar sail concept also enables multi-mission missions such as sample returns, and supply transportation from Earth to Mars as well as station-keeping missions to provide enhanced warning of solar storm. This paper describes deployment technology being developed at NASA Langley Research Center to deploy and control the center-of-mass/center-of-pressure using a twin bladed heliogyro solar sail 6-unit (6U) CubeSat. The 6U comprises 2x2U blade deployers and 2U for payload. The 2U blade deployers can be mounted to 6U or larger scaled systems to serve as a non-chemical in-space propulsion system. A single solar sail blade length is estimated to be 2.4 km with a total area from two blades of 720 m2; total allowable weight

Advanced Materials and Production Technology for Very Large Solar Sail Structures, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Solar sails are an attractive means for propulsion of future spacecraft. One potential device for deploying and supporting very large solar sails is the CoilAble...

Recent Progress in Heliogyro Solar Sail Structural Dynamics

Science.gov (United States)

Wilkie, William K.; Warren, Jerry E.; Horta, Lucas G.; Juang, Jer-Nan; Gibbs, Samuel C.; Dowell, E.; Guerrant, Daniel; Lawrence Dale

2014-01-01

Results from recent National Aeronautics and Space Administration (NASA) research on the structural dynamics and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment, and results from small-scale in vacuo dynamics experiments with spinning high-aspect ratio membranes. A low-cost, rideshare payload heliogyro technology demonstration mission concept, used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, is also described.

Logarithmic spiral trajectories generated by Solar sails

Science.gov (United States)

Bassetto, Marco; Niccolai, Lorenzo; Quarta, Alessandro A.; Mengali, Giovanni

2018-02-01

Analytic solutions to continuous thrust-propelled trajectories are available in a few cases only. An interesting case is offered by the logarithmic spiral, that is, a trajectory characterized by a constant flight path angle and a fixed thrust vector direction in an orbital reference frame. The logarithmic spiral is important from a practical point of view, because it may be passively maintained by a Solar sail-based spacecraft. The aim of this paper is to provide a systematic study concerning the possibility of inserting a Solar sail-based spacecraft into a heliocentric logarithmic spiral trajectory without using any impulsive maneuver. The required conditions to be met by the sail in terms of attitude angle, propulsive performance, parking orbit characteristics, and initial position are thoroughly investigated. The closed-form variations of the osculating orbital parameters are analyzed, and the obtained analytical results are used for investigating the phasing maneuver of a Solar sail along an elliptic heliocentric orbit. In this mission scenario, the phasing orbit is composed of two symmetric logarithmic spiral trajectories connected with a coasting arc.

Design and Development of NEA Scout Solar Sail Deployer Mechanism

Science.gov (United States)

Sobey, Alexander R.; Lockett, Tiffany Russell

2016-01-01

The 6U (approx.10 cm x 20 cm x 30 cm) cubesat Near Earth Asteroid (NEA) Scout1, projected for launch in September 2018 aboard the maiden voyage of the Space Launch System, will utilize a solar sail as its main method of propulsion throughout its approx.3-year mission to a Near Earth Asteroid. Due to the extreme volume constraints levied onto the mission, an acutely compact solar sail deployment mechanism has been designed to meet the volume and mass constraints, as well as provide enough propulsive solar sail area and quality in order to achieve mission success. The design of such a compact system required the development of approximately half a dozen prototypes in order to identify unforeseen problems, advance solutions, and build confidence in the final design product. This paper focuses on the obstacles of developing a solar sail deployment mechanism for such an application and the lessons learned from a thorough development process. The lessons presented will have significant applications beyond the NEA Scout mission, such as the development of other deployable boom mechanisms and uses for gossamer-thin films in space.

Flights of a spacecraft with a solar sail out of ecliptic plane

Science.gov (United States)

Polyakhova, Elena; Starkov, Vladimir; Stepenko, Nikolai

2018-05-01

Solar sailing is an unique form of spacecraft (SC) propulsion that uses the free and limitless supply of photons from the Sun. The investigation of near-the-Sun space properties is of the great scientific interest. It can be realized by help of solar sailing. We present the numerical simulation of several closed modelled trajectories of a spacecraft with a controlled solar sail to reach out of ecliptic plane, to flight over the Sun north and south poles and return to the Earth.

Invariant Solar Sail Formations in Elliptical Sun-Synchronous Orbits

Science.gov (United States)

Parsay, Khashayar

Current and past missions that study the Earth's geomagnetic tail require multiple spacecraft to fly in formation about a highly eccentric Keplerian reference orbit that has its apogee inside a predefined science region of interest. Because the geomagnetic tail is directed along the Sun-Earth line and therefore rotates annually, inertially fixed Keplerian orbits are only aligned with the geomagnetic tail once per year. This limitation reduces the duration of the science phase to less than a few months annually. Solar sails are capable of creating non-Keplerian, Sun-synchronous orbits that rotate with the geomagnetic tail. A solar sail flying in a Sun-synchronous orbit will have a continuous presence in the geomagnetic tail throughout the entire year, which significantly improves the in situ observations of the magnetosphere. To achieve a Sun-synchronous orbit, a solar sail is required to maintain a Sun-pointing attitude, which leads to the artificial precession of the orbit apse line in a Sun-synchronous manner, leaving the orbit apogee inside the science region of interest throughout entire the year. To study the spatial and temporal variations of plasma in the highly dynamic environment of the magnetosphere, multiple spacecraft must fly in a formation. The objective for this dissertation is to investigate the feasibility of solar sail formation flying in the Earth-centered, Sun-synchronous orbit regime. The focus of this effort is to enable formation flying for a group of solar sails that maintain a nominally fixed Sun-pointing attitude during formation flight, solely for the purpose of precessing their orbit apse lines Sun-synchronously. A fixed-attitude solar sail formation is motivated by the difficulties in the simultaneous control of orbit and attitude in flying solar sails. First, the secular rates of the orbital elements resulting from the effects of solar radiation pressure (SRP) are determined using averaging theory for a Sun-pointing attitude sail

Utilization of an H-reversal trajectory of a solar sail for asteroid deflection

International Nuclear Information System (INIS)

Gong Shengping; Li Junfeng; Zeng Xiangyuan

2011-01-01

Near Earth Asteroids have a possibility of impacting the Earth and always represent a threat. This paper proposes a way of changing the orbit of the asteroid to avoid an impact. A solar sail evolving in an H-reversal trajectory is utilized for asteroid deflection. Firstly, the dynamics of the solar sail and the characteristics of the H-reversal trajectory are analyzed. Then, the attitude of the solar sail is optimized to guide the sail to impact the target asteroid along an H-reversal trajectory. The impact velocity depends on two important parameters: the minimum solar distance along the trajectory and lightness number of the solar sail. A larger lightness number and a smaller solar distance lead to a higher impact velocity. Finally, the deflection capability of a solar sail impacting the asteroid along the H-reversal trajectory is discussed. The results show that a 10 kg solar sail with a lead-time of one year can move Apophis out of a 600-m keyhole area in 2029 to eliminate the possibility of its resonant return in 2036. (editor's recommendation)

Parametric Studies of Square Solar Sails Using Finite Element Analysis

Science.gov (United States)

Sleight, David W.; Muheim, Danniella M.

2004-01-01

Parametric studies are performed on two generic square solar sail designs to identify parameters of interest. The studies are performed on systems-level models of full-scale solar sails, and include geometric nonlinearity and inertia relief, and use a Newton-Raphson scheme to apply sail pre-tensioning and solar pressure. Computational strategies and difficulties encountered during the analyses are also addressed. The purpose of this paper is not to compare the benefits of one sail design over the other. Instead, the results of the parametric studies may be used to identify general response trends, and areas of potential nonlinear structural interactions for future studies. The effects of sail size, sail membrane pre-stress, sail membrane thickness, and boom stiffness on the sail membrane and boom deformations, boom loads, and vibration frequencies are studied. Over the range of parameters studied, the maximum sail deflection and boom deformations are a nonlinear function of the sail properties. In general, the vibration frequencies and modes are closely spaced. For some vibration mode shapes, local deformation patterns that dominate the response are identified. These localized patterns are attributed to the presence of negative stresses in the sail membrane that are artifacts of the assumption of ignoring the effects of wrinkling in the modeling process, and are not believed to be physically meaningful. Over the range of parameters studied, several regions of potential nonlinear modal interaction are identified.

Electric solar wind sail mass budget model

Directory of Open Access Journals (Sweden)

P. Janhunen

2013-02-01

Full Text Available The electric solar wind sail (E-sail is a new type of propellantless propulsion system for Solar System transportation, which uses the natural solar wind to produce spacecraft propulsion. The E-sail consists of thin centrifugally stretched tethers that are kept charged by an onboard electron gun and, as such, experience Coulomb drag through the high-speed solar wind plasma stream. This paper discusses a mass breakdown and a performance model for an E-sail spacecraft that hosts a mission-specific payload of prescribed mass. In particular, the model is able to estimate the total spacecraft mass and its propulsive acceleration as a function of various design parameters such as the number of tethers and their length. A number of subsystem masses are calculated assuming existing or near-term E-sail technology. In light of the obtained performance estimates, an E-sail represents a promising propulsion system for a variety of transportation needs in the Solar System.

Mars Sample Return Using Solar Sail Propulsion

Science.gov (United States)

Johnson, Les; Macdonald, Malcolm; Mcinnes, Colin; Percy, Tom

2012-01-01

Many Mars Sample Return (MSR) architecture studies have been conducted over the years. A key element of them is the Earth Return Stage (ERS) whose objective is to obtain the sample from the Mars Ascent Vehicle (MAV) and return it safely to the surface of the Earth. ERS designs predominantly use chemical propulsion [1], incurring a significant launch mass penalty due to the low specific impulse of such systems coupled with the launch mass sensitivity to returned mass. It is proposed to use solar sail propulsion for the ERS, providing a high (effective) specific impulse propulsion system in the final stage of the multi-stage system. By doing so to the launch mass of the orbiter mission can be significantly reduced and hence potentially decreasing mission cost. Further, solar sailing offers a unique set of non-Keplerian low thrust trajectories that may enable modifications to the current approach to designing the Earth Entry Vehicle by potentially reducing the Earth arrival velocity. This modification will further decrease the mass of the orbiter system. Solar sail propulsion uses sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like surface made of a lightweight, reflective material. The continuous photonic pressure provides propellantless thrust to conduct orbital maneuvering and plane changes more efficiently than conventional chemical propulsion. Because the Sun supplies the necessary propulsive energy, solar sails require no onboard propellant, thus reducing system mass. This technology is currently at TRL 7/8 as demonstrated by the 2010 flight of the Japanese Aerospace Exploration Agency, JAXA, IKAROS mission. [2

Moving an asteroid with electric solar wind sail

Science.gov (United States)

Merikallio, S.; Janhunen, P.

2010-12-01

The electric solar wind sail (E-Sail) is a new propulsion method for interplanetary travel which was invented in 2006 and is currently under development. The E-Sail uses charged tethers to extract momentum from the solar wind particles to obtain propulsive thrust. According to current estimates, the E-Sail is 2-3 orders of magnitude better than traditional propulsion methods (chemical rockets and ion engines) in terms of produced lifetime-integrated impulse per propulsion system mass. Here we analyze the problem of using the E-Sail for directly deflecting an Earth-threatening asteroid. The problem then culminates into how to attach the E-Sail device to the asteroid. We assess alternative attachment strategies, namely straightforward direct towing with a cable and the gravity tractor method which works for a wider variety of situations. We also consider possible techniques to scale up the E-Sail force beyond the baseline one Newton level to deal with more imminent or larger asteroid or cometary threats. As a baseline case we consider an asteroid of effective diameter of 140 m and mass of 3 million tons, which can be deflected with a baseline 1 N E-Sail within 10 years. With a 5 N E-Sail the deflection could be achieved in 5 years. Once developed, the E-Sail would appear to provide a safe and reasonably low-cost way of deflecting dangerous asteroids and other heavenly bodies in cases where the collision threat becomes known several years in advance.

Solar Sails: Sneaking up on Interstellar Travel

Science.gov (United States)

Johnson, L.

Throughout the world, government agencies, universities and private companies are developing solar sail propulsion systems to more efficiently explore the solar system and to enable science and exploration missions that are simply impossible to accomplish by any other means. Solar sail technology is rapidly advancing to support these demonstrations and missions, and in the process, is incrementally advancing one of the few approaches allowed by physics that may one day take humanity to the stars. Continuous solar pressure provides solar sails with propellantless thrust, potentially enabling them to propel a spacecraft to tremendous speeds ­ theoretically much faster than any present-day propulsion system. The next generation of sails will enable us to take our first real steps beyond the edge of the solar system, sending spacecraft out to distances of 1000 Astronomical Units, or more. In the farther term, the descendants of these first and second generation sails will augment their thrust by using high power lasers and enable travel to nearby stellar systems with flight times less than 500 years ­ a tremendous improvement over what is possible with conventional chemical rockets. By fielding these first solar sail systems, we are sneaking up on a capability to reach the stars.

European sail tower SPS [Solar Power Satellite] concept

Energy Technology Data Exchange (ETDEWEB)

Seboldt, W.; Leipold, M.; Hanowski, N. [Institute of Space Sensor Technology and Planetary Exploration, Cologne (Germany). German Aerospace Center; Klimke, M. [HOPE Worldwide Deutschland, Berlin (Germany)

2001-06-01

Based on a DLR-study in 1998/99 on behalf of ESA/ESTEC called ''System Concepts, Architectures and Technologies for Space Exploration and Utilization (SE and U)'' a new design for an Earth-orbiting Solar Power Satellite (SPS) has been developed. The design is called ''European Sail Tower SPS'' and consists mainly of deplorable sail-like structures derived from the ongoing DLR/ESA solar sail technology development activity. Such an SPS satellite features an extremely light-weight and large tower-like orbital system and could supply Europe with significant amounts of electrical power generated by photovoltaic cells and subsequently transmitted to earth via microwaves. In order to build up the sail tower, 60 units - each consisting of a pair of square-shaped sails - are moved from LEO to GEO with electric propulsion and successively assembled in GEO robotically on a central strut. Each single sail has dimensions of 150 m x 150 m and is automatically deployed, using four diagonal lightweight carbon fiber (CFRP) booms which are initially rolled up on a central hub. The electric thrusters for the transport to GEO could also be used for orbit and attitude control of the assembled tower which has a total length of about 15 km and would be mainly gravity gradient stabilized. Employing thin film solar cell technology, each sail is used as a solar array and produces an electric power in orbit of about 3.7 MW{sub e}. A microwave antenna with a diameter of 1 km transmits the power to a 10 km rectenna on the ground. The total mass of this 450 MW SPS is about 2100 tons. First estimates indicate that the costs for one kWh delivered in this way could compete with present day energy costs, if launch costs would decrease by two orders of magnitude. Furthermore, mass production and large numbers of installed SPS systems must be assumed in order to lower significantly the production costs and to reduce the influence of the expensive technology

The effects of Poynting–Robertson drag on solar sails

Directory of Open Access Journals (Sweden)

F.A. Abd El-Salam

2018-06-01

Full Text Available In the present work, the concept of solar sailing and its developing spacecraft are presented. The effects of Poynting–Robertson drag on solar sails are considered. Some analytical control laws with some mentioned input constraints for optimizing solar sails dynamics in heliocentric orbit using Lagrange’s planetary equations are obtained. Optimum force vector in a required direction is maximized by deriving optimal sail cone angle. New control laws that maximize thrust to obtain certain required maximization in some particular orbital element are obtained. Keywords: Poynting–Robertson drag, Solar sail, Control laws, Optimal sail, Cone angle

Scale-model Experiment of Magnetoplasma Sail for Future Deep Space Missions

International Nuclear Information System (INIS)

Funaki, Ikkoh; Yamakawa, Hiroshi; Ueno, Kazuma; Kimura, Toshiyuki; Ayabe, Tomohiro; Horisawa, Hideyuki

2008-01-01

When Magnetic sail (MagSail) spacecraft is operated in space, the supersonic solar wind plasma flow is blocked by an artificially produced magnetic cavity to accelerate the spacecraft in the direction leaving the Sun. To evaluate the momentum transferring process from the solar wind to the coil onboard the MagSail spacecraft, we arranged a laboratory experiment of MagSail spacecraft. Based on scaling considerations, a solenoidal coil was immersed into the plasma flow from a magnetoplasmadynamic arcjet in a quasi-steady mode of about 1 ms duration. In this setup, it is confirmed that a magnetic cavity, which is similar to that of the geomagnetic field, was formed around the coil to produce thrust in the ion Larmor scale interaction. Also, the controllability of magnetic cavity size by a plasma jet from inside the coil of MagSail is demonstrated, although the thrust characteristic of the MagSail with plasma jet, which is so called plasma sail, is to be clarified in our next step

Hybrids of Solar Sail, Solar Electric, and Solar Thermal Propulsion for Solar-System Exploration

Science.gov (United States)

Wilcox, Brian H.

2012-01-01

Solar sails have long been known to be an attractive method of propulsion in the inner solar system if the areal density of the overall spacecraft (S/C) could be reduced to approx.10 g/sq m. It has also long been recognized that the figure (precise shape) of useful solar sails needs to be reasonably good, so that the reflected light goes mostly in the desired direction. If one could make large reflective surfaces with reasonable figure at an areal density of approx.10 g/sq m, then several other attractive options emerge. One is to use such sails as solar concentrators for solar-electric propulsion. Current flight solar arrays have a specific output of approx. 100W/kg at 1 Astronomical Unit (AU) from the sun, and near-term advances promise to significantly increase this figure. A S/C with an areal density of 10 g/sq m could accelerate up to 29 km/s per year as a solar sail at 1 AU. Using the same sail as a concentrator at 30 AU, the same spacecraft could have up to approx. 45 W of electric power per kg of total S/C mass available for electric propulsion (EP). With an EP system that is 50% power-efficient, exhausting 10% of the initial S/C mass per year as propellant, the exhaust velocity is approx. 119 km/s and the acceleration is approx. 12 km/s per year. This hybrid thus opens attractive options for missions to the outer solar system, including sample-return missions. If solar-thermal propulsion were perfected, it would offer an attractive intermediate between solar sailing in the inner solar system and solar electric propulsion for the outer solar system. In the example above, both the solar sail and solar electric systems don't have a specific impulse that is near-optimal for the mission. Solar thermal propulsion, with an exhaust velocity of the order of 10 km/s, is better matched to many solar system exploration missions. This paper derives the basic relationships between these three propulsion options and gives examples of missions that might be enabled by

The solar sail: Current state of the problem

Science.gov (United States)

Polyakhova, Elena; Korolev, Vladimir

2018-05-01

Mathematical models of dynamics of the spacecraft with a solar sail to control orbital motion and rotation of the entire structureare considered. The movement of a spacecraftby a solar sail is based on the effect of light pressure. The magnitude and direction of the light pressure force vector is determined by the size and properties of the sail surface and the orientation angle relative to the sunlight flux. It is possible to vary the properties, sizes or locations of the sails to control the motion. Turning the elements of the sail, we get the opportunity to control the direction of the vector of the acting force and the moment with respect to the center of mass. Specificity of solar sail control is the interaction of orbital motion and rotational movements of the entire structure, which could provide the desired orientation and stability at small perturbations. The solar sail can be used for flights to the major planets, to meet with asteroids and comet, to realize a special desired motion in the neighborhood of the Sun or near the Earth.

Model and trajectory optimization for an ideal laser-enhanced solar sail

NARCIS (Netherlands)

Carzana (student TUDelft), Livio; Dachwald, Bernd; Noomen, R.

2017-01-01

A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure onto the sail. The

A solar sail design for a mission to the near-interstellar medium

International Nuclear Information System (INIS)

Garner, Charles E.; Layman, William; Gavit, Sarah A.; Knowles, Timothy

2000-01-01

Mission concepts to several hundred AU are under study at NASA Marshall Space Flight Center (MSFC) and NASA Jet Propulsion Laboratory (JPL). In order to send a scientific probe beyond the heliopause in a reasonable length of time - no more than 15 yr and preferably 10 yr - the ΔV requirements are approximately 70 km/s. The preliminary results of these mission studies indicate that a solar sail can provide a cumulative ΔV of over 70 km/s to send a probe to a distance of 200 AU from the Sun in under 15 years. This is done by using photon pressure on the sail to shape the trajectory in the inner solar system so that a perihelion of 0.25 AU is achieved. This paper presents the results of a design study for a solar sail to achieve the performance requirements identified in an interstellar probe (ISP) mission study to the near-interstellar medium. The baseline solar sail design for this ISP mission assumes an areal density of 1g/m2 (including film and structure), and a diameter of ∼410 m with an 11-m-wide central opening. The sail will be used from 0.25 to 5 AU, where it will be jettisoned. The total spacecraft module mass propelled by the sail is ∼191 kg. The gores of the sail are folded together and wrapped around a small cylinder. Centripetal force is used for sail deployment. The spacecraft is moved off-center with booms for sail attitude control and thrust vector pointing

In-Space Propulsion (ISP) Solar Sail Propulsion Technology Development

Science.gov (United States)

Montgomery, Edward E., IV

2004-01-01

An overview of the rationale and content for Solar Sail Propulsion (SSP), the on-going project to advance solar technology from technology readiness level 3 to 6 will be provided. A descriptive summary of the major and minor component efforts underway will include identification of the technology providers and a listing of anticipated products Recent important results from major system ground demonstrators will be provided. Finally, a current status of all activities will provided along with the most recent roadmap for the SSP technology development program.

Model and trajectory optimization for an ideal laser-enhanced solar sail

OpenAIRE

Carzana (student TUDelft), Livio; Dachwald, Bernd; Noomen, R.

2017-01-01

A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure onto the sail. The potential source of the laser beam is a laser satellite that coverts solar power (in the inner solar system) or nuclear power (in the outer solar system) into laser power. Such a laser satellite (o...

TRL Assessment of Solar Sail Technology Development Following the 20-Meter System Ground Demonstrator Hardware Testing

Science.gov (United States)

Young, Roy M.; Adams, Charles L.

2010-01-01

The NASA In-Space Propulsion Technology (ISPT) Projects Office sponsored two separate, independent solar sail system design and development demonstration activities during 2002-2005. ATK Space Systems of Goleta, CA was the prime contractor for one development team and L' Garde, Inc. of Tustin, CA was the prime contractor for the other development team. The goal of these activities was to advance the technology readiness level (TRL) of solar sail propulsion from 3 towards 6 by the year 2006. Component and subsystem fabrication and testing were completed successfully, including the ground deployment of 10-meter and 20-meter demonstration hardware systems under vacuum conditions. The deployment and structural testing of the 20-meter solar sail systems was conducted in the 30 meter diameter Space Power Facility thermal-vacuum chamber at NASA Glenn Plum Brook in April though August, 2005. This paper will present the results of the TRL assessment following the solar sail technology development activities associated with the design, development, analysis and testing of the 20-meter system ground demonstrators.

The effects of Poynting-Robertson drag on solar sails

Science.gov (United States)

Abd El-Salam, F. A.

2018-06-01

In the present work, the concept of solar sailing and its developing spacecraft are presented. The effects of Poynting-Robertson drag on solar sails are considered. Some analytical control laws with some mentioned input constraints for optimizing solar sails dynamics in heliocentric orbit using Lagrange's planetary equations are obtained. Optimum force vector in a required direction is maximized by deriving optimal sail cone angle. New control laws that maximize thrust to obtain certain required maximization in some particular orbital element are obtained.

SOLAR SAIL PROPULSION SENSITIVITY TO MEMBRANE SHAPE AND OPTICAL PROPERTIES USING THE SOLAR VECTORING EVALUATION TOOL (SVET)

Science.gov (United States)

Ewing, Anthony

2005-01-01

Solar sail propulsive performance is dependent on sail membrane optical properties and on sail membrane shape. Assumptions of an ideal sail (flat, perfect reflector) can result in errors which can affect spacecraft control, trajectory analyses, and overall evaluation of solar sail performance. A MATLAB(R) program has been developed to generate sail shape point cloud files for two square-architecture solar sail designs. Simple parabolic profiles are assumed for sail shape under solar pressure loading. These files are then input into the Solar Vectoring Evaluation Tool (SVET) software to determine the propulsive force vector, center of pressure, and moments about the sail body axes as a function of sail shape and optical properties. Also, the impact of the center-line angle, due to non-perfect optical properties, is addressed since this constrains sail force vector cone angle and is often overlooked when assuming ideal-reflector membranes. Preliminary sensitivity analysis using these tools aids in determining the key geometric and optical parameters that drive solar sail propulsive performance.

Electrodynamic Tethers and E-Sails as Active Experiment Testbeds and Technologies in Space

Science.gov (United States)

Gilchrist, B. E.; Wiegmann, B.; Johnson, L.; Bilen, S. G.; Habash Krause, L.; Miars, G.; Leon, O.

2017-12-01

The use of small-to-large flexible structures in space such as tethers continues to be studied for scientific and technology applications. Here we will consider tether electrodynamic and electrostatic interactions with magneto-plasmas in ionospheres, magnetospheres, and interplanetary space. These systems are enabling fundamental studies of basic plasma physics phenomena, allowing direct studies of the space environment, and generating technological applications beneficial for science missions. Electrodynamic tethers can drive current through the tether based on the Lorenz force adding or extracting energy from its orbit allowing for the study of charged bodies or plasma plumes moving through meso-sonic magnetoplasmas [1]. Technologically, this also generates propulsive forces requiring no propellant and little or no consumables in any planetary system with a magnetic field and ionosphere, e.g., Jupiter [2]. Further, so called electric sails (E-sails) are being studied to provide thrust through momentum exchange with the hypersonic solar wind. The E-sail uses multiple, very long (10s of km) charged, mostly bare rotating conducting tethers to deflect solar wind protons. It is estimated that a spacecraft could achieve a velocity over 100 km/s with time [3,4]. 1. Banks, P.M., "Review of electrodynamic tethers for space plasma science," J. Spacecraft and Rockets, vol. 26, no. 4, pp. 234-239, 1989. 2. Talley, C., J. Moore, D. Gallagher, and L. Johnson, "Propulsion and power from a rotating electrodynamic tether at Jupiter," 38th AIAA Aerospace Sciences Meeting and Exhibit, January 2000. 3. Janhunen, P., "The electric sail—A new propulsion method which may enable fast missions to the outer solar system," J. British Interpl. Soc., vol. 61, no. 8, pp. 322-325, 2008. 4. Wiegman, B., T. Scheider, A. Heaton, J. Vaughn, N. Stone, and K. Wright, "The Heliopause Electrostatic Rapid Transit System (HERTS)—Design, trades, and analyses performed in a two-year NASA investigation

Asteroid body-fixed hovering using nonideal solar sails

International Nuclear Information System (INIS)

Zeng, Xiang-Yuan; Jiang, Fang-Hua; Li, Jun-Feng

2015-01-01

The problem of body-fixed hovering over an asteroid using a compact form of nonideal solar sails with a controllable area is investigated. Nonlinear dynamic equations describing the hovering problem are constructed for a spherically symmetric asteroid. Numerical solutions of the feasible region for body-fixed hovering are obtained. Different sail models, including the cases of ideal, optical, parametric and solar photon thrust, on the feasible region is studied through numerical simulations. The influence of the asteroid spinning rate and the sail area-to-mass ratio on the feasible region is discussed. The required orientations for the sail and their corresponding variable lightness numbers are given for different hovering radii to identify the feasible region of the body-fixed hovering. An attractive scenario for a mission is introduced to take advantage of solar sail hovering. (paper)

Fast Solar Sailing Astrodynamics of Special Sailcraft Trajectories

CERN Document Server

Vulpetti, Giovanni

2013-01-01

The range of solar sailing is very vast; it is a fully in-space means of propellantless propulsion that should allow us to accomplish various mission classes that are unviable using near or medium-term rocket propulsion, no matter if nuclear or electric. Fast and very fast solar sailings are special classes of sailcraft missions, initially developed only in the first half of the 1990s and still evolving, especially after the latest advances in nanotechnology.   This book describes how to plan, compute and optimize the trajectories of sailcraft with speeds considerably higher than the Earth’s orbital speed (30 km/s); such sailcraft would be able to explore the outer heliosphere, the near interstellar medium and the solar gravitational lens (550-800 astronomical units) in times significantly shorter than the span of an average career (~ 35 years), just to cite a few examples. The scientific interest in this type of exploration is huge.

Angular velocity determination of spinning solar sails using only a sun sensor

Directory of Open Access Journals (Sweden)

Kun Zhai

2017-02-01

Full Text Available The direction of the sun is the easiest and most reliable observation vector for a solar sail running in deep space exploration. This paper presents a new method using only raw measurements of the sun direction vector to estimate angular velocity for a spinning solar sail. In cases with a constant spin angular velocity, the estimation equation is formed based on the kinematic model for the apparent motion of the sun direction vector; the least-squares solution is then easily calculated. A performance criterion is defined and used to analyze estimation accuracy. In cases with a variable spin angular velocity, the estimation equation is developed based on the kinematic model for the apparent motion of the sun direction vector and the attitude dynamics equation. Simulation results show that the proposed method can quickly yield high-precision angular velocity estimates that are insensitive to certain measurement noises and modeling errors.

On Possibility of Direct Asteroid Deflection by Electric Solar Wind Sail

Science.gov (United States)

Merikallio, Sini; Janhunen, Pekka

2010-05-01

The Electric Solar Wind Sail (E-sail) is a new propulsion method for interplanetary travel which was invented in 2006 and is currently under development. The E-sail uses charged tethers to extract momentum from the solar wind particles to obtain propulsive thrust. According to current estimates, the E-sail is 2-3 orders of magnitude better than traditional propulsion methods (chemical rockets and ion engines) in terms of produced lifetime-integrated impulse per propulsion system mass. Here we analyze the problem of using the E-sail for directly deflecting an Earth-threatening asteroid. The problem then culminates into how to attach the E-sail device to the asteroid. We assess a number of alternative attachment strategies and arrive at a recommendation of using the gravity tractor method because of its workability for a wide variety of asteroid types. We also consider possible techniques to scale up the E-sail force beyond the baseline one Newton level to deal with more imminent or larger asteroid or cometary threats. As a baseline case we consider a 3 million ton asteroid which can be deflected with a baseline 1 N E-sail in 5-10 years. Once developed, the E-sail would appear to provide a safe and reasonably low-cost way of deflecting dangerous asteroids and other heavenly bodies in cases where the collision threat becomes known several years in advance.

Meteoroid Measurements in the Deep Space Cruising and the Jupiter Trojan Rendezvous Phases of the Solar Power Sail Mission by the Arrayed Large-Area Dust Detectors in INterplanetary Space (ALADDIN)-II

Science.gov (United States)

Yano, H.; Hirai, T.; Arai, K.; Fujii, M.

2017-12-01

The PVDF thin films have been long, space-proven instruments for hypervelocity impact detection in the diverse regions of the Solar System from orbits of Venus by IKAROS and of Pluto by New Horizons. In particular, light weight but large area membranes of a solar sail spacecraft is an ideal location for such detectors to be deployed for detecting statistically enough nubers of so large micrometeoroids that are sensitive to mean motion resonances and other gravitational effects of flux enhancements and voids with planets. The IKAROS spacecraft first detected in situ dust flux enhancement and gap region within the Earth's circumsolar dust ring as well as those of Venus by 0.54 m^2 detection area of ALADDIN sensors on the slar sail membrane. Advancing this heritage, the Solar Power Sail membrane will carry 0.4+ m^2 ALADDIN-II PVDF sensors with improved impact signal prosessng units to detect both hyperveloity dust impacts in the interplanetary space cruising phase and slow dust impacts bound to the Jupiter Trojan region in its rendezvours phase.

An Update to the NASA Reference Solar Sail Thrust Model

Science.gov (United States)

Heaton, Andrew F.; Artusio-Glimpse, Alexandra B.

2015-01-01

An optical model of solar sail material originally derived at JPL in 1978 has since served as the de facto standard for NASA and other solar sail researchers. The optical model includes terms for specular and diffuse reflection, thermal emission, and non-Lambertian diffuse reflection. The standard coefficients for these terms are based on tests of 2.5 micrometer Kapton sail material coated with 100 nm of aluminum on the front side and chromium on the back side. The original derivation of these coefficients was documented in an internal JPL technical memorandum that is no longer available. Additionally more recent optical testing has taken place and different materials have been used or are under consideration by various researchers for solar sails. Here, where possible, we re-derive the optical coefficients from the 1978 model and update them to accommodate newer test results and sail material. The source of the commonly used value for the front side non-Lambertian coefficient is not clear, so we investigate that coefficient in detail. Although this research is primarily designed to support the upcoming NASA NEA Scout and Lunar Flashlight solar sail missions, the results are also of interest to the wider solar sail community.

Power Beamed Photon Sails: New Capabilities Resulting From Recent Maturation Of Key Solar Sail And High Power Laser Technologies

International Nuclear Information System (INIS)

Montgomery, Edward E. IV

2010-01-01

This paper revisits some content in the First International Symposium on Beamed Energy Propulsion in 2002 related to the concept of propellantless in-space propulsion utilizing an external high energy laser to provide momentum to an ultralightweight (gossamer) spacecraft. The design and construction of the NanoSail-D solar sail demonstration spacecraft has demonstrated in space flight hardware the concept of small, very light--yet capable--spacecraft. The results of the Joint High Power Solid State Laser (JHPSSL) have also increased the effectiveness and reduced the cost of an entry level laser source. This paper identifies the impact from improved system parameters on current mission applications.

Periodic orbits of solar sail equipped with reflectance control device in Earth-Moon system

Science.gov (United States)

Yuan, Jianping; Gao, Chen; Zhang, Junhua

2018-02-01

In this paper, families of Lyapunov and halo orbits are presented with a solar sail equipped with a reflectance control device in the Earth-Moon system. System dynamical model is established considering solar sail acceleration, and four solar sail steering laws and two initial Sun-sail configurations are introduced. The initial natural periodic orbits with suitable periods are firstly identified. Subsequently, families of solar sail Lyapunov and halo orbits around the L1 and L2 points are designed with fixed solar sail characteristic acceleration and varying reflectivity rate and pitching angle by the combination of the modified differential correction method and continuation approach. The linear stabilities of solar sail periodic orbits are investigated, and a nonlinear sliding model controller is designed for station keeping. In addition, orbit transfer between the same family of solar sail orbits is investigated preliminarily to showcase reflectance control device solar sail maneuver capability.

Fuzzy attitude control of solar sail via linear matrix inequalities

Science.gov (United States)

Baculi, Joshua; Ayoubi, Mohammad A.

2017-09-01

This study presents a fuzzy tracking controller based on the Takagi-Sugeno (T-S) fuzzy model of the solar sail. First, the T-S fuzzy model is constructed by linearizing the existing nonlinear equations of motion of the solar sail. Then, the T-S fuzzy model is used to derive the state feedback controller gains for the Twin Parallel Distributed Compensation (TPDC) technique. The TPDC tracks and stabilizes the attitude of the solar sail to any desired state in the presence of parameter uncertainties and external disturbances while satisfying actuator constraints. The performance of the TPDC is compared to a PID controller that is tuned using the Ziegler-Nichols method. Numerical simulation shows the TPDC outperforms the PID controller when stabilizing the solar sail to a desired state.

Lightweight Light Sail Propulsion

Data.gov (United States)

National Aeronautics and Space Administration — The areal density of solar sails and laser sails is large due to the heavy support structure made of Mylar, Kapton or CP-1. Replacing this support structure with...

New applications of the H-reversal trajectory using solar sails

International Nuclear Information System (INIS)

Zeng Xiangyuan; Baoyin Hexi; Li Junfeng; Gong Shengping

2011-01-01

Advanced solar sailing has been an increasingly attractive propulsion system for highly non-Keplerian orbits. Three new applications of the orbital angular momentum reversal (H-reversal) trajectories using solar sails are presented: space observation, heliocentric orbit transfer and collision orbits with asteroids. A theoretical proof for the existence of double H-reversal trajectories (referred to as 'H2RTs') is given, and the characteristics of the H2RTs are introduced before a discussion of the mission applications. A new family of H2RTs was obtained using a 3D dynamic model of the two-body frame. In a time-optimal control model, the minimum period H2RTs both inside and outside the ecliptic plane were examined using an ideal solar sail. Due to the quasi-heliostationary property at its two symmetrical aphelia, the H2RTs were deemed suitable for space observation. For the second application, the heliocentric transfer orbit was able to function as the time-optimal H-reversal trajectory, since its perihelion velocity is a circular or elliptic velocity. Such a transfer orbit can place the sailcraft into a clockwise orbit in the ecliptic plane, with a high inclination or displacement above or below the Sun. The third application of the H-reversal trajectory was simulated impacting an asteroid passing near Earth in a head-on collision. The collision point can be designed through selecting different perihelia or different launch windows. Sample orbits of each application were presented through numerical simulation. The results can serve as a reference for theoretical research and engineering design.

Optimal heliocentric trajectories for solar sail with minimum area

Science.gov (United States)

Petukhov, Vyacheslav G.

2018-05-01

The fixed-time heliocentric trajectory optimization problem is considered for planar solar sail with minimum area. Necessary optimality conditions are derived, a numerical method for solving the problem is developed, and numerical examples of optimal trajectories to Mars, Venus and Mercury are presented. The dependences of the minimum area of the solar sail from the date of departure from the Earth, the time of flight and the departing hyperbolic excess of velocity are analyzed. In particular, for the rendezvous problem (approaching a target planet with zero relative velocity) with zero departing hyperbolic excess of velocity for a flight duration of 1200 days it was found that the minimum area-to-mass ratio should be about 12 m2/kg for trajectory to Venus, 23.5 m2/kg for the trajectory to Mercury and 25 m2/kg for trajectory to Mars.

Sunlight reflection off the spacecraft with a solar sail on the surface of mars

Science.gov (United States)

Starinova, O. L.; Rozhkov, M. A.; Gorbunova, I. V.

2018-05-01

Modern technologies make it possible to fulfill many projects in the field of space exploration. One such project is the colonization of Mars and providing favorable conditions for living on it. Authors propose principles of functioning of the spacecraft with a solar sail, intended to create a thermal and light spot in a predetermined area of the Martian surface. This additional illumination can maintain and support certain climatic conditions on a small area where a Mars base could be located. This paper investigate the possibility of the spacecraft continuously reflect the sunlight off the solar sail on the small area of the Mars surface. The mathematical motion model in such condition of the solar sail's orientation is considered and used for motion simulation session. Moreover, the analysis of this motion is performed. Thus, were obtained parameters of the synchronic non-Keplerian orbit and spacecraft construction. In addition, were given recommendations for further applying satellites to reflect the sunlight on a planet's surface.

Dynamic and optical characterization of dusty plasmas for use as solar sails

International Nuclear Information System (INIS)

Sheldon, Robert; Thomas, Edward Jr.; Abbas, Mian; Gallagher, Dennis; Adrian, Mark; Craven, Paul

2002-01-01

Solar sails presently have mass loadings of 5 gm/m2 that, when including the support structure and payload, could easily average to >10 gm/m2. For reasonably sized spacecraft, the critical parameter is the total mass per total area, which when combined with the reflectivity, yield the true acceleration. We propose that dusty plasmas trapped in a 'Mini-Magnetosphere' (Winglee, 2000) can produce a solar sail with a total mass loading <0.01 gm/m2, and reflectivities of ∼1%. This configuration provides an acceleration equivalent to a standard sail of 95% reflectivity with <1 gm/m2. However, the physics of dusty plasma sails is not mature and several important questions need to be resolved before a large scale effort is warranted. Foremost among these questions are, what is the largest force a dusty plasma can sustain before it demagnetizes and separates from the binding magnetic field; what are the charging properties of dust under solar UV conditions; what is the light scattering cross section for the dust; what is the optimum dust grain size for magnetization and scattering; and, what are the optimum dust grain materials? We outline what we know about dusty plasmas, and what we are hoping to learn from two existing dusty plasma experiments at the National Space Science and Technology Center (NSSTC) and Auburn University

Numerical analysis of orbital transfers to Mars using solar sails and attitude control

Science.gov (United States)

Pereira, M. C.; de Melo, C. F.; Meireles, L. G.

2017-10-01

Solar sails present a promising alternative method of propulsion for the coming phases of the space exploration. With the recent advances in materials engineering, the construction of lighter and more resistant materials capable of impelling spaceships with the use of solar radiation pressure has become increasingly viable technologically and economically. The studies, simulations and analysis of orbital transfers from Earth to Mars proposed in this work were implemented considering the use of a flat solar sail. Maneuvers considering the delivery of a sailcraft from a Low Earth Orbit to the border of the Earth’s sphere of influence and interplanetary trajectories to Mars were investigated. A set of simulations were implemented varying the attitude of the sail relative to the Sun. Results show that a sailcraft can carry out transfers with final velocity with respect to Mars smaller than the interplanetary Patched-conic approximation, although this requires a longer time of transfers, provided the attitude of the sailcraft relative to the Sun can be controlled in some points of the trajectories.

Phobos/Deimos sample return via solar sail.

Science.gov (United States)

Matloff, Gregory L; Taylor, Travis; Powell, Conley; Moton, Tryshanda

2005-12-01

A sample-return mission to the Martian satellites using a con-temporary solar sail for all post-Earth-escape propulsion is proposed. The 0.015 kg/m(2) areal mass-thickness sail unfurls after launch and injection onto a Mars-bound Hohmann-transfer ellipse. Structure and payload increase spacecraft areal mass thickness to 0.028 kg/m(2). During the Mars encounter, the sail functions as a parachute in the outer atmosphere of Mars to accomplish aerocapture. On-board thrusters or the sail maneuver the spacecraft into an orbit with periapsis near Mars and apoapsis near Phobos. The orbit is circularized for Phobos-rendezvous; surface samples are collected. The sail then raises the orbit for Deimos-rendezvous and sample collection. The sail next places the spacecraft on an Earth-bound Hohmann-transfer ellipse. During Earth encounter, the sail accomplishes Earth-aerocapture or partially decelerates the sample container for entry into the Earth's atmosphere. Mission mass budget is about 218 grams and mission duration is less than five years.

Improving magnetosphere in situ observations using solar sails

Science.gov (United States)

Parsay, Khashayar; Schaub, Hanspeter; Schiff, Conrad; Williams, Trevor

2018-01-01

Past and current magnetosphere missions employ conventional spacecraft formations for in situ observations of the geomagnetic tail. Conventional spacecraft flying in inertially fixed Keplerian orbits are only aligned with the geomagnetic tail once per year, since the geomagnetic tail is always aligned with the Earth-Sun line, and therefore, rotates annually. Solar sails are able to artificially create sun-synchronous orbits such that the orbit apse line remains aligned with the geomagnetic tail line throughout the entire year. This continuous presence in the geomagnetic tail can significantly increase the science phase for magnetosphere missions. In this paper, the problem of solar sail formation design is explored using nonlinear programming to design optimal two-craft, triangle, and tetrahedron solar sail formations, in terms of formation quality and formation stability. The designed formations are directly compared to the formations used in NASA's Magnetospheric Multi-Scale mission.

Flowing Plasma Interaction with an Electric Sail Tether Element

Science.gov (United States)

Schneider, Todd; Vaughn, Jason; Wright, Kenneth; Anderson, Allen; Stone, Nobie

2017-01-01

Harnessing the power of the solar wind, an Electric Sail, or E-sail, is a relatively new concept that promises to deliver high speed propellant-less propulsion. The electric sail is an invention made in 2006 at the Kumpula Space Centre in Finland by Pekka Janhunen [Janhunen and Sandroos, 2007]. At its core, an electric sail utilizes multiple positively biased tethers which exchange momentum with solar wind protons via the repelling electric field established around each tether, in other words, by reflecting the solar wind protons. Recognizing the solar wind is a plasma, the effective repelling area of each tether is increased significantly by the formation a plasma sheath around each tether. Fig. 1 shows schematically a spacecraft employing an electric sail. The positive voltage bias (greater than10kV) applied to each tether naturally results in electron collection. Therefore, the electric sail concept necessarily includes an electron source (electron gun) to return collected electrons to space and maintain the positive bias of the tether system.

Escape trajectories of solar sails and general relativity

Energy Technology Data Exchange (ETDEWEB)

Kezerashvili, Roman Ya. [Physics Department, New York City College of Technology, City University of New York, 300 Jay Street, Brooklyn, NY 11201 (United States); Graduate School and University Center, City University of New York, 365 Fifth Avenue, New York, NY 10016 (United States); Vazquez-Poritz, Justin F., E-mail: jvazquez-poritz@citytech.cuny.ed [Physics Department, New York City College of Technology, City University of New York, 300 Jay Street, Brooklyn, NY 11201 (United States); Graduate School and University Center, City University of New York, 365 Fifth Avenue, New York, NY 10016 (United States)

2009-11-16

General relativity can have a significant impact on the long-range escape trajectories of solar sails deployed near the sun. For example, spacetime curvature in the vicinity of the sun can cause a solar sail traveling from about 4 solar radii to 2550 AU to be deflected by on the order of a million kilometers, and should therefore be taken into account at the beginning of the mission. There are a number of smaller general relativistic effects, such as frame dragging due to the slow rotation of the sun which can cause a deflection of more than one thousand kilometers.

Escape trajectories of solar sails and general relativity

International Nuclear Information System (INIS)

Kezerashvili, Roman Ya.; Vazquez-Poritz, Justin F.

2009-01-01

General relativity can have a significant impact on the long-range escape trajectories of solar sails deployed near the sun. For example, spacetime curvature in the vicinity of the sun can cause a solar sail traveling from about 4 solar radii to 2550 AU to be deflected by on the order of a million kilometers, and should therefore be taken into account at the beginning of the mission. There are a number of smaller general relativistic effects, such as frame dragging due to the slow rotation of the sun which can cause a deflection of more than one thousand kilometers.

Simulation study of solar wind push on a charged wire: basis of solar wind electric sail propulsion

Directory of Open Access Journals (Sweden)

P. Janhunen

2007-03-01

Full Text Available One possibility for propellantless propulsion in space is to use the momentum flux of the solar wind. A way to set up a solar wind sail is to have a set of thin long wires which are kept at high positive potential by an onboard electron gun so that the wires repel and deflect incident solar wind protons. The efficiency of this so-called electric sail depends on how large force a given solar wind exerts on a wire segment and how large electron current the wire segment draws from the solar wind plasma when kept at a given potential. We use 1-D and 2-D electrostatic plasma simulations to calculate the force and present a semitheoretical formula which captures the simulation results. We find that under average solar wind conditions at 1 AU the force per unit length is (5±1×10−8 N/m for 15 kV potential and that the electron current is accurately given by the well-known orbital motion limited (OML theory cylindrical Langmuir probe formula. Although the force may appear small, an analysis shows that because of the very low weight of a thin wire per unit length, quite high final speeds (over 50 km/s could be achieved by an electric sailing spacecraft using today's flight-proved components. It is possible that artificial electron heating of the plasma in the interaction region could increase the propulsive effect even further.

Novel Solar Sail Mission Concepts for High-Latitude Earth and Lunar Observation

NARCIS (Netherlands)

Heiligers, M.J.; Parker, Jeffrey S.; Macdonald, Malcolm

2016-01-01

This paper proposes the use of solar sail periodic orbits in the Earth-Moon system for ob-servation of the high-latitudes of the Earth and Moon. At the Earth, the high-latitudes will be crucial in answering questions concerning global climate change, monitoring space weather events and ensuring

Steering Concept of a 2-Blade Heliogyro Solar Sail Spacecraft

Science.gov (United States)

Wiwattananon, Peerawan; Bryant, Robert G.

2017-01-01

Solar sails can be classified into two groups based on their method of stabilization: 1) truss supported, and 2) centrifugally (spin) supported. The truss configuration requires masts or booms to deploy, support, and rigidize the sails whereas the spin type uses the spacecraft’s centrifugal force to deploy and stabilize the sails. The truss-supported type sail has a scaling limitation because as the sail area gets larger, the sail is increasingly more difficult to make and stow: the masts and booms get heavier, occupying more volume, and have increased risk during deployment. This major disadvantage limits the size of the sail area. The spin type comes in two configurations: 1) spinning square/disk sail and 2) heliogyro sail. This spinning square/disk sail architecture suffers the same sail area limitation as the truss-supported sail.

NASA's Advanced Solar Sail Propulsion System for Low-Cost Deep Space Exploration and Science Missions that Use High Performance Rollable Composite Booms

Science.gov (United States)

Fernandez, Juan M.; Rose, Geoffrey K.; Younger, Casey J.; Dean, Gregory D.; Warren, Jerry E.; Stohlman, Olive R.; Wilkie, W. Keats

2017-01-01

Several low-cost solar sail technology demonstrator missions are under development in the United States. However, the mass saving derived benefits that composites can offer to such a mass critical spacecraft architecture have not been realized yet. This is due to the lack of suitable composite booms that can fit inside CubeSat platforms and ultimately be readily scalable to much larger sizes, where they can fully optimize their use. With this aim, a new effort focused at developing scalable rollable composite booms for solar sails and other deployable structures has begun. Seven meter booms used to deploy a 90 m2 class solar sail that can fit inside a 6U CubeSat have already been developed. The NASA road map to low-cost solar sail capability demonstration envisioned, consists of increasing the size of these composite booms to enable sailcrafts with a reflective area of up to 2000 m2 housed aboard small satellite platforms. This paper presents a solar sail system initially conceived to serve as a risk reduction alternative to Near Earth Asteroid (NEA) Scout's baseline design but that has recently been slightly redesigned and proposed for follow-on missions. The features of the booms and various deployment mechanisms for the booms and sail, as well as ground support equipment used during testing, are introduced. The results of structural analyses predict the performance of the system under microgravity conditions. Finally, the results of the functional and environmental testing campaign carried out are shown.

Extension of Earth-Moon libration point orbits with solar sail propulsion

NARCIS (Netherlands)

Heiligers, M.J.; Macdonald, Malcolm; Parker, Jeffrey S.

2016-01-01

This paper presents families of libration point orbits in the Earth-Moon system that originate from complementing the classical circular restricted three-body problem with a solar sail. Through the use of a differential correction scheme in combination with a continuation on the solar sail

Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices

Science.gov (United States)

Munday, Jeremy

2016-01-01

Solar sails offer an opportunity for a CubeSatscale, propellant-free spacecraft technology that enables long-term and long-distance missions not possible with traditional methods. Solar sails operate using the transfer of linear momentum from photons of sunlight reflected from the surface of the sail. To propel the spacecraft, no mechanically moving parts, thrusters, or propellant are needed. However, attitude control, or orientation, is still performed using traditional methods involving reaction wheels and propellant ejection, which severely limit mission lifetime. For example, the current state of the art solutions employed by upcoming missions couple solar sails with a state of the art propellant ejection gas system. Here, the use of the gas thruster has limited the lifetime of the mission. To solve the limited mission lifetime problem, the Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices project team is working on propellantless attitude control using thin layers of material, an optical film, electrically switchable from transparent to reflective. The technology is based on a polymer-dispersed liquid crystal (PDLC), which allows this switch upon application of a voltage. This technology removes the need for propellant, which reduces weight and cost while improving performance and lifetime.

Electric solar-wind sail for asteroid touring missions and planetary protection

Science.gov (United States)

Janhunen, P.

2014-07-01

long time, moving from asteroid to asteroid in a bit similar way as, e.g., Mars rovers move from rock to rock on the planet's surface. After starting from the Earth, the mission would slowly spiral outward, making rendezvous with interesting asteroids along the way, as well as flybys or even a larger number of asteroids as opportunities arise. The spacecraft would do remote sensing of the bodies and perhaps also deploy small CubeSat-sized expendable landers on them (the mother spacecraft cannot land on an asteroid or else it would lose the E-sail tethers). The mission would first explore near-Earth objects, then pass through the main belt and end up with the Trojans, exploring asteroids in rendezvous and flyby modes all the time. Asteroids in roughly circular orbits and at low inclination would be the easiest and most likely targets for rendezvous mode encounters, while there would be less restrictions for flyby mode observations. Besides for pure asteroid science, the E-sail could also be used for planetary protection, either through direct propulsive deflection of a dangerous asteroid [4] or by accelerating a relatively lightweight impactor spacecraft to a retrograde orbit and in that way maximizing the available deflecting impact energy for given impactor mass. E-sails could take a number of such impactors to retrograde storage orbits from which they could be commanded to impact a dangerous asteroid with relatively short warning time. Such impactor fleet would not be dangerous to the Earth because the vehicles can be designed to burn completely in the atmosphere, in the unlikely event that due to some mishap one of them would collide with the Earth. The E-sail has potentially large applicability to asteroids as it promises ''free'' transportation in the solar system. As a next step, a solar-wind test mission is needed to demonstrate the technology in the authentic environment.

Simulation study of solar wind push on a charged wire: basis of solar wind electric sail propulsion

Directory of Open Access Journals (Sweden)

P. Janhunen

2007-03-01

Full Text Available One possibility for propellantless propulsion in space is to use the momentum flux of the solar wind. A way to set up a solar wind sail is to have a set of thin long wires which are kept at high positive potential by an onboard electron gun so that the wires repel and deflect incident solar wind protons. The efficiency of this so-called electric sail depends on how large force a given solar wind exerts on a wire segment and how large electron current the wire segment draws from the solar wind plasma when kept at a given potential. We use 1-D and 2-D electrostatic plasma simulations to calculate the force and present a semitheoretical formula which captures the simulation results. We find that under average solar wind conditions at 1 AU the force per unit length is (5±1×10⁻⁸ N/m for 15 kV potential and that the electron current is accurately given by the well-known orbital motion limited (OML theory cylindrical Langmuir probe formula. Although the force may appear small, an analysis shows that because of the very low weight of a thin wire per unit length, quite high final speeds (over 50 km/s could be achieved by an electric sailing spacecraft using today's flight-proved components. It is possible that artificial electron heating of the plasma in the interaction region could increase the propulsive effect even further.

Solar Sail Models and Test Measurements Correspondence for Validation Requirements Definition

Science.gov (United States)

Ewing, Anthony; Adams, Charles

2004-01-01

Solar sails are being developed as a mission-enabling technology in support of future NASA science missions. Current efforts have advanced solar sail technology sufficient to justify a flight validation program. A primary objective of this activity is to test and validate solar sail models that are currently under development so that they may be used with confidence in future science mission development (e.g., scalable to larger sails). Both system and model validation requirements must be defined early in the program to guide design cycles and to ensure that relevant and sufficient test data will be obtained to conduct model validation to the level required. A process of model identification, model input/output documentation, model sensitivity analyses, and test measurement correspondence is required so that decisions can be made to satisfy validation requirements within program constraints.

Momentum Management for the NASA Near Earth Asteroid Scout Solar Sail Mission

Science.gov (United States)

Heaton, Andrew; Diedrich, Benjamin L.; Orphee, Juan; Stiltner, Brandon; Becker, Christopher

2017-01-01

The Momentum Management (MM) system is described for the NASA Near Earth Asteroid Scout (NEA Scout) cubesat solar sail mission. Unlike many solar sail mission proposals that used solar torque as the primary or only attitude control system, NEA Scout uses small reaction wheels (RW) and a reaction control system (RCS) with cold gas thrusters, as described in the abstract "Solar Sail Attitude Control System for Near Earth Asteroid Scout Cubesat Mission." The reaction wheels allow fine pointing and higher rates with low mass actuators to meet the science, communication, and trajectory guidance requirements. The MM system keeps the speed of the wheels within their operating margins using a combination of solar torque and the RCS.

Relativistic solar sails

Science.gov (United States)

Güémez, J.; Fiolhais, M.

2018-05-01

We apply the four-vector formalism of special relativity to describe various interaction processes of photons with a solar sail, in two cases: when the sail’s surface is a perfect mirror, and when it is a body coated with a totally absorbing material. We stress the pedagogical value of implementing simultaneously both the linear momentum and the energy conservation in a covariant fashion, as our formalism inherently does. It also allows for a straightforward change of the description of a certain process in different inertial reference frames.

Solar sail time-optimal interplanetary transfer trajectory design

International Nuclear Information System (INIS)

Gong Shengpin; Gao Yunfeng; Li Junfeng

2011-01-01

The fuel consumption associated with some interplanetary transfer trajectories using chemical propulsion is not affordable. A solar sail is a method of propulsion that does not consume fuel. Transfer time is one of the most pressing problems of solar sail transfer trajectory design. This paper investigates the time-optimal interplanetary transfer trajectories to a circular orbit of given inclination and radius. The optimal control law is derived from the principle of maximization. An indirect method is used to solve the optimal control problem by selecting values for the initial adjoint variables, which are normalized within a unit sphere. The conditions for the existence of the time-optimal transfer are dependent on the lightness number of the sail and the inclination and radius of the target orbit. A numerical method is used to obtain the boundary values for the time-optimal transfer trajectories. For the cases where no time-optimal transfer trajectories exist, first-order necessary conditions of the optimal control are proposed to obtain feasible solutions. The results show that the transfer time decreases as the minimum distance from the Sun decreases during the transfer duration. For a solar sail with a small lightness number, the transfer time may be evaluated analytically for a three-phase transfer trajectory. The analytical results are compared with previous results and the associated numerical results. The transfer time of the numerical result here is smaller than the transfer time from previous results and is larger than the analytical result.

Multiple NEO Rendezvous Using Solar Sails

Science.gov (United States)

Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

2012-01-01

Mission concept is to assess the feasibility of using solar sail propulsion to enable a robotic precursor that would survey multiple Near Earth Objects (NEOs) for potential future human visits. Single spacecraft will rendezvous with and image 3 NEOs within 6 years of launch

Communicating LightSail: Embedded Reporting and Web Strategies for Citizen-Funded Space Missions

Science.gov (United States)

Hilverda, M.; Davis, J.

2015-12-01

The Planetary Society (TPS) is a non-profit space advocacy group with a stated mission to "empower the world's citizens to advance space science and exploration." In 2009, TPS began work on LightSail, a small, citizen-funded spacecraft to demonstrate solar sailing propulsion technology. The program included a test flight, completed in June 2015, with a primary mission slated for late 2016. TPS initiated a LightSail public engagement campaign to provide the public with transparent mission updates, and foster educational outreach. A credentialed science journalist was given unrestricted access to the team and data, and provided regular reports without editorial oversight. An accompanying website, sail.planetary.org, provided project updates, multimedia, and real-time spacecraft data during the mission. Design approaches included a clean layout with text optimized for easy reading, balanced by strong visual elements to enhance reader comprehension and interest. A dedicated "Mission Control" page featured social media feeds, links to most recent articles, and a ground track showing the spacecraft's position, including overflight predictions based on user location. A responsive, cross-platform design allowed easy access across a broad range of devices. Efficient web server performance was prioritized by implementing a static content management system (CMS). Despite two spacecraft contingencies, the test mission successfully completed its primary objective of solar sail deployment. Qualitative feedback on the transparent, embedded reporting style was positive, and website metrics showed high user retention times. The website also grew awareness and support for the primary 2016 mission, driving traffic to a Kickstarter campaign that raised $1.24 million. Websites constantly evolve, and changes for the primary mission will include a new CMS to better support multiple authors and a custom dashboard to display real-time spacecraft sensor data.

Study of a 30-M Boom For Solar Sail-Craft: Model Extendibility and Control Strategy

Science.gov (United States)

Keel, Leehyun

2005-01-01

Space travel propelled by solar sails is motivated by the fact that the momentum exchange that occurs when photons are reflected and/or absorbed by a large solar sail generates a small but constant acceleration. This acceleration can induce a constant thrust in very large sails that is sufficient to maintain a polar observing satellite in a constant position relative to the Sun or Earth. For long distance propulsion, square sails (with side length greater than 150 meters) can reach Jupiter in two years and Pluto in less than ten years. Converting such design concepts to real-world systems will require accurate analytical models and model parameters. This requires extensive structural dynamics tests. However, the low mass and high flexibility of large and light weight structures such as solar sails makes them unsuitable for ground testing. As a result, validating analytical models is an extremely difficult problem. On the other hand, a fundamental question can be asked. That is whether an analytical model that represents a small-scale version of a solar-sail boom can be extended to much larger versions of the same boom. To answer this question, we considered a long deployable boom that will be used to support the solar sails of the sail-craft. The length of fully deployed booms of the actual solar sail-craft will exceed 100 meters. However, the test-bed we used in our study is a 30 meter retractable boom at MSFC. We first develop analytical models based on Lagrange s equations and the standard Euler-Bernoulli beam. Then the response of the models will be compared with test data of the 30 meter boom at various deployed lengths. For this stage of study, our analysis was limited to experimental data obtained at 12ft and 18ft deployment lengths. The comparison results are positive but speculative. To observe properly validate the analytic model, experiments at longer deployment lengths, up to the full 30 meter, have been requested. We expect the study to answer the

Solar/Space Environment Data (Satellites)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) monitors the geospace and solar environments using a variety of space weather sensors aboard its fleet of...

A novel experimental mechanics method for measuring the light pressure acting on a solar sail membrane

Science.gov (United States)

Shi, Aiming; Jiang, Li; Dowell, Earl H.; Qin, Zhixuan

2017-02-01

Solar sail is a high potential `sailing craft' for interstellar exploration. The area of the first flight solar sail demonstrator named "IKAROS" is 200 square meters. Future interplanetary missions will require solar sails at least on the order of 10000 square meters (or larger). Due to the limitation of ground facilities, the size of experimental sample should not be large. Furthermore the ground experiments have to be conducted in gravitational field, so the gravity effect must be considered in a ground test. To obtain insight into the solar sail membrane dynamics, a key membrane flutter (or limit cycle oscillations) experiment with light forces acting on it must be done. But one big challenge is calibrating such a tiny light force by as a function of the input power. In this paper, a gravity-based measuring method for light pressure acting on membrane is presented. To explain the experimental principle, an ideal example of a laser beam with expanders and a metal film is studied. Based on calculations, this experimental mechanics method for calibrating light pressure with an accuracy of 0.01 micro-Newton may be realized by making the light force balance the gravity force on the metal films. This gravity-based measuring method could not only be applied to study the dynamics characteristics of solar sail membrane structure with different light forces, but could also be used to determine more accurate light forces/loads acting on solar sail films and hence to enhance the determination of the mechanical properties of the solar sail membrane structure.

The Coupled Orbit-Attitude Dynamics and Control of Electric Sail in Displaced Solar Orbits

Directory of Open Access Journals (Sweden)

Mingying Huo

2017-01-01

Full Text Available Displaced solar orbits for spacecraft propelled by electric sails are investigated. Since the propulsive thrust is induced by the sail attitude, the orbital and attitude dynamics of electric-sail-based spacecraft are coupled and required to be investigated together. However, the coupled dynamics and control of electric sails have not been discussed in most published literatures. In this paper, the equilibrium point of the coupled dynamical system in displaced orbit is obtained, and its stability is analyzed through a linearization. The results of stability analysis show that only some of the orbits are marginally stable. For unstable displaced orbits, linear quadratic regulator is employed to control the coupled attitude-orbit system. Numerical simulations show that the proposed strategy can control the coupled system and a small torque can stabilize both the attitude and orbit. In order to generate the control force and torque, the voltage distribution problem is studied in an optimal framework. The numerical results show that the control force and torque of electric sail can be realized by adjusting the voltage distribution of charged tethers.

Findings from NASA's 2015-2017 Electric Sail Investigations

Science.gov (United States)

Wiegmann, Bruce. M.

2017-01-01

Electric Sail (E-Sail) propulsion systems will enable scientific spacecraft to obtain velocities of up to 10 astronomical units per year without expending any on-board propellant. The E-Sail propulsion is created from the interaction of a spacecraft's positively charged multi-kilometer-length conductor/s with protons that are present in the naturally occurring hypersonic solar wind. The protons are deflected via natural electrostatic repulsion forces from the Debye sheath that is formed around a charged wire in space, and this deflection of protons creates thrust or propulsion in the opposite direction. It is envisioned that this E-Sail propulsion system can provide propulsion throughout the solar system and to the heliosphere and beyond. Consistent with the concept of a "sail," no propellant is needed as electrostatic repulsion interactions between the naturally occurring solar wind protons and a positively charged wire creates the propulsion. The basic principle on which the Electric Sail operates is the exchange of momentum between an "electric sail" and solar wind, which continually flows radially away from the sun at speeds ranging from 300 to 700 kilometers per second. The "sail" consists of an array of long, charged wires which extend radially outward 10 to 30 kilometers from a slowly rotating spacecraft. Momentum is transferred from the solar wind to the array through the deflection of the positively charged solar wind protons by a high voltage potential applied to the wires. The thrust generated by an E-Sail is proportional to the area of the sail, which is given by the product of the total length of the wires and the effective wire diameter. The wire is approximately 0.1 millimeters in diameter. However, the effective diameter is determined by the distance the applied electric potential penetrates into space around the wire (on the order of 10 meters at 1 astronomical unit). As a result, the effective area over which protons are repelled is proportional

Design and Characterization of a Small-Scale Solar Sail Prototype by Integrating NiTi SMA and Carbon Fibre Composite

Directory of Open Access Journals (Sweden)

Girolamo Costanza

2017-01-01

Full Text Available Solar sails are propellantless systems where the propulsive force is given by the momentum exchange of reflecting photons. In this study, a self-deploying system based on NiTi shape memory wires and sheets has been designed and manufactured. A small-scale prototype of solar sail with carbon fibre loom has been developed. Different configurations have been tested to optimize material and structure design of the small-scale solar sail. In particular the attention has been focused on the surface/weight ratio and the deployment of the solar sail. By reducing weight and enlarging the surface, it is possible to obtain high values of characteristic acceleration that is one of the main parameters for a successful use of the solar sail as propulsion system. Thanks to the use of shape memory alloys for self-actuation of the system, complexity of the structure itself decreases. Moreover, sail deployment is simpler.

In-Space Propulsion Technologies for Robotic Exploration of the Solar System

Science.gov (United States)

Johnson, Les; Meyer, Rae Ann; Frame, Kyle

2006-01-01

Supporting NASA's Science Mission Directorate, the In-Space Propulsion Technology Program is developing the next generation of space propulsion technologies for robotic, deep-space exploration. Recent technological advancements and demonstrations of key, high-payoff propulsion technologies have been achieved and will be described. Technologies under development and test include aerocapture, solar electric propulsion, solar sail propulsion, and advanced chemical propulsion.

Towing Asteroids with Gravity Tractors Enhanced by Tethers and Solar Sails

Science.gov (United States)

Shen, Haijun; Roithmayr, Carlos M.

2015-01-01

Material collected from an asteroid's surface can be used to increase gravitational attraction between the asteroid and a Gravity Tractor (GT); the spacecraft therefore operates more effectively and is referred to as an Enhanced Gravity Tractor (EGT). The use of tethers and solar sails to further improve effectiveness and simplify operations is investigated. By employing a tether, the asteroidal material can be placed close to the asteroid while the spacecraft is stationed farther away, resulting in a better safety margin and improved thruster efficiency. A solar sail on a spacecraft can naturally provide radial offset and inter-spacecraft separation required for multiple EGTs.

One kilometer (1 km) electric solar wind sail tether produced automatically.

Science.gov (United States)

Seppänen, Henri; Rauhala, Timo; Kiprich, Sergiy; Ukkonen, Jukka; Simonsson, Martin; Kurppa, Risto; Janhunen, Pekka; Hæggström, Edward

2013-09-01

We produced a 1 km continuous piece of multifilament electric solar wind sail tether of μm-diameter aluminum wires using a custom made automatic tether factory. The tether comprising 90,704 bonds between 25 and 50 μm diameter wires is reeled onto a metal reel. The total mass of 1 km tether is 10 g. We reached a production rate of 70 m/24 h and a quality level of 1‰ loose bonds and 2‰ rebonded ones. We thus demonstrated that production of long electric solar wind sail tethers is possible and practical.

Three-Axis Attitude Control of Solar Sails Utilising Reflectivity Control Devices

Science.gov (United States)

Theodorou, Theodoros

Solar sails are spacecraft that utilise the Solar Radiation Pressure, the force generated by impinging photons, to propel themselves. Conventional actuators are not suitable for controlling the attitude of solar sails therefore specific attitude control methods have been devised to tackle this. One of these methods is to change the centre of pressure with respect to the center of mass thus creating a torque. Reflectivity Control Devices (RCDs) have been proposed and successfully used to change the centre of pressure. Current methods that utilise RCDs have control authority over two axis only with no ability to control the torque about the normal of the sail surface. This thesis extends the state of the art and demonstrates 3-axis control by generating arbitrary torque vectors within a convex polyhedron. Two different RCD materials are considered, transmission and diffusion technologies both compatible with the proposed concept. A number of metrics have been developed which facilitate the comparison of different sail configurations. One of these metics is the sun map which is a graphic representation of the sun angles for which control authority is maintained. An iterative design process is presented which makes use of the metrics developed and aids in the design of a sail which meets the mission requirements and constraints. Moreover, the effects of different parameters on the performance of the proposed control concept are discussed. For example it is shown that by alternating the angle between the edge and middle RCDs the control authority increases. The concept's scalability has been investigated and a hybrid control scheme has been devised which makes use of both RCDs and reaction wheels. The RCDs are complemented by the reaction wheels to achieve higher slew rates while in turn the RCDs desaturate the reaction wheels. Finally, a number of simulations are conducted to verify the validity of the proposed concept.

On the feasibility of a negative polarity electric sail

Directory of Open Access Journals (Sweden)

P. Janhunen

2009-04-01

Full Text Available An electric solar wind sail is a recently introduced propellantless space propulsion method whose technical development has also started. In its original version, the electric sail consists of a set of long, thin, centrifugally stretched and conducting tethers which are charged positively and kept in a high positive potential of 20 kV by an onboard electron gun. The positively charged tethers deflect solar wind protons, thus tapping momentum from the solar wind stream and producing thrust. Here we consider a variant of the idea with negatively charged tethers. The negative polarity electric sail seems to be more complex to implement than the positive polarity variant since it needs an ion gun instead of an electron gun as well as a more complex tether structure to keep the electron field emission current in check with the tether surface. However, since this first study of the negative polarity electric sail does not reveal any fundamental issues, more detailed studies would be warranted.

Radiation and Internal Charging Environments for Thin Dielectrics in Interplanetary Space

Science.gov (United States)

Minow, Joseph I.; Parker, Linda Neergaard; Altstatt, Richard L.

2004-01-01

Spacecraft designs using solar sails for propulsion or thin membranes to shade instruments from the sun to achieve cryogenic operating temperatures are being considered for a number of missions in the next decades. A common feature of these designs are thin dielectric materials that will be exposed to the solar wind, solar energetic particle events, and the distant magnetotail plasma environments encountered by spacecraft in orbit about the Earth-Sun L2 point. This paper will discuss the relevant radiation and internal charging environments developed to support spacecraft design for both total dose radiation effects as well as dose rate dependent phenomenon, such as internal charging in the solar wind and distant magnetotail environments. We will describe the development of radiation and internal charging environment models based on nearly a complete solar cycle of Ulysses solar wind plasma measurements over a complete range of heliocentric latitudes and the early years of the Geotail mission where distant magnetotail plasma environments were sampled beyond X(sub GSE) = -100 Re to nearly L2 (X(sub GSE) -236 Re). Example applications of the environment models are shown to demonstrate the radiation and internal charging environments of thin materials exposed to the interplanetary space plasma environments.

Deployable Propulsion, Power and Communication Systems for Solar System Exploration

Science.gov (United States)

Johnson, Les; Carr, John A.; Boyd, Darren

2017-01-01

NASA is developing thin-film based, deployable propulsion, power, and communication systems for small spacecraft that could provide a revolutionary new capability allowing small spacecraft exploration of the solar system. By leveraging recent advancements in thin films, photovoltaics, and miniaturized electronics, new mission-level capabilities will be enabled aboard lower-cost small spacecraft instead of their more expensive, traditional counterparts, enabling a new generation of frequent, inexpensive deep space missions. Specifically, thin-film technologies are allowing the development and use of solar sails for propulsion, small, lightweight photovoltaics for power, and omnidirectional antennas for communication. Like their name implies, solar sails 'sail' by reflecting sunlight from a large, lightweight reflective material that resembles the sails of 17th and 18th century ships and modern sloops. Instead of wind, the sail and the ship derive their thrust by reflecting solar photons. Solar sail technology has been discussed in the literature for quite some time, but it is only since 2010 that sails have been proven to work in space. Thin-film photovoltaics are revolutionizing the terrestrial power generation market and have been found to be suitable for medium-term use in the space environment. When mounted on the thin-film substrate, these photovoltaics can be packaged into very small volumes and used to generate significant power for small spacecraft. Finally, embedded antennas are being developed that can be adhered to thin-film substrates to provide lightweight, omnidirectional UHF and X-band coverage, increasing bandwidth or effective communication ranges for small spacecraft. Taken together, they may enable a host of new deep space destinations to be reached by a generation of spacecraft smaller and more capable than ever before.

Solar Sail Attitude Control System for the NASA Near Earth Asteroid Scout Mission

Science.gov (United States)

Orphee, Juan; Diedrich, Ben; Stiltner, Brandon; Becker, Chris; Heaton, Andrew

2017-01-01

An Attitude Control System (ACS) has been developed for the NASA Near Earth Asteroid (NEA) Scout mission. The NEA Scout spacecraft is a 6U cubesat with an eighty-six square meter solar sail for primary propulsion that will launch as a secondary payload on the Space Launch System (SLS) Exploration Mission 1 (EM-1) and rendezvous with a target asteroid after a two year journey, and will conduct science imagery. The spacecraft ACS consists of three major actuating subsystems: a Reaction Wheel (RW) control system, a Reaction Control System (RCS), and an Active Mass Translator (AMT) system. The reaction wheels allow fine pointing and higher rates with low mass actuators to meet the science, communication, and trajectory guidance requirements. The Momentum Management System (MMS) keeps the speed of the wheels within their operating margins using a combination of solar torque and the RCS. The AMT is used to adjust the sign and magnitude of the solar torque to manage pitch and yaw momentum. The RCS is used for initial de-tumble, performing a Trajectory Correction Maneuver (TCM), and performing momentum management about the roll axis. The NEA Scout ACS is able to meet all mission requirements including attitude hold, slews, pointing for optical navigation and pointing for science with margin and including flexible body effects. Here we discuss the challenges and solutions of meeting NEA Scout mission requirements for the ACS design, and present a novel implementation of managing the spacecraft Center of Mass (CM) to trim the solar sail disturbance torque. The ACS we have developed has an applicability to a range of potential missions and does so in a much smaller volume than is traditional for deep space missions beyond Earth.

Recent Advances in Heliogyro Solar Sail Structural Dynamics, Stability, and Control Research

Science.gov (United States)

Wilkie, W. Keats; Warren, Jerry E.; Horta, Lucas G.; Lyle, Karen H.; Juang, Jer-Nan; Gibbs, S. Chad; Dowell, Earl H.; Guerrant, Daniel V.; Lawrence, Dale

2015-01-01

Results from recent NASA sponsored research on the structural dynamics, stability, and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, and solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment. Recent results from terrestrial 1-g blade dynamics and control experiments on "rope ladder" membrane blade analogs, and small-scale in vacuo system identification experiments with hanging and spinning high-aspect ratio membranes will also be presented. A low-cost, rideshare payload heliogyro technology demonstration mission concept is used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, and is also described. Blade torsional dynamic response and control are also shown to be significantly improved through the use of edge stiffening structural features or inclusion of modest tip masses to increase centrifugal stiffening of the blade structure. An output-only system identification procedure suitable for on-orbit blade dynamics investigations is also developed and validated using ground tests of spinning sub-scale heliogyro blade models. Overall, analytical and experimental investigations to date indicate no intractable stability or control issues for the heliogyro solar sail concept.

Lessons for Interstellar Travel from the G&C Design of the NEA Scout Solar Sail Mission

Science.gov (United States)

Heaton, Andrew; Diedrich, Benjamin

2017-01-01

NASA is developing the Near Earth Asteroid (NEA) Scout mission that will use a solar sail to travel to an asteroid where it will perform a slow flyby to acquire science imagery. A guidance and control system was developed to meet the science and trajectory requirements. The NEA Scout design process can be applied to an interstellar or precursor mission that uses a beam-propelled sail. The scientific objectives are met by accurately targeting the destination trajectory position and velocity. The destination is targeted by understanding the force on the sail from the beam (or sunlight in the case of NEA Scout) over the duration of the thrust maneuver. The propulsive maneuver is maintained by accurate understanding of the torque on the sail, which is a function of sail shape, optical properties, and mass properties, all of which apply to NEA Scout and beam propelled sails. NEA Scout uses active control of the sail attitude while trimming the solar torque, which could be used on a beamed propulsion sail if necessary. The biggest difference is that NEA Scout can correct for uncertainties in sail thrust modeling, spacecraft orbit, and target orbit throughout the flight to the target, while beamed propulsion needs accurate operation for the short duration of the beamed propulsion maneuver, making accurate understanding of the sail thrust and orbits much more critical.

Simulations of momentum transfer process between solar wind plasma and bias voltage tethers of electric sail thruster

Science.gov (United States)

Xia, Guangqing; Han, Yajie; Chen, Liuwei; Wei, Yanming; Yu, Yang; Chen, Maolin

2018-06-01

The interaction between the solar wind plasma and the bias voltage of long tethers is the basic mechanism of the electric sail thruster. The momentum transfer process between the solar wind plasma and electric tethers was investigated using a 2D full particle PIC method. The coupled electric field distribution and deflected ion trajectory under different bias voltages were compared, and the influence of bias voltage on momentum transfer process was analyzed. The results show that the high potential of the bias voltage of long tethers will slow down, stagnate, reflect and deflect a large number of ions, so that ion cavities are formed in the vicinity of the tether, and the ions will transmit the axial momentum to the sail tethers to produce the thrust. Compared to the singe tether, double tethers show a better thrust performance.

NanoSail - D Orbital and Attitude Dynamics

Science.gov (United States)

Heaton, Andrew F.; Faller, Brent F.; Katan, Chelsea K.

2013-01-01

NanoSail-D unfurled January 20th, 2011 and successfully demonstrated the deployment and deorbit capability of a solar sail in low Earth orbit. The orbit was strongly perturbed by solar radiation pressure, aerodynamic drag, and oblate gravity which were modeled using STK HPOP. A comparison of the ballistic coefficient history to the orbit parameters exhibits a strong relationship between orbital lighting, the decay rate of the mean semi-major axis and mean eccentricity. A similar comparison of mean solar area using the STK HPOP solar radiation pressure model exhibits a strong correlation of solar radiation pressure to mean eccentricity and mean argument of perigee. NanoSail-D was not actively controlled and had no capability on-board for attitude or orbit determination. To estimate attitude dynamics we created a 3-DOF attitude dynamics simulation that incorporated highly realistic estimates of perturbing forces into NanoSail-D torque models. By comparing the results of this simulation to the orbital behavior and ground observations of NanoSail-D, we conclude that there is a coupling between the orbit and attitude dynamics as well as establish approximate limits on the location of the NanoSail-D solar center of pressure. Both of these observations contribute valuable data for future solar sail designs and missions.

Plasma Deflection Test Setup for E-Sail Propulsion Concept

Science.gov (United States)

Andersen, Allen; Vaughn, Jason; Schneider, Todd; Wright, Ken

2016-01-01

The Electronic Sail or E-Sail is a novel propulsion concept based on momentum exchange between fast solar wind protons and the plasma sheath of long positively charged conductors comprising the E-Sail. The effective sail area increases with decreasing plasma density allowing an E-Sail craft to continue to accelerate at predicted ranges well beyond the capabilities of existing electronic or chemical propulsion spacecraft. While negatively charged conductors in plasmas have been extensively studied and flown, the interaction between plasma and a positively charged conductor is not well studied. We present a plasma deflection test method using a differential ion flux probe (DIFP). The DIFP measures the angle and energy of incident ions. The plasma sheath around a charged body can measured by comparing the angular distribution of ions with and without a positively charged test body. These test results will be used to evaluate numerical calculations of expected thrust per unit length of conductor in the solar wind plasma. This work was supported by a NASA Space Technology Research Fellowship.

Thrust evaluation of magneto plasma sail that obtains an electromagnetic thrust from the solar wind

International Nuclear Information System (INIS)

Kajimura, Yoshihiro; Funaki, Ikkoh; Usui, Hideyuki; Yamakawa, Hiroshi

2011-01-01

Magneto Plasma Sail (MPS) is a propulsion system used in space, which generates its force by the interaction between the solar wind and an inflated magnetic field via a plasma injection. The quantitative evaluation of the thrust increment generated by injecting a plasma jet with a β in less than unity was conducted by three-dimensional hybrid particle-in-cell (PIC) simulations in an ion inertia scale. The injected plasma β in is 0.02 and the ratio of Larmor radius of injected ion to the representative length of the magnetic field is 0.5 at the injection point. In this situation, the obtained thrust of the MPS is 1.6 mN compared with the 0.2 mN of the thrust obtained by the pure magnetic sail since the induced current region on magnetosphere expanded by the magnetic inflation. (author)

Dielectric films for solar and laser-pushed lightsails

International Nuclear Information System (INIS)

Landis, Geoffrey A.

2000-01-01

This project analyzed the potential use of dielectric thin films for solar and laser sails. Such light-pushed sails allow the possibility of fuel-free propulsion in space. This makes possible missions of extremely high delta-V, potentially as high as 30,000 km/sec (0.1c), which is required for a fly-by mission to a nearby star

Studies of Earth Space Environment and Sudden Disappearances of Solar Prominences

National Research Council Canada - National Science Library

Huang, Tian-Sen

2005-01-01

With the support from AFOSR's Minority University Program, we worked on research of Sun-Earth space environment, conducted daily solar observation programs, improved solar instruments, and established...

Lessons for Interstellar Travel from the Guidance and Control Design of the Near Earth Asteroid Scout Solar Sail Mission

Science.gov (United States)

Diedrich, Benjamin; Heaton, Andrew

2017-01-01

NASA is developing the Near Earth Asteroid (NEA) Scout mission that will use a solar sail to travel to an asteroid where it will perform a slow flyby to acquire science imagery. A guidance and control system was developed to meet the science and trajectory requirements. The NEA Scout design process can be applied to an interstellar or precursor mission that uses a beam propelled sail. The scientific objectives are met by accurately targeting the destination trajectory position and velocity. The destination is targeted by understanding the force on the sail from the beam (or sunlight in the case of NEA Scout) over the duration of the thrust maneuver. The propulsive maneuver is maintained by accurate understanding of the torque on the sail, which is a function of sail shape, optical properties, and mass properties, all of which apply to NEA Scout and beam propelled sails. NEA Scout uses active control of the sail attitude while trimming the solar torque, which could be used on a beamed propulsion sail if necessary. The biggest difference is that NEA Scout can correct for uncertainties in sail thrust modeling, spacecraft orbit, and target orbit throughout the flight to the target, while beamed propulsion needs accurate operation for the short duration of the beamed propulsion maneuver, making accurate understanding of the sail thrust and orbits much more critical.

MODEL CORRELATION STUDY OF A RETRACTABLE BOOM FOR A SOLAR SAIL SPACECRAFT

Science.gov (United States)

Adetona, O.; Keel, L. H.; Oakley, J. D.; Kappus, K.; Whorton, M. S.; Kim, Y. K.; Rakpczy, J. M.

2005-01-01

To realize design concepts, predict dynamic behavior and develop appropriate control strategies for high performance operation of a solar-sail spacecraft, we developed a simple analytical model that represents dynamic behavior of spacecraft with various sizes. Since motion of the vehicle is dominated by retractable booms that support the structure, our study concentrates on developing and validating a dynamic model of a long retractable boom. Extensive tests with various configurations were conducted for the 30 Meter, light-weight, retractable, lattice boom at NASA MSFC that is structurally and dynamically similar to those of a solar-sail spacecraft currently under construction. Experimental data were then compared with the corresponding response of the analytical model. Though mixed results were obtained, the analytical model emulates several key characteristics of the boom. The paper concludes with a detailed discussion of issues observed during the study.

Simulation of space radiation effects on polyimide film materials for high temperature applications. Final report

International Nuclear Information System (INIS)

Fogdall, L.B.; Cannaday, S.S.

1977-11-01

Space environment effects on candidate materials for the solar sail film are determined. Polymers, including metallized polyimides that might be suitable solar radiation receivers, were exposed to combined proton and solar electromagnetic radiation. Each test sample was weighted, to simulate the tension on the polymer when it is stretched into near-planar shape while receiving solar radiation. Exposure rates up to 16 times that expected in Earth orbit were employed, to simulate near-sun solar sailing conditions. Sample appearance, elongation, and shrinkage were monitored, noted, and documented in situ. Thermosetting polyimides showed less degradation or visual change in appearance than thermoplastics

Boltzmann electron PIC simulation of the E-sail effect

Directory of Open Access Journals (Sweden)

P. Janhunen

2015-12-01

Full Text Available The solar wind electric sail (E-sail is a planned in-space propulsion device that uses the natural solar wind momentum flux for spacecraft propulsion with the help of long, charged, centrifugally stretched tethers. The problem of accurately predicting the E-sail thrust is still somewhat open, however, due to a possible electron population trapped by the tether. Here we develop a new type of particle-in-cell (PIC simulation for predicting E-sail thrust. In the new simulation, electrons are modelled as a fluid, hence resembling hybrid simulation, but in contrast to normal hybrid simulation, the Poisson equation is used as in normal PIC to calculate the self-consistent electrostatic field. For electron-repulsive parts of the potential, the Boltzmann relation is used. For electron-attractive parts of the potential we employ a power law which contains a parameter that can be used to control the number of trapped electrons. We perform a set of runs varying the parameter and select the one with the smallest number of trapped electrons which still behaves in a physically meaningful way in the sense of producing not more than one solar wind ion deflection shock upstream of the tether. By this prescription we obtain thrust per tether length values that are in line with earlier estimates, although somewhat smaller. We conclude that the Boltzmann PIC simulation is a new tool for simulating the E-sail thrust. This tool enables us to calculate solutions rapidly and allows to easily study different scenarios for trapped electrons.

Thrust calculation of electric solar wind sail by particle-in-cell simulation

Energy Technology Data Exchange (ETDEWEB)

Hoshi, Kento [Kyoto Univ. (Japan). Dept. of Electrical Engineering; Kojima, Hirotsugu; Yamakawa, Hiroshi [Kyoto Univ. (Japan). Research Inst. for Sustainable Humanosphere; Muranaka, Takanobu [Chukyo Univ., Nagoya (Japan). Dept. of Electrical Engineering

2016-07-01

In this study, thrust characteristics of an electric solar wind sail were numerically evaluated using full threedimensional particle-in-cell (PIC) simulation. The thrust obtained from the PIC simulation was lower than the thrust estimations obtained in previous studies. The PIC simulation indicated that ambient electrons strongly shield the electrostatic potential of the tether of the sail, and the strong shield effect causes a greater thrust reduction than has been obtained in previous studies. Additionally, previous expressions of the thrust estimation were modified by using the shielded potential structure derived from the present simulation results. The modified thrust estimation agreed very well with the thrust obtained from the PIC simulation.

Thrust calculation of electric solar wind sail by particle-in-cell simulation

International Nuclear Information System (INIS)

Hoshi, Kento; Kojima, Hirotsugu; Yamakawa, Hiroshi; Muranaka, Takanobu

2016-01-01

In this study, thrust characteristics of an electric solar wind sail were numerically evaluated using full threedimensional particle-in-cell (PIC) simulation. The thrust obtained from the PIC simulation was lower than the thrust estimations obtained in previous studies. The PIC simulation indicated that ambient electrons strongly shield the electrostatic potential of the tether of the sail, and the strong shield effect causes a greater thrust reduction than has been obtained in previous studies. Additionally, previous expressions of the thrust estimation were modified by using the shielded potential structure derived from the present simulation results. The modified thrust estimation agreed very well with the thrust obtained from the PIC simulation.

Electric sail elliptic displaced orbits with advanced thrust model

Science.gov (United States)

Niccolai, Lorenzo; Quarta, Alessandro A.; Mengali, Giovanni

2017-09-01

This paper analyzes the performance of an Electric Solar Wind Sail for generating and maintaining an elliptic, heliocentric, displaced non-Keplerian orbit. In this sense, this paper extends and completes recent studies regarding the performances of an Electric Solar Wind Sail that covers a circular, heliocentric, displaced orbit of given characteristics. The paper presents the general equations that describe the elliptic orbit maintenance in terms of both spacecraft attitude and performance requirements, when a refined thrust model (recently proposed for the preliminary mission design) is taken into account. In particular, the paper also discusses some practical applications on particular mission scenarios in which an analytic solution of the governing equations has been found.

SailSpy: a vision system for yacht sail shape measurement

Science.gov (United States)

Olsson, Olof J.; Power, P. Wayne; Bowman, Chris C.; Palmer, G. Terry; Clist, Roger S.

1992-11-01

SailSpy is a real-time vision system which we have developed for automatically measuring sail shapes and masthead rotation on racing yachts. Versions have been used by the New Zealand team in two America's Cup challenges in 1988 and 1992. SailSpy uses four miniature video cameras mounted at the top of the mast to provide views of the headsail and mainsail on either tack. The cameras are connected to the SailSpy computer below deck using lightweight cables mounted inside the mast. Images received from the cameras are automatically analyzed by the SailSpy computer, and sail shape and mast rotation parameters are calculated. The sail shape parameters are calculated by recognizing sail markers (ellipses) that have been attached to the sails, and the mast rotation parameters by recognizing deck markers painted on the deck. This paper describes the SailSpy system and some of the vision algorithms used.

Photogrammetry and Videogrammetry Methods Development for Solar Sail Structures. Masters Thesis awarded by George Washington Univ.

Science.gov (United States)

Pappa, Richard S. (Technical Monitor); Black, Jonathan T.

2003-01-01

This report discusses the development and application of metrology methods called photogrammetry and videogrammetry that make accurate measurements from photographs. These methods have been adapted for the static and dynamic characterization of gossamer structures, as four specific solar sail applications demonstrate. The applications prove that high-resolution, full-field, non-contact static measurements of solar sails using dot projection photogrammetry are possible as well as full-field, non-contact, dynamic characterization using dot projection videogrammetry. The accuracy of the measurement of the resonant frequencies and operating deflection shapes that were extracted surpassed expectations. While other non-contact measurement methods exist, they are not full-field and require significantly more time to take data.

Conceptual Design of an Electric Sail Technology Demonstration Mission Spacecraft

Science.gov (United States)

Wiegmann, Bruce M.

2017-01-01

There is great interest in examining the outer planets of our solar system and Heliopause region (edge of Solar System) and beyond regions of interstellar space by both the Planetary and Heliophysics communities. These needs are well docu-mented in the recent National Academy of Sciences Decadal Surveys. There is significant interest in developing revolutionary propulsion techniques that will enable such Heliopause scientific missions to be completed within 10 to15 years of the launch date. One such enabling propulsion technique commonly known as Electric Sail (E-Sail) propulsion employs positively charged bare wire tethers that extend radially outward from a rotating spacecraft spinning at a rate of one revolution per hour. Around the positively charged bare-wire tethers, a Debye Sheath is created once positive voltage is applied. This sheath stands off of the bare wire tether at a sheath diameter that is proportional to the voltage in the wire coupled with the flux density of solar wind ions within the solar system (or the location of spacecraft in the solar system. The protons that are expended from the sun (solar wind) at 400 to 800 km/sec are electrostatically repelled away from these positively charged Debye sheaths and propulsive thrust is produced via the resulting momentum transfer. The amount of thrust produced is directly proportional to the total wire length. The Marshall Space Flight Center (MSFC) Electric Sail team is currently funded via a two year Phase II NASA Innovative Advanced Concepts (NIAC) awarded in July 2015. The team's current activities are: 1) Developing a Particle in Cell (PIC) numeric engineering model from the experimental data collected at MSFC's Solar Wind Facility on the interaction between simulated solar wind interaction with a charged bare wire that can be applied to a variety of missions, 2) The development of the necessary tether deployers and tethers to enable successful de-ployment of multiple, multi km length bare tethers

Low-cost gossamer systems for solar sailing and spacecraft deorbiting applications.

OpenAIRE

Fernandez, Juan M.

2015-01-01

Nowadays, a technology demonstrator platform popular amongst the research community given their relatively low cost and short development time are cubesats. Nevertheless, cubesats are by definition nano-satellites of small volume and mass, and therefore, they traditionally only allowed very limited sizes of any expandable structure onboard with final deployed areas in the order of a few square meters. This conflicts with the large areas required for efficient solar sails, making the demonstra...

Attitude Operation Results of Solar Sail Demonstrator IKAROS

Science.gov (United States)

Saiki, Takanao; Tsuda, Yuichi; Funase, Ryu; Mimasu, Yuya; Shirasawa, Yoji; Ikaros Demonstration Team,

This paper shows the attitude operation results of Japanese interplanetary solar sail demonstration spacecraft IKAROS. IKAROS was launched on 21 May 2010(JST) aboard an H-IIA rocket, together with the AKATSUKI Venus climate orbiter. As IKAROS is the secondary payload, the development cost and period were restricted and the onboard attitude system is very simple. This paper introduces the attitude determination and control system. And as IKAROS is spin type spacecraft and it has the large membrane, the attitude control is not easy and it is very important to determine the long-term attitude plan in advance. This paper also shows the outline of the IKAROS attitude operation plan and its operation results.

Increased electric sail thrust through removal of trapped shielding electrons by orbit chaotisation due to spacecraft body

Directory of Open Access Journals (Sweden)

P. Janhunen

2009-08-01

Full Text Available An electric solar wind sail is a recently introduced propellantless space propulsion method whose technical development has also started. The electric sail consists of a set of long, thin, centrifugally stretched and conducting tethers which are charged positively and kept in a high positive potential of order 20 kV by an onboard electron gun. The positively charged tethers deflect solar wind protons, thus tapping momentum from the solar wind stream and producing thrust. The amount of obtained propulsive thrust depends on how many electrons are trapped by the potential structures of the tethers, because the trapped electrons tend to shield the charged tether and reduce its effect on the solar wind. Here we present physical arguments and test particle calculations indicating that in a realistic three-dimensional electric sail spacecraft there exist a natural mechanism which tends to remove the trapped electrons by chaotising their orbits and causing them to eventually collide with the conducting tethers. We present calculations which indicate that if these mechanisms were able to remove trapped electrons nearly completely, the electric sail performance could be about five times higher than previously estimated, about 500 nN/m, corresponding to 1 N thrust for a baseline construction with 2000 km total tether length.

Attitude and orbital dynamics modeling for an uncontrolled solar-sail experiment in low-Earth orbit

NARCIS (Netherlands)

Pirovano, L.; Seefeldt, P.; Dachwald, B.; Noomen, R.

2015-01-01

Gossamer-1 is the first project of the three-step Gossamer roadmap, the purpose of which is to develop, prove and demonstrate that solar-sail technology is a safe and reliable propulsion technique for long-lasting and high-energy missions. This paper firstly presents the structural analysis

NASA's Electric Sail Propulsion System Investigations over the Past Three Years

Science.gov (United States)

Wiegmann, Bruce M.

2017-01-01

Personnel from NASA's MSFC have been investigating the feasibility of an advanced propulsion system known as the Electric Sail for future scientific missions of exploration. This team initially won a NASA Space Technology Mission Directorate (STMD) Phase I NASA Innovative Advanced Concept (NIAC) award and then a two year follow-on Phase II NIAC award. This paper documents the findings from this three year investigation. An Electric sail propulsion system is a propellant-less and extremely fast propulsion system that takes advantage of the ions that are present in the solar wind to provide very rapid transit speeds whether to deep space or to the inner solar system. Scientific spacecraft could arrive to Pluto in 5 years, to the boundary of the solar system in ten to twelve years vs. thirty five plus years it took the Voyager spacecraft. The team's recent focused activities are: 1) Developing a Particle in Cell (PIC) numeric engineering model from the experimental data collected at MSFC's Solar Wind Facility on the interaction between simulated solar wind interaction with a charged bare wire that can be applied to a variety of missions, 2) The development of the necessary tether deployers/tethers to enable successful deployment of multiple, multi km length bare tethers, 3) Determining the different missions that can be captured from this revolutionary propulsion system 4) Conceptual designs of spacecraft to reach various destinations whether to the edge of the solar system, or as Heliophysics sentinels around the sun, or to trips to examine a multitude of asteroids These above activities, once demonstrated analytically, will require a technology demonstration mission (2021 to 2023) to demonstrate that all systems work together seamlessly before a Heliophysics Electrostatic Rapid Transit System (HERTS) could be given the go-ahead. The proposed demonstration mission will require that a small spacecraft must first travel to cis-lunar space as the Electric Sail must be

Orbital Dynamics of an Oscillating Sail in the Earth-Moon System

NARCIS (Netherlands)

Heiligers, M.J.; Ceriotti, M.

2017-01-01

The oscillating sail is a novel solar sail configuration where a triangular sail is released at a deflected angle with respect to the Sun-direction. As a result, the sail will conduct an undamped oscillating motion around the Sun-line due to the offset between the centre-of-pressure and

Deployable Propulsion and Power Systems for Solar System Exploration

Science.gov (United States)

Johnson, Les; Carr, John

2017-01-01

NASA is developing thin-film based, deployable propulsion, power and communication systems for small spacecraft that could provide a revolutionary new capability allowing small spacecraft exploration of the solar system. The Near Earth Asteroid (NEA) Scout reconnaissance mission will demonstrate solar sail propulsion on a 6U CubeSat interplanetary spacecraft and lay the groundwork for their future use in deep space science and exploration missions. Solar sails use sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like sail made of a lightweight, highly reflective material. This continuous photon pressure provides propellantless thrust, allowing for very high delta V maneuvers on long-duration, deep space exploration. Since reflected light produces thrust, solar sails require no onboard propellant. The Lightweight Integrated Solar Array and Transceiver (LISA-T) is a launch stowed, orbit deployed array on which thin-film photovoltaic and antenna elements are embedded. Inherently, small satellites are limited in surface area, volume, and mass allocation; driving competition between power, communications, and GN&C (guidance navigation and control) subsystems. This restricts payload capability and limits the value of these low-cost satellites. LISA-T is addressing this issue, deploying large-area arrays from a reduced volume and mass envelope - greatly enhancing power generation and communications capabilities of small spacecraft. The NEA Scout mission, funded by NASA's Advanced Exploration Systems Program and managed by NASA MSFC, will use the solar sail as its primary propulsion system, allowing it to survey and image one or more NEA's of interest for possible future human exploration. NEA Scout uses a 6U cubesat (to be provided by NASA's Jet Propulsion Laboratory), an 86 sq m solar sail and will weigh less than 12 kilograms. NEA Scout will be launched on the first flight of the Space Launch System in 2018. Similar in concept

Sustained Manned Mars Presence Enabled by E-sail Technology and Asteroid Water Mining

Science.gov (United States)

Janhunen, Pekka; Merikallio, Sini; Toivanen, Petri; Envall, M. Jouni

would be reduced because of intermediate tankings plus opening up the possibility of making the craft reusable for several back and forth trips. The manned spacecraft can be tanked first time at Earth C3, second time in Mars orbit for the return trip, and again in Earth C3 for the next trip if the spacecraft is reusable. When propellant is cheap in Mars orbit, it may also make sense to perform an all-propulsive landing which would make thermal shielding unnecessary. In this case the manned spacecraft would be tanked in Mars orbit two times plus once on the surface per each bidirectional mission. We estimate that the dry mass of cryogenic propellant factories and their associated temporary storage tanks that can process 50 tonnes of water per year is 20 tonnes. By developing the E-sail as enabling technology and by employing asteroid water mining, we think that sustained bidirectional Earth-Mars manned transportation could be created which would asymptotically require no more resources than what running the International Space Station requires today. References [1] Janhunen, P., et. al, Electric solar wind sail: Towards test missions (Invited article), Rev. Sci. Instrum., 81, 111301, 2010. [2] Janhunen, P., A. Quarta and G. Mengali G., Electric solar wind sail mass budget model, Geosci. Instrum. Method. Data Syst., 2, 85-95, 2013.

Thermally Induced Vibrations of the Hubble Space Telescope's Solar Array 3 in a Test Simulated Space Environment

Science.gov (United States)

Early, Derrick A.; Haile, William B.; Turczyn, Mark T.; Griffin, Thomas J. (Technical Monitor)

2001-01-01

NASA Goddard Space Flight Center and the European Space Agency (ESA) conducted a disturbance verification test on a flight Solar Array 3 (SA3) for the Hubble Space Telescope using the ESA Large Space Simulator (LSS) in Noordwijk, the Netherlands. The LSS cyclically illuminated the SA3 to simulate orbital temperature changes in a vacuum environment. Data acquisition systems measured signals from force transducers and accelerometers resulting from thermally induced vibrations of the SAI The LSS with its seismic mass boundary provided an excellent background environment for this test. This paper discusses the analysis performed on the measured transient SA3 responses and provides a summary of the results.

Physics-based Space Weather Forecasting in the Project for Solar-Terrestrial Environment Prediction (PSTEP) in Japan

Science.gov (United States)

Kusano, K.

2016-12-01

Project for Solar-Terrestrial Environment Prediction (PSTEP) is a Japanese nation-wide research collaboration, which was recently launched. PSTEP aims to develop a synergistic interaction between predictive and scientific studies of the solar-terrestrial environment and to establish the basis for next-generation space weather forecasting using the state-of-the-art observation systems and the physics-based models. For this project, we coordinate the four research groups, which develop (1) the integration of space weather forecast system, (2) the physics-based solar storm prediction, (3) the predictive models of magnetosphere and ionosphere dynamics, and (4) the model of solar cycle activity and its impact on climate, respectively. In this project, we will build the coordinated physics-based model to answer the fundamental questions concerning the onset of solar eruptions and the mechanism for radiation belt dynamics in the Earth's magnetosphere. In this paper, we will show the strategy of PSTEP, and discuss about the role and prospect of the physics-based space weather forecasting system being developed by PSTEP.

The Heliopause Electrostatic Rapid Transit System (HERTS) - Design, Trades, and Analyses Performed in a Two Year NASA Investigation of Electric Sail Propulsion Systems

Science.gov (United States)

Wiegmann, Bruce M.; Scheider, Todd; Heaton, Andrew; Vaughn, Jason; Stone, Nobie; Wright, Ken

2017-01-01

Personnel from NASA's MSFC have been investigating the feasibility of an advanced propulsion system known as the Electric Sail (E-Sail) for future scientific exploration missions. This team initially won a NASA Space Technology Mission Directorate (STMD) Phase I NASA Innovative Advanced Concept (NIAC) award and then a two-year follow-on Phase II NIAC award in October 2015. This paper documents the findings from this three-year investigation. An Electric sail, a propellant-less propulsion system, uses solar wind ions to rapidly travel either to deep space or the inner solar system. Scientific spacecraft could reach Pluto in 5 years, or the boundary of the solar system in ten to twelve years compared to the thirty-five plus years the Voyager spacecraft took. The team's recent focuses have been: 1) Developing a Particle in Cell (PIC) numeric engineering model from MSFC's experimental data on the interaction between simulated solar wind and a charged bare wire that can be applied to a variety of missions, 2) Determining what missions could benefit from this revolutionary propulsion system, 3) Conceptualizing spacecraft designs for various tasks: to reach the solar system's edge, to orbit the sun as Heliophysics sentinels, or to examine a multitude of asteroids.

7th International Robotic Sailing Conference

CERN Document Server

Tynan, Dermot

2015-01-01

An autonomous sailboat robot is a boat that only uses the wind on its sail as the propelling force, without remote control or human assistance to achieve its mission. Robotic sailing offers the potential of long range and long term autonomous wind propelled, solar or wave-powered carbon neutral devices. Robotic sailing devices could contribute to monitoring of environmental, ecological, meteorological, hydrographic and oceanographic data. These devices can also be used in traffic monitoring, border surveillance, security, assistance and rescue. The dependency on changing winds and sea conditions presents a considerable challenge for short and long term route and stability planning, collision avoidance and boat control. Building a robust and seaworthy sailing robot presents a truly complex and multi-disciplinary challenge for boat designers, naval architects, systems/electrical engineers and computer scientists. Over the last decade, several events such as Sailbot, World Robotic Sailing Championship and the In...

CFD simulation of two-sail interaction about a sailing yacht; Sailing Yacht no niyoku kansho no CFD simulation

Energy Technology Data Exchange (ETDEWEB)

Lee, Y.; Miyata, H.; Sato, T. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering

1997-06-01

Numerical analysis of sail characteristics was done by the finite volume method for an IACC class racing yacht, in compliance to the WISDAM-7 method for analyzing flow fields around the hull. The simulation code makes discrete the Navier-Stokes equation for non-compressive fluid in a conserved system by the finite volume method, and tries to find the solutions following the algorithm of the MAC method in a time-dependent manner. The H-H grids generated by an interface boundary technique for each sail are integrated for the two-sail configuration. It is found that combination of the finite volume method and grid integration is an adequate CFD procedure for simulation of interactions between the two sails. Performance of two-sail configuration, involving complex mechanisms such as interactions and separation of flows, is found by the method in which viscosity is taken into consideration. 5 refs., 20 figs., 3 tabs.

In-Situ Sampling Analysis of a Jupiter Trojan Asteroid by High Resolution Mass Spectrometry in the Solar Power Sail Mission

Science.gov (United States)

Kebukawa, Y.; Aoki, J.; Ito, M.; Kawai, Y.; Okada, T.; Matsumoto, J.; Yano, H.; Yurimoto, H.; Terada, K.; Toyoda, M.; Yabuta, H.; Nakamura, R.; Cottin, H.; Grand, N.; Mori, O.

2017-12-01

The Solar Power Sail (SPS) mission is one of candidates for the upcoming strategic middle-class space exploration to demonstrate the first outer Solar System journey of Japan. The mission concept includes in-situ sampling analysis of the surface and subsurface (up to 1 m) materials of a Jupiter Trojan asteroid using high resolution mass spectrometry (HRMS). The candidates for the HRMS are multi-turn time-of-flight mass spectrometer (MULTUM) type and Cosmorbitrap type. We plan to analyze isotopic and elemental compositions of volatile materials from organic matter, hydrated minerals, and ice (if any), in order to understand origin and evolution of the Jupiter Trojan asteroids. It will provide insights into planet formation/migration theories, evolution and distribution of volatiles in the Solar System, and missing link between asteroids and comets on evolutional. The HRMS system allows to measure H, N, C, O isotopic compositions and elemental compositions of molecules prepared by various pre-MS procedures including stepwise heating up to 600ºC, gas chromatography (GC), and high-temperature pyrolysis with catalyst to decompose the samples into simple gaseous molecules (e.g., H2, CO, and N2) for isotopic ratio analysis. The required mass resolution should be at least 30,000 for analyzing isotopic ratios for simple gaseous molecules. For elemental compositions, mass accuracy of 10 ppm is required to determine elemental compositions for molecules with m/z up to 300 (as well as compound specific isotopic compositions for smaller molecules). Our planned analytical sequences consist of three runs for both surface and subsurface samples. In addition, `sniff mode' which simply introduces environmental gaseous molecules into a HRMS will be done by the system.

Numerical Analysis of Magnetic Sail Spacecraft

International Nuclear Information System (INIS)

Sasaki, Daisuke; Yamakawa, Hiroshi; Usui, Hideyuki; Funaki, Ikkoh; Kojima, Hirotsugu

2008-01-01

To capture the kinetic energy of the solar wind by creating a large magnetosphere around the spacecraft, magneto-plasma sail injects a plasma jet into a strong magnetic field produced by an electromagnet onboard the spacecraft. The aim of this paper is to investigate the effect of the IMF (interplanetary magnetic field) on the magnetosphere of magneto-plasma sail. First, using an axi-symmetric two-dimensional MHD code, we numerically confirm the magnetic field inflation, and the formation of a magnetosphere by the interaction between the solar wind and the magnetic field. The expansion of an artificial magnetosphere by the plasma injection is then simulated, and we show that the magnetosphere is formed by the interaction between the solar wind and the magnetic field expanded by the plasma jet from the spacecraft. This simulation indicates the size of the artificial magnetosphere becomes smaller when applying the IMF.

Science Experiments of a Jupiter Trojan asteroid in the Solar Power Sail Mission

Science.gov (United States)

Okada, T.; Kebukawa, Y.; Aoki, J.; Kawai, Y.; Ito, M.; Yano, H.; Okamoto, C.; Matsumoto, J.; Bibring, J. P.; Ulamec, S.; Jaumann, R.; Iwata, T.; Mori, O.; Kawaguchi, J.

2017-12-01

A Jupiter Trojan asteroid mission using a large area solar power sail (SPS) is under study in JAXA in collaboration with DLR and CNES. The asteroid will be investigated through remote sensing, followed by in situ in-depth observations on the asteroid with a lander. A sample-return is also studied as an option. LUCY has been selected as the NASA's future Discovery class mission which aims at understanding the diversity of Jupiter Trojans by multiple flybys, complementally to the SPS mission. The SPS is a candidate of the next medium class space science mission in Japan. The 1.4-ton spacecraft will carry a 100-kg class lander and 20-kg mission payloads on it. Its launch is expected in mid 2020s, and will take at least 11 years to visit a Jupiter Trojan asteroid. During the cruise phase, science experiments will be performed such as an infrared astronomy, a very long baseline gamma ray interferometry, and dust and magnetic field measurements. A classical static model of solar system suggests that the Jupiter Trojans were formed around the Jupiter region, while a dynamical model such as Nice model indicates that they formed at the far end of the solar system and then scattered inward due to a dynamical migration of giant planets. The physical, mineralogical, organics and isotopic distribution in the heliocentric distance could solve their origin and evolution of the solar system. A global mapping of the asteroid from the mothership will be conducted such as high-resolved imaging, NIR and TIR imaging spectrometry, and radar soundings. The lander will characterize the asteroid with geological, mineralogical, and geophysical observations using a panoramic camera, an infrared hyperspectral imager, a magnetometer, and a thermal radiometer. These samples will be measured by a high resolved mass spectrometer (HRMS) to investigate isotopic ratios of hydrogen, nitrogen, oxygen, as well as organic species.

Laser-light sailing and non-stationary power stations applied to robotic star probes

International Nuclear Information System (INIS)

Matloff, Gregory L.

2000-01-01

The light sail has emerged as a leading contender to propel extrasolar expeditions. Because solar-sail performance is limited by the inverse-square law, one-way expeditions to other stars requiring voyage durations of a few centuries or less may be propelled by radiation pressure from a laser beam originating from a location closer to the Sun than the space probe. Maintaining a stationary laser power station in position between Sun and spacecraft for years or decades presents many technical challenges. This paper presents a variation on the laser power station that may be simpler to implement, in which the Sun-pumped laser power station follows the spacecraft on a parabolic or slightly hyperbolic trajectory

Tidal sails : an alternative to turbines for harvesting tidal current energy

Energy Technology Data Exchange (ETDEWEB)

Hanssen, J.E. [Tidal Sails, Haugesund (Norway)

2008-07-01

Tidal sail technology harnesses the energy of tidal streams in order to produce electricity. Tidal currents move the sails that are attached to wires that rotate generator wheels to produce electricity. The technology has a low impact on the surrounding environment and is simple to install. This presentation discussed the methods used to determine the influence of relative sail velocity and measure estimated energy output levels. The sails were recently tested at an on-grid tidal stream pilot in the Norwegian Arctic. A 300 kW turbine installed at the site demonstrated that the site was suitable for a full-scale development of 20 tripod-mounted 600 kW turbines placed at 50 m depth. It was estimated that the 10 strings of 1000 m length provided between 200 and 250 GWh per year. The sails have also been used at a high speed site in Washington state in the United States. The 25 m pilot plant was installed to verify site suitability and examine sail behaviour in real, high-flow currents. It is expected that the technology will be fully commercialized by 2011. Other pilot tests are being conducted to examine flow behaviour; mooring and flotation functionality; and launch and lift capabilities. Engineering work is ongoing to examine plant designs, variable sail spacing, and collaborations with key component suppliers. tabs., figs.

Re-Thinking the Use of the OML Model in Electric-Sail Development

Science.gov (United States)

Stone, Nobie H.

2016-01-01

The Orbit Motion Limited (OML) model commonly forms the basis for calculations made to determine the effect of the long, biased wires of an Electric Sail on solar wind protons and electrons (which determines the thrust generated and the required operating power). A new analysis of the results of previously conducted ground-based experimental studies of spacecraft-space plasma interactions indicate that the expected thrust created by deflected solar wind protons and the current of collected solar wind electrons could be considerably higher than the OML model would suggest. Herein the experimental analysis will be summarized and the assumptions and approximations required to derive the OML equation-and the limitations they impose-will be considered.

Displaced Electric Sail Orbits Design and Transition Trajectory Optimization

Directory of Open Access Journals (Sweden)

Naiming Qi

2014-01-01

Full Text Available Displaced orbits for spacecraft propelled by electric sails are investigated as an alternative to the use of solar sails. The orbital dynamics of electric sails based spacecraft are studied within a spherical coordinate system, which permits finding the solutions of displaced electric sail orbits and optimize transfer trajectory. Transfer trajectories from Earth's orbit to displaced orbit are also studied in an optimal framework, by using genetic algorithm and Gauss pseudospectral method. The initial guesses for the state and control histories used in the Gauss pseudospectral method are interpolated from the best solution of a genetic algorithm. Numerical simulations show that the electric sail is able to perform the transfer from Earth’s orbit to displaced orbit in acceptable time, and the hybrid optimization method has the capability to search the feasible and optimal solution without any initial value guess.

In-Space Propulsion (346620) Technology Project

Data.gov (United States)

National Aeronautics and Space Administration — Technologies include, but are not limited to, electric and advanced chemical propulsion, propellantless propulsion such as aerocapture and solar sails, sample return...

Thrust and torque vector characteristics of axially-symmetric E-sail

Science.gov (United States)

Bassetto, Marco; Mengali, Giovanni; Quarta, Alessandro A.

2018-05-01

The Electric Solar Wind Sail is an innovative propulsion system concept that gains propulsive acceleration from the interaction with charged particles released by the Sun. The aim of this paper is to obtain analytical expressions for the thrust and torque vectors of a spinning sail of given shape. Under the only assumption that each tether belongs to a plane containing the spacecraft spin axis, a general analytical relation is found for the thrust and torque vectors as a function of the spacecraft attitude relative to an orbital reference frame. The results are then applied to the noteworthy situation of a Sun-facing sail, that is, when the spacecraft spin axis is aligned with the Sun-spacecraft line, which approximatively coincides with the solar wind direction. In that case, the paper discusses the equilibrium shape of the generic conducting tether as a function of the sail geometry and the spin rate, using both a numerical and an analytical (approximate) approach. As a result, the structural characteristics of the conducting tether are related to the spacecraft geometric parameters.

Performance Comparisons and Down Selection of Small Motors for Two-Blade Heliogyro Solar Sail 6U CubeSat

Science.gov (United States)

Wiwattananon, Peerawan; Bryant, Robert G.

2015-01-01

This report compiles a review of 130 commercial small scale motors (piezoelectric and electric motors) and almost 20 researched-type small scale piezoelectricmotors for potential use in a 2 blades Heliogyro Solar Sail 6U CubeSat. In this application, a motor and gearhead (drive system) will deploy a roll of solar sailthin film (2 um thick)accommodated in a 2U CubeSat (100 x 200 x 100 mm) housing. The application requirements are: space rated, output torque at fulldeployment of 0.8 Nm, reel speed of 3 rpm, drive system weight limited to 150 grams, diameter limited to 50 mm, and the length not to exceed 40 mm. The 50mm diameter limit was imposed as motors with larger diameters would likely weigh too much and use more space on the satellite wall. This would limit theamount of the payload. The motors performance are compared between small scale, volume within 3x102 cm3 (3x105 mm3), commercial electric DC motors,commercial piezoelectric motors, and researched-type (non-commercial) piezoelectric motors extracted from scientific and product literature. The comparisonssuggest that piezoelectric motors without a gearhead exhibit larger output torque with respect to their volume and weight and require less input power toproduce high torque. A commercially available electric motor plus a gearhead was chosen through a proposed selection process to meet the applications designrequirements.

Handbook of the Solar-Terrestrial Environment

CERN Document Server

Kamide, Y

2007-01-01

The Handbook of the Solar-Terrestrial Environment is a unique compendium. Recognized international leaders in their field contribute chapters on basic topics of solar physics, space plasmas and the Earth's magnetosphere, and on applied topics like the aurora, magnetospheric storms, space weather, space climatology and planetary science. This book will be of highest value as a reference for researchers working in the area of planetary and space science. However, it is also written in a style accessible to graduate students majoring in those fields.

The Orbitrap mass analyzer as a space instrument for the understanding of prebiotic chemistry in the Solar System

Science.gov (United States)

Vuitton, Véronique; Briois, Christelle; Makarov, Alexander

Over the past decade, it has become apparent that organic molecules are widespread in our Solar System and beyond. The better understand of the prebiotic chemistry leading to their formation is a primary objective of many ongoing space missions. Cassini-Huygens revealed the existence of very large molecular structures in Titan's atmosphere as well as on its surface, in the form of dune deposits, but their exact nature remains elusive. One key science goal of the Mars Science Laboratory Curiosity rover is to assess the presence of organics on the red planet. Rosetta will characterize the elemental and isotopic composition of the gas and dust ejected from comet Churyumov-Gerasimenko, while amino acids have been detected in meteorites. This search for complex organics relies heavily on mass spectrometry, which has the remarkable ability to analyze and quantify species from almost any type of sample (provided that the appropriate sampling and ionizing method is used). Because of the harsh constraints of the spatial environment, the mass resolution of the spectrometers onboard current space probes is quite limited compared to laboratory instruments, leading to significant limitations in the scientific return of the data collected. Therefore, future in situ solar system exploration missions would significantly benefit from instruments relying on High Resolution Mass Spectrometry (HRMS). Since 2009, 5 French laboratories (LPC2E, IPAG, LATMOS, LISA, CSNSM) involved in the chemical investigation of solar system bodies form a Consortium to develop HRMS for future space exploration, based on the use of the Orbitrap technology (C. Briois et al., 2014, to be submitted). The work is undertaken in close collaboration with the Thermo Fisher Scientific Company, which commercializes Orbitrap based laboratory instruments. The Orbitrap is an electrostatic mass analyzer, it is compact, lightweight, and can reach a good sensitivity and dynamic range. A prototype is under development at

Accurate approximation of in-ecliptic trajectories for E-sail with constant pitch angle

Science.gov (United States)

Huo, Mingying; Mengali, Giovanni; Quarta, Alessandro A.

2018-05-01

Propellantless continuous-thrust propulsion systems, such as electric solar wind sails, may be successfully used for new space missions, especially those requiring high-energy orbit transfers. When the mass-to-thrust ratio is sufficiently large, the spacecraft trajectory is characterized by long flight times with a number of revolutions around the Sun. The corresponding mission analysis, especially when addressed within an optimal context, requires a significant amount of simulation effort. Analytical trajectories are therefore useful aids in a preliminary phase of mission design, even though exact solution are very difficult to obtain. The aim of this paper is to present an accurate, analytical, approximation of the spacecraft trajectory generated by an electric solar wind sail with a constant pitch angle, using the latest mathematical model of the thrust vector. Assuming a heliocentric circular parking orbit and a two-dimensional scenario, the simulation results show that the proposed equations are able to accurately describe the actual spacecraft trajectory for a long time interval when the propulsive acceleration magnitude is sufficiently small.

Sailing: Cognition, action, communication

Directory of Open Access Journals (Sweden)

Thora Tenbrink

2017-12-01

Full Text Available How do humans perceive and think about space, and how can this be represented adequately? For everyday activities such as locating objects or places, route planning, and the like, many insights have been gained over the past few decades, feeding into theories of spatial cognition and frameworks for spatial information science. In this paper, we explore sailing as a more specialized domain that has not yet been considered in this way, but has a lot to offer precisely because of its peculiarities. Sailing involves ways of thinking about space that are not normally required (or even acquired in everyday life. Movement in this domain is based on a combination of external forces and internal (human intentions that impose various kinds of directionality, affecting local action as well as global planning. Sailing terminology is spatial to a high extent, and involves a range of concepts that have received little attention in the spatial cognition community. We explore the area by focusing on the core features of cognition, action, and communication, and suggest a range of promising future areas of research in this domain as a showcase of the fascinating flexibility of human spatial cognition.

Developments of an Interactive Sail Design Method

Directory of Open Access Journals (Sweden)

S. M. Malpede

2000-01-01

Full Text Available This paper presents a new tool for performing the integrated design and analysis of a sail. The features of the system are the geometrical definition of a sail shape, using the Bezier surface method, the creation of a finite element model for the non-linear structural analysis and a fluid-dynamic model for the aerodynamic analysis. The system has been developed using MATLAB(r. Recent sail design efforts have been focused on solving the aeroelastic behavior of the sail. The pressure distribution on a sail changes continuously, by virtue of cloth stretch and flexing. The sail shape determines the pressure distribution and, at the same time, the pressure distribution on the sail stretches and flexes the sail material determining its shape. This characteristic non-linear behavior requires iterative solution strategies to obtain the equilibrium configuration and evaluate the forces involved. The aeroelastic problem is tackled by combining structural with aerodynamic analysis. Firstly, pressure loads for a known sail-shape are computed (aerodynamic analysis. Secondly, the sail-shape is analyzed for the obtained external loads (structural analysis. The final solution is obtained by using an iterative analysis process, which involves both aerodynamic and the structural analysis. When the solution converges, it is possible to make design modifications.

Space Environment Information System (SPENVIS)

Science.gov (United States)

Kruglanski, Michel; de Donder, Erwin; Messios, Neophytos; Hetey, Laszlo; Calders, Stijn; Evans, Hugh; Daly, Eamonn

SPENVIS is an ESA operational software developed and maintained at BIRA-IASB since 1996. It provides standardized access to most of the recent models of the hazardous space environment, through a user-friendly Web interface (http://www.spenvis.oma.be/). The system allows spacecraft engineers to perform a rapid analysis of environmental problems related to natural radiation belts, solar energetic particles, cosmic rays, plasmas, gases, magnetic fields and micro-particles. Various reporting and graphical utilities and extensive help facilities are included to allow engineers with relatively little familiarity to produce reliable results. SPENVIS also contains an active, integrated version of the ECSS Space Environment Standard and access to in-flight data on the space environment. Although SPENVIS in the first place is designed to help spacecraft designers, it is also used by technical universities in their educational programs. In the framework of the ESA Space Situational Awareness Preparatory Programme, SPENVIS will be part of the initial set of precursor services of the Space Weather segment. SPENVIS includes several engineering models to assess to effects of the space environment on spacecrafts such as surface and internal charging, energy deposition, solar cell damage and SEU rates. The presentation will review how such models could be connected to in situ measurements or forecasting models of the space environment in order to produce post event analysis or in orbit effects alert. The last developments and models implemented in SPENVIS will also be presented.

Assembly of Space CFRP Structures with Racing Sailing Boats Technology

Science.gov (United States)

Nieto, Jose; Yuste, Laura; Pipo, Alvaro; Santarsiero, Pablo; Bureo, Rafael

2014-06-01

Carbon Fiber Reinforced Plastic (CFRP) is commonly used in space applications to get structures with good mechanical performances and a reduced mass. Most of larger parts of spatial structures are already made of CFRP but the achieved weight saving may be jeopardized by the use of metallic brackets as joining elements. This paper describes the work carried out to study and evaluate ways of reducing weight and costs of the joints between structural elements commonly used in space applications.The main objective of this project is to adapt design solutions coming from the racing sailing boats technology to space applications: the use of out-of autoclave (OoA) cured CFRP joints. In addition to that other CFRP solution common in space business, 3D- RTM Bracket, has been evaluated.This development studies the manufacturing and assembly feasibility making use of these CFRP technologies.This study also compares traditional metallic solutions with innovative CFRP ones in terms of mechanical performances at elementary level. Weight and cost of presented solutions are also compared.

Effects of Solar Activity and Space Environment in 2003 Oct.

Directory of Open Access Journals (Sweden)

Kyung-Seok Cho

2004-12-01

Full Text Available In this paper, we present a good example of extreme solar and geomagnetic activities from October to November, 2003. These activities are characterized by very large sunspot groups, X-class solar flares, strong particle events, and huge geomagnetic storms. We discuss ground-based and space-based data in terms of space weather scales. Especially, we present several solar and geomagnetic disturbance data produced in Korea : sunspots, geo-magnetograms, aurora, Ionogram, and Total Electron Content (TEC map by GPS data. Finally, we introduce some examples of the satellite orbit and communication effects caused by these activities; e.g., the disturbances of the KOMPSAT-1 operational orbit and HF communication.

Space Station solar water heater

Science.gov (United States)

Horan, D. C.; Somers, Richard E.; Haynes, R. D.

1990-01-01

The feasibility of directly converting solar energy for crew water heating on the Space Station Freedom (SSF) and other human-tended missions such as a geosynchronous space station, lunar base, or Mars spacecraft was investigated. Computer codes were developed to model the systems, and a proof-of-concept thermal vacuum test was conducted to evaluate system performance in an environment simulating the SSF. The results indicate that a solar water heater is feasible. It could provide up to 100 percent of the design heating load without a significant configuration change to the SSF or other missions. The solar heater system requires only 15 percent of the electricity that an all-electric system on the SSF would require. This allows a reduction in the solar array or a surplus of electricity for onboard experiments.

Formation flying for electric sails in displaced orbits. Part I: Geometrical analysis

Science.gov (United States)

Wang, Wei; Mengali, Giovanni; Quarta, Alessandro A.; Yuan, Jianping

2017-09-01

We present a geometrical methodology for analyzing the formation flying of electric solar wind sail based spacecraft that operate in heliocentric, elliptic, displaced orbits. The spacecraft orbit is maintained by adjusting its propulsive acceleration modulus, whose value is estimated using a thrust model that takes into account a variation of the propulsive performance with the sail attitude. The properties of the relative motion of the spacecraft are studied in detail and a geometrical solution is obtained in terms of relative displaced orbital elements, assumed to be small quantities. In particular, for the small eccentricity case (i.e. for a near-circular displaced orbit), the bounds characterized by the extreme values of relative distances are analytically calculated, thus providing an useful mathematical tool for preliminary design of the spacecraft formation structure.

Space Weather, Environment and Societies

CERN Document Server

Lilensten, Jean

2006-01-01

Our planet exists within a space environment affected by constantly changing solar atmosphere producing cosmic particles and electromagnetic waves. This "space weather" profoundly influences the performance of our technology because we primarily use two means for transmitting information and energy; namely, electromagnetic waves and electricity. On an everyday basis, we have developed methods to cope with the normal conditions. However, the sun remains a fiery star whose 'angry' outbursts can potentially destroy spacecrafts, kill astronauts, melt electricity transformers, stop trains, and generally wreak havoc with human activities. Space Weather is the developing field within astronomy that aims at predicting the sun’s violent activity and minimizing the impacts on our daily lives. Space Weather, Environment, and Societies explains why our technological societies are so dependent on solar activity and how the Sun disturbs the transmission of information and energy. Footnotes expand specific points and the ...

Development of a Motion System for an Advanced Sailing Simulator

NARCIS (Netherlands)

Mulder, F.A.; Verlinden, J.C.

2013-01-01

To train competitive sailing in a virtual setting, motion of the boat as well as haptic feedback of the sail lines is essential. When discussing virtual environments (VEs) the concept of presence is often used. In this study we develop a sailing simulator motion system to research what factors

Solar Torque Management for the Near Earth Asteroid Scout CubeSat Using Center of Mass Position Control

Science.gov (United States)

Orphee, Juan; Heaton, Andrew; Diedrich, Ben; Stiltner, Brandon C.

2018-01-01

A novel mechanism, the Active Mass Translator (AMT), has been developed for the NASA Near Earth Asteroid (NEA) Scout mission to autonomously manage the spacecraft momentum. The NEA Scout CubeSat will launch as a secondary payload onboard Exploration Mission 1 of the Space Launch System. To accomplish its mission, the CubeSat will be propelled by an 86 square-meter solar sail during its two-year journey to reach asteroid 1991VG. NEA Scout's primary attitude control system uses reaction wheels for holding attitude and performing slew maneuvers, while a cold gas reaction control system performs the initial detumble and early trajectory correction maneuvers. The AMT control system requirements, feedback architecture, and control performance will be presented. The AMT reduces the amount of reaction control propellant needed for momentum management and allows for smaller capacity reaction wheels suitable for the limited 6U spacecraft volume. The reduced spacecraft mass allows higher in-space solar sail acceleration, thus reducing time-of-flight. The reduced time-of-flight opens the range of possible missions, which is limited by the lifetime of typical non-radiation tolerant CubeSat avionics exposed to the deep-space environment.

Implications for space radiation environment models from CREAM and CREDO measurements over half a solar cycle

International Nuclear Information System (INIS)

Dyer, C.S.; Truscott, P.R.; Peerless, C.L.; Watson, C.J.; Evans, H.E.; Knight, P.; Cosby, M.; Underwood, C.; Cousins, T.; Noulty, R.; Maag, C.

1999-01-01

Flight data obtained between 1990 and 1997 from the Cosmic Radiation Environment Monitors CREAM and CREDO carried on UoSAT-3, Space Shuttle, STRV-1a (Space Technology Research Vehicle) and APEX (Advanced Photovoltaic and Electronics Experiment Spacecraft) provide coverage over half a solar cycle. The modulation of cosmic rays and evolution of the South Atlantic Anomaly are observed, the former comprising a factor of three increase at high latitudes and the latter a general increase accompanied by a north-westward drift. Comparison of particle fluxes and linear energy transfer (LET) spectra is made with improved environment and radiation transport calculations which account for shield distributions and secondary particles. While there is an encouraging convergence between predictions and observations, significant improvements are still required, particularly in the treatment of locally produced secondary particles. Solar-particle events during this time period have LET spectra significantly below the October 1989 event which has been proposed as a worst case model

Space plasma observations - observations of solar-terrestrial environment. Space Weather Forecast

International Nuclear Information System (INIS)

Sagawa, Eiichi; Akioka, Maki

1996-01-01

The space environment becomes more important than ever before because of the expansion in the utilization of near-earth space and the increase in the vulnerability of large scale systems on the ground such as electrical power grids. The concept of the Space Weather Forecast program emerged from the accumulation of understanding on basic physical processes and from our activities as one of the regional warning centers of the international network of space environment services. (author)

Space environment studies for the SZ-4 spacecraft

International Nuclear Information System (INIS)

Ye Zonghai

2004-01-01

The space environment, especially the solar-terrestrial space environment, has close bearings on mankind's astronautical activities. An overview is presented of the space environment and safeguard services on the 'SZ' series of spacecraft, with special reference to the SZ-4 spacecraft. These include monitoring of the space environment on SZ-4, studies on its distribution, variation and effects on astronautical performance, as well as space environment forecasts for safe launching, normal operation and safe return of SZ-4. Current progress both in China and overseas is covered

Sail '76

Science.gov (United States)

Vandewalle, Raymond

1976-01-01

A new nationwide program called Sail '76 has been launched to give more people the opportunity to try the sport of sailing and to teach people the proper sailing techniques before they invest in a sailboat. (SK)

Interfacing Sail Modules for Use with “Space Tugs”

Directory of Open Access Journals (Sweden)

Florio Dalla Vedova

2018-05-01

Full Text Available The paper introduces and describes the recent and still ongoing development activities performed in Luxembourg for In-Orbit Attach Mechanisms for (Drag Sails Modules to be operated from Space Tugs. After some preparatory work aiming at understanding the possible operational aspects and implications of mating interfaces between these space systems, three possible designs of In-Orbit Attach Mechanisms have been proposed and completed for their 3D (Metal and Plastic Printing, a new manufacturing technology assessed within this project. The Plastic-printed prototype underwent a series of automated tests in which a robotic arm, equipped with an advanced force sensor, replicated four docking scenarii in ideal and degraded modes. The observation of the forces and torque behaviors at and after impact allowed one to characterize the typical patterns for the various contacts but also, to identify a type of potentially dramatic impact for the safety of the docking and its equipment: in the case of the off-axis approach, “point” contacts shall be avoided, as they instantaneously transfer the total kinetic energy in a small area that could break.

Trajectory Design in a Combined Low-Thrust Multi-Body Environment

Data.gov (United States)

National Aeronautics and Space Administration — Low-thrust propulsion (e.g. electric propulsion, solar sailing, etc.) is a promising new technology that may allow smaller, more efficient spacecraft to participate...

The Near-Earth Space Radiation Environment

Science.gov (United States)

Xapsos, Michael

2008-01-01

This viewgraph presentation reviews the effects of the Near-Earth space radiation environment on NASA missions. Included in this presentation is a review of The Earth s Trapped Radiation Environment, Solar Particle Events, Galactic Cosmic Rays and Comparison to Accelerator Facilities.

The Heliopause Electrostatic Rapid Transit System (HERTS) Design, Trades, and Analyses Performed in a Two Year NASA Investigation of Electric Sail Propulsion Systems

Science.gov (United States)

Wiegmann, Bruce M.

2017-01-01

The Heliopause Electrostatic Rapid Transit System (HERTS) was one of the seven total Phase II NASA Innovative Advanced Concepts (NIAC) that was down-selected in 2015 for continued funding and research. In Phase I our team learned that a spacecraft propelled by an Electric Sail (E-Sail) can travel great astronomical distances, such as to the Heliopause region of the solar system (approx. 100 to 120 AU) in approximately one quarter of the time (10 years) versus the time it took the Voyager spacecraft launched in 1977 (36 years). The completed work within the Phase II NIAC funded effort builds upon the work that was done in the Phase I NIAC and is focused on: 1) Testing of plasma interaction with a charged wire in a MSFC simulated solar environment vacuum test chamber. 2) Development of a Particle-in-Cell (PIC) models that are validated in the plasma testing and used to extrapolate to the E-Sail propulsion system design. 3) Conceptual design of a Technology Demonstration Mission (TDM) spacecraft developed to showcase E-Sail propulsion systems. 4) Down selection of both: a) Materials for a multi km length conductor and, b) Best configuration of the proposed conductor deployment subsystem. This paper will document the findings to date (June, 2017) of the above focused areas.

NASA Space Environments Technical Discipline Team Space Weather Activities

Science.gov (United States)

Minow, J. I.; Nicholas, A. C.; Parker, L. N.; Xapsos, M.; Walker, P. W.; Stauffer, C.

2017-12-01

The Space Environment Technical Discipline Team (TDT) is a technical organization led by NASA's Technical Fellow for Space Environments that supports NASA's Office of the Chief Engineer through the NASA Engineering and Safety Center. The Space Environments TDT conducts independent technical assessments related to the space environment and space weather impacts on spacecraft for NASA programs and provides technical expertise to NASA management and programs where required. This presentation will highlight the status of applied space weather activities within the Space Environment TDT that support development of operational space weather applications and a better understanding of the impacts of space weather on space systems. We will first discuss a tool that has been developed for evaluating space weather launch constraints that are used to protect launch vehicles from hazardous space weather. We then describe an effort to better characterize three-dimensional radiation transport for CubeSat spacecraft and processing of micro-dosimeter data from the International Space Station which the team plans to make available to the space science community. Finally, we will conclude with a quick description of an effort to maintain access to the real-time solar wind data provided by the Advanced Composition Explorer satellite at the Sun-Earth L1 point.

WORLD TRAINING SAILING BOATS

Directory of Open Access Journals (Sweden)

Svitlana Yeroshkina

2016-06-01

Full Text Available In scientific article is researched tendencies, which took place in historical process of the world segmentation of sailing tall ships and their influence on modern composition on whole word’s training sailing boats. By variety parameters modern composition of ships was done the estimation of most biggest tall sailing ships. Complete technical description of the powerful sailing tall ships was done on the present day. Identified and given the technical possibilities for further exploitation of  Ukrainian training sailing boats. Assesses the current state of the sailing fleet in terms of economic costs and expenses of Crimea’s occupation and continuous war on eastern region of Ukraine.Key words: training sailing boats, world segment of sailing boats, sailing boats. JEL: L 92

Deceleration of High-velocity Interstellar Photon Sails into Bound Orbits at α Centauri

Energy Technology Data Exchange (ETDEWEB)

Heller, René [Max Planck Institute for Solar System Research Justus-von-Liebig-Weg 3, 37077 Göttingen (Germany); Hippke, Michael, E-mail: heller@mps.mpg.de, E-mail: hippke@ifda.eu [Luiter Straße 21b, 47506 Neukirchen-Vluyn (Germany)

2017-02-01

At a distance of about 4.22 ly, it would take about 100,000 years for humans to visit our closest stellar neighbor Proxima Centauri using modern chemical thrusters. New technologies are now being developed that involve high-power lasers firing at 1 gram solar sails in near-Earth orbits, accelerating them to 20% the speed of light ( c ) within minutes. Although such an interstellar probe could reach Proxima 20 years after launch, without propellant to slow it down it would traverse the system within hours. Here we demonstrate how the stellar photon pressures of the stellar triple α Cen A, B, and C (Proxima) can be used together with gravity assists to decelerate incoming solar sails from Earth. The maximum injection speed at α Cen A to park a sail with a mass-to-surface ratio ( σ ) similar to graphene (7.6 × 10{sup −4} gram m{sup −2}) in orbit around Proxima is about 13,800 km s{sup −1} (4.6% c ), implying travel times from Earth to α Cen A and B of about 95 years and another 46 years (with a residual velocity of 1280 km s{sup −1}) to Proxima. The size of such a low- σ sail required to carry a payload of 10 grams is about 10{sup 5} m{sup 2} = (316 m){sup 2}. Such a sail could use solar photons instead of an expensive laser system to gain interstellar velocities at departure. Photogravitational assists allow visits of three stellar systems and an Earth-sized potentially habitable planet in one shot, promising extremely high scientific yields.

Deceleration of High-velocity Interstellar Photon Sails into Bound Orbits at α Centauri

International Nuclear Information System (INIS)

Heller, René; Hippke, Michael

2017-01-01

At a distance of about 4.22 ly, it would take about 100,000 years for humans to visit our closest stellar neighbor Proxima Centauri using modern chemical thrusters. New technologies are now being developed that involve high-power lasers firing at 1 gram solar sails in near-Earth orbits, accelerating them to 20% the speed of light ( c ) within minutes. Although such an interstellar probe could reach Proxima 20 years after launch, without propellant to slow it down it would traverse the system within hours. Here we demonstrate how the stellar photon pressures of the stellar triple α Cen A, B, and C (Proxima) can be used together with gravity assists to decelerate incoming solar sails from Earth. The maximum injection speed at α Cen A to park a sail with a mass-to-surface ratio ( σ ) similar to graphene (7.6 × 10"−"4 gram m"−"2) in orbit around Proxima is about 13,800 km s"−"1 (4.6% c ), implying travel times from Earth to α Cen A and B of about 95 years and another 46 years (with a residual velocity of 1280 km s"−"1) to Proxima. The size of such a low- σ sail required to carry a payload of 10 grams is about 10"5 m"2 = (316 m)"2. Such a sail could use solar photons instead of an expensive laser system to gain interstellar velocities at departure. Photogravitational assists allow visits of three stellar systems and an Earth-sized potentially habitable planet in one shot, promising extremely high scientific yields.

Enhancement of Presence in a Virtual Sailing Environment through Localized Wind Simulation

NARCIS (Netherlands)

Verlinden, J.C.; Mulder, F.A.; Vergeest, J.S.; De Jonge, A.; Krutiy, D.; Nagy, Z.; Logeman, B.J.; Schouten, P.

2013-01-01

In the context of sailing, wind plays an important role. However, there is little knowledge on how wind influences presence – the sense of “being there” - while immersed in a virtual setting. This article explores several wind parameters and presents a wind array to explore presence in a sail

A first course in optimum design of yacht sails

Science.gov (United States)

Sugimoto, Takeshi

1993-03-01

The optimum sail geometry is analytically obtained for the case of maximizing the thrust under equality and inequality constraints on the lift and the heeling moment. A single mainsail is assumed to be set close-hauled in uniform wind and upright on the flat sea surface. The governing parameters are the mast height and the gap between the sail foot and the sea surface. The lifting line theory is applied to analyze the aerodynamic forces acting on a sail. The design method consists of the variational principle and a feasibility study. Almost triangular sails are found to be optimum. Their advantages are discussed.

New solar irradiances for use in space research

Science.gov (United States)

Tobiska, W.; Bouwer, D.; Jones, A.

Space environment research applications require solar irradiances in a variety of time scales and spectral formats We describe the development of research grade modeled solar irradiances using four models and systems that are also used for space weather operations The four models systems include SOLAR2000 S2K SOLARFLARE SFLR APEX and IDAR which are used by Space Environment Technologies SET to provide solar irradiances from the soft X-rays through the visible spectrum SFLR uses the GOES 0 1--0 8 nm X-rays in combination with a Mewe model subroutine to provide 0 1--30 0 nm irradiances at 0 1 nm spectral resolution at 1 minute time resolution and in a 6-hour XUV--EUV spectral solar flare evolution forecast with a 7 minute latency and a 2 minute cadence These irradiances have been calibrated with the SORCE XPS observations and we report on the inclusion of these irradiances in the S2K model There are additional developments with S2K that we discuss particularly the method by which S2K is emerging as a hybrid model empirical plus physics-based and real-time data integration platform Numerous new solar indices have been recently developed for the operations community and we describe their inclusion in S2K The APEX system is a real-time data retrieval system developed under contract to the University of Southern California Space Sciences Center SSC to provide SOHO SEM data processing and distribution SSC provides the updated SEM data to the research community and SET provides the operational data to the space operations community We

Stability of a Light Sail Riding on a Laser Beam

Energy Technology Data Exchange (ETDEWEB)

Manchester, Zachary [John A. Paulson School of Engineering and Applied Science, Harvard University, 60 Oxford St., Cambridge, MA 02138 (United States); Loeb, Abraham, E-mail: zmanchester@seas.harvard.edu [Astronomy Department, Harvard University, 60 Garden St., Cambridge, MA 02138 (United States)

2017-03-10

The stability of a light sail riding on a laser beam is analyzed both analytically and numerically. Conical sails on Gaussian beams, which have been studied in the past, are shown to be unstable without active control or additional mechanical modifications. A new architecture for a passively stable sail-and-beam configuration is proposed. The novel spherical shell design for the sail is capable of “beam riding” without the need for active feedback control. Full three-dimensional ray-tracing simulations are performed to verify our analytical results.

Stability of a Light Sail Riding on a Laser Beam

International Nuclear Information System (INIS)

Manchester, Zachary; Loeb, Abraham

2017-01-01

The stability of a light sail riding on a laser beam is analyzed both analytically and numerically. Conical sails on Gaussian beams, which have been studied in the past, are shown to be unstable without active control or additional mechanical modifications. A new architecture for a passively stable sail-and-beam configuration is proposed. The novel spherical shell design for the sail is capable of “beam riding” without the need for active feedback control. Full three-dimensional ray-tracing simulations are performed to verify our analytical results.

HORIZONTAL AXIS MARINE CURRENT TURBINE DESIGN FOR WIND-ELECTRIC HYBRID SAILING BOAT

Directory of Open Access Journals (Sweden)

Serkan Ekinci

2017-01-01

Full Text Available In recent decades, the number of theoretical studies and applications on electric power production from renewable sources such as wind, solar, sea and tidal flows, has been increasing rapidly. Marine Current Turbines (MCTs, among the power turbines, produce power from alternating flows and are a means of power production even at lower flow rates in oceans and seas. In this study, while maintaining functional requirements, an initial and detailed design (mechanic and hydrodynamic, of an MCT fixed on a sailing boat and at sail which extracts power from the flow around the boat, is undertaken. In the design stages, for analysis and optimization of the marine turbine blade design, the Momentum Blade Element Method is utilized. The Horizontal Axis Marine Turbine (HAMT, determined by the initial and mechanical design, is illustrated with its components included. Computational fluid dynamics (CFD analyses, covering turbine pod geometry at required flow rates and turbine speeds are performed. These analyses are performed very close to real conditions, considering sailing with and without the turbine running (on and off states. The alternator is determined from the results, and the final design which meets the design requirements, is obtained. As a result, a user friendly and innovative turbine design for sail boats, offering more power and efficiency, which is longer lasting compared to solar and wind technologies, that also makes use of renewable sources, such as wind and/or solar, and in addition stores and uses accumulated energy when needed, is proposed.

Solar and terrestrial physics. [effects of solar activities on earth environment

Science.gov (United States)

1975-01-01

The effects of solar radiation on the near space and biomental earth, the upper atmosphere, and the magnetosphere are discussed. Data obtained from the OSO satellites pertaining to the solar cycle variation of extreme ultraviolet (EUV) radiation are analyzed. The effects of solar cycle variation of the characteristics of the solar wind are examined. The fluid mechanics of shock waves and the specific relationship to the characteristics of solar shock waves are investigated. The solar and corpuscular heating of the upper atmosphere is reported based on the findings of the AEROS and NATE experiments. Seasonal variations of the upper atmosphere composition are plotted based on OGO-6 mass spectrometer data.

Pluto's interaction with its space environment: Solar wind, energetic particles, and dust.

Science.gov (United States)

Bagenal, F; Horányi, M; McComas, D J; McNutt, R L; Elliott, H A; Hill, M E; Brown, L E; Delamere, P A; Kollmann, P; Krimigis, S M; Kusterer, M; Lisse, C M; Mitchell, D G; Piquette, M; Poppe, A R; Strobel, D F; Szalay, J R; Valek, P; Vandegriff, J; Weidner, S; Zirnstein, E J; Stern, S A; Ennico, K; Olkin, C B; Weaver, H A; Young, L A

2016-03-18

The New Horizons spacecraft carried three instruments that measured the space environment near Pluto as it flew by on 14 July 2015. The Solar Wind Around Pluto (SWAP) instrument revealed an interaction region confined sunward of Pluto to within about 6 Pluto radii. The region's surprisingly small size is consistent with a reduced atmospheric escape rate, as well as a particularly high solar wind flux. Observations from the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument suggest that ions are accelerated and/or deflected around Pluto. In the wake of the interaction region, PEPSSI observed suprathermal particle fluxes equal to about 1/10 of the flux in the interplanetary medium and increasing with distance downstream. The Venetia Burney Student Dust Counter, which measures grains with radii larger than 1.4 micrometers, detected one candidate impact in ±5 days around New Horizons' closest approach, indicating an upper limit of <4.6 kilometers(-3) for the dust density in the Pluto system. Copyright © 2016, American Association for the Advancement of Science.

Radiation hardened high efficiency silicon space solar cell

International Nuclear Information System (INIS)

Garboushian, V.; Yoon, S.; Turner, J.

1993-01-01

A silicon solar cell with AMO 19% Beginning of Life (BOL) efficiency is reported. The cell has demonstrated equal or better radiation resistance when compared to conventional silicon space solar cells. Conventional silicon space solar cell performance is generally ∼ 14% at BOL. The Radiation Hardened High Efficiency Silicon (RHHES) cell is thinned for high specific power (watts/kilogram). The RHHES space cell provides compatibility with automatic surface mounting technology. The cells can be easily combined to provide desired power levels and voltages. The RHHES space cell is more resistant to mechanical damage due to micrometeorites. Micro-meteorites which impinge upon conventional cells can crack the cell which, in turn, may cause string failure. The RHHES, operating in the same environment, can continue to function with a similar crack. The RHHES cell allows for very efficient thermal management which is essential for space cells generating higher specific power levels. The cell eliminates the need for electrical insulation layers which would otherwise increase the thermal resistance for conventional space panels. The RHHES cell can be applied to a space concentrator panel system without abandoning any of the attributes discussed. The power handling capability of the RHHES cell is approximately five times more than conventional space concentrator solar cells

The Living With a Star Program Space Environment Testbed

Science.gov (United States)

Barth, Janet; Day, John H. (Technical Monitor)

2001-01-01

This viewgraph presentation describes the objective, approach, and scope of the Living With a Star (LWS) program at the Marshall Space Flight Center. Scientists involved in the project seek to refine the understanding of space weather and the role of solar variability in terrestrial climate change. Research and the development of improved analytic methods have led to increased predictive capabilities and the improvement of environment specification models. Specifically, the Space Environment Testbed (SET) project of LWS is responsible for the implementation of improved engineering approaches to observing solar effects on climate change. This responsibility includes technology development, ground test protocol development, and the development of a technology application model/engineering tool.

The Solar Connections Observatory for Planetary Environments

Science.gov (United States)

Oliversen, Ronald J.; Harris, Walter M.; Oegerle, William R. (Technical Monitor)

2002-01-01

The NASA Sun-Earth Connection theme roadmap calls for comparative study of how the planets, comets, and local interstellar medium (LISM) interact with the Sun and respond to solar variability. Through such a study we advance our understanding of basic physical plasma and gas dynamic processes, thus increasing our predictive capabilities for the terrestrial, planetary, and interplanetary environments where future remote and human exploration will occur. Because the other planets have lacked study initiatives comparable to the terrestrial ITM, LWS, and EOS programs, our understanding of the upper atmospheres and near space environments on these worlds is far less detailed than our knowledge of the Earth. To close this gap we propose a mission to study {\\it all) of the solar interacting bodies in our planetary system out to the heliopause with a single remote sensing space observatory, the Solar Connections Observatory for Planetary Environments (SCOPE). SCOPE consists of a binocular EUV/FUV telescope operating from a remote, driftaway orbit that provides sub-arcsecond imaging and broadband medium resolution spectro-imaging over the 55-290 nm bandpass, and high (R>10$^{5}$ resolution H Ly-$\\alpha$ emission line profile measurements of small scale planetary and wide field diffuse solar system structures. A key to the SCOPE approach is to include Earth as a primary science target. From its remote vantage point SCOPE will be able to observe auroral emission to and beyond the rotational pole. The other planets and comets will be monitored in long duration campaigns centered when possible on solar opposition when interleaved terrestrial-planet observations can be used to directly compare the response of both worlds to the same solar wind stream and UV radiation field. Using a combination of observations and MHD models, SCOPE will isolate the different controlling parameters in each planet system and gain insight into the underlying physical processes that define the

Independent sailing with high tetraplegia using sip and puff controls: integration into a community sailing center.

Science.gov (United States)

Rojhani, Solomon; Stiens, Steven A; Recio, Albert C

2017-07-01

We are continually rediscovering how adapted recreational activity complements the rehabilitation process, enriches patients' lives and positively impacts outcome measures. Although sports for people with spinal cord injuries (SCI) has achieved spectacular visibility, participation by high cervical injuries is often restricted due to poor accessibility, safety concerns, lack of adaptability, and high costs of technology. We endeavor to demonstrate the mechanisms, adaptability, accessibility, and benefits the sport of sailing creates in the rehabilitative process. Our sailor is a 27-year-old man with a history of traumatic SCI resulting in C4 complete tetraplegia. The participant completed an adapted introductory sailing course, and instruction on the sip-and-puff sail and tiller control mechanism. With practice, he navigated an on-water course in moderate winds of 5 to 15 knots. Despite trends toward shorter rehabilitation stays, aggressive transdisciplinary collaboration with recreation therapy can provide community and natural environment experiences while inpatient and continuing post discharge. Such peak physical and psychological experiences provide a positive perspective for the future that can be shared on the inpatient unit, with families and support systems like sailing clubs in the community. Rehabilitation theory directs a team process to achieve patient self-awareness and initiate self-actualization in spite of disablement. Utilization of local community sailing centers that have provided accessible assisted options provides person-centered self-realization of goals as assisted by family and natural supports. Such successful patients become native guides for others seeking the same experience.

Space Environment Modelling with the Use of Artificial Intelligence Methods

Science.gov (United States)

Lundstedt, H.; Wintoft, P.; Wu, J.-G.; Gleisner, H.; Dovheden, V.

1996-12-01

Space based technological systems are affected by the space weather in many ways. Several severe failures of satellites have been reported at times of space storms. Our society also increasingly depends on satellites for communication, navigation, exploration, and research. Predictions of the conditions in the satellite environment have therefore become very important. We will here present predictions made with the use of artificial intelligence (AI) techniques, such as artificial neural networks (ANN) and hybrids of AT methods. We are developing a space weather model based on intelligence hybrid systems (IHS). The model consists of different forecast modules, each module predicts the space weather on a specific time-scale. The time-scales range from minutes to months with the fundamental time-scale of 1-5 minutes, 1-3 hours, 1-3 days, and 27 days. Solar and solar wind data are used as input data. From solar magnetic field measurements, either made on the ground at Wilcox Solar Observatory (WSO) at Stanford, or made from space by the satellite SOHO, solar wind parameters can be predicted and modelled with ANN and MHD models. Magnetograms from WSO are available on a daily basis. However, from SOHO magnetograms will be available every 90 minutes. SOHO magnetograms as input to ANNs will therefore make it possible to even predict solar transient events. Geomagnetic storm activity can today be predicted with very high accuracy by means of ANN methods using solar wind input data. However, at present real-time solar wind data are only available during part of the day from the satellite WIND. With the launch of ACE in 1997, solar wind data will on the other hand be available during 24 hours per day. The conditions of the satellite environment are not only disturbed at times of geomagnetic storms but also at times of intense solar radiation and highly energetic particles. These events are associated with increased solar activity. Predictions of these events are therefore

Development of logistic support for space equipment on the base of the “Sail-BMSTU” midget spacecraft

Directory of Open Access Journals (Sweden)

Brom Alla

2016-01-01

Full Text Available The paper envisages the application of integrated logistic support conception (ILS for space equipment on the base of the example of the student’s «Sail BMSTU» midget spacecraft (MS. The peculiarities of space equipment logistic support in operation phase are considered. The special focus is done to the problem of decrease in production expenses of spacecrafts. The paper suggests that the solution of this problem has to be based on tools commonly used in engineering fields – functional analysis and FMECA. The fragment of FMECA is presented. Due to FMECA it is clear what products in spacecrafts should be calibrated in accordance with quality requirements of military class and what ones should be calibrated in accordance with quality requirements of commercial and industrial classes. Each failure mode of midget spacecraft, identified within FMECA, is studied by assessing of criticality, severity and probability of emergence. The paper describes the main procedures of integrated logistic support on the base of the student’s «Sail MGTU» midget spacecraft. Recommended guidelines providing reliability of electro radio products are elaborated. The practical application of integrated logistic support in aerospace industry is reasonably presented.

Heliosheath Space Environment Interactions with Icy Bodies in the Outermost Solar System

Science.gov (United States)

Cooper, John F.; Hill, Matthew E.; Richardson, John D.; Sturner, Steven J.

2006-01-01

The Voyager 1 and 2 spacecraft are exploring the space environment of the outermost solar system at the same time that earth-based astronomy continues to discover new icy bodies, one larger than Pluto, in the transitional region outward from the Classical Kuiper Belt to the Inner Oort Cloud. Some of the Scattered Disk Objects in this region periodically pass through the heliosheath, entered by Voyager 1 in Dec. 2004 and later expected to be reached by Voyager 2, and out even beyond the heliopause into the Very Local Interstellar Medium. The less energetic heliosheath ions, important for implantation and sputtering processes, are abundant near and beyond the termination shock inner boundary, but the source region of the more penetrating anomalous cosmic ray component has not yet been found. Advantageous for modeling of icy body interactions, the measured heliosheath flux spectra are relatively more stable within this new regime of isotropic compressional magnetic turbulence than in the upstream heliospheric environment. The deepest interactions and resultant radiation-induced chemistry arise from the inwardly diffusing component of the galactic cosmic ray ions with significant intensity modulation also arising in the heliosheath beyond Voyager 1. Surface gardening by high-velocity impacts of smaller bodies (e.g., fragments of previous KBO collisions) and dust is a further space weathering process setting the time scales for long term exposure of different regolith layers to the ion irradiation. Sputtering and ionization of impact ejecta grains may provide a substantial feedback of pickup ions for multiple cycles of heliosheath acceleration and icy body interaction. Thus the space weathering interactions are potentially of interest not only for effects on sensible surface composition of the icy bodies but also for evolution of the heliosheath plasma energetic ion, and neutral emission environment.

Analysis of the effects of simulated synergistic LEO environment on solar panels

Science.gov (United States)

Allegri, G.; Corradi, S.; Marchetti, M.; Scaglione, S.

2007-02-01

The effects due to the LEO environment exposure of a solar array primary structure are here presented and discussed in detail. The synergistic damaging components featuring LEO environment are high vacuum, thermal cycling, neutral gas, ultraviolet (UV) radiation and cold plasma. The synergistic effects due to these environmental elements are simulated by "on ground" tests, performed in the Space Environment Simulator (SAS) at the University of Rome "La Sapienza"; numerical simulations are performed by the Space Environment Information System (SPENVIS), developed by the European Space Agency (ESA). A "safe life" design for a solar array primary structure is developed, taking into consideration the combined damaging action of the LEO environment components; therefore results from both numerical and experimental simulations are coupled within the framework of a standard finite element method (FEM) based design. The expected durability of the solar array primary structure, made of laminated sandwich composite, is evaluated assuming that the loads exerted on the structure itself are essentially dependent on thermo-elastic stresses. The optical degradation of surface materials and the stiffness and strength degradation of structural elements are taken into account to assess the global structural durability of the solar array under characteristic operative conditions in LEO environment.

OLTARIS: An Efficient Web-Based Tool for Analyzing Materials Exposed to Space Radiation

Science.gov (United States)

Slaba, Tony; McMullen, Amelia M.; Thibeault, Sheila A.; Sandridge, Chris A.; Clowdsley, Martha S.; Blatting, Steve R.

2011-01-01

The near-Earth space radiation environment includes energetic galactic cosmic rays (GCR), high intensity proton and electron belts, and the potential for solar particle events (SPE). These sources may penetrate shielding materials and deposit significant energy in sensitive electronic devices on board spacecraft and satellites. Material and design optimization methods may be used to reduce the exposure and extend the operational lifetime of individual components and systems. Since laboratory experiments are expensive and may not cover the range of particles and energies relevant for space applications, such optimization may be done computationally with efficient algorithms that include the various constraints placed on the component, system, or mission. In the present work, the web-based tool OLTARIS (On-Line Tool for the Assessment of Radiation in Space) is presented, and the applicability of the tool for rapidly analyzing exposure levels within either complicated shielding geometries or user-defined material slabs exposed to space radiation is demonstrated. An example approach for material optimization is also presented. Slabs of various advanced multifunctional materials are defined and exposed to several space radiation environments. The materials and thicknesses defining each layer in the slab are then systematically adjusted to arrive at an optimal slab configuration.

11th International Space Conference on Protection of Materials and Structures from Space Environment

CERN Document Server

2017-01-01

The proceedings published in this book document and foster the goals of the 11th International Space Conference on “Protection of Materials and Structures from Space Environment” ICPMSE-11 to facilitate exchanges between members of the various engineering and science disciplines involved in the development of space materials. Contributions cover aspects of interaction with space environment of LEO, GEO, Deep Space, Planetary environments, ground-based qualification and in-flight experiments, as well as lessons learned from operational vehicles that are closely interrelated to disciplines of atmospheric sciences, solar-terrestrial interactions and space life sciences.

On the effects of solar storms to the decaying orbital space debris

International Nuclear Information System (INIS)

Herdiwijaya, Dhani; Rachman, Abdul

2014-01-01

Any man-made object in Earth's orbit that no longer serves a useful purpose is classified as orbital debris. Debris objects come from a variety of sources. The majority is related to satellite fragmentation. Other major sources of debris are propulsion systems, and fragmentation of spent upper stages, payload and mission related debris. Serious concern about orbital debris has been growing. Knowledge of the future debris environment is important to both satellite designers, and mission planners, who need to know what hazards a satellite might encounter during the course of its mission. Therefore, it is important to know how much debris is in orbit, where it is located, and when it will decay. The debris environment is complex and dynamically evolving. Objects of different shape and size behave differently in orbit. The geoeffectiveness space environments include solar flux at 10.7 cm, solar energetic particles flux or speed, solar wind flow pressure, electric field, and geomagnetic indices. We study the decaying orbital debris from Tracking and Impact Prediction (TIP) messages in conjuction with geoeffectiveness space environments through time epoch correlation. We found that the decaying and reentry orbital debris are triggered by space environment enhancement within at least one week before reentry. It is not necessary a transient or high energetic and severe solar storm events are needed in decaying processes. We propose that the gradual enhancement processes of space environment will cause satellite surface charging due to energetic electron and enhance drag force

On the effects of solar storms to the decaying orbital space debris

Energy Technology Data Exchange (ETDEWEB)

Herdiwijaya, Dhani, E-mail: dhani@as.itb.ac.id [Astronomy Division and Bosscha Observatory, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10, Bandung 40132 (Indonesia); Rachman, Abdul [Space Science Center, National Institute of Aeronautics and Space, Junjunan 133, Bandung 40173 (Indonesia)

2014-03-24

Any man-made object in Earth's orbit that no longer serves a useful purpose is classified as orbital debris. Debris objects come from a variety of sources. The majority is related to satellite fragmentation. Other major sources of debris are propulsion systems, and fragmentation of spent upper stages, payload and mission related debris. Serious concern about orbital debris has been growing. Knowledge of the future debris environment is important to both satellite designers, and mission planners, who need to know what hazards a satellite might encounter during the course of its mission. Therefore, it is important to know how much debris is in orbit, where it is located, and when it will decay. The debris environment is complex and dynamically evolving. Objects of different shape and size behave differently in orbit. The geoeffectiveness space environments include solar flux at 10.7 cm, solar energetic particles flux or speed, solar wind flow pressure, electric field, and geomagnetic indices. We study the decaying orbital debris from Tracking and Impact Prediction (TIP) messages in conjuction with geoeffectiveness space environments through time epoch correlation. We found that the decaying and reentry orbital debris are triggered by space environment enhancement within at least one week before reentry. It is not necessary a transient or high energetic and severe solar storm events are needed in decaying processes. We propose that the gradual enhancement processes of space environment will cause satellite surface charging due to energetic electron and enhance drag force.

Solar sail trajectory design in the Earth-Moon circular restricted three body problem

Science.gov (United States)

Das, Ashwati

The quest to explore the Moon has helped resolve scientific questions, has spurred leaps in technology development, and has revealed Earth's celestial companion to be a gateway to other destinations. With a renewed focus on returning to the Moon in this decade, alternatives to chemical propulsion systems are becoming attractive methods to efficiently use scarce resources and support extended mission durations. Thus, an investigation is conducted to develop a general framework, that facilitates propellant-free Earth-Moon transfers by exploiting sail dynamics in combination with advantageous transfer options offered in the Earth-Moon circular restricted multi-body dynamical model. Both periodic orbits in the vicinity of the Earth-Moon libration points, and lunar-centric long-term capture orbits are incorporated as target destinations to demonstrate the applicability of the general framework to varied design scanarios, each incorporating a variety of complexities and challenges. The transfers are comprised of three phases - a spiral Earth escape, a transit period, and, finally, the capture into a desirable orbit in the vicinity of the Moon. The Earth-escape phase consists of spiral trajectories constructed using three different sail steering strategies - locally optimal, on/off and velocity tangent. In the case of the Earth-libration point transfers, naturally occurring flow structures (e.g., invariant manifolds) arising from the mutual gravitational interaction of the Earth and Moon are exploited to link an Earth departure spiral with a destination orbit. In contrast, sail steering alone is employed to establish a link between the Earth-escape phase and capture orbits about the Moon due to a lack of applicable natural structures for the required connection. Metrics associated with the transfers including flight-time and the influence of operational constraints, such as occultation events, are investigated to determine the available capabilities for Earth

Space Radiation Environment Prediction for VLSI microelectronics devices onboard a LEO Satellite using OMERE-Trad Software

Science.gov (United States)

Sajid, Muhammad

This tutorial/survey paper presents the assessment/determination of level of hazard/threat to emerging microelectronics devices in Low Earth Orbit (LEO) space radiation environment with perigee at 300 Km, apogee at 600Km altitude having different orbital inclinations to predict the reliability of onboard Bulk Built-In Current Sensor (BBICS) fabricated in 350nm technology node at OptMA Lab. UFMG Brazil. In this context, the various parameters for space radiation environment have been analyzed to characterize the ionizing radiation environment effects on proposed BBICS. The Space radiation environment has been modeled in the form of particles trapped in Van-Allen radiation belts(RBs), Energetic Solar Particles Events (ESPE) and Galactic Cosmic Rays (GCR) where as its potential effects on Device- Under-Test (DUT) has been predicted in terms of Total Ionizing Dose (TID), Single-Event Effects (SEE) and Displacement Damage Dose (DDD). Finally, the required mitigation techniques including necessary shielding requirements to avoid undesirable effects of radiation environment at device level has been estimated /determined with assumed standard thickness of Aluminum shielding. In order to evaluate space radiation environment and analyze energetic particles effects on BBICS, OMERE toolkit developed by TRAD was utilized.

Coupled attitude-orbit dynamics and control for an electric sail in a heliocentric transfer mission.

Science.gov (United States)

Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

2015-01-01

The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail.

A stowing and deployment strategy for large membrane space systems on the example of Gossamer-1

Science.gov (United States)

Seefeldt, Patric

2017-09-01

Deployment systems for innovative space applications such as solar sails require a technique for a controlled and autonomous deployment in space. The deployment process has a strong impact on the mechanism and structural design and sizing. On the example of the design implemented in the Gossamer-1 project of the German Aerospace Center (DLR), such a stowing and deployment process is analyzed. It is based on a combination of zig-zag folding and coiling of triangular sail segments spanned between crossed booms. The deployment geometry and forces introduced by the mechanism considered are explored in order to reveal how the loads are transferred through the membranes to structural components such as the booms. The folding geometry and force progressions are described by function compositions of an inverse trigonometric function with the considered trigonometric function itself. If these functions are evaluated over several periods of the trigonometric function, a non-smooth oscillating curve occurs. Depending on the trigonometric function, these are often vividly described as zig-zag or sawtooth functions. The developed functions are applied to the Gossamer-1 design. The deployment geometry reveals a tendency that the loads are transferred along the catheti of the sail segments and therefore mainly along the boom axes. The load introduced by the spool deployment mechanism is described. By combining the deployment geometry with that load, a prediction of the deployment load progression is achieved. The mathematical description of the stowing and deployment geometry, as well as the forces inflicted by the mechanism provides an understanding of how exactly the membrane deploys and through which edges the deployment forces are transferred. The mathematical analysis also gives an impression of sensitive parameters that could be influenced by manufacturing tolerances or unsymmetrical deployment of the sail segments. While the mathematical model was applied on the design of

Simulated Space Environmental Effects on Thin Film Solar Array Components

Science.gov (United States)

Finckenor, Miria; Carr, John; SanSoucie, Michael; Boyd, Darren; Phillips, Brandon

2017-01-01

The Lightweight Integrated Solar Array and Transceiver (LISA-T) experiment consists of thin-film, low mass, low volume solar panels. Given the variety of thin solar cells and cover materials and the lack of environmental protection typically afforded by thick coverglasses, a series of tests were conducted in Marshall Space Flight Center's Space Environmental Effects Facility to evaluate the performance of these materials. Candidate thin polymeric films and nitinol wires used for deployment were also exposed. Simulated space environment exposures were selected based on SSP 30425 rev. B, "Space Station Program Natural Environment Definition for Design" or AIAA Standard S-111A-2014, "Qualification and Quality Requirements for Space Solar Cells." One set of candidate materials were exposed to 5 eV atomic oxygen and concurrent vacuum ultraviolet (VUV) radiation for low Earth orbit simulation. A second set of materials were exposed to 1 MeV electrons. A third set of samples were exposed to 50, 100, 500, and 700 keV energy protons, and a fourth set were exposed to >2,000 hours of near ultraviolet (NUV) radiation. A final set was rapidly thermal cycled between -55 and +125degC. This test series provides data on enhanced power generation, particularly for small satellites with reduced mass and volume resources. Performance versus mass and cost per Watt is discussed.

Large size space construction for space exploitation

Science.gov (United States)

Kondyurin, Alexey

2016-07-01

Space exploitation is impossible without large space structures. We need to make sufficient large volume of pressurized protecting frames for crew, passengers, space processing equipment, & etc. We have to be unlimited in space. Now the size and mass of space constructions are limited by possibility of a launch vehicle. It limits our future in exploitation of space by humans and in development of space industry. Large-size space construction can be made with using of the curing technology of the fibers-filled composites and a reactionable matrix applied directly in free space. For curing the fabric impregnated with a liquid matrix (prepreg) is prepared in terrestrial conditions and shipped in a container to orbit. In due time the prepreg is unfolded by inflating. After polymerization reaction, the durable construction can be fitted out with air, apparatus and life support systems. Our experimental studies of the curing processes in the simulated free space environment showed that the curing of composite in free space is possible. The large-size space construction can be developed. A project of space station, Moon base, Mars base, mining station, interplanet space ship, telecommunication station, space observatory, space factory, antenna dish, radiation shield, solar sail is proposed and overviewed. The study was supported by Humboldt Foundation, ESA (contract 17083/03/NL/SFe), NASA program of the stratospheric balloons and RFBR grants (05-08-18277, 12-08-00970 and 14-08-96011).

Space environments and their effects on space automation and robotics

Science.gov (United States)

Garrett, Henry B.

1990-01-01

Automated and robotic systems will be exposed to a variety of environmental anomalies as a result of adverse interactions with the space environment. As an example, the coupling of electrical transients into control systems, due to EMI from plasma interactions and solar array arcing, may cause spurious commands that could be difficult to detect and correct in time to prevent damage during critical operations. Spacecraft glow and space debris could introduce false imaging information into optical sensor systems. The presentation provides a brief overview of the primary environments (plasma, neutral atmosphere, magnetic and electric fields, and solid particulates) that cause such adverse interactions. The descriptions, while brief, are intended to provide a basis for the other papers presented at this conference which detail the key interactions with automated and robotic systems. Given the growing complexity and sensitivity of automated and robotic space systems, an understanding of adverse space environments will be crucial to mitigating their effects.

SETI VIA LEAKAGE FROM LIGHT SAILS IN EXOPLANETARY SYSTEMS

International Nuclear Information System (INIS)

Guillochon, James; Loeb, Abraham

2015-01-01

The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI)

SETI via Leakage from Light Sails in Exoplanetary Systems

Science.gov (United States)

Guillochon, James; Loeb, Abraham

2015-10-01

The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI).

SETI VIA LEAKAGE FROM LIGHT SAILS IN EXOPLANETARY SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Guillochon, James; Loeb, Abraham, E-mail: jguillochon@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, The Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States)

2015-10-01

The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI)

Economic feasibility of solar water and space heating.

Science.gov (United States)

Bezdek, R H; Hirshberg, A S; Babcock, W H

1979-03-23

The economic feasibility in 1977 and 1978 of solar water and combined water and space heating is analyzed for single-family detached residences and multi-family apartment buildings in four representative U.S. cities: Boston, Massachusetts; Washington, D.C.; Grand Junction, Colorado; and Los Angeles, California. Three economic decision criteria are utilized: payback period, years to recovery of down payment, and years to net positive cash flow. The cost competitiveness of the solar systems compared to heating systems based on electricity, fuel oil, and natural gas is then discussed for each city, and the impact of the federal tax credit for solar energy systems is assessed. It is found that even without federal incentives some solar water and space heating systems are competitive. Enactment of the solar tax credit, however, greatly enhances their competitiveness. The implications of these findings for government tax and energy pricing policies are discussed.

Solar water heater for NASA's Space Station

Science.gov (United States)

Somers, Richard E.; Haynes, R. Daniel

1988-01-01

The feasibility of using a solar water heater for NASA's Space Station is investigated using computer codes developed to model the Space Station configuration, orbit, and heating systems. Numerous orbit variations, system options, and geometries for the collector were analyzed. Results show that a solar water heater, which would provide 100 percent of the design heating load and would not impose a significant impact on the Space Station overall design is feasible. A heat pipe or pumped fluid radial plate collector of about 10-sq m, placed on top of the habitat module was found to be well suited for satisfying water demand of the Space Station. Due to the relatively small area required by a radial plate, a concentrator is unnecessary. The system would use only 7 to 10 percent as much electricity as an electric water-heating system.

Solar origins of space weather and space climate

CERN Document Server

Komm, Rudolf; Pevtsov, Alexei; Leibacher, John

2014-01-01

This topical issue is based on the presentations given at the 26th National Solar Observatory (NSO) Summer Workshop held at the National Solar Observatory/Sacramento Peak, New Mexico, USA from 30 April to 4 May 2012. This unique forum brought together experts in different areas of solar and space physics to help in developing a full picture of the origin of solar phenomena that affect Earth’s technological systems.  The articles include theory, model, and observation research on the origin of the solar activity and its cycle, as well as a discussion on how to incorporate the research into space-weather forecasting tools.  This volume is aimed at graduate students and researchers active in solar physics and space science.  Previously published in Solar Physics, Vol. 289/2, 2014.

Building Space Heating with a Solar-Assisted Heat Pump Using Roof-Integrated Solar Collectors

Directory of Open Access Journals (Sweden)

Zhiyong Yang

2011-03-01

Full Text Available A solar assisted heat pump (SAHP system was designed by using a roof-integrated solar collector as the evaporator, and then it was demonstrated to provide space heating for a villa in Tianjin, China. A building energy simulation tool was used to predict the space heating load and a three dimensional theoretical model was established to analyze the heat collection performance of the solar roof collector. A floor radiant heating unit was used to decrease the energy demand. The measurement results during the winter test period show that the system can provide a comfortable living space in winter, when the room temperature averaged 18.9 °C. The average COP of the heat pump system is 2.97 and with a maximum around 4.16.

Carbon Nanotube/Space Durable Polymer Nanocomposite Films for Electrostatic Charge Dissipation

Science.gov (United States)

Smith, J. G., Jr.; Watson, K. A.; Thompson, C. M.; Connell, J. W.

2002-01-01

Low solar absorptivity, space environmentally stable polymeric materials possessing sufficient electrical conductivity for electrostatic charge dissipation (ESD) are of interest for potential applications on spacecraft as thin film membranes on antennas, solar sails, large lightweight space optics, and second surface mirrors. One method of imparting electrical conductivity while maintaining low solar absorptivity is through the use of single wall carbon nanotubes (SWNTs). However, SWNTs are difficult to disperse. Several preparative methods were employed to disperse SWNTs into the polymer matrix. Several examples possessed electrical conductivity sufficient for ESD. The chemistry, physical, and mechanical properties of the nanocomposite films will be presented.

Solar Pumped Solid State Lasers for Space Solar Power: Experimental Path

Science.gov (United States)

Fork, Richard L.; Carrington, Connie K.; Walker, Wesley W.; Cole, Spencer T.; Green, Jason J. A.; Laycock, Rustin L.

2003-01-01

We outline an experimentally based strategy designed to lead to solar pumped solid state laser oscillators useful for space solar power. Our method involves solar pumping a novel solid state gain element specifically designed to provide efficient conversion of sunlight in space to coherent laser light. Kilowatt and higher average power is sought from each gain element. Multiple such modular gain elements can be used to accumulate total average power of interest for power beaming in space, e.g., 100 kilowatts and more. Where desirable the high average power can also be produced as a train of pulses having high peak power (e.g., greater than 10(exp 10 watts). The modular nature of the basic gain element supports an experimental strategy in which the core technology can be validated by experiments on a single gain element. We propose to do this experimental validation both in terrestrial locations and also on a smaller scale in space. We describe a terrestrial experiment that includes diagnostics and the option of locating the laser beam path in vacuum environment. We describe a space based experiment designed to be compatible with the Japanese Experimental Module (JEM) on the International Space Station (ISS). We anticipate the gain elements will be based on low temperature (approx. 100 degrees Kelvin) operation of high thermal conductivity (k approx. 100 W/cm-K) diamond and sapphire (k approx. 4 W/cm-K). The basic gain element will be formed by sequences of thin alternating layers of diamond and Ti:sapphire with special attention given to the material interfaces. We anticipate this strategy will lead to a particularly simple, robust, and easily maintained low mass modelocked multi-element laser oscillator useful for space solar power.

Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

Science.gov (United States)

Phillips, Brandon S.; Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H., Jr.

2015-01-01

To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of the space environment. It is critical to understand space environment interactions not only on the PV components, but also the array substrate materials, wiring harnesses, connectors, and protection circuitry (e.g. blocking diodes). Key elements of the space environment which must be accounted for in a PV system design include: Solar Photon Radiation, Charged Particle Radiation, Plasma, and Thermal Cycling. While solar photon radiation is central to generating power in PV systems, the complete spectrum includes short wavelength ultraviolet components, which photo-ionize materials, as well as long wavelength infrared which heat materials. High energy electron radiation has been demonstrated to significantly reduce the output power of III-V type PV cells; and proton radiation damages material surfaces - often impacting coverglasses and antireflective coatings. Plasma environments influence electrostatic charging of PV array materials, and must be understood to ensure that long duration arcs do not form and potentially destroy PV cells. Thermal cycling impacts all components on a PV array by inducing stresses due to thermal expansion and contraction. Given such demanding environments, and the complexity of structures and materials that form a PV array system, mission success can only be ensured through realistic testing in the laboratory. NASA's Marshall Space Flight Center has developed a broad space environment test capability to allow PV array designers and manufacturers to verify their system's integrity and avoid costly on-orbit failures. The Marshall Space Flight Center test capabilities are available to government, commercial, and university customers. Test solutions are tailored to meet the customer's needs, and can include performance assessments, such as flash testing in the case of PV cells.

The effect of motion on presence during virtual sailing for advanced training

NARCIS (Netherlands)

Mulder, F.A.; Verlinden, J.C.; Dukalski, R.R.

2012-01-01

This paper explores the amount of motion simulation required to influence presence and immersion on a dinghy sailing simulator. We specifically focused on the effects of roll, pitch and heave, when sailing an course with up-, side-and down-wind sections in a virtual environment. A real dingy was

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

Solar-pumped lasers for space power transmission

Science.gov (United States)

Taussig, R.; Bruzzone, C.; Nelson, L.; Quimby, D.; Christiansen, W.

1979-01-01

Multi-Megawatt CW solar-pumped lasers appear to be technologically feasible for space power transmission in the 1990s time frame. A new concept for a solar-pumped laser is presented which utilizes an intermediate black body cavity to provide a uniform optical pumping environment for the lasant, either CO or CO2. Reradiation losses are minimized with resulting high efficiency operation. A 1 MW output laser may weigh as little as 8000 kg including solar collector, black body cavity, laser cavity and ducts, pumps, power systems and waste heat radiator. The efficiency of such a system will be on the order of 10 to 20%. Details of the new concept, laser design, comparison to competing solar-powered lasers and applications to a laser solar power satellite (SPS) concept are presented.

Concentrated solar power in the built environment

Science.gov (United States)

Montenon, Alaric C.; Fylaktos, Nestor; Montagnino, Fabio; Paredes, Filippo; Papanicolas, Costas N.

2017-06-01

Solar concentration systems are usually deployed in large open spaces for electricity generation; they are rarely used to address the pressing energy needs of the built environment sector. Fresnel technology offers interesting and challenging CSP energy pathways suitable for the built environment, due to its relatively light weight (Heating, Ventilation, and Air Conditioning) system of a recently constructed office & laboratory building, the Novel Technologies Laboratory (NTL). The multi-generative system will support cooling, heating and hot water production feeding the system of the NTL building, as a demonstration project, part of the STS-MED program (Small Scale Thermal Solar District Units for Mediterranean Communities) financed by the European Commission under the European Neighbourhood and Partnership Instrument (ENPI), CBCMED program.

System identification and the modeling of sailing yachts

Science.gov (United States)

Legursky, Katrina

This research represents an exploration of sailing yacht dynamics with full-scale sailing motion data, physics-based models, and system identification techniques. The goal is to provide a method of obtaining and validating suitable physics-based dynamics models for use in control system design on autonomous sailing platforms, which have the capacity to serve as mobile, long range, high endurance autonomous ocean sensing platforms. The primary contributions of this study to the state-of-the-art are the formulation of a five degree-of-freedom (DOF) linear multi-input multi-output (MIMO) state space model of sailing yacht dynamics, the process for identification of this model from full-scale data, a description of the maneuvers performed during on-water tests, and an analysis method to validate estimated models. The techniques and results described herein can be directly applied to and tested on existing autonomous sailing platforms. A full-scale experiment on a 23ft monohull sailing yacht is developed to collect motion data for physics-based model identification. Measurements include 3 axes of accelerations, velocities, angular rates, and attitude angles in addition to apparent wind speed and direction. The sailing yacht herein is treated as a dynamic system with two control inputs, the rudder angle, deltaR, and the mainsail angle, delta B, which are also measured. Over 20 hours of full scale sailing motion data is collected, representing three sail configurations corresponding to a range of wind speeds: the Full Main and Genoa (abbrev. Genoa) for lower wind speeds, the Full Main and Jib (abbrev. Jib) for mid-range wind speeds, and the Reefed Main and Jib (abbrev. Reef) for the highest wind speeds. The data also covers true wind angles from upwind through a beam reach. A physics-based non-linear model to describe sailing yacht motion is outlined, including descriptions of methods to model the aerodynamics and hydrodynamics of a sailing yacht in surge, sway, roll, and

Radiation Environment at LEO in the frame of Space Monitoring Data Center at Moscow State University - recent, current and future missions

Science.gov (United States)

Myagkova, Irina; Kalegaev, Vladimir; Panasyuk, Mikhail; Svertilov, Sergey; Bogomolov, Vitaly; Bogomolov, Andrey; Barinova, Vera; Barinov, Oleg; Bobrovnikov, Sergey; Dolenko, Sergey; Mukhametdinova, Ludmila; Shiroky, Vladimir; Shugay, Julia

2016-04-01

Radiation Environment of Near-Earth space is one of the most important factors of space weather. Space Monitoring Data Center of Moscow State University provides operational control of radiation conditions at Low Earth's Orbits (LEO) of the near-Earth space using data of recent (Vernov, CORONAS series), current (Meteor-M, Electro-L series) and future (Lomonosov) space missions. Internet portal of Space Monitoring Data Center of Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University (SINP MSU) http://swx.sinp.msu.ru/ provides possibilities to control and analyze the space radiation conditions in the real time mode together with the geomagnetic and solar activity including hard X-ray and gamma- emission of solar flares. Operational data obtained from space missions at L1, GEO and LEO and from the Earth's magnetic stations are used to represent radiation and geomagnetic state of near-Earth environment. The models of space environment that use space measurements from different orbits were created. Interactive analysis and operational neural network forecast services are based on these models. These systems can automatically generate alerts on particle fluxes enhancements above the threshold values, both for SEP and relativistic electrons of outer Earth's radiation belt using data from GEO and LEO as input. As an example of LEO data we consider data from Vernov mission, which was launched into solar-synchronous orbit (altitude 640 - 83 0 km, inclination 98.4°, orbital period about 100 min) on July 8, 2014 and began to receive scientific information since July 20, 2014. Vernov mission have provided studies of the Earth's radiation belt relativistic electron precipitation and its possible connection with atmosphere transient luminous events, as well as the solar hard X-ray and gamma-emission measurements. Radiation and electromagnetic environment monitoring in the near-Earth Space, which is very important for space weather study, was also realised

Information Space, Information Field, Information Environment

Directory of Open Access Journals (Sweden)

Victor Ya. Tsvetkov

2014-08-01

Full Text Available The article analyzes information space, information field and information environment; shows that information space can be natural and artificial; information field is substantive and processual object and articulates the space property; information environment is concerned with some object and acts as the surrounding in relation to it and is considered with regard to it. It enables to define information environment as a subset of information space. It defines its passive description. Information environment can also be defined as a subset of information field. It corresponds to its active description.

Project Dragonfly: A feasibility study of interstellar travel using laser-powered light sail propulsion

Science.gov (United States)

Perakis, Nikolaos; Schrenk, Lukas E.; Gutsmiedl, Johannes; Koop, Artur; Losekamm, Martin J.

2016-12-01

Light sail-based propulsion systems are a candidate technology for interplanetary and interstellar missions due to their flexibility and the fact that no fuel has to be carried along. In 2014, the Initiative for Interstellar Studies (i4is) hosted the Project Dragonfly Design Competition, which aimed at assessing the feasibility of sending an interstellar probe propelled by a laser-powered light sail to another star system. We analyzed and designed a mission to the Alpha Centauri system, with the objective to carry out science operations at the destination. Based on a comprehensive evaluation of currently available technologies and possible locations, we selected a lunar architecture for the laser system. It combines the advantages of surface- and space-based systems, as it requires no station keeping and suffers no atmospheric losses. We chose a graphene-based sandwich material for the light sail because of its low density. Deceleration of the spacecraft sufficient for science operations at the target system is achieved using both magnetic and electric sails. Applying these assumptions in a simulation leads to the conclusion that 250 kg of scientific payload can be sent to Alpha Centauri within the Project Dragonfly Design Competition's constraints of 100 year travel duration and 100 GW laser beam power. This is only sufficient to fulfill parts of the identified scientific objectives, and therefore renders the usefulness of such a mission questionable. A better sail material or higher laser power would improve the acceleration behavior, an increase in the mission time would allow for larger spacecraft masses.

Book Review: Physics of the Space Environment

Science.gov (United States)

Holman, Gordon D.

1998-01-01

Space physics, narrowly defined as the study of Earth's plasma environment, has had an identity crisis throughout its relatively brief existence as a discipline. - The limited and often serendipitous nature of the data requires the research style of an astrophysicist. However, the in situ observations and instrumentation that are central to the field are quite different from the remote observations and instrumentation of astronomy. Compared to neutral gases, the wealth of additional phenomena and the complexity associated with magnetized plasmas and their interaction leaves little in common with the atmospheric scientist. Although the phenomena studied in space physics are ultimately important to astrophysics, the intimate measurements of plasma properties provide a greater commonality with the plasma physicist. Space physics has experienced something of a renaissance in the past few years. The interdisciplinary umbrella "Solar-Terrestrial Physics" or "Sun-Earth Connection" has stimulated an increasing interaction of space physicists, solar physicists and atmospheric scientists. Spectacular images of the Sun from Yohkoh and SOHO and solar-activity-related damage to communications satellites have increased the public's awareness of and interest in "space weather". The dangers of energetic particles and currents in space to technological systems and to future space exploration have elevated space physics observations from interesting scientific measurements that can be included on a space probe to critically important measurements that must be made.

The research on wing sail of a land-yacht robot

Directory of Open Access Journals (Sweden)

Shaorong Xie

2015-12-01

Full Text Available A wind-driven land-yacht robot which will be applied in polar expedition is presented in this article. As the main power of robot is provided by wing sail, improving the efficiency of wing sail is the key for its motion. Wing sail is composed of airfoil, so airfoil theory is researched first, and then several airfoils and their aerodynamic performance are compared, and a high-efficiency airfoil is selected. After that, overturning torque and start wind speed of robot are analyzed to determine the size of the wing sail. At last, the wing sail is manufactured and checked, and it is tested by start wind speed experiments, running speed experiments, steering motion, and obstacle avoidance experiments. The minimum start wind speed is 6 m/s. When wind speed is 10.3 m/s and angle of attack is 90°, running velocity of robot is 1.285 m/s. A land-yacht robot can run steering motion well and avoid obstacle to the target. The result shows that wing sail satisfies the motion requirement of land-yacht robot.

Investigations on sail force by full scale measurement and numerical calculation. Part 1. Steady sailing performance; Sail ryutairyoku ni kansuru jissen shiken to suchi keisan. 1. Teijo hanso seino

Energy Technology Data Exchange (ETDEWEB)

Masuyama, Y.; Fukasawa, T. [Kanazawa Institute of Technology, Ishikawa (Japan); Kitazaki, T. [DMW Corp., Tokyo (Japan)

1997-06-01

Sailing forces are measured with a 10.3m long full-scale sailing boat, equipped with a sail force dynamometer, CCD camera for sail shape measurement and an instrument for detecting sailing conditions of the hull, in order to obtain highly reliable performance data of a sailing yacht. The vortex lattice method is used for step-by-step numerical calculations, and the results are compared with the observed ones. The test results clearly show performance changing with slight changes in relative wind directions and sail shapes, which are not clearly obtained by the traditional wind tunnel tests. The calculated results, although deviating from the observed ones to some extent, well represent trends of performance changing with wind directions and sail shapes. In particular, changed performance caused by slight changes in draft at the main sail is clearly demonstrated. The numerical calculation is considered to be useful for searching for sail trim conditions. 17 refs., 18 figs., 1 tab.

Calculation of Flows Over Underwater Bodies with Hull, Sail and Appendages

International Nuclear Information System (INIS)

Shoab, M.; Ayub, M.; Bilal, S.; Zahir, S.; Khan, M.A.

2004-01-01

A comprehensive study has been made for the hydrodynamic analysis of the submarine DARPA 2. The analysis was first performed for hull, then hull with sail on top and then for the complete submarine including hull, sail and appendages. A comparison of tangential velocity and pressure distribution for hull is accomplished using CFD flow solvers and published data. Further, the pressure distribution over the hull with sail is also analyzed. Finally, pressure distribution, forces and moments were calculated over the complete submarine including hull, sail and appendages. Comparison 01 pressure distribution and tangential velocity for the hull show a good agreement with published data. Pressure coefficient comparison for the hull with sail shows the good CFD-CFD agreement. Comparison of Normal force and pitching moment of complete submarine having hull, sail and appendages shows a reasonable agreement with the experimental results of DARPA 2. Both quantitative and qualitative analysis of the complete submarine estimates the required design force and moment at different angles of attack and also demonstrate the flow visualization. (author)

Isometric quadriceps strength determines sailing performance and neuromuscular fatigue during an upwind sailing emulation.

Science.gov (United States)

Bourgois, Jan G; Callewaert, Margot; Celie, Bert; De Clercq, Dirk; Boone, Jan

2016-01-01

This study investigates the physiological responses to upwind sailing on a laser emulation ergometer and analyses the components of the physical profile that determine the physiological responses related to sailing level. Ten male high-level laser sailors performed an upwind sailing test, incremental cycling test and quadriceps strength test. During the upwind sailing test, heart rate (HR), oxygen uptake, ventilation, respiratory exchange ratio, rating of perceived exertion (RPE) and lactate concentration were measured, combined with near-infrared spectroscopy (NIRS) and electromyography (EMG) registration of the M. Vastus lateralis. Repeated measures ANOVA showed for the cardio-respiratory, metabolic and muscles responses (mean power frequency [MPF], root mean square [RMS], deoxy[Hb+Mb]) during the upwind sailing test an initial significant increase followed by a stabilisation, despite a constant increase in RPE. Stepwise regression analysis showed that better sailing level was for 46.5% predicted by lower MPF decrease. Lower MPF decrease was for 57.8% predicted by a higher maximal isometric quadriceps strength. In conclusion, this study indicates that higher sailing level was mainly determined by a lower rate of neuromuscular fatigue during the upwind sailing test (as indicated by MPF decrease). Additionally, the level of neuromuscular fatigue was mainly determined by higher maximal isometric quadriceps strength stressing the importance of resistance training in the planning of training.

Solar Effects on Tensile and Optical Properties of Hubble Space Telescope Silver-Teflon(Registered Trademark) Insulation

Science.gov (United States)

deGroh, Kim, K.; Dever, Joyce A.; Snyder, Aaron; Kaminski, Sharon; McCarthy, Catherine E.; Rapoport, Alison L.; Rucker, Rochelle N.

2006-01-01

A section of the retrieved Hubble Space Telescope (HST) solar array drive arm (SADA) multilayer insulation (MLI), which experienced 8.25 years of space exposure, was analyzed for environmental durability of the top layer of silver-Teflon (DuPont) fluorinated ethylene propylene (Ag-FEP). Because the SADA MLI had solar and anti-solar facing surfaces and was exposed to the space environment for a long duration, it provided a unique opportunity to study solar effects on the environmental degradation of Ag-FEP, a commonly used spacecraft thermal control material. Data obtained included tensile properties, solar absorptance, surface morphology and chemistry. The solar facing surface was found to be extremely embrittled and contained numerous through-thickness cracks. Tensile testing indicated that the solar facing surface lost 60% of its mechanical strength and 90% of its elasticity while the anti-solar facing surface had ductility similar to pristine FEP. The solar absorptance of both the solar facing surface (0.155 plus or minus 0.032) and the anti-solar facing surface (0.208 plus or minus 0.012) were found to be greater than pristine Ag-FEP (0.074). Solar facing and anti-solar facing surfaces were microscopically textured, and locations of isolated contamination were present on the anti-solar surface resulting in increased localized texturing. Yet, the overall texture was significantly more pronounced on the solar facing surface indicating a synergistic effect of combined solar exposure and increased heating with atomic oxygen erosion. The results indicate a very strong dependence of degradation, particularly embrittlement, upon solar exposure with orbital thermal cycling having a significant effect.

Heliogyro Orbital Control Authority

NARCIS (Netherlands)

Heiligers, M.J.; Guerrant, D.; Lawrence, D

2015-01-01

Solar sailing is an elegant form of space propulsion that reflects solar photons to produce thrust. Different sail configurations exist, including a traditional flat sail (either square- or disc-shaped) and a heliogyro, which divides the sail membrane into a number of long, slender blades, analogous

Effects of DeOrbitSail as applied to Lifetime predictions of Low Earth Orbit Satellites

Science.gov (United States)

Afful, Andoh; Opperman, Ben; Steyn, Herman

2016-07-01

Orbit lifetime prediction is an important component of satellite mission design and post-launch space operations. Throughout its lifetime in space, a spacecraft is exposed to risk of collision with orbital debris or operational satellites. This risk is especially high within the Low Earth Orbit (LEO) region where the highest density of space debris is accumulated. This paper investigates orbital decay of some LEO micro-satellites and accelerating orbit decay by using a deorbitsail. The Semi-Analytical Liu Theory (SALT) and the Satellite Toolkit was employed to determine the mean elements and expressions for the time rates of change. Test cases of observed decayed satellites (Iridium-85 and Starshine-1) are used to evaluate the predicted theory. Results for the test cases indicated that the theory fitted observational data well within acceptable limits. Orbit decay progress of the SUNSAT micro-satellite was analysed using relevant orbital parameters derived from historic Two Line Element (TLE) sets and comparing with decay and lifetime prediction models. This paper also explored the deorbit date and time for a 1U CubeSat (ZACUBE-01). The use of solar sails as devices to speed up the deorbiting of LEO satellites is considered. In a drag sail mode, the deorbitsail technique significantly increases the effective cross-sectional area of a satellite, subsequently increasing atmospheric drag and accelerating orbit decay. The concept proposed in this study introduced a very useful technique of orbit decay as well as deorbiting of spacecraft.

Space solar array reliability: A study and recommendations

Science.gov (United States)

Brandhorst, Henry W., Jr.; Rodiek, Julie A.

2008-12-01

Providing reliable power over the anticipated mission life is critical to all satellites; therefore solar arrays are one of the most vital links to satellite mission success. Furthermore, solar arrays are exposed to the harshest environment of virtually any satellite component. In the past 10 years 117 satellite solar array anomalies have been recorded with 12 resulting in total satellite failure. Through an in-depth analysis of satellite anomalies listed in the Airclaim's Ascend SpaceTrak database, it is clear that solar array reliability is a serious, industry-wide issue. Solar array reliability directly affects the cost of future satellites through increased insurance premiums and a lack of confidence by investors. Recommendations for improving reliability through careful ground testing, standardization of testing procedures such as the emerging AIAA standards, and data sharing across the industry will be discussed. The benefits of creating a certified module and array testing facility that would certify in-space reliability will also be briefly examined. Solar array reliability is an issue that must be addressed to both reduce costs and ensure continued viability of the commercial and government assets on orbit.

A comparative study between control strategies for a solar sailcraft in an Earth-Mars transfer

Science.gov (United States)

Mainenti-Lopes, I.; Souza, L. C. Gadelha; De Sousa, Fabiano. L.

2016-10-01

The goal of this work was a comparative study of solar sail trajectory optimization using different control strategies. Solar sailcraft is propulsion system with great interest in space engineering, since it uses solar radiation to propulsion. So there is no need for propellant to be used, thus it can remains active throughout the entire transfer maneuver. This type of propulsion system opens the possibility to reduce the cost of exploration missions in the solar system. In its simplest configuration, a Flat Solar Sail (FSS) consists of a large and thin structure generally composed by a film fixed to flexible rods. The performance of these vehicles depends largely on the sails attitude relative to the Sun. Using a FSS as propulsion, an Earth-Mars transfer optimization problem was tackled by the algorithms GEOreal1 and GEOreal2 (Generalized Extremal Optimization with real codification). Those algorithms are Evolutionary Algorithms (AE) based on the theory of Self-Organized Criticality. They were used to optimize the FSS attitude angle so it could reach Mars orbit in minimum time. It was considered that the FSS could perform up to ten attitude maneuvers during orbital transfer. Moreover, the time between maneuvers can be different. So, the algorithms had to optimize an objective function with 20 design variables. The results obtained in this work were compared with previously results that considered constant values of time between maneuvers.

The coronas-F space mission key results for solar terrestrial physics

CERN Document Server

2014-01-01

This volume is the updated and extended translation of the Russian original. It presents the results of observations of solar activity and its effects in the Earth space environment carried out from July 2001 to December 2005 on board the CORONAS-F space mission. The general characteristics of the CORONAS-F scientific payload are provided with a description of the principal experiments. The main results focus on the global oscillations of the Sun (p-modes), solar corona, solar flares, solar cosmic rays, Earth’s radiation belts, and upper atmosphere. The book will be welcomed by students, post-graduates, and scientists working in the field of solar and solar-terrestrial physics. This English edition is supplemented by sections presenting new results of the SPIRIT and TESIS experiments under the CORONAS solar program, as well as from the SONG experiment onboard the CORONAS-F satellite.

Effects of a Green Space Layout on the Outdoor Thermal Environment at the Neighborhood Level

Directory of Open Access Journals (Sweden)

Chi-Ming Lai

2012-09-01

Full Text Available This study attempted to address the existing urban design needs and computer-aided thermal engineering and explore the optimal green space layout to obtain an acceptable thermal environment at the neighborhood scale through a series of building energy and computational fluid dynamics (CFD simulations. The building-energy analysis software eQUEST and weather database TMY2 were adopted to analyze the electric energy consumed by air conditioners and the analysis results were incorporated to derive the heat dissipated from air conditioners. Then, the PHOENICS CFD software was used to analyze how the green space layout influences outdoor thermal environment based on the heat dissipated from air conditioners and the solar heat reemitted from the built surfaces. The results show that a green space located in the center of this investigated area and at the far side of the downstream of a summer monsoon is the recommended layout. The layouts, with green space in the center, can decrease the highest temperature by 0.36 °C.

Solar radiation in forested urban environments with dry climate. Case: Metropolitan Area of Mendoza, Argentina

Directory of Open Access Journals (Sweden)

Mariela Edith Arboit

2014-12-01

Full Text Available The aim of this work is to advance the understanding of the solar potential of urban residential environments which, by their morphology, and the impact of urban trees, present values of irradiance very different from full solar collection. Morphological variables of urban settings and urban trees, a very distinctive feature of the Mendoza Metropolitan Area (MMA, have a fundamental impact on the feasibility of implementing strategies for solar energy utilization in urban environments. The results achieved will contribute to modify and gradually update urban and building legislation to implement higher levels of energy efficiency and minimum environmental impacts.This work proposes to study the potential of solar collection in urban environments, analyzing eleven urban configurations selected according to their building and urban morphological characteristics.Methodologically, we have monitored the global solar irradiance on vertical plane on northern facades, completely sunny and partly sunny, affected by solid masking and arboreal masking. Results obtained so far indicate that solar masking is critical for vertical surfaces, with a reduction of the available solar energy between 2% and 66% in the winter season. However, these drawbacks caused by urban trees are compensated by benefits in the warm season: controlling the intensity of the urban heat island, absorption of pollutants, cooling and humidifying the air through evapotranspiration, reducing thermal loads of buildings, occupancy of public open spaces, and an invaluable contribution to the urban aesthetic.

The aerodynamics of sailing apparel

NARCIS (Netherlands)

Jansen, A.J.; Van Deursen, B.; Howe, C.

2012-01-01

The paper presents the effect of changes in sailing apparel on aerodynamic drag, starting from the assumption that drag reduction of sailing apparel will increase the speed of an Olympic class sailing boat (in this case the Laser, a single-handed Olympic dinghy), mainly on upwind courses. Due to the

Technical and operational assessment of molecular nanotechnology for space operations

Science.gov (United States)

McKendree, Thomas Lawrence

2001-07-01

This study assesses the performance of conventional technology and three levels of molecular nanotechnology (MNT) for space operations. The measures of effectiveness are technical performance parameters for five space transportation architectures, and the total logistics cost for an evaluation scenario with mining, market and factory locations on the Moon, Mars and asteroids. On these measures of effectiveness, improvements of 2--4 orders of magnitude are seen in chemical rockets, solar electric ion engines, solar sail accelerations (but not transit times), and in structural masses for planetary skyhooks and towers. Improvements in tether performance and logistics costs are nearer to 1 order of magnitude. Appendices suggest additional improvements may be possible in space mining, closed-environment life support, flexible operations, and with other space transportation architectures. In order to assess logistics cost, this research extends the facility location problem of location theory to orbital space. This extension supports optimal siting of a single facility serving circular, coplanar orbits, locations in elliptic planetary and moon orbits, and heuristic siting of multiple facilities. It focuses on conventional rocket transportation, and on high performance rockets supplying at least 1 m/s2 acceleration and 500,000 m/s exhaust velocity. Mathematica implementations are provided in appendices. Simple MNT allows diamond and buckytube construction. The main benefits are in chemical rocket performance, solar panel specific power, solar electric ion engine performance, and skyhook and tower structural masses. Complex MNT allows very small machinery, permitting large increases in solar panel specific power, which enables solar electric ion engines that are high performance rockets, and thus reduces total logistics costs an order of magnitude. Most Advance MNT allows molecular manufacturing, which enables self-repair, provides at least marginal improvements in nearly

Space weather: Why are magnetospheric physicists interested in solar explosive phenomena

Science.gov (United States)

Koskinen, H. E. J.; Pulkkinen, T. I.

That solar activity drives magnetospheric dynamics has for a long time been the basis of solar-terrestrial physics. Numerous statistical studies correlating sunspots, 10.7 cm radiation, solar flares, etc., with various magnetospheric and geomagnetic parameters have been performed. However, in studies of magnetospheric dynamics the role of the Sun has often remained in the background and only the actual solar wind impinging the magnetosphere has gained most of the attention. During the last few years a new applied field of solar-terrestrial physics, space weather, has emerged. The term refers to variable particle and field conditions in our space environment, which may be hazardous to space-borne or ground-based technological systems and can endanger human life and health. When the modern society is becoming increasingly dependent on space technology, the need for better modelling and also forecasting of space weather becomes urgent. While for post analysis of magnetospheric phenomena it is quite sufficient to include observations from the magnetospheric boundaries out to L1 where SOHO is located, these observations do not provide enough lead-time to run space weather forecasting models and to distribute the forecasts to potential customers. For such purposes we need improved physical understanding and models to predict which active processes on the Sun will impact the magnetosphere and what their expected consequences are. An important change of view on the role of the Sun as the origin of magnetospheric disturbances has taken place during last 10--20 years. For a long time, the solar flares were thought to be the most geoeffective solar phenomena. Now the attention has shifted much more towards coronal mass ejections and the SOHO coronal observations seem to have turned the epoch irreversibly. However, we are not yet ready to make reliable perdictions of the terrestrial environment based on CME observations. From the space weather viewpoint, the key questions are

The Living With a Star Space Environment Testbed Program

Science.gov (United States)

Barth, Janet; LaBel, Kenneth; Day, John H. (Technical Monitor)

2001-01-01

NASA has initiated the Living with a Star (LWS) Program to develop the scientific understanding to address the aspects of the Connected Sun-Earth system that affects life and society. The Program Architecture includes science missions, theory and modeling and Space Environment Testbeds (SET). This current paper discusses the Space Environment Testbeds. The goal of the SET program is to improve the engineering approach to accomodate and/or mitigate the effects of solar variability on spacecraft design and operations. The SET Program will infuse new technologies into the space programs through collection of data in space and subsequent design and validation of technologies. Examples of these technologies are cited and discussed.

Luffing of planar sails

International Nuclear Information System (INIS)

Newman, B.G.

1985-01-01

In this paper the luffing of an unstiffened, two-dimensional impervious membrane is examined. When a sail boat is close-hauled the sails are required to generate high 'lift' with minimum drag. They therefore operate, as do those on hang-wing gliders, at incidences below the stall. However, unlike solid wings they must also avoid negative incidences for then a sail begins to lose its concave shape, to become S shaped and finally, as the incidence is further reduced, to oscillate, a behaviour known as luffing

Relativistic Light Sails

Energy Technology Data Exchange (ETDEWEB)

Kipping, David, E-mail: dkipping@astro.columbia.edu [Department of Astronomy, Columbia University, 550 W. 120th St., New York, NY 10027 (United States)

2017-06-01

One proposed method for spacecraft to reach nearby stars is by accelerating sails using either solar radiation pressure or directed energy. This idea constitutes the thesis behind the Breakthrough Starshot project, which aims to accelerate a gram-mass spacecraft up to one-fifth the speed of light toward Proxima Centauri. For such a case, the combination of the sail’s low mass and relativistic velocity renders previous treatments incorrect at the 10% level, including that of Einstein himself in his seminal 1905 paper introducing special relativity. To address this, we present formulae for a sail’s acceleration, first in response to a single photon and then extended to an ensemble. We show how the sail’s motion in response to an ensemble of incident photons is equivalent to that of a single photon of energy equal to that of the ensemble. We use this principle of ensemble equivalence for both perfect and imperfect mirrors, enabling a simple analytic prediction of the sail’s velocity curve. Using our results and adopting putative parameters for Starshot , we estimate that previous relativistic treatments underestimate the spacecraft’s terminal velocity by ∼10% for the same incident energy. Additionally, we use a simple model to predict the sail’s temperature and diffraction beam losses during the laser firing period; this allows us to estimate that, for firing times of a few minutes and operating temperatures below 300°C (573 K), Starshot will require a sail that absorbs less than one in 260,000 photons.

Relativistic Light Sails

International Nuclear Information System (INIS)

Kipping, David

2017-01-01

One proposed method for spacecraft to reach nearby stars is by accelerating sails using either solar radiation pressure or directed energy. This idea constitutes the thesis behind the Breakthrough Starshot project, which aims to accelerate a gram-mass spacecraft up to one-fifth the speed of light toward Proxima Centauri. For such a case, the combination of the sail’s low mass and relativistic velocity renders previous treatments incorrect at the 10% level, including that of Einstein himself in his seminal 1905 paper introducing special relativity. To address this, we present formulae for a sail’s acceleration, first in response to a single photon and then extended to an ensemble. We show how the sail’s motion in response to an ensemble of incident photons is equivalent to that of a single photon of energy equal to that of the ensemble. We use this principle of ensemble equivalence for both perfect and imperfect mirrors, enabling a simple analytic prediction of the sail’s velocity curve. Using our results and adopting putative parameters for Starshot , we estimate that previous relativistic treatments underestimate the spacecraft’s terminal velocity by ∼10% for the same incident energy. Additionally, we use a simple model to predict the sail’s temperature and diffraction beam losses during the laser firing period; this allows us to estimate that, for firing times of a few minutes and operating temperatures below 300°C (573 K), Starshot will require a sail that absorbs less than one in 260,000 photons.

Investigation of the Airflow around a Sail.

Science.gov (United States)

Gray, Rachel P.

1986-01-01

Shows how air flows around a sail, explaining why a dinghy is able to move toward the wind rather than be blown backwards. Also illustrates the effects of alternating the angle of a sail, using different sail shapes and using a rig consisting of two sails. (JN)

Starship Sails Propelled by Cost-Optimized Directed Energy

Science.gov (United States)

Benford, J.

Microwave and laser-propelled sails are a new class of spacecraft using photon acceleration. It is the only method of interstellar flight that has no physics issues. Laboratory demonstrations of basic features of beam-driven propulsion, flight, stability (`beam-riding'), and induced spin, have been completed in the last decade, primarily in the microwave. It offers much lower cost probes after a substantial investment in the launcher. Engineering issues are being addressed by other applications: fusion (microwave, millimeter and laser sources) and astronomy (large aperture antennas). There are many candidate sail materials: carbon nanotubes and microtrusses, beryllium, graphene, etc. For acceleration of a sail, what is the cost-optimum high power system? Here the cost is used to constrain design parameters to estimate system power, aperture and elements of capital and operating cost. From general relations for cost-optimal transmitter aperture and power, system cost scales with kinetic energy and inversely with sail diameter and frequency. So optimal sails will be larger, lower in mass and driven by higher frequency beams. Estimated costs include economies of scale. We present several starship point concepts. Systems based on microwave, millimeter wave and laser technologies are of equal cost at today's costs. The frequency advantage of lasers is cancelled by the high cost of both the laser and the radiating optic. Cost of interstellar sailships is very high, driven by current costs for radiation source, antennas and especially electrical power. The high speeds necessary for fast interstellar missions make the operating cost exceed the capital cost. Such sailcraft will not be flown until the cost of electrical power in space is reduced orders of magnitude below current levels.

Application of the idea of morphism in solar-terrestrial physics and space weather

International Nuclear Information System (INIS)

Mateev, Lachezar; Tassev, Yordan; Velinov, Peter

2016-01-01

The actual problems of solar-terrestrial physics, in particular of space weather are related to the prediction of the space environment state and are solved by means of different analyses and models. In the present work we introduce a new mathematical approach to the study of physical processes in the system Sun-Earth. For example, in the ionization of the ionosphere and atmosphere under the influence of cosmic rays a model is used that applies the principle of homomorphism. When calculating the parameters of space weather such as solar wind, interplanetary magnetic fields, Earth’s magnetosphere, geomagnetic storms and others, the introduction and application of mathematical objects is appropriate: morphisms, groups, categories, monads, functors, natural transformations and others. Such an approach takes into account the general laws of physical processes in the system Sun – Earth and helps in their testing and calculation. It is useful for such complex systems and processes as these in the solar-terrestrial physics and space weather. Some methods for algebraic structures can be introduced. These methods give the possibility for axiomatization of the physical data reality and the application of algebraic methods for their processing. Here we give the base for the transformation from the algebraic theory of categories and morphisms to the physical structure of concepts and data. Such problems are principally considered in the proposed work. Key words: pace weather, space radiation environment, solar effects, forecasting, energetic solar particles, cosmic rays

Deployable Propulsion, Power and Communications Systems for Solar System Exploration

Science.gov (United States)

Johnson, L.; Carr, J.; Boyd, D.

2017-01-01

NASA is developing thin-film based, deployable propulsion, power, and communication systems for small spacecraft that could provide a revolutionary new capability allowing small spacecraft exploration of the solar system. By leveraging recent advancements in thin films, photovoltaics, and miniaturized electronics, new mission-level capabilities will be enabled aboard lower-cost small spacecraft instead of their more expensive, traditional counterparts, enabling a new generation of frequent, inexpensive deep space missions. Specifically, thin-film technologies are allowing the development and use of solar sails for propulsion, small, lightweight photovoltaics for power, and omnidirectional antennas for communication.

Physical requirements in Olympic sailing

DEFF Research Database (Denmark)

Bojsen-Møller, J; Larsson, B; Aagaard, Per

2015-01-01

Abstract Physical fitness and muscular strength are important performance parameters in Olympic sailing although their relative importance changes between classes. The Olympic format consists of eight yacht types combined into 10 so-called events with total 15 sailors (male and female) in a compl...... to yacht types, and reviews the existing knowledge on physical requirements in modern Olympic sailing. Finally, recommendations for future research in sailing are given.......Abstract Physical fitness and muscular strength are important performance parameters in Olympic sailing although their relative importance changes between classes. The Olympic format consists of eight yacht types combined into 10 so-called events with total 15 sailors (male and female......) in a complete national Olympic delegation. The yachts have different requirements with respect to handling, and moreover, each sailor plays a specific role when sailing. Therefore physical demands remain heterogeneous for Olympic sailors. Previous studies have mainly examined sailors where 'hiking' (the task...

9th International Robotic Sailing Conference

CERN Document Server

Cruz, Nuno

2017-01-01

This book contains selected papers that address a variety of topics related to the design, development and operation of unmanned and fully autonomous sailing boats. These papers were presented in the 9th International Robotic Sailing Conference, in association with the 9th World Robotic Sailing Championship that took place in Viana do Castelo, Portugal from the 5th to 10th of September 2016. The book is divided in three parts, each focusing on key aspects of robotic sailing. The first part addresses the design, construction and validation of autonomous sailboat platforms, including their rigs, appendages and control mechanisms. The second part is devoted to the development of sensors and algorithms to enhance the performance of robotic sailing boats, in terms of their speed, course control and manoeuvring ability. Finally, the papers in the last part are dedicated to the improvement of behaviours required for the accomplishment of complex autonomous missions. Robotic sailing is a relatively new multidisciplin...

5th International Robotic Sailing Conference

CERN Document Server

Finnis, James

2013-01-01

Robotic sailing offers the potential of wind propelled vehicles which are sufficiently autonomous to remain at sea for months at a time. These could replace or augment existing oceanographic sampling systems, be used in border surveillance and security or offer a means of carbon neutral transportation. To achieve this represents a complex, multi-disciplinary challenge to boat designers and naval architects, systems/electrical engineers and computer scientists.  Since 2004 a series of competitions in the form of the Sailbot, World Robotic Sailing Championship and Microtransat competitions have sparked an explosion in the number of groups working on autonomous sailing robots. Despite this interest the longest distance sailed autonomously remains only a few hundred miles. Many of the challenges in building truly autonomous sailing robots still remain unsolved. These proceedings present the cutting edge of work in a variety of fields related to robotic sailing. They will be presented during the 5th International...

Do Inner Planets Modulate the Space Environment of the Earth?

Directory of Open Access Journals (Sweden)

Jung-Hee Kim

2014-03-01

Full Text Available Variabilities in the solar wind cause disturbances throughout the heliosphere on all temporal and spatial scales, which leads to changeable space weather. As a view of space weather forecasting, in particular, it is important to know direct and indirect causes modulating the space environment near the Earth in advance. Recently, there are discussions on a role of the interaction of the solar wind with Mercury in affecting the solar wind velocity in the Earth’s neighborhood during its inferior conjunctions. In this study we investigate a question of whether other parameters describing the space environment near the Earth are modulated by the inner planets’ wake, by examining whether the interplanetary magnetic field and the proton density in the solar wind observed by the Advanced Composition Explorer (ACE spacecraft, and the geomagnetic field via the Dst index and Auroral Electrojet index (AE index are dependent upon the relative position of the inner planets. We find there are indeed apparent variations. For example, the mean variations of the geomagnetic fields measured in the Earth’s neighborhood apparently have varied with a timescale of about 10 to 25 days. Those variations in the parameters we have studied, however, turn out to be a part of random fluctuations and have nothing to do with the relative position of inner planets. Moreover, it is found that variations of the proton density in the solar wind, the Dst index, and the AE index are distributed with the Gaussian distribution. Finally, we point out that some of properties in the behavior of the random fluctuation are to be studied.

Development of an upwind sailing ergometer.

Science.gov (United States)

Callewaert, Margot; Geerts, Stefan; Lataire, Evert; Boone, Jan; Vantorre, Marc; Bourgois, Jan

2013-11-01

To develop a sailing ergometer that accurately simulates upwind sailing exercise. A sailing ergometer that measures roll moment accompanied by a biofeedback system that allows imposing a certain quasi-isometric upwind sailing protocol (ie, 18 bouts of 90-s hiking at constantly varying hiking intensity interspersed with 10 s to tack) was developed. Ten male high-level Laser sailors performed an incremental cycling test (ICT; ie, step protocol at 80 W + 40 W/3 min) and an upwind sailing test (UST). During both, heart rate (HR), oxygen uptake (VO(2)), ventilation (V(E)), respiratory-exchange ratio, and rating of perceived exertion were measured. During UST, also the difference between the required and produced hiking moment (HM) was calculated as error score (ES). HR, VO(2), and V(E) were calculated relative to their peak values determined during ICT. After UST, the subjects were questioned about their opinion on the resemblance between this UST and real-time upwind sailing. An average HM of 89.0% ± 2.2% HM(max) and an average ES of 4.1% ± 1.8% HM(max) were found. Mean HR, VO(2), and V(E) were, respectively, 80% ± 4% HR(peak), 39.5% ± 4.5% VO(2peak), and 30.3% ± 3.7% VE(peak). Both HM and cardiorespiratory values appear to be largely comparable to literature reports during on-water upwind sailing. Moreover, the subjects gave the upwind sailing ergometer a positive resemblance score. Results suggest that this ergometer accurately simulates on-water upwind sailing exercise. As such, this ergometer could be a great help in performance diagnostics and training follow-up.

On-Orbit Measurement of Next Generation Space Solar Cell Technology on the International Space Station

Science.gov (United States)

Wolford, David S.; Myers, Matthew G.; Prokop, Norman F.; Krasowski, Michael J.; Parker, David S.; Cassidy, Justin C.; Davies, William E.; Vorreiter, Janelle O.; Piszczor, Michael F.; McNatt, Jeremiah S.

2015-01-01

Measurement is essential for the evaluation of new photovoltaic (PV) technology for space solar cells. NASA Glenn Research Center (GRC) is in the process of measuring several solar cells in a supplemental experiment on NASA Goddard Space Flight Center's (GSFC) Robotic Refueling Mission's (RRM) Task Board 4 (TB4). Four industry and government partners have provided advanced PV devices for measurement and orbital environment testing. The experiment will be on-orbit for approximately 18 months. It is completely self-contained and will provide its own power and internal data storage. Several new cell technologies including four- junction (4J) Inverted Metamorphic Multijunction (IMM) cells will be evaluated and the results compared to ground-based measurements.

Conceptual model study using origami for membrane space structures : a perspective of origami-based engineering

OpenAIRE

NATORI, M. C.; SAKAMOTO, Hiraku; KATSUMATA, Nobuhisa; YAMAKAWA, Hiroshi; KISHIMOTO, Naoko

2015-01-01

This paper discusses what has been found and what will be found using conceptual “origami” models to develop deployable space structures. The study covers the following: (i) one-dimensional structural elements, which are axially buckled inflatable tubes; (ii) two-dimensional elements, which are deployable membranes, such as solar arrays and solar sails; and (iii) deployable elements in nature. The study clarifies what design considerations are necessary to adapt the basic concepts to actual s...

Photovoltaic Engineering Testbed: A Facility for Space Calibration and Measurement of Solar Cells on the International Space Station

Science.gov (United States)

Landis, Geoffrey A.; Bailey, Sheila G.; Jenkins, Phillip; Sexton, J. Andrew; Scheiman, David; Christie, Robert; Charpie, James; Gerber, Scott S.; Johnson, D. Bruce

2001-01-01

The Photovoltaic Engineering Testbed ("PET") is a facility to be flown on the International Space Station to perform calibration, measurement, and qualification of solar cells in the space environment and then returning the cells to Earth for laboratory use. PET will allow rapid turnaround testing of new photovoltaic technology under AM0 conditions.

46 CFR 15.725 - Sailing short.

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Sailing short. 15.725 Section 15.725 Shipping COAST... Limitations and Qualifying Factors § 15.725 Sailing short. Whenever a vessel is deprived of the service of a... vessel is sufficiently manned for the voyage. A report of sailing short must be filed in writing with the...

The formation of ice sails

Science.gov (United States)

Fowler, A. C.; Mayer, C.

2017-11-01

Debris-covered glaciers are prone to the formation of a number of supraglacial geomorphological features, and generally speaking, their upper surfaces are far from level surfaces. Some of these features are due to radiation screening or enhancing properties of the debris cover, but theoretical explanations of the consequent surface forms are in their infancy. In this paper we consider a theoretical model for the formation of "ice sails", which are regularly spaced bare ice features which are found on debris-covered glaciers in the Karakoram.

Considering the space environment

International Nuclear Information System (INIS)

Boudenot, J.C.; Fillon, T.; Barrillot, C.; Calvet, M.C.

1999-01-01

The high levels of radiation encountered in space and in the upper atmosphere can affect the onboard electronics in satellites, launch vehicles and aircraft. The main categories of radiation in space have been classified into four distinct types; radiation belts, solar flares, cosmic radiation and the solar wind. Most of the risk to modern electronic systems arises from heavy ions. In geostationary and low polar orbits, these originate mainly as protons from solar flares. In medium earth orbits, the main source is trapped protons and the South Atlantic anomaly. (authors)

8th International Robotic Sailing Conference

CERN Document Server

Haug, Florian

2016-01-01

This book presents the cutting edge developments within a broad field related to robotic sailing. The contributions were presented during the 8th International Robotic Sailing Conference, which has taken place as a part of the 2015 World Robotic Sailing Championships in Mariehamn, Åland (Finland), August 31st – September 4th 2015. Since more than a decade, a series of competitions such as the World Robotic Sailing Championship have stimulated a variety of groups to work on research and development around autonomous sailing robots, which involves boat designers, naval architects, electrical engineers and computer scientists. While many of the challenges in building a truly autonomous sailboat are still unsolved, the books presents the state of the art of research and development within platform optimization, route and stability planning, collision avoidance, power management and boat control.

International Living With a Star (ILWS), a new collaborative space program in Solar, Heliospheric and Solar-Terrestrial Physics

Science.gov (United States)

Opgenoorth, H. J.; Guhathakurta, M.; Liu, W.; Kosugi, T.; Zelenyi, L.

2003-04-01

International cooperation has long been a vital element in the scientific investigation of solar variability and its impact on Earth and its space environment. Recently a new international cooeperative program in solar terrestrial physics has been established by the major space agencies of the world, called the International Living With a Star (ILWS) program. ILWS is a follow on to the highly successful International Solar Terrestrial Physics (ISTP) program which involved international parterners. ISTP, with its steady flow of discoveries and new knowledge in solar Terrestrial physics, has laid the foundation for the coordinated study of the Sun-Earth sytem as a connected stellar-planetary system, system which is humanity's home. The first step in establishing ILWS was taken in the fall of 2000 when funding was approved for the NASA's Living With a Star (LWS) program whose goal is to develop the scientific understanding necessary to effectively address those aspects of the connected Sun-Earth system that directly affect life and society. The scientific goals of ILWS are defined in a broader sense, aiming to include future solar, heliospheric and solar terrestrial missions of both applied and fundamental scientific focus. The ultimate goal of ILWS wil be to increase our understanding of how solar variability affects the terrestrial and other planetary environments both in the short and long term, and in particular how man and society may be affected by solar variability and its consequences. The mission charter of ILWS is 'to stimulate, strengthen and coordinate space research in order to understand the governing processes of the connected Sun-Earth System as an integrated entity'. More detailed ILWS Objectives are to stimulate and facilitate: - The study of the Sun Earth connected system and the effects which influence life and society - Collaboration among all potential partners in solar-terrestrial space missions - Synergistic coordination of international

SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 1. Project summary

Energy Technology Data Exchange (ETDEWEB)

1985-12-30

A summary of the Solar Controlled Environment Agriculture Project is presented. The design of the greenhouses include transparent double pane glass roof with channels for fluid between the panes, inner pane tinted and double pane extruded acrylic aluminized mylar shade and diffuser. Solar energy technologies provide power for water desalination, for pumping irrigation water, and for cooling and heating the controlled environment space so that crops can grow in arid lands. The project is a joint effort between the United States and Saudi Arabia. (BCS)

Solar Probe ANalyzer for Ions - Laboratory Performance

Science.gov (United States)

Livi, R.; Larson, D. E.; Kasper, J. C.; Korreck, K. E.; Whittlesey, P. L.

2017-12-01

The Parker Solar Probe (PSP) mission is a heliospheric satellite that will orbit the Sun closer than any prior mission to date with a perihelion of 35 solar radii (RS) and an aphelion of 10 RS. PSP includes the Solar Wind Electrons Alphas and Protons (SWEAP) instrument suite, which in turn consists of four instruments: the Solar Probe Cup (SPC) and three Solar Probe ANalyzers (SPAN) for ions and electrons. Together, this suite will take local measurements of particles and electromagnetic fields within the Sun's corona. SPAN-Ai has completed flight calibration and spacecraft integration and is set to be launched in July of 2018. The main mode of operation consists of an electrostatic analyzer (ESA) at its aperture followed by a Time-of-Flight section to measure the energy and mass per charge (m/q) of the ambient ions. SPAN-Ai's main objective is to measure solar wind ions within an energy range of 5 eV - 20 keV, a mass/q between 1-60 [amu/q] and a field of view of 2400x1200. Here we will show flight calibration results and performance.

TDRS-1 single event upsets and the effect of the space environment

International Nuclear Information System (INIS)

Wilkinson, D.C.; Daughtridge, S.C.; Stone, J.L.; Sauer, H.H.; Darling, P.

1991-01-01

The systematic recording of Single Event Upsets on TDRS-1 from 1984 to 1990 allows correlations to be drawn between those upsets and the space environment. In this paper, ground based neutron monitor data are used to illustrate the long-term relationship between galactic cosmic rays and TDRS-1 upsets. The short-term effects of energetic solar particles are illustrated with space environment data from GOES-7

Chart links solar, geophysical events with impacts on space technologies

Science.gov (United States)

Davenport, George R.

While developing a Space Weather Training Program for Air Force Space Command and the 50th Weather Squadron, both based in Colorado, ARINC Incorporated produced a flowchart that correlates solar and geophysical events with their impacts on Air Force systems.Personnel from both organizations collaborated in the development of the flowchart and provided many comments and suggestions. The model became the centerpiece of the Space Environment Impacts Reference Pamphlet, as well as the formal Space Weather Training Program. Although it is not a numerical or computer model, the flowchart became known as the “Space Environmental Impacts Model.”

Plasma physics and the 2013-2022 decadal survey in solar and space physics

Science.gov (United States)

Baker, Daniel N.

2016-11-01

The U.S. National Academies established in 2011 a steering committee to develop a comprehensive strategy for solar and space physics research. This updated and extended the first (2003) solar and space physics decadal survey. The latest decadal study implemented a 2008 Congressional directive to NASA for the fields of solar and space physics, but also addressed research in other federal agencies. The new survey broadly canvassed the fields of research to determine the current state of the discipline, identified the most important open scientific questions, and proposed the measurements and means to obtain them so as to advance the state of knowledge during the years 2013-2022. Research in this field has sought to understand: dynamical behaviour of the Sun and its heliosphere; properties of the space environments of the Earth and other solar system bodies; multiscale interaction between solar system plasmas and the interstellar medium; and energy transport throughout the solar system and its impact on the Earth and other solar system bodies. Research in solar and space plasma processes using observation, theory, laboratory studies, and numerical models has offered the prospect of understanding this interconnected system well enough to develop a predictive capability for operational support of civil and military space systems. We here describe the recommendations and strategic plans laid out in the 2013-2022 decadal survey as they relate to measurement capabilities and plasma physical research. We assess progress to date. We also identify further steps to achieve the Survey goals with an emphasis on plasma physical aspects of the program.

The upper atmosphere and solar-terrestrial relations - An introduction to the aerospace environment

International Nuclear Information System (INIS)

Hargreaves, J.K.

1979-01-01

A theoretical and observational overview of earth's aerospace environment is presented in this book. Emphasis is placed on the principles and observed phenomena of the neutral upper atmosphere, particularly in relation to solar activity. Topics include the structure of the ionosphere and magnetosphere, waves in the magnetosphere, solar flares and solar protons, and storms and other disturbance phenomena, while applications to communications, navigation and space technology are also discussed

The leading-edge vortex of yacht sails

Science.gov (United States)

Arredondo-Galeana, Abel; Viola, Ignazio Maria

2017-11-01

We experimentally show, for the first time, that a stable Leading-Edge Vortex (LEV) can be formed on an asymmetric spinnaker, which is a high-lift sail used by yachts to sail downwind. We tested a 3D printed rigid sail in a water flume at a chord-based Reynolds number of ca. 104. We found that on the leeward side of the sail (the suction side), the flow separates at the leading edge reattaching further downstream and forming a stable LEV. The LEV grows in diameter from the root to the tip of the sail, where it merges with the tip vortex. We detected the LEV using the γ criterion, and we verified its stability over time. The lift contribution provided by the LEV was computed solving a complex potential model of each sail section. This analysis indicated that the LEV provides a substantial contribution to the total sail's lift. These findings suggest that the maximum lift of low-aspect-ratio wings with a sharp leading edge, such as spinnakers, can be enhanced by promoting a stable LEV. This work was funded by the Consejo Nacional de Ciencia y Tecnologia (CONACYT).

Space Solar Power: Satellite Concepts

Science.gov (United States)

Little, Frank E.

1999-01-01

Space Solar Power (SSP) applies broadly to the use of solar power for space related applications. The thrust of the NASA SSP initiative is to develop concepts and demonstrate technology for applying space solar power to NASA missions. Providing power from satellites in space via wireless transmission to a receiving station either on earth, another celestial body or a second satellite is one goal of the SSP initiative. The sandwich design is a satellite design in which the microwave transmitting array is the front face of a thin disk and the back of the disk is populated with solar cells, with the microwave electronics in between. The transmitter remains aimed at the earth in geostationary orbit while a system of mirrors directs sunlight to the photovoltaic cells, regardless of the satellite's orientation to the sun. The primary advantage of the sandwich design is it eliminates the need for a massive and complex electric power management and distribution system for the satellite. However, it requires a complex system for focusing sunlight onto the photovoltaic cells. In addition, positioning the photovoltaic array directly behind the transmitting array power conversion electronics will create a thermal management challenge. This project focused on developing designs and finding emerging technology to meet the challenges of solar tracking, a concentrating mirror system including materials and coatings, improved photovoltaic materials and thermal management.

Solar journey: The significance of our galactic environment for the heliosphere and earth

CERN Document Server

Frisch, Priscilla C

2006-01-01

Humans evolved when the Sun was in the great void of the Local Bubble. The Sun entered the present environment of interstellar clouds only during the late Quaternary. Astronomical data reveal these long and short term changes in our galactic environment. Theoretical models then tell us how these changes affect interplanetary particles, planetary magnetospheres, and the Earth itself. Cosmic rays leave an isotopic signature in the paleoclimate record that helps trace the solar journey through space. "Solar Journey: The Significance of Our Galactic Environment for the Heliosphere and Earth" lays the foundation for an interdisciplinary study of the influence of interstellar material on the solar system and Earth as we travel through the Milky Way Galaxy. The solar wind bubble responds dynamically to interstellar material flowing past the Sun, regulating interstellar gas, dust, and cosmic particle fluxes in the interplanetary medium and the Earth. Cones of interstellar gas and dust focused by solar gravity, the ma...

Developments of an Interactive Sail Design Method

OpenAIRE

S. M. Malpede; M. Vezza

2000-01-01

This paper presents a new tool for performing the integrated design and analysis of a sail. The features of the system are the geometrical definition of a sail shape, using the Bezier surface method, the creation of a finite element model for the non-linear structural analysis and a fluid-dynamic model for the aerodynamic analysis. The system has been developed using MATLAB(r). Recent sail design efforts have been focused on solving the aeroelastic behavior of the sail. The pressure dis...

An Overview of the Space Environments and Spacecraft Effects Organization Concept

Science.gov (United States)

Edwards, David L.; Burns, Howard D.; Garrett, Henry B.; Miller, Sharon K.; Peddie, Darilyn; Porter Ron; Spann, James F.; Xapsos, Michael A.

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 our Earth, and 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 on the solar system and the unique environments for each mission target. NASA has multiple technical and science discipline areas specializing in specific space environments fields that will serve to enable these missions. To complement these existing discipline areas, a concept is presented focusing on the development of a space environment and spacecraft effects (SESE) organization. This SESE 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. Environment effects focuses on the material, component, sub-system, and system-level response to the space environment and include the selection and 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

Space Weather: The Solar Perspective

Directory of Open Access Journals (Sweden)

Schwenn Rainer

2006-08-01

Full Text Available The term space weather refers to conditions on the Sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and that can affect human life and health. Our modern hi-tech society has become increasingly vulnerable to disturbances from outside the Earth system, in particular to those initiated by explosive events on the Sun: Flares release flashes of radiation that can heat up the terrestrial atmosphere such that satellites are slowed down and drop into lower orbits, solar energetic particles accelerated to near-relativistic energies may endanger astronauts traveling through interplanetary space, and coronal mass ejections are gigantic clouds of ionized gas ejected into interplanetary space that after a few hours or days may hit the Earth and cause geomagnetic storms. In this review, I describe the several chains of actions originating in our parent star, the Sun, that affect Earth, with particular attention to the solar phenomena and the subsequent effects in interplanetary space.

Space Weather: The Solar Perspective

Science.gov (United States)

Schwenn, Rainer

2006-08-01

The term space weather refers to conditions on the Sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and that can affect human life and health. Our modern hi-tech society has become increasingly vulnerable to disturbances from outside the Earth system, in particular to those initiated by explosive events on the Sun: Flares release flashes of radiation that can heat up the terrestrial atmosphere such that satellites are slowed down and drop into lower orbits, solar energetic particles accelerated to near-relativistic energies may endanger astronauts traveling through interplanetary space, and coronal mass ejections are gigantic clouds of ionized gas ejected into interplanetary space that after a few hours or days may hit the Earth and cause geomagnetic storms. In this review, I describe the several chains of actions originating in our parent star, the Sun, that affect Earth, with particular attention to the solar phenomena and the subsequent effects in interplanetary space.

Viking-Age Sails: Form and Proportion

Science.gov (United States)

Bischoff, Vibeke

2017-04-01

Archaeological ship-finds have shed much light on the design and construction of vessels from the Viking Age. However, the exact proportions of their sails remain unknown due to the lack of fully preserved sails, or other definite indicators of their proportions. Key Viking-Age ship-finds from Scandinavia—the Oseberg Ship, the Gokstad Ship and Skuldelev 3—have all revealed traces of rigging. In all three finds, the keelson—with the mast position—is preserved, together with fastenings for the sheets and the tack, indicating the breadth of the sail. The sail area can then be estimated based on practical experience of how large a sail the specific ship can carry, in conjunction with hull form and displacement. This article presents reconstructions of the form and dimensions of rigging and sail based on the archaeological finds, evidence from iconographic and written sources, and ethnographic parallels with traditional Nordic boats. When these sources are analysed, not only do the similarities become apparent, but so too does the relative disparity between the archaeological record and the other sources. Preferential selection in terms of which source is given the greatest merit is therefore required, as it is not possible to afford them all equal value.

Solar radio bursts as a tool for space weather forecasting

Science.gov (United States)

Klein, Karl-Ludwig; Matamoros, Carolina Salas; Zucca, Pietro

2018-01-01

The solar corona and its activity induce disturbances that may affect the space environment of the Earth. Noticeable disturbances come from coronal mass ejections (CMEs), which are large-scale ejections of plasma and magnetic fields from the solar corona, and solar energetic particles (SEPs). These particles are accelerated during the explosive variation of the coronal magnetic field or at the shock wave driven by a fast CME. In this contribution, it is illustrated how full Sun microwave observations can lead to (1) an estimate of CME speeds and of the arrival time of the CME at the Earth, (2) the prediction of SEP events attaining the Earth. xml:lang="fr"

Materials on the International Space Station - Forward Technology Solar Cell Experiment

Science.gov (United States)

Walters, R. J.; Garner, J. C.; Lam, S. N.; Vazquez, J. A.; Braun, W. R.; Ruth, R. E.; Lorentzen, J. R.; Bruninga, R.; Jenkins, P. P.; Flatico, J. M.

2005-01-01

This paper describes a space solar cell experiment currently being built by the Naval Research Laboratory (NRL) in collaboration with NASA Glenn Research Center (GRC), and the US Naval Academy (USNA). The experiment has been named the Forward Technology Solar Cell Experiment (FTSCE), and the purpose is to rapidly put current and future generation space solar cells on orbit and provide validation data for these technologies. The FTSCE is being fielded in response to recent on-orbit and ground test anomalies associated with space solar arrays that have raised concern over the survivability of new solar technologies in the space environment and the validity of present ground test protocols. The FTSCE is being built as part of the Fifth Materials on the International Space Station (MISSE) Experiment (MISSE-5), which is a NASA program to characterize the performance of new prospective spacecraft materials when subjected to the synergistic effects of the space environment. Telemetry, command, control, and communication (TNC) for the FTSCE will be achieved through the Amateur Satellite Service using the PCSat2 system, which is an Amateur Radio system designed and built by the USNA. In addition to providing an off-the-shelf solution for FTSCE TNC, PCSat2 will provide a communications node for the Amateur Radio satellite system. The FTSCE and PCSat2 will be housed within the passive experiment container (PEC), which is an approximately 2ft x2ft x 4in metal container built by NASA Langley Research Center (NASA LaRC) as part of the MISSE-5 program. NASA LaRC has also supplied a thin film materials experiment that will fly on the exterior of the thermal blanket covering the PCSat2. The PEC is planned to be transported to the ISS on a Shuttle flight. The PEC will be mounted on the exterior of the ISS by an astronaut during an extravehicular activity (EVA). After nominally one year, the PEC will be retrieved and returned to Earth. At the time of writing this paper, the

SAIL: automating interlibrary loan.

Science.gov (United States)

Lacroix, E M

1994-01-01

The National Library of Medicine (NLM) initiated the System for Automated Interlibrary Loan (SAIL) pilot project to study the feasibility of using imaging technology linked to the DOCLINE system to deliver copies of journal articles. During the project, NLM converted a small number of print journal issues to electronic form, linking the captured articles to the MEDLINE citation unique identifier. DOCLINE requests for these journals that could not be filled by network libraries were routed to SAIL. Nearly 23,000 articles from sixty-four journals recently selected for indexing in Index Medicus were scanned to convert them to electronic images. During fiscal year 1992, 4,586 scanned articles were used to fill 10,444 interlibrary loan (ILL) requests, and more than half of these were used only once. Eighty percent of all the articles were not requested at all. The total cost per article delivered was $10.76, substantially more than it costs to process a photocopy request. Because conversion costs were the major component of the total SAIL cost, and most of the articles captured for the project were not requested, this model was not cost-effective. Data on SAIL journal article use was compared with all ILL requests filled by NLM for the same period. Eighty-eight percent of all articles requested from NLM were requested only once. The results of the SAIL project demonstrated that converting journal articles to electronic images and storing them in anticipation of repeated requests would not meet NLM's objective to improve interlibrary loan. PMID:8004020

Becoming a Coach in Developmental Adaptive Sailing: A Lifelong Learning Perspective.

Science.gov (United States)

Duarte, Tiago; Culver, Diane M

2014-10-02

Life-story methodology and innovative methods were used to explore the process of becoming a developmental adaptive sailing coach. Jarvis's (2009) lifelong learning theory framed the thematic analysis. The findings revealed that the coach, Jenny, was exposed from a young age to collaborative environments. Social interactions with others such as mentors, colleagues, and athletes made major contributions to her coaching knowledge. As Jenny was exposed to a mixture of challenges and learning situations, she advanced from recreational para-swimming instructor to developmental adaptive sailing coach. The conclusions inform future research in disability sport coaching, coach education, and applied sport psychology.

Radiation Effects in the Space Telecommunications Environment

Energy Technology Data Exchange (ETDEWEB)

Fleetwood, Daniel M.; Winokur, Peter S.

1999-05-17

Trapped protons and electrons in the Earth's radiation belts and cosmic rays present significant challenges for electronics that must operate reliably in the natural space environment. Single event effects (SEE) can lead to sudden device or system failure, and total dose effects can reduce the lifetime of a telecommmiications system with significant space assets. One of the greatest sources of uncertainty in developing radiation requirements for a space system is accounting for the small but finite probability that the system will be exposed to a massive solar particle event. Once specifications are decided, standard laboratory tests are available to predict the total dose response of MOS and bipolar components in space, but SEE testing of components can be more challenging. Prospects are discussed for device modeling and for the use of standard commercial electronics in space.

Radiation Effects in the Space Telecommunications Environment

International Nuclear Information System (INIS)

Fleetwood, Daniel M.; Winokur, Peter S.

1999-01-01

Trapped protons and electrons in the Earth's radiation belts and cosmic rays present significant challenges for electronics that must operate reliably in the natural space environment. Single event effects (SEE) can lead to sudden device or system failure, and total dose effects can reduce the lifetime of a telecommmiications system with significant space assets. One of the greatest sources of uncertainty in developing radiation requirements for a space system is accounting for the small but finite probability that the system will be exposed to a massive solar particle event. Once specifications are decided, standard laboratory tests are available to predict the total dose response of MOS and bipolar components in space, but SEE testing of components can be more challenging. Prospects are discussed for device modeling and for the use of standard commercial electronics in space

Solar EUV irradiance for space weather applications

Science.gov (United States)

Viereck, R. A.

2015-12-01

Solar EUV irradiance is an important driver of space weather models. Large changes in EUV and x-ray irradiances create large variability in the ionosphere and thermosphere. Proxies such as the F10.7 cm radio flux, have provided reasonable estimates of the EUV flux but as the space weather models become more accurate and the demands of the customers become more stringent, proxies are no longer adequate. Furthermore, proxies are often provided only on a daily basis and shorter time scales are becoming important. Also, there is a growing need for multi-day forecasts of solar EUV irradiance to drive space weather forecast models. In this presentation we will describe the needs and requirements for solar EUV irradiance information from the space weather modeler's perspective. We will then translate these requirements into solar observational requirements such as spectral resolution and irradiance accuracy. We will also describe the activities at NOAA to provide long-term solar EUV irradiance observations and derived products that are needed for real-time space weather modeling.

Radiation Environments for Future Human Exploration Throughout the Solar System.

Science.gov (United States)

Schwadron, N.; Gorby, M.; Linker, J.; Riley, P.; Torok, T.; Downs, C.; Spence, H. E.; Desai, M. I.; Mikic, Z.; Joyce, C. J.; Kozarev, K. A.; Townsend, L. W.; Wimmer-Schweingruber, R. F.

2016-12-01

Acute space radiation hazards pose one of the most serious risks to future human and robotic exploration. The ability to predict when and where large events will occur is necessary in order to mitigate their hazards. The largest events are usually associated with complex sunspot groups (also known as active regions) that harbor strong, stressed magnetic fields. Highly energetic protons accelerated very low in the corona by the passage of coronal mass ejection (CME)-driven compressions or shocks and from flares travel near the speed of light, arriving at Earth minutes after the eruptive event. Whether these particles actually reach Earth, the Moon, Mars (or any other point) depends on their transport in the interplanetary magnetic field and their magnetic connection to the shock. Recent contemporaneous observations during the largest events in almost a decade show the unique longitudinal distributions of this ionizing radiation broadly distributed from sources near the Sun and yet highly isolated during the passage of CME shocks. Over the last decade, we have observed space weather events as the solar wind exhibits extremely low densities and magnetic field strengths, representing states that have never been observed during the space age. The highly abnormal solar activity during cycles 23 and 24 has caused the longest solar minimum in over 80 years and continues into the unusually small solar maximum of cycle 24. As a result of the remarkably weak solar activity, we have also observed the highest fluxes of galactic cosmic rays in the space age and relatively small particle radiation events. We have used observations from LRO/CRaTER to examine the implications of these highly unusual solar conditions for human space exploration throughout the inner solar system. While these conditions are not a show-stopper for long-duration missions (e.g., to the Moon, an asteroid, or Mars), galactic cosmic ray radiation remains a significant and worsening factor that limits

Project SAIL: An Evaluation of a Dropout Prevention Program.

Science.gov (United States)

Thompson, John L.; And Others

Project SAIL (Student Advocates Inspire Learning) is a Title IV-C Project located in Hopkins, Minnesota, designed to prevent students from dropping out of school by keeping them successfully involved in the mainstream environment. This study presents a review of other dropout prevention approaches, describes the intervention strategies involved in…

Real-time sail and heading optimization for a surface sailing vessel by extremum seeking control

DEFF Research Database (Denmark)

Treichel, Kai; Jouffroy, Jerome

2010-01-01

In this paper we develop a simplified mathematical model representing the main elements of the behaviour of sailing vessels as a basis for simulation and controller design. For adaptive real-time optimization of the sail and heading angle we then apply extremum seeking control (which is a gradient...

Deployment Testing of the De-Orbit Sail Flight Hardware

OpenAIRE

Hillebrandt, Martin; Meyer, Sebastian; Zander, Martin; Hühne, Christian

2015-01-01

The paper describes the results of the deployment testing of the De-Orbit Sail flight hardware, a drag sail for de-orbiting applications, performed by DLR. It addresses in particular the deployment tests of the fullscale sail subsystem and deployment force tests performed on the boom deployment module. For the fullscale sail testing a gravity compensation device is used which is described in detail. It allows observations of the in-plane interaction of the booms with the sail membrane and the...

Space solar power - An energy alternative

Science.gov (United States)

Johnson, R. W.

1978-01-01

The space solar power concept is concerned with the use of a Space Power Satellite (SPS) which orbits the earth at geostationary altitude. Two large symmetrical solar collectors convert solar energy directly to electricity using photovoltaic cells woven into blankets. The dc electricity is directed to microwave generators incorporated in a transmitting antenna located between the solar collectors. The antenna directs the microwave beam to a receiving antenna on earth where the microwave energy is efficiently converted back to dc electricity. The SPS design promises 30-year and beyond lifetimes. The SPS is relatively pollution free as it promises earth-equivalence of 80-85% efficient ground-based thermal power plant.

Development of Space Qualified Microlens Arrays for Solar Cells Used on Satellite Power Systems

Directory of Open Access Journals (Sweden)

Ömer Faruk Keser

2017-08-01

Full Text Available The power system, one of the main systems of satellite, provides energy required for the satellite. Solar cells are also the most used energy source in the power system. The third generation multi-junction solar cells are known as the ones with highest performance. One of the methods to increase the performance of the solar cells is anti-reflective surface coatings with the Micro Lens Array-MLA. It's expected that satellite technologies has high power efficiency and low mass. The space environment has many effects like atomic oxygen, radiation and thermal cycles. Researches for increasing the solar cells performance shows that MLA coated solar cell has increased light absorption performance and less cell heating with very low additional mass. However, it is established that few studies on MLA coatings of solar cells are not applicable on space platforms. In this study, the process of development of MLA which is convenient to space power systems is investigated in a methodological way. In this context, a method which is developed based on MLA coatings of multi-junction solar cells for satellite power systems is presented.

Extraterrestrial fiberglass production using solar energy. [lunar plants or space manufacturing facilities

Science.gov (United States)

Ho, D.; Sobon, L. E.

1979-01-01

A conceptual design is presented for fiberglass production systems in both lunar and space environments. The raw material, of lunar origin, will be plagioclase concentrate, high silica content slag, and calcium oxide. Glass will be melted by solar energy. The multifurnace in the lunar plant and the spinning cylinder in the space plant are unique design features. Furnace design appears to be the most critical element in optimizing system performance. A conservative estimate of the total power generated by solar concentrators is 1880 kW; the mass of both plants is 120 tons. The systems will reproduce about 90 times their total mass in fiberglass in 1 year. A new design concept would be necessary if glass rods were produced in space.

Adult Sail Sign: Radiographic and Computed Tomographic Features

Energy Technology Data Exchange (ETDEWEB)

Lee, Yu-Jin; Han, Daehee; Koh, Young Hwan; Zo, Joo Hee; Kim, Sang-Hyun; Kim, Deog Kyeom; Lee, Jeong Sang; Moon, Hyeon Jong; Kim, Jong Seung; Chun, Eun Ju; Youn, Byung Jae; Lee, Chang Hyun; Kim, Sam Soo (Dept. of Radiology, Cheil General Hospital, Kwandong Univ. College of Medicine, Seoul (KR))

2008-02-15

Background: The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason. Purpose: To investigate the sail sign appearing in adult chest radiography. Material and Methods: Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT). Results: The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure. Conclusion: The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging

Adult Sail Sign: Radiographic and Computed Tomographic Features

International Nuclear Information System (INIS)

Lee, Yu-Jin; Han, Daehee; Koh, Young Hwan; Zo, Joo Hee; Kim, Sang-Hyun; Kim, Deog Kyeom; Lee, Jeong Sang; Moon, Hyeon Jong; Kim, Jong Seung; Chun, Eun Ju; Y oun, Byung Jae; Lee, Chang Hyun; Kim, Sam Soo

2008-01-01

Background: The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason. Purpose: To investigate the sail sign appearing in adult chest radiography. Material and Methods: Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT). Results: The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure. Conclusion: The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging

Adult sail sign: radiographic and computed tomographic features.

Science.gov (United States)

Lee, Yu-Jin; Han, Daehee; Koh, Young Hwan; Zo, Joo Hee; Kim, Sang-Hyun; Kim, Deog Kyeom; Lee, Jeong Sang; Moon, Hyeon Jong; Kim, Jong Seung; Chun, Eun Ju; Youn, Byung Jae; Lee, Chang Hyun; Kim, Sam Soo

2008-02-01

The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason. To investigate the sail sign appearing in adult chest radiography. Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT). The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure. The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging.

Solar and Space Physics: A Science for a Technological Society

Science.gov (United States)

2013-01-01

From the interior of the Sun, to the upper atmosphere and near-space environment of Earth, and outward to a region far beyond Pluto where the Sun's influence wanes, advances during the past decade in space physics and solar physics the disciplines NASA refers to as heliophysics have yielded spectacular insights into the phenomena that affect our home in space. This report, from the National Research Council's (NRC's) Committee for a Decadal Strategy in Solar and Space Physics, is the second NRC decadal survey in heliophysics. Building on the research accomplishments realized over the past decade, the report presents a program of basic and applied research for the period 2013-2022 that will improve scientific understanding of the mechanisms that drive the Sun's activity and the fundamental physical processes underlying near-Earth plasma dynamics, determine the physical interactions of Earth's atmospheric layers in the context of the connected Sun-Earth system, and enhance greatly the capability to provide realistic and specific forecasts of Earth's space environment that will better serve the needs of society. Although the recommended program is directed primarily to NASA (Science Mission Directorate -- Heliophysics Division) and the National Science Foundation (NSF) (Directorate for Geosciences -- Atmospheric and Geospace Sciences) for action, the report also recommends actions by other federal agencies, especially the National Oceanic and Atmospheric Administration (NOAA) those parts of NOAA charged with the day-to-day (operational) forecast of space weather. In addition to the recommendations included in this summary, related recommendations are presented in the main text of the report.

Concept-Development of a Structure Supported Membrane for Deployable Space Applications - From Nature to Manufacture and Testing

Science.gov (United States)

Zander, Martin; Belvin, W. K.

2012-01-01

Current space applications of membrane structures include large area solar power arrays, solar sails, antennas, and numerous other large aperture devices like the solar shades of the new James Webb Space Telescope. These expandable structural systems, deployed in-orbit to achieve the desired geometry, are used to collect, reflect and/or transmit electromagnetic radiation. This work, a feasibility study supporting a diploma thesis, describes the systematic process for developing a biologically inspired concept for a structure supported (integrated) membrane, that features a rip stop principle, makes self-deployment possible and is part of an ultra-light weight space application. Novel manufacturing of membrane prototypes and test results are presented for the rip-stop concepts. Test data showed that the new membrane concept has a higher tear resistance than neat film of equivalent mass.

Radiation resistance of solar cells for space application, 1

International Nuclear Information System (INIS)

Mitsui, Hiroshi; Tanaka, Ryuichi; Sunaga, Hiromi

1989-07-01

A 50-μm thick ultrathin silicon solar cell and a 280-μm thick high performance AlGaAs/GaAs solar cell with high radiation resistance have been recently developed by National Space Development Agency of Japan (NASDA). In order to study the radiation resistance of these cells, a joint research was carried out between Japan Atomic Energy Research Institute (JAERI) and NASDA from 1984 through 1987. In this research, the irradiation method of electron beams, the effects of the irradiation conditions on the deterioration of solar cells by electron beams, and the annealing effects of the radiation damage in solar cells were investigated. This paper is the first one of a series of reports of the joint research. In this paper, the space radiation environment which artificial satellites will encounter, the solar cells used, and the experimental methods are described. In addition to these, the results of the study on the irradiation procedure of electron beams are reported. In the study of the irradiation method of electron beams, three methods, that is, the fixed irradiation method, the moving irradiation method, and the spot irradiation method were examined. In the fixed irradiation method and moving one, stationary solar cells and solar cells moving by conveyer were irradiated by scanning electron beams, respectively. On the other hand, in the spot irradiation method, stationary solar cells were irradiated by non-scanning steady electron beams. It was concluded that the fixed irradiation method was the most proper method. In addition to this, in this study, some pieces of information were obtained with respect to the changes in the electrical characteristics of solar cells caused by the irradiation of electron beams. (author) 52 refs

New directions for space solar power

Science.gov (United States)

Mankins, John C.

2009-07-01

Several of the central issues associated with the eventual realization of the vision of solar power from space for terrestrial markets resolve around the expect costs associated with the assembly, inspection, maintenance and repair of future solar power satellite (SPS) stations. In past studies (for example, NASA's "Fresh Look Study", c. 1995-1997) efforts were made to reduce both the scale and mass of large, systems-level interfaces (e.g., the power management and distribution (PMAD) system) and on-orbit fixed infrastructures through the use of modular systems strategies. These efforts have had mixed success (as reflected in the projected on-orbit mass of various systems concepts. However, the author remains convinced of the importance of modular strategies for exceptionally large space systems in eventually realizing the vision of power from space. This paper will introduce some of the key issues associated with cost-competitive space solar power in terrestrial markets. It will examine some of the relevant SPS concepts and will assess the 'pros and cons' of each in terms of space assembly, maintenance and servicing (SAMS) requirements. The paper discusses at a high level some relevant concepts and technologies that may play r role in the eventual, successful resolution of these challenges. The paper concludes with an example of the kind of novel architectural approach for space solar power that is needed.

Key techniques for space-based solar pumped semiconductor lasers

Science.gov (United States)

He, Yang; Xiong, Sheng-jun; Liu, Xiao-long; Han, Wei-hua

2014-12-01

In space, the absence of atmospheric turbulence, absorption, dispersion and aerosol factors on laser transmission. Therefore, space-based laser has important values in satellite communication, satellite attitude controlling, space debris clearing, and long distance energy transmission, etc. On the other hand, solar energy is a kind of clean and renewable resources, the average intensity of solar irradiation on the earth is 1353W/m2, and it is even higher in space. Therefore, the space-based solar pumped lasers has attracted much research in recent years, most research focuses on solar pumped solid state lasers and solar pumped fiber lasers. The two lasing principle is based on stimulated emission of the rare earth ions such as Nd, Yb, Cr. The rare earth ions absorb light only in narrow bands. This leads to inefficient absorption of the broad-band solar spectrum, and increases the system heating load, which make the system solar to laser power conversion efficiency very low. As a solar pumped semiconductor lasers could absorb all photons with energy greater than the bandgap. Thus, solar pumped semiconductor lasers could have considerably higher efficiencies than other solar pumped lasers. Besides, solar pumped semiconductor lasers has smaller volume chip, simpler structure and better heat dissipation, it can be mounted on a small satellite platform, can compose satellite array, which can greatly improve the output power of the system, and have flexible character. This paper summarizes the research progress of space-based solar pumped semiconductor lasers, analyses of the key technologies based on several application areas, including the processing of semiconductor chip, the design of small and efficient solar condenser, and the cooling system of lasers, etc. We conclude that the solar pumped vertical cavity surface-emitting semiconductor lasers will have a wide application prospects in the space.

Optimized Trajectories to the Nearest Stars Using Lightweight High-velocity Photon Sails

Science.gov (United States)

Heller, René; Hippke, Michael; Kervella, Pierre

2017-09-01

New means of interstellar travel are now being considered by various research teams, assuming lightweight spaceships to be accelerated via either laser or solar radiation to a significant fraction of the speed of light (c). We recently showed that gravitational assists can be combined with the stellar photon pressure to decelerate an incoming lightsail from Earth and fling it around a star or bring it to rest. Here, we demonstrate that photogravitational assists are more effective when the star is used as a bumper (I.e., the sail passes “in front of” the star) rather than as a catapult (I.e., the sail passes “behind” or “around” the star). This increases the maximum deceleration at α Cen A and B and reduces the travel time of a nominal graphene-class sail (mass-to-surface ratio 8.6× {10}-4 {{g}} {{{m}}}-2) from 95 to 75 years. The maximum possible velocity reduction upon arrival depends on the required deflection angle from α Cen A to B and therefore on the binary’s orbital phase. Here, we calculate the variation of the minimum travel times from Earth into a bound orbit around Proxima for the next 300 years and then extend our calculations to roughly 22,000 stars within about 300 lt-yr. Although α Cen is the most nearby star system, we find that Sirius A offers the shortest possible travel times into a bound orbit: 69 years assuming 12.5% c can be obtained at departure from the solar system. Sirius A thus offers the opportunity of flyby exploration plus deceleration into a bound orbit of the companion white dwarf after relatively short times of interstellar travel.

Unsteady Sail Dynamics in Olympic Class Sailboats

Science.gov (United States)

Williamson, Charles; Schutt, Riley

2016-11-01

Unsteady sailing techniques have evolved in competitive sailboat fleets, in cases where the relative weight of the sailor is sufficient to impart unsteady motions to the boat and sails. We will discuss three types of motion that are used by athletes to propel their boats on an Olympic race course faster than using the wind alone. In all of our cases, body weight movements induce unsteady sail motion, increasing driving force and speed through the water. In this research, we explore the dynamics of an Olympic class Laser sailboat equipped with a GPS, IMU, wind sensor, and a 6-GoPro camera array. We shall briefly discuss "sail flicking", whereby the helmsman periodically rolls the sail into the apparent wind, at an angle which is distinct from classical heave (in our case, the oscillations are not normal to the apparent flow). We also demonstrate "roll tacking", where there are considerable advantages to rolling the boat during such a maneuver, especially in light wind. In both of the above examples from on-the-water studies, corresponding experiments using a towing tank exhibit increases in the driving force, associated with the formation of strong vortex pairs into the flow. Finally, we focus on a technique known as "S-curving" in the case where the boat sails downwind. In contrast to the previous cases, it is drag force rather than lift force that the sailor is trying to maximise as the boat follows a zig-zag trajectory. The augmented apparent wind strength due to the oscillatory sail motion, and the growth of strong synchronised low-pressure wake vortices on the low-pressure side of the sail, contribute to the increase in driving force, and velocity-made-good downwind.

Space polypropulsion

Science.gov (United States)

Kellett, B. J.; Griffin, D. K.; Bingham, R.; Campbell, R. N.; Forbes, A.; Michaelis, M. M.

2008-05-01

Hybrid space propulsion has been a feature of most space missions. Only the very early rocket propulsion experiments like the V2, employed a single form of propulsion. By the late fifties multi-staging was routine and the Space Shuttle employs three different kinds of fuel and rocket engines. During the development of chemical rockets, other forms of propulsion were being slowly tested, both theoretically and, relatively slowly, in practice. Rail and gas guns, ion engines, "slingshot" gravity assist, nuclear and solar power, tethers, solar sails have all seen some real applications. Yet the earliest type of non-chemical space propulsion to be thought of has never been attempted in space: laser and photon propulsion. The ideas of Eugen Saenger, Georgii Marx, Arthur Kantrowitz, Leik Myrabo, Claude Phipps and Robert Forward remain Earth-bound. In this paper we summarize the various forms of nonchemical propulsion and their results. We point out that missions beyond Saturn would benefit from a change of attitude to laser-propulsion as well as consideration of hybrid "polypropulsion" - which is to say using all the rocket "tools" available rather than possibly not the most appropriate. We conclude with three practical examples, two for the next decades and one for the next century; disposal of nuclear waste in space; a grand tour of the Jovian and Saturnian moons - with Huygens or Lunoxod type, landers; and eventually mankind's greatest space dream: robotic exploration of neighbouring planetary systems.

Future Market Share of Space Solar Electric Power Under Open Competition

Science.gov (United States)

Smith, S. J.; Mahasenan, N.; Clarke, J. F.; Edmonds, J. A.

2002-01-01

This paper assesses the value of Space Solar Power deployed under market competition with a full suite of alternative energy technologies over the 21st century. Our approach is to analyze the future energy system under a number of different scenarios that span a wide range of possible future demographic, socio-economic, and technological developments. Scenarios both with, and without, carbon dioxide concentration stabilization policies are considered. We use the comprehensive set of scenarios created for the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (Nakicenovic and Swart 2000). The focus of our analysis will be the cost of electric generation. Cost is particularly important when considering electric generation since the type of generation is, from a practical point of view, largely irrelevant to the end-user. This means that different electricity generation technologies must compete on the basis of price. It is important to note, however, that even a technology that is more expensive than average can contribute to the overall generation mix due to geographical and economic heterogeneity (Clarke and Edmonds 1993). This type of competition is a central assumption of the modeling approach used here. Our analysis suggests that, under conditions of full competition of all available technologies, Space Solar Power at 7 cents per kW-hr could comprise 5-10% of global electric generation by the end of the century, with a global total generation of 10,000 TW-hr. The generation share of Space Solar Power is limited due to competition with lower-cost nuclear, biomass, and terrestrial solar PV and wind. The imposition of a carbon constraint does not significantly increase the total amount of power generated by Space Solar Power in cases where a full range of advanced electric generation technologies are also available. Potential constraints on the availability of these other electric generation options can increase the amount of

A Solar Sailcraft Simulation Application

Science.gov (United States)

Celeda, Tomáš

2013-01-01

An application was created to encourage students' practical knowledge of gravitational fields, the law of conservation of energy and other phenomena, such as gravitational slingshots. The educational software simulates the flight of a solar sail spacecraft between two planets of the Solar System using the laws of gravity and radiation…

Effects of the space environment on the health and safety of space workers

Science.gov (United States)

Hull, W. E.

1980-07-01

Large numbers of individuals are required to work in space to assemble and operate a Solar Power Satellite. The physiological and behavioral consequences for large groups of men and women who perform complex tasks in the vehicular or extravehicular environments over long periods of orbital stay time were considered. The most disturbing consequences of exposure to the null gravity environment found relate to: (1) a generalized cardiovascular deconditioning along with loss of a significant amount of body fluid volume; (2) loss of bone minerals and muscle mass; and (3) degraded performance of neutral mechanisms which govern equilibrium and spatial orientation.

Effects of the space environment on the health and safety of space workers

Science.gov (United States)

Hull, W. E.

1980-01-01

Large numbers of individuals are required to work in space to assemble and operate a Solar Power Satellite. The physiological and behavioral consequences for large groups of men and women who perform complex tasks in the vehicular or extravehicular environments over long periods of orbital stay time were considered. The most disturbing consequences of exposure to the null gravity environment found relate to: (1) a generalized cardiovascular deconditioning along with loss of a significant amount of body fluid volume; (2) loss of bone minerals and muscle mass; and (3) degraded performance of neutral mechanisms which govern equilibrium and spatial orientation.

Measurement result of the neutron monitor onboard the Space Environment Data Acquisition Equipment - Attached Payload (SEDA-AP)

Science.gov (United States)

Koga, K.; Muraki, Y.; Shibata, S.; Yamamoto, T.; Matsumoto, H.; Okudaira, O.; Kawano, H.; Yumoto, K.

2013-12-01

To support future space activities, it is crucial to acquire space environmental data related to the space-radiation degradation of space parts and materials, and spacecraft anomalies. Such data are useful for spacecraft design and manned space activity. SEDA-AP was mounted on 'Kibo' of the ISS (International Space Station) to measure the space environment at a 400-kilometer altitude. Neutrons are very harmful radiation, with electrical neutrality that makes them strongly permeable. SEDA-AP measures the energy of neutrons from thermal to 100 MeV in real time using a Bonner Ball Detector (BBND) and a Scintillation Fiber Detector (FIB). BBND detects neutrons using He-3 counters, which have high sensitivity to thermal neutrons. Neutron energy is derived using the relative response function of polyethylene moderators of 6 different thicknesses. FIB measures the tracks of recoil protons caused by neutrons within a cubic arrayed sensor of 512 scintillation fibers. The charged particles are excluded using an anti-scintillator which surrounds the cube sensor, and the neutron energy is obtained from the track length of a recoil proton. There are three sources of neutrons in space; 1. Albedo Neutrons Produced by reactions of galactic cosmic rays or radiation belt particles with the atmosphere 2. Local Neutrons Produced by the reactions of galactic cosmic rays or radiation belt particles with spacecraft 3. Solar Neutrons Produced by accelerated particles in solar flares An accurate energy spectrum of the solar neutrons includes important information on high-energy particle generation mechanism in a solar flare, because neutrons are unaffected by interplanetary magnetic fields. These data will become useful to forecast solar energetic particles in future. Some candidate events involving solar neutrons were found as a result of analyzing data of the solar flare of M>2 since September 2009. Moreover, it is important to measure albedo neutrons, since protons generated by neutron

Reactor Start-up and Control Methodologies: Consideration of the Space Radiation Environment

International Nuclear Information System (INIS)

Bragg-Sitton, Shannon M.; Holloway, James Paul

2004-01-01

The use of fission energy in space power and propulsion systems offers considerable advantages over chemical propulsion. Fission provides over six orders of magnitude higher energy density, which translates to higher vehicle specific impulse and lower specific mass. These characteristics enable the accomplishment of ambitious space exploration missions. The natural radiation environment in space provides an external source of protons and high energy, high Z particles that can result in the production of secondary neutrons through interactions in reactor structures. Initial investigation using MCNPX 2.5.b for proton transport through the SAFE-400 reactor indicates a secondary neutron net current of 1.4x107 n/s at the core-reflector interface, with an incoming current of 3.4x106 n/s due to neutrons produced in the Be reflector alone. This neutron population could provide a reliable startup source for a space reactor. Additionally, this source must be considered in developing a reliable control strategy during reactor startup, steady-state operation, and power transients. An autonomous control system is developed and analyzed for application during reactor startup, accounting for fluctuations in the radiation environment that result from changes in vehicle location (altitude, latitude, position in solar system) or due to temporal variations in the radiation field, as may occur in the case of solar flares. One proposed application of a nuclear electric propulsion vehicle is in a tour of the Jovian system, where the time required for communication to Earth is significant. Hence, it is important that a reactor control system be designed with feedback mechanisms to automatically adjust to changes in reactor temperatures, power levels, etc., maintaining nominal operation without user intervention. This paper will evaluate the potential use of secondary neutrons produced by proton interactions in the reactor vessel as a startup source for a space reactor and will present a

Economic feasibility of sail power devices on Great Lakes bulk carriers

Energy Technology Data Exchange (ETDEWEB)

None

1982-09-22

Three ships were examined, the ED RYERSON, the ST. CLAIR, and the STEWART CORT to determine if retro-fitting these ships with a 3000 sq ft soft sail cat rig is economically feasible. By using existing weather data taken from recorded observations on Lake Michigan and Lake Superior and known performance characteristics of both the sailplan and hull, a computer program was written to model the problem. Three cases for each ship were estimated. The first was the average fuel savings, second was an optimistic estimate of fuel savings, and the third was a pessimistic estimate of fuel savings. Several considerations had to be taken into account that had serious consequences for the economic viability of the idea. One was the fact that all of the aforementioned ships have self unloading equipment that require about 80% of the deck space to be clear. This limited the choice of sailplans to one per ship. Another consideration is that due to bridge clearance problems an air draft of less than 125' was required. These two factors limited the size and efficiency of the sail plan. The third consideration is that due to the very tight shipping channels on the Great Lakes, there is no provision for altering course to take advantage of prevailing winds in order to maximize the usefulness of the sail device. The sail device on the ED RYERSON does not seem to be economically feasible. Even at the lowest interest rate investigated in this study (8%) the average annual cost improves only in the optimistic estimates. At 12% interest even this slight advantage disappears. The sail devices on the STEWART CORT and ST. CLAIR seem to be marginally feasible at low interest rates and the present cost of fuel. The STEWART CORT seems to benefit most from the fitting of a sail device. A modest increase in fuel prices, perhaps possible, will make both of these ships look substantially better.

Aerodynamic-structural model of offwind yacht sails

Science.gov (United States)

Mairs, Christopher M.

An aerodynamic-structural model of offwind yacht sails was created that is useful in predicting sail forces. Two sails were examined experimentally and computationally at several wind angles to explore a variety of flow regimes. The accuracy of the numerical solutions was measured by comparing to experimental results. The two sails examined were a Code 0 and a reaching asymmetric spinnaker. During experiment, balance, wake, and sail shape data were recorded for both sails in various configurations. Two computational steps were used to evaluate the computational model. First, an aerodynamic flow model that includes viscosity effects was used to examine the experimental flying shapes that were recorded. Second, the aerodynamic model was combined with a nonlinear, structural, finite element analysis (FEA) model. The aerodynamic and structural models were used iteratively to predict final flying shapes of offwind sails, starting with the design shapes. The Code 0 has relatively low camber and is used at small angles of attack. It was examined experimentally and computationally at a single angle of attack in two trim configurations, a baseline and overtrimmed setting. Experimentally, the Code 0 was stable and maintained large flow attachment regions. The digitized flying shapes from experiment were examined in the aerodynamic model. Force area predictions matched experimental results well. When the aerodynamic-structural tool was employed, the predictive capability was slightly worse. The reaching asymmetric spinnaker has higher camber and operates at higher angles of attack than the Code 0. Experimentally and computationally, it was examined at two angles of attack. Like the Code 0, at each wind angle, baseline and overtrimmed settings were examined. Experimentally, sail oscillations and large flow detachment regions were encountered. The computational analysis began by examining the experimental flying shapes in the aerodynamic model. In the baseline setting, the

A Deweyian Framework for Youth Development in Experiential Education: Perspectives from Sail Training and Sailing Instruction

Science.gov (United States)

Wojcikiewicz, Steven K.; Mural, Zachary B.

2010-01-01

In this piece, we put forth a Deweyian framework for youth development activities in outdoor and adventure education programs, and we show how such a framework may be exemplified by activities in sail training and sailing instruction. The paper begins with a discussion of the theoretical features of Deweyian educational experiences and makes…

SAIL--A Way to Success and Independence for Low-Achieving Readers.

Science.gov (United States)

Bergman, Janet L.

1992-01-01

Argues that providing students with a repertoire of important learning strategies is one crucial way of helping all students to become independent readers, thinkers, and learners. Describes a third grade reading environment and the practices of the Students Achievement Independent Learning Program (SAIL). (PRA)

Space Solar Power Program. Final report

Energy Technology Data Exchange (ETDEWEB)

Arif, Humayun; Barbosa, Hugo; Bardet, Christophe; Baroud, Michel; Behar, Alberto; Berrier, Keith; Berthe, Phillipe; Bertrand, Reinhold; Bibyk, Irene; Bisson, Joel; Bloch, Lawrence; Bobadilla, Gabriel; Bourque, Denis; Bush, Lawrence; Carandang, Romeo; Chiku, Takemi; Crosby, Norma; De Seixas, Manuel; De Vries, Joha; Doll, Susan; Dufour, Francois; Eckart, Peter; Fahey, Michael; Fenot, Frederic; Foeckersperger, Stefan; Fontaine, Jean-Emmanuel; Fowler, Robert; Frey, Harald; Fujio, Hironobu; Gasa, Jaume Munich; Gleave, Janet; Godoe, Jostein; Green, Iain; Haeberli, Roman; Hanada, Toshiya; Harris, Peter; Hucteau, Mario; Jacobs, Didier Fernand; Johnson, Richard; Kanno, Yoshitsugu; Koenig, Eva Maria; Kojima, Kazuo; Kondepudi, Phani; Kottbauer, Christian; Kulper, Doede; Kulagin, Konstantin; Kumara, Pekka; Kurz, Rainer; Laaksonen, Jyrki; Lang, Andrew Neill; Lathan, Corinna; Le Fur, Thierry; Lewis, David; Louis, Alain; Mori, Takeshi; Morlanes, Juan; Murbach, Marcus; Nagatomo, Hideo; O' brien, Ivan; Paines, Justin; Palaszewski, Bryan; Palmnaes, Ulf; Paraschivolu, Marius; Pathare, Asmin; Perov, Egor; Persson, Jan; Pessoa-Lopes, Isabel; Pinto, Michel; Porro, Irene; Reichert, Michael; Ritt-Fischer, Monika; Roberts, Margaret; Robertson II, Lawrence; Rogers, Keith; Sasaki, Tetsuo; Scire, Francesca; Shibatou, Katsuya; Shirai, Tatsuya; Shiraishi, Atsushi; Soucaille, Jean-Francois; Spivack, Nova; St. Pierre, Dany; Suleman, Afzal; Sullivan, Thomas; Theelen, Bas Johan; Thonstad, Hallvard; Tsuji, Masatoshi; Uchiumi, Masaharu; Vidqvist, Jouni; Warrell, David; Watanabe, Takafumi; Willis, Richard; Wolf, Frank; Yamakawa, Hiroshi; Zhao, Hong

1992-08-01

Information pertaining to the Space Solar Power Program is presented on energy analysis; markets; overall development plan; organizational plan; environmental and safety issues; power systems; space transportation; space manufacturing, construction, operations; design examples; and finance.

Trans-Pacific voyage in a solar-powered boat built of recycled aluminium

Energy Technology Data Exchange (ETDEWEB)

Anon.

1997-03-01

The first solo crossing of the Pacific was made in 1962 by Mr Kenichi Horie in a tiny yacht called ``Mermaid``. In 1996, Mr. Horie made the first solo, non-stop, trans-Pacific voyage in a solar-powered boat made of recycled aluminium. The boat, called ``Malt`s Mermaid``, sailed 16,000 km from Ecuador to Tokyo in 138 days. The themes of the project were preserving the environment and using resources efficiently. (Author)

The space radiation environment

International Nuclear Information System (INIS)

Robbins, D.E.

1997-01-01

There are three primary sources of space radiation: galactic cosmic rays (GCR), trapped belt radiation, and solar particle events (SPE). All are composed of ions, the nuclei of atoms. Their energies range from a few MeV u -1 to over a GeV u -1 . These ions can fragment when they interact with spacecraft materials and produce energetic neutrons and ions of lower atomic mass. Absorbed dose rates inside a typical spacecraft (like the Space Shuttle) in a low inclination (28.5 degrees) orbit range between 0.05 and 2 mGy d -1 depending on the altitude and flight inclination (angle of orbit with the equator). The quality factor of radiation in orbit depends on the relative contributions of trapped belt radiation and GCR, and the dose rate varies both with orbital altitude and inclination. The corresponding equivalent dose rate ranges between 0.1 and 4 mSv d -1 . In high inclination orbits, like that of the Mir Space Station and as is planned for the International Space Station, blood-forming organ (BFO) equivalent dose rates as high as 1.5 mSv d -1 . Thus, on a 1 y mission, a crew member could obtain a total dose of 0.55 Sv. Maximum equivalent dose rates measured in high altitude passes through the South Atlantic Anomaly (SAA) were 10 mSv h -1 . For an interplanetary space mission (e.g., to Mars) annual doses from GCR alone range between 150 mSv y -1 at solar maximum and 580 mSv y -1 at solar minimum. Large SPE, like the October 1989 series, are more apt to occur in the years around solar maximum. In free space, such an event could contribute another 300 mSv, assuming that a warning system and safe haven can be effectively used with operational procedures to minimize crew exposures. Thus, the total dose for a 3 y mission to Mars could exceed 2 Sv

The « 3-D donut » electrostatic analyzer for millisecond timescale electron measurements in the solar wind

Science.gov (United States)

Berthomier, M.; Techer, J. D.

2017-12-01

Understanding electron acceleration mechanisms in planetary magnetospheres or energy dissipation at electron scale in the solar wind requires fast measurement of electron distribution functions on a millisecond time scale. Still, since the beginning of space age, the instantaneous field of view of plasma spectrometers is limited to a few degrees around their viewing plane. In Earth's magnetosphere, the NASA MMS spacecraft use 8 state-of-the-art sensor heads to reach a time resolution of 30 milliseconds. This costly strategy in terms of mass and power consumption can hardly be extended to the next generation of constellation missions that would use a large number of small-satellites. In the solar wind, using the same sensor heads, the ESA THOR mission is expected to reach the 5ms timescale in the thermal energy range, up to 100eV. We present the « 3-D donut » electrostatic analyzer concept that can change the game for future space missions because of its instantaneous hemispheric field of view. A set of 2 sensors is sufficient to cover all directions over a wide range of energy, e.g. up to 1-2keV in the solar wind, which covers both thermal and supra-thermal particles. In addition, its high sensitivity compared to state of the art instruments opens the possibility of millisecond time scale measurements in space plasmas. With CNES support, we developed a high fidelity prototype (a quarter of the full « 3-D donut » analyzer) that includes all electronic sub-systems. The prototype weights less than a kilogram. The key building block of the instrument is an imaging detector that uses EASIC, a low-power front-end electronics that will fly on the ESA Solar Orbiter and on the NASA Parker Solar Probe missions.

NASA Glenn Research Center Solar Cell Experiment Onboard the International Space Station

Science.gov (United States)

Myers, Matthew G.; Wolford, David S.; Prokop, Norman F.; Krasowski, Michael J.; Parker, David S.; Cassidy, Justin C.; Davies , William E.; Vorreiter, Janelle O.; Piszczor, Michael F.; Mcnatt, Jeremiah S.;

Space Environments and Effects Concept: Transitioning Research to Operations and Applications

Science.gov (United States)

Edwards, David L.; Spann, James; Burns, Howard D.; Schumacher, Dan

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 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. NASA has established numerous offices specializing in specific space environments disciplines that will serve to enable these missions. To complement these existing discipline offices, a concept focusing on the development of space environment and effects application is presented. This includes space climate, space weather, and natural and induced space environments. This space environment and effects application is composed of 4 topic areas; characterization and modeling, engineering effects, prediction and operation, and mitigation and avoidance. These topic areas are briefly described below. Characterization and modeling of space environments will primarily focus on utilization during Program mission concept, planning, and design phases. Engineering effects includes materials testing and flight experiments producing data to be used in mission planning and design phases. Prediction and operation pulls data from existing sources into decision-making tools and empirical data sets to be used during the operational phase of a mission. Mitigation and avoidance will develop techniques and strategies used in the design and operations phases of the mission. The goal of this space environment and effects application is to develop decision-making tools and engineering products to support the mission phases of mission concept through operations by focusing on transitioning research to operations. Products generated by this space environments and effects application are suitable for use in anomaly investigations. This paper will outline the four topic areas, describe the need, and discuss an organizational structure for this space environments and effects

[A paraplegic skipper of his own sailing yacht].

Science.gov (United States)

Christians, U

1985-05-01

Drawing on personal experience, the author points out that paraplegics too are capable of independent sailing. Physical restrictions relative to on-board mobility, sail manoeuvring and change of sides can be made up for by structural adaptions and special techniques. Certain safety precautions are indispensable. The sailing performance of paraplegics compares with that of ablebodied sailors, and cruising under a paraplegic skipper's responsibility is certainly possible.

Solar cell radiation handbook

Science.gov (United States)

Tada, H. Y.; Carter, J. R., Jr.; Anspaugh, B. E.; Downing, R. G.

1982-01-01

The handbook to predict the degradation of solar cell electrical performance in any given space radiation environment is presented. Solar cell theory, cell manufacturing and how they are modeled mathematically are described. The interaction of energetic charged particles radiation with solar cells is discussed and the concept of 1 MeV equivalent electron fluence is introduced. The space radiation environment is described and methods of calculating equivalent fluences for the space environment are developed. A computer program was written to perform the equivalent fluence calculations and a FORTRAN listing of the program is included. Data detailing the degradation of solar cell electrical parameters as a function of 1 MeV electron fluence are presented.

Potential for solar space heating in Scotland

Energy Technology Data Exchange (ETDEWEB)

Macgregor, A W.K.

1980-07-01

This paper investigates the relative effectiveness of passive-type solar-assisted space heating systems at various latitudes within the British Isles. A comparison is made of the useful solar gain of the same system linked to the same house at four different locations. Month-by-month energy balances indicate that the annual useful solar contribution at the highest latitude (Lerwick, 60 deg N) is about 35% higher than at the lowest latitude (Kew, 53 deg N). The main reason for this difference is the higher heating loads in the north, particularly outside the winter months. The estimated available irradiation on south-facing vertical surfaces was almost the same at all four locations. Previous work in the UK indicates that, contrary to the conclusions in this paper, more southerly latitudes were the most favorable for solar space heating. The reasons for the disparity are discussed. It is recommended that research and development of passive solar-assisted space heating systems should be most vigorously pursued in the more northerly latitudes of the British Isles, where both the potential benefit and the need are greatest.

Hiking strap force decreases during sustained upwind sailing

DEFF Research Database (Denmark)

Buchardt, R; Bay, Jonathan; Bojsen-Møller, Jens

2017-01-01

The hypothesis, that sailing upwind in wind speeds above 12 knots causes fatigue, which manifests as a reduction in exerted hiking strap force and/or maximal isometric voluntary contraction force (MVC) of the knee extensors, was evaluated. Additionally, it was investigated if a relationship exists...... between maximal exerted hiking force (hMVC) and sailing performance. In part 1 of the study, 12 national level athletes sailed upwind for 2 × 10 min while hiking strap forces were continuously acquired. Before, in between and after sailing periods, the MVC of the knee extensors was measured. In part 2...... of the study, hMVC was measured dry land in a hiking bench and correlated with the overall results at a national championship. Hiking strap force decreased from the first to the last minute in both 10 min sailing periods (430 ± 131 vs. 285 ± 130 N, P 

Opportunities for Utilizing the International Space Station for Studies of F2- Region Plasma Science and High Voltage Solar Array Interactions with the Plasma Environment

Science.gov (United States)

Minow, Joseph I.; Coffey, Victoria; Wright, Kenneth; Craven, Paul; Koontz, Steven

2010-01-01

The near circular, 51.6deg inclination orbit of the International Space Station (ISS) is maintained within an altitude range of approximately 300 km to 400 km providing an ideal platform for conducting in-situ studies of space weather effects on the mid and low-latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) is a suite of instruments installed on the ISS in August 2006 which includes a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep Langmuir Probe (WLP), and a Narrow-sweep Langmuir Probe (NLP). The primary purpose for deploying the FPMU is to characterize ambient plasma temperatures and densities in which the ISS operates and to obtain measurements of the ISS potential relative to the space plasma environment for use in characterizing and mitigating spacecraft charging hazards to the vehicle and crew. In addition to the engineering goals, data from the FPMU instrument package is available for collaborative multi-satellite and ground based instrument studies of the F-region ionosphere during both quiet and disturbed periods. Finally, the FPMU measurements supported by ISS engineering telemetry data provides a unique opportunity to investigate interactions of the ISS high voltage (160 volt) solar array system with the plasma environment. This presentation will provide examples of FPMU measurements along the ISS orbit including night-time equatorial plasma density depletions sampled near the peak electron density in the F2-region ionosphere, charging phenomenon due to interaction of the ISS solar arrays with the plasma environment, and modification of ISS charging due to visiting vehicles demonstrating the capabilities of the FPMU probes for monitoring mid and low latitude plasma processes as well as vehicle interactions with the plasma environment.

Roles of Solar Power from Space for Europe - Space Exploration and Combinations with Terrestrial Solar Plant Concepts

Science.gov (United States)

Summerer, L.; Pipoli, T.; Galvez, A.; Ongaro, F.; Vasile, M.

The paper presents the prospective roles of SPS concepts for Europe, shows the outcome of recent studies undertaken by ESA's Advanced Concepts Team (ACT) together with European industry and research centres and gives insight into planned activities. The main focus is on the assessment of the principal validity and economic viability of solar power from space concepts in the light of advances in alternative sustainable, clean and potentially abundant solar-based terrestrial concepts. The paper takes into account expected changes in the European energy system (e.g. gradual introduction of hydrogen as energy vector). Special emphasis is given to the possibilities of integrating space and terrestrial solar plants. The relative geographic proximity of areas in North Africa with high average solar irradiation to the European energy consumer market puts Europe in a special position regarding the integration of space and terrestrial solar power concepts. The paper presents a method to optimise such an integration, taking into account different possible orbital constellations, terrestrial locations, plant number and sizes as well as consumer profiles and extends the scope from the European-only to a multi continental approach including the fast growing Chinese electricity market. The work intends to contribute to the discussion on long-term options for the European commitment to worldwide CO2 emission reduction. Cleaner electricity generation and environmentally neutral transport fuels (e.g. solar generated hydrogen) might be two major tools in reaching this goal.

Formation flying for electric sails in displaced orbits. Part II: Distributed coordinated control

Science.gov (United States)

Wang, Wei; Mengali, Giovanni; Quarta, Alessandro A.; Yuan, Jianping

2017-09-01

We analyze a cooperative control framework for electric sail formation flying around a heliocentric displaced orbit, aiming at observing the polar region of a celestial body. The chief spacecraft is assumed to move along an elliptic displaced orbit, while each deputy spacecraft adjusts its thrust vector (that is, both its sail attitude and characteristic acceleration) in order to track a prescribed relative trajectory. The relative motion of the electric sail formation system is formulated in the chief rotating frame, where the control inputs of each deputy are the relative sail attitude angles and the relative lightness number with respect to those of the chief. The information exchange among the spacecraft, characterized by the communication topology, is represented by a weighted graph. Two typical cases, according to whether the communication graph is directed or undirected, are discussed. For each case, a distributed coordinated control law is designed in such a way that each deputy not only tracks the chief state, but also makes full use of information from its neighbors, thus increasing the redundancy and robustness of the formation system in case of failure among the communication links. Illustrative examples show the effectiveness of the proposed approach.

Janus: Graphical Software for Analyzing In-Situ Measurements of Solar-Wind Ions

Science.gov (United States)

Maruca, B.; Stevens, M. L.; Kasper, J. C.; Korreck, K. E.

2016-12-01

In-situ observations of solar-wind ions provide tremendous insights into the physics of space plasmas. Instrument on spacecraft measure distributions of ion energies, which can be processed into scientifically useful data (e.g., values for ion densities and temperatures). This analysis requires a strong, technical understanding of the instrument, so it has traditionally been carried out by the instrument teams using automated software that they had developed for that purpose. The automated routines are optimized for typical solar-wind conditions, so they can fail to capture the complex (and scientifically interesting) microphysics of transient solar-wind - such as coronal mass ejections (CME's) and co-rotating interaction regions (CIR's) - which are often better analyzed manually.This presentation reports on the ongoing development of Janus, a new software package for processing in-situ measurement of solar-wind ions. Janus will provide user with an easy-to-use graphical user interface (GUI) for carrying out highly customized analyses. Transparent to the user, Janus will automatically handle the most technical tasks (e.g., the retrieval and calibration of measurements). For the first time, users with only limited knowledge about the instruments (e.g., non-instrumentalists and students) will be able to easily process measurements of solar-wind ions. Version 1 of Janus focuses specifically on such measurements from the Wind spacecraft's Faraday Cups and is slated for public release in time for this presentation.

Synthesis of stereoarray isotope labeled (SAIL) lysine via the "head-to-tail" conversion of SAIL glutamic acid.

Science.gov (United States)

Terauchi, Tsutomu; Kamikawai, Tomoe; Vinogradov, Maxim G; Starodubtseva, Eugenia V; Takeda, Mitsuhiro; Kainosho, Masatsune

2011-01-07

A stereoarray isotope labeled (SAIL) lysine, (2S,3R,4R,5S,6R)-[3,4,5,6-(2)H(4);1,2,3,4,5,6-(13)C(6);2,6-(15)N(2)]lysine, was synthesized by the "head-to-tail" conversion of SAIL-Glu, (2S,3S,4R)-[3,4-(2)H(2);1,2,3,4,5-(13)C(5);2-(15)N]glutamic acid, with high stereospecificities for all five chiral centers. With the SAIL-Lys in hand, the unambiguous simultaneous stereospecific assignments were able to be established for each of the prochiral protons within the four methylene groups of the Lys side chains in proteins.

Flight Plasma Diagnostics for High-Power, Solar-Electric Deep-Space Spacecraft

Science.gov (United States)

Johnson, Lee; De Soria-Santacruz Pich, Maria; Conroy, David; Lobbia, Robert; Huang, Wensheng; Choi, Maria; Sekerak, Michael J.

2018-01-01

NASA's Asteroid Redirect Robotic Mission (ARRM) project plans included a set of plasma and space environment instruments, the Plasma Diagnostic Package (PDP), to fulfill ARRM requirements for technology extensibility to future missions. The PDP objectives were divided into the classes of 1) Plasma thruster dynamics, 2) Solar array-specific environmental effects, 3) Plasma environmental spacecraft effects, and 4) Energetic particle spacecraft environment. A reference design approach and interface requirements for ARRM's PDP was generated by the PDP team at JPL and GRC. The reference design consisted of redundant single-string avionics located on the ARRM spacecraft bus as well as solar array, driving and processing signals from multiple copies of several types of plasma, effects, and environments sensors distributed over the spacecraft and array. The reference design sensor types were derived in part from sensors previously developed for USAF Research Laboratory (AFRL) plasma effects campaigns such as those aboard TacSat-2 in 2007 and AEHF-2 in 2012.

Fluid-structure interaction analysis of deformation of sail of 30-foot yacht

Science.gov (United States)

Bak, Sera; Yoo, Jaehoon; Song, Chang Yong

2013-06-01

Most yacht sails are made of thin fabric, and they have a cambered shape to generate lift force; however, their shape can be easily deformed by wind pressure. Deformation of the sail shape changes the flow characteristics over the sail, which in turn further deforms the sail shape. Therefore, fluid-structure interaction (FSI) analysis is applied for the precise evaluation or optimization of the sail design. In this study, fluid flow analyses are performed for the main sail of a 30-foot yacht, and the results are applied to loading conditions for structural analyses. By applying the supporting forces from the rig, such as the mast and boom-end outhaul, as boundary conditions for structural analysis, the deformed sail shape is identified. Both the flow analyses and the structural analyses are iteratively carried out for the deformed sail shape. A comparison of the flow characteristics and surface pressures over the deformed sail shape with those over the initial shape shows that a considerable difference exists between the two and that FSI analysis is suitable for application to sail design.

Fluid-structure interaction analysis of deformation of sail of 30-foot yacht

Directory of Open Access Journals (Sweden)

Sera Bak

2013-06-01

Full Text Available Most yacht sails are made of thin fabric, and they have a cambered shape to generate lift force; however, their shape can be easily deformed by wind pressure. Deformation of the sail shape changes the flow characteristics over the sail, which in turn further deforms the sail shape. Therefore, fluid-structure interaction (FSI analysis is applied for the precise evaluation or optimization of the sail design. In this study, fluid flow analyses are performed for the main sail of a 30-foot yacht, and the results are applied to loading conditions for structural analyses. By applying the supporting forces from the rig, such as the mast and boom-end outhaul, as boundary conditions for structural analysis, the deformed sail shape is identified. Both the flow analyses and the structural analyses are iteratively carried out for the deformed sail shape. A comparison of the flow characteristics and surface pressures over the deformed sail shape with those over the initial shape shows that a considerable difference exists between the two and that FSI analysis is suitable for application to sail design.

Developing a business plan for a company in Finland owned by foreigners. Case: Prime Sails Ltd

OpenAIRE

Honkonen-Kulagina, Alina Linda

2012-01-01

To establish a new company is challenging for any businessman or businesswomen. Starting up a company in a foreign country is twice is hard. The purpose of the thesis is to examine the factors that affect the success of a company newly-established by immigrants. These include such areas as good business plan, market research, cultural knowledge and awareness of the legislative environment. The case study focuses on the company Prime Sails Ltd, which is a supplier of sails. The main ob...

An Examination of Radiation Induced Tensile Failure of Stressed and Unstressed Polymer Films Flown on MISSE-6

Science.gov (United States)

Miller, Sharon K.; Sechkar, Edward A.

2012-01-01

Thin film polymers are used in many spacecraft applications for thermal control (multilayer insulation and sunshields), as lightweight structural members (solar array blankets, inflatable/deployable structures) and have been proposed for propulsion (solar sails). Polymers in these applications are often under a tensile load and are directly exposed to the space environment, therefore it is important to understand the effect of stress in combination with the environment on the durability of these polymer films. The purpose of the Polymer Film Tensile Experiment, flown as part of Materials International Space Station Experiment 6 (MISSE 6), was to expose a variety of polymer films to the low Earth orbital environment under both relaxed and tension conditions. This paper describes the results of post flight tensile testing of these samples.

UltraSail Solar Sail Flight Experiment, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — A team of CU Aerospace, the University of Illinois, and ManTech SRS Technologies proposes Phase II development of a 3 kg CubeSat spacecraft for initial flight test...

FASt - An autonomous sailing platform for oceanographic missions

OpenAIRE

Jose C Alves; Nuno A Cruz

2008-01-01

Sailing has been for long times the only means of ship propulsion at sea. Although the performance of a sailing vessel is well below the present power driven ships, either in terms of navigation speed and predictability, wind energy is absolutely renewable, clean and free. Unmanned autonomous sailing boats may exhibit a virtually unlimited autonomy and be able to perform unassisted missions at sea for long periods of time. Promising applications include oceanographic and weather data collecti...

School-Based Adolescent Groups: The Sail Model.

Science.gov (United States)

Thompson, John L.; And Others

The manual outlines the processes, policies, and actual program implementation of one component of a Minnesota program for emotionally disturbed adolescents (Project SAIL): the development of school-based therapy/intervention groups. The characteristics of SAIL students are described, and some considerations involved in providing group services…

High Fidelity Measurement of Free Space Solar Particle Event and Galactic Cosmic Ray Environments at Intermediate Energies

Science.gov (United States)

Leitgab, M.

2018-02-01

A charged particle measurement experiment mounted externally to the Deep Space Gateway is proposed, contributing to improving astronaut radiation exposure management during Solar Particle Events and Extra Vehicular Activities.

Making and Executing Decisions for Safe and Independent Living (MED-SAIL): development and validation of a brief screening tool.

Science.gov (United States)

Mills, Whitney L; Regev, Tziona; Kunik, Mark E; Wilson, Nancy L; Moye, Jennifer; McCullough, Laurence B; Naik, Aanand D

2014-03-01

Older adults prefer to remain in their own homes for as long as possible. The purpose of this article is to describe the development and preliminary validation of Making and Executing Decisions for Safe and Independent Living (MED-SAIL), a brief screening tool for capacity to live safely and independently in the community. Prospective preliminary validation study. Outpatient geriatrics clinic located in a community-based hospital. Forty-nine community-dwelling older adults referred to the clinic for a comprehensive capacity assessment. We examined internal consistency, criterion-based validity, concurrent validity, and accuracy of classification for MED-SAIL. The items included in MED-SAIL demonstrated internal consistency (5 items; α = 0.85). MED-SAIL was significantly correlated with the Independent Living Scales (r = 0.573, p ≤0.001) and instrumental activities of daily living (r = 0.440, p ≤0.01). The Mann-Whitney U test revealed significant differences between the no capacity and partial/full capacity classifications on MED-SAIL (U(48) = 60.5, Z = -0.38, p SAIL as a brief screening tool to identify older adults with impaired capacity for remaining safe and independent in their current living environment. MED-SAIL is useful tool for health and social service providers in the community for the purpose of referral for definitive capacity evaluation. Published by Elsevier Inc.

Physics of the Space Environment

Science.gov (United States)

Vasyliünas, Vytenis M.

This book, one in the Cambridge Atmospheric and Space Science Series, joins a growing list of advanced-level textbooks in a field of study and research known under a variety of names: space plasma physics, solar-terrestrial or solar-planetary relations, space weather, or (the official name of the relevant AGU section) space physics and aeronomy. On the basis of graduate courses taught by the author in various departments at the University of Michigan, complete with problems and with appendices of physical constants and mathematical identities, this is indeed a textbook, systematic and severe in its approach. The book is divided into three parts, in length ratios of roughly 6:4:5. Part I, “Theoretical Description of Gases and Plasmas,” starts by writing down Maxwell's equations and the Lorentz transformation (no nonsense about any introductory material of a descriptive or historical nature) and proceeds through particle orbit theory, kinetics, and plasma physics with fluid and MHD approximations to waves, shocks, and energetic particle transport. Part II, “The Upper Atmosphere,” features chapters on the terrestrial upper atmosphere, airglow and aurora, and the ionosphere. Part III, “Sun-Earth Connection,” deals with the Sun, the solar wind, cosmic rays, and the terrestrial magnetosphere. The book thus covers, with two exceptions, just about all the topics of interest to Space Physics and Aeronomy scientists, and then some (the chapter on the Sun, for instance, briefly discusses also topics of the solar interior: thermonuclear energy generation, equilibrium structure, energy transfer, with a page or two on each). One exception reflects a strong geocentric bias: there is not one word in the main text on magnetospheres and ionospheres of other planets and their interaction with the solar wind (they are mentioned in a few problems). The other exception: the chapter on the terrestrial magnetosphere lacks a systematic exposition of the theory of

A UKSeRP for SAIL: striking a balance

Directory of Open Access Journals (Sweden)

Kerina Jones

2017-04-01

The SAIL UKSeRP represents a powerful analytical environment within a privacy-protecting safe haven and secure remote access system which has been designed to be scalable and adaptable to meet the needs of the rapidly growing data linkage community. Further challenges lie ahead as the landscape develops and emerging data types become more available. UKSeRP technology is available and customisable for other use cases within the UK and international jurisdictions, to operate within their respective governance frameworks.

Design of Sail-Assisted Unmanned Surface Vehicle Intelligent Control System

OpenAIRE

Ma, Yong; Zhao, Yujiao; Diao, Jiantao; Gan, Langxiong; Bi, Huaxiong; Zhao, Jingming

2016-01-01

To achieve the wind sail-assisted function of the unmanned surface vehicle (USV), this work focuses on the design problems of the sail-assisted USV intelligent control systems (SUICS) and illustrates the implementation process of the SUICS. The SUICS consists of the communication system, the sensor system, the PC platform, and the lower machine platform. To make full use of the wind energy, in the SUICS, we propose the sail angle of attack automatic adjustment (Sail_4A) algorithm and present ...

A study of dynamical behavior of space environment

Science.gov (United States)

Wu, S. T.

1974-01-01

Studies have covered a wide range of problems in the space environment, such as the problems of the dynamical behavior of the thermosphere, hydromagnetic wave propagation in the ionosphere, and interplanetary space environment. The theories used to analyze these problems range from a continuum theory of magnetohydrodynamics to the kinetic theory of free molecular flow. This is because the problems encountered covered the entire range of the Knudsen number (i.e., the ratio of mean free path to the characteristic length). Significant results are summarized.

Electrostatic Discharge Test of Multi-Junction Solar Array Coupons After Combined Space Environmental Exposures

Science.gov (United States)

Wright, Kenneth H.; Schneider, Todd; Vaughn, Jason; Hoang, Bao; Funderburk, Victor V.; Wong, Frankie; Gardiner, George

2010-01-01

A set of multi-junction GaAs/Ge solar array test coupons were subjected to a sequence of 5-year increments of combined environmental exposure tests. The test coupons capture an integrated design intended for use in a geosynchronous (GEO) space environment. A key component of this test campaign is conducting electrostatic discharge (ESD) tests in the inverted gradient mode. The protocol of the ESD tests is based on the ISO/CD 11221, the ISO standard for ESD testing on solar array panels. This standard is currently in its final review with expected approval in 2010. The test schematic in the ISO reference has been modified with Space System/Loral designed circuitry to better simulate the on-orbit operational conditions of its solar array design. Part of the modified circuitry is to simulate a solar array panel coverglass flashover discharge. All solar array coupons used in the test campaign consist of 4 cells. The ESD tests are performed at the beginning of life (BOL) and at each 5-year environment exposure point. The environmental exposure sequence consists of UV radiation, electron/proton particle radiation, thermal cycling, and ion thruster plume. This paper discusses the coverglass flashover simulation, ESD test setup, and the importance of the electrical test design in simulating the on-orbit operational conditions. Results from 5th-year testing are compared to the baseline ESD characteristics determined at the BOL condition.

A basic tool for computer-aided sail design

International Nuclear Information System (INIS)

Thrasher, D.F.; Dunyak, T.J.; Mook, D.T.; Nayfeh, A.H.

1985-01-01

Recent developments in modelling lifting surfaces have provided a tool that also can be used to model sails. The simplest of the adequate models is the vortex-lattice method. This method can fully account for the aerodynamic interactions among several lifting surfaces having arbitrary platforms, camber, and twist as long as separation occurs only along the edges and the phenomenon known as vortex bursting does not occur near the sails. This paper describes this method and how it can be applied to the design of sails

A Strategic Roadmap to Centauri

Science.gov (United States)

Johnson, L.; Harris, D.; Trausch, A.; Matloff, G. L.; Taylor, T.; Cutting, K.

This paper discusses the connectivity between in-space propulsion and in-space fabrication/repair and is based upon a workshop presentation by Les Johnson, manager of the In-Space Propulsion (ISP) Technology Project at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama. Technologies under study by ISP include aerocapture, advanced solar- electric propulsion, solar-thermal propulsion, advanced chemical propulsion, tethers and solar-photon sails. These propulsion systems are all approaching technology readiness levels (TRLs) at which they can be considered for application in space- science and exploration missions. Historically, human frontiers have expanded as people have learned to “live-off-the-land” in new environments and to exploit local resources. With this expansion, frontier settlements have required development of transportation improvements to carry tools and manufactured products to and from the frontier. It is demonstrated how ISP technologies will assist in the development of the solar-system frontier. In-space fabrication and repair will both require and assist the development of ISP propulsion systems, whether humans choose to settle planetary surfaces or to exploit resources of small Solar System bodies. As was true for successful terrestrial pioneers, in-space settlement and exploitation will require sophisticated surveys of inner and outer Solar System objects. ISP technologies will contribute to the success of these surveys, as well as to the efforts to retrieve Solar System resources. In a similar fashion, the utility of ISP products will be greatly enhanced by the technologies of in-space repair and fabrication. As in-space propulsion, fabrication and repair develop, human civilization may expand well beyond the Earth. In the future, small human communities (preceded by robotic explorers) may utilize these techniques to set sail for the nearest stars.

Assessment of Nutrient Stability in Space Foods

Science.gov (United States)

Zwart, S. R.; Perchonok, M.; Braby, L. A.; Kloeris, V. A.; Smith, S. M.

2009-01-01

Maintaining an intact nutrient supply in the food system flown on spacecraft is a critical issue for mission success and crew health and safety. Early polar expeditions and exploration expeditions by sailing vessels have taught us that a deficiency, or excess, of even a single vitamin in the food supply can be catastrophic. Evidence from ground-based research indicates that some vitamins are destroyed and fatty acids are oxidized (and therefore rendered dangerous or useless) by different types of radiation and by conditions of long-term storage. We hypothesize that radiation and long-term storage in the space-flight environment will affect the stability of vitamins, amino acids, and fatty acids in the space food system. The research objectives of our ongoing stability studies are to determine the stability of water- and fat-soluble vitamins, fatty acids, and amino acids in the space food supply before and after space flight on the International Space Station (ISS). Foods were analyzed after 2 weeks (a flight control), 11, 19, and 28 months of flight. Along with the space-flown foods, ground-based controls matched for time, light, and temperature are analyzed. The flight studies complement planned ground-based studies of the effects of radiation on vitamins, amino acids, and fatty acids. Flight studies are needed because a model based on ground-based data cannot predict all of the effects of the space-flight environment. Flight studies provide a more accurate test system to determine the effects on these nutrients of the temperature, and radiation conditions in the space-flight environment. Ground studies are required to evaluate longer missions and higher radiation levels expected outside low-Earth orbit. In addition to providing information about nutrient stability in space, the results of these studies will help NASA determine if a need exists to develop special packaging that can ensure stability of foods and nutrients in space, or if further studies of nutrient

Research on the Design of Public Space Environment for Aging Society

Science.gov (United States)

Fang, Gu; Soo, Kim Chul

2018-03-01

This paper studies the living space environment suitable for the elderly, because the elderly and the disabled have become increasingly prominent social problems. Through the discussion of the humanistic environment design method of the elderly and the disabled, the paper puts forward a new environment design which has the traditional characteristics and adapts to the new society to care for the elderly (the disabled).By studying and analyzing the background of social aging, the theory of public space environment design and the needs of the elderly, it is pointed out that the design of public space environment in the aged society needs to be implemented in detail design. The number of elderly people in public space will increase, give full attention to the public space outdoor environment quality, for the elderly to provide a variety of environmental facilities have long-term significance.

Space Environment Effects on Materials at Different Positions and Operational Periods of ISS

Science.gov (United States)

Kimoto, Yugo; Ichikawa, Shoichi; Miyazaki, Eiji; Matsumoto, Koji; Ishizawa, Junichiro; Shimamura, Hiroyuki; Yamanaka, Riyo; Suzuki, Mineo

2009-01-01

A space materials exposure experiment was condcuted on the exterior of the Russian Service Module (SM) of the International Space Station (ISS) using the Micro-Particles Capturer and Space Environment Exposure Device (MPAC&SEED) of the Japan Aerospace Exploration Agency (JAXA). Results reveal artificial environment effects such as sample contamination, attitude change effects on AO fluence, and shading effects of UV on ISS. The sample contamination was coming from ISS components. The particles attributed to micrometeoroids and/or debris captured by MPAC might originate from the ISS solar array. Another MPAC&SEED will be aboard the Exposure Facility of the Japanese Experiment Module, KIBO Exposure Facility (EF) on ISS. The JEM/MPAC&SEED is attached to the Space Environment Data Acquisition Equipment-Attached Payload (SEDA-AP) and is exposed to space. Actually, SEDA-AP is a payload on EF to be launched by Space Shuttle flight 2J/A. In fact, SEDA-AP has space environment monitors such as a high-energy particle monitor, atomic oxygen monitor, and plasma monitor to measure in-situ natural space environment data during JEM/MPAC&SEED exposure. Some exposure samples for JEM/MPAC&SEED are identical to SM/MPAC&SEED samples. Consequently, effects on identical materials at different positions and operation periods of ISS will be evaluated. This report summarizes results from space environment monitoring samples for atomic oxygen analysis on SM/MPAC&SEED, along with experimental plans for JEM/MPAC&SEED.

Space solar power satellite systems with a space elevator

Energy Technology Data Exchange (ETDEWEB)

Kellum, M. J. (Mervyn J.); Laubscher, B. E. (Bryan E.)

2004-01-01

The Space Elevator (SE) represents a major paradigm shift in mankind's access to outer space. If the SE's promise of low-cost access to space can be realized, the economics of space-based business endeavors becomes much more feasible. In this paper, we describe a Solar Power Satellite (SPS) system and estimate its costs within the context of an SE. We also offer technical as well as financial comparisons between SPS and terrestrial solar photovoltaic technologies. Even though SPS systems have been designed for over 35 years, technologies pertinent to SPS systems are continually evolving. One of the designs we present includes an evolving technology, optical rectennas. SPS systems could be a long-term energy source that is clean, technologically feasible, and virtually limitless. Moreover, electrical energy could be distributed inexpensively to remote areas where such power does not currently exist, thereby raising the quality of life of the people living in those areas. The energy 'playing field' will be leveled across the world and the resulting economic growth will improve the lot of humankind everywhere.

Validated TRNSYS Model for Solar Assisted Space Heating System

International Nuclear Information System (INIS)

Abdalla, Nedal

2014-01-01

The present study involves a validated TRNSYS model for solar assisted space heating system as applied to a residential building in Jordan using new detailed radiation models of the TRNSYS 17.1 and geometric building model Trnsys3d for the Google SketchUp 3D drawing program. The annual heating load for a building (Solar House) which is located at the Royal ScientiFIc Society (RS5) in Jordan is estimated under climatological conditions of Amman. The aim of this Paper is to compare measured thermal performance of the Solar House with that modeled using TRNSYS. The results showed that the annual measured space heating load for the building was 6,188 kWh while the heati.ng load for the modeled building was 6,391 kWh. Moreover, the measured solar fraction for the solar system was 50% while the modeled solar fraction was 55%. A comparison of modeled and measured data resulted in percentage mean absolute errors for solar energy for space heating, auxiliary heating and solar fraction of 13%, 7% and 10%, respectively. The validated model will be useful for long-term performance simulation under different weather and operating conditions.(author)

Analysis on Space Environment from the Anomalies of Geosynchronous Satellites

Directory of Open Access Journals (Sweden)

Jaejin Lee

2009-12-01

Full Text Available While it is well known that space environment can produce spacecraft anomaly, defining space environment effects for each anomalies is difficult. This is caused by the fact that spacecraft anomaly shows various symptoms and reproducing it is impossible. In this study, we try to find the conditions of when spacecraft failures happen more frequently and give satellite operators useful information. Especially, our study focuses on the geosynchronous satellites which cost is high and required high reliability. We used satellite anomaly data given by Satellite News Digest which is internet newspaper providing space industry news. In our analysis, 88 anomaly cases occurred from 1997 to 2008 shows bad corelation with Kp index. Satellite malfunctions were likely to happen in spring and fall and in local time from midnight to dawn. In addition, we found the probability of anomaly increase when high energy electron flux is high. This is more clearly appeared in solar minimum than maximum period.

Solar Power Beaming: From Space to Earth

Energy Technology Data Exchange (ETDEWEB)

Rubenchik, A M; Parker, J M; Beach, R J; Yamamoto, R M

2009-04-14

Harvesting solar energy in space and power beaming the collected energy to a receiver station on Earth is a very attractive way to help solve mankind's current energy and environmental problems. However, the colossal and expensive 'first step' required in achieving this goal has to-date stifled its initiation. In this paper, we will demonstrate that recent advance advances in laser and optical technology now make it possible to deploy a space-based system capable of delivering 1 MW of energy to a terrestrial receiver station, via a single unmanned commercial launch into Low Earth Orbit (LEO). Figure 1 depicts the overall concept of our solar power beaming system, showing a large solar collector in space, beaming a coherent laser beam to a receiving station on Earth. We will describe all major subsystems and provide technical and economic discussion to support our conclusions.

Recent advances in celestial and space mechanics

CERN Document Server

Chyba, Monique

2016-01-01

This book presents recent advances in space and celestial mechanics, with a focus on the N-body problem and astrodynamics, and explores the development and application of computational techniques in both areas. It highlights the design of space transfers with various modes of propulsion, like solar sailing and low-thrust transfers between libration point orbits, as well as a broad range of targets and applications, like rendezvous with near Earth objects. Additionally, it includes contributions on the non-integrability properties of the collinear three- and four-body problem, and on general conditions for the existence of stable, minimum energy configurations in the full N-body problem. A valuable resource for physicists and mathematicians with research interests in celestial mechanics, astrodynamics and optimal control as applied to space transfers, as well as for professionals and companies in the industry.

DISILICIDE BASE REFRACTORY METAL COATINGS IN SPACE ENVIRONMENT

Energy Technology Data Exchange (ETDEWEB)

Bocarsly, Sidney I.

1963-03-15

Studies of probable effects of space environment exposure of Durak B'' (a Chromizing Corp. proprietary disilicide coating) coated Mo are described. It was concluded that, in a high-temperature environment, solar radiation will not affect the material system. Sputtering will not cause a structural problem, but it may cause a change in optical properties. Meteoroids may cause coating spalling and minimum to possibly total failure. Some protection system will probably be necessary. Vacuum will cause some coating evaporation. The rate will be temperature-dependent and probably of a low order. The possible problem area is that the evaporation appears to occur preferentially at crack sites. Ionized nitrogen and hydrogen may react with the coating and charge physical or mechanical properties. (A.G.W.)

SAIL--stereo-array isotope labeling.

Science.gov (United States)

Kainosho, Masatsune; Güntert, Peter

2009-11-01

Optimal stereospecific and regiospecific labeling of proteins with stable isotopes enhances the nuclear magnetic resonance (NMR) method for the determination of the three-dimensional protein structures in solution. Stereo-array isotope labeling (SAIL) offers sharpened lines, spectral simplification without loss of information and the ability to rapidly collect and automatically evaluate the structural restraints required to solve a high-quality solution structure for proteins up to twice as large as before. This review gives an overview of stable isotope labeling methods for NMR spectroscopy with proteins and provides an in-depth treatment of the SAIL technology.

SOLAR-LIKE OSCILLATIONS IN A METAL-POOR GLOBULAR CLUSTER WITH THE HUBBLE SPACE TELESCOPE

International Nuclear Information System (INIS)

Stello, Dennis; Gilliland, Ronald L.

2009-01-01

We present analyses of variability in the red giant stars in the metal-poor globular cluster NGC 6397, based on data obtained with the Hubble Space Telescope. We use a nonstandard data reduction approach to turn a 23 day observing run originally aimed at imaging the white dwarf population, into time-series photometry of the cluster's highly saturated red giant stars. With this technique we obtain noise levels in the final power spectra down to 50 parts per million, which allows us to search for low-amplitude solar-like oscillations. We compare the observed excess power seen in the power spectra with estimates of the typical frequency range, frequency spacing, and amplitude from scaling the solar oscillations. We see evidence that the detected variability is consistent with solar-like oscillations in at least one and perhaps up to four stars. With metallicities 2 orders of magnitude lower than those of the Sun, these stars present so far the best evidence of solar-like oscillations in such a low-metallicity environment.

Cermet Coatings for Solar Stirling Space Power

Science.gov (United States)

Jaworske, Donald A.; Raack, Taylor

2004-01-01

Cermet coatings, molecular mixtures of metal and ceramic are being considered for the heat inlet surface of a solar Stirling space power converter. This paper will discuss the solar absorption characteristics of as-deposited cermet coatings as well as the solar absorption characteristics of the coatings after heating. The role of diffusion and island formation, during the deposition process and during heating will also be discussed.

Scattering Effects of Solar Panels on Space Station Antenna Performance

Science.gov (United States)

Panneton, Robert J.; Ngo, John C.; Hwu, Shian U.; Johnson, Larry A.; Elmore, James D.; Lu, Ba P.; Kelley, James S.

1994-01-01

Characterizing the scattering properties of the solar array panels is important in predicting Space Station antenna performance. A series of far-field, near-field, and radar cross section (RCS) scattering measurements were performed at S-Band and Ku-Band microwave frequencies on Space Station solar array panels. Based on investigation of the measured scattering patterns, the solar array panels exhibit similar scattering properties to that of the same size aluminum or copper panel mockup. As a first order approximation, and for worse case interference simulation, the solar array panels may be modeled using perfect reflecting plates. Numerical results obtained using the Geometrical Theory of Diffraction (GTD) modeling technique are presented for Space Station antenna pattern degradation due to solar panel interference. The computational and experimental techniques presented in this paper are applicable for antennas mounted on other platforms such as ship, aircraft, satellite, and space or land vehicle.

NASA Strategy to Safely Live and Work in the Space Radiation Environment

Science.gov (United States)

Cucinotta, Francis; Wu, Honglu; Corbin, Barbara; Sulzman, Frank; Kreneck, Sam

2007-01-01

This viewgraph document reviews the radiation environment that is a significant potential hazard to NASA's goals for space exploration, of living and working in space. NASA has initiated a Peer reviewed research program that is charged with arriving at an understanding of the space radiation problem. To this end NASA Space Radiation Laboratory (NSRL) was constructed to simulate the harsh cosmic and solar radiation found in space. Another piece of the work was to develop a risk modeling tool that integrates the results from research efforts into models of human risk to reduce uncertainties in predicting risk of carcinogenesis, central nervous system damage, degenerative tissue disease, and acute radiation effects acute radiation effects.

The Objectives of NASA's Living with a Star Space Environment Testbed

Science.gov (United States)

Barth, Janet L.; LaBel, Kenneth A.; Brewer, Dana; Kauffman, Billy; Howard, Regan; Griffin, Geoff; Day, John H. (Technical Monitor)

2001-01-01

NASA is planning to fly a series of Space Environment Testbeds (SET) as part of the Living With A Star (LWS) Program. The goal of the testbeds is to improve and develop capabilities to mitigate and/or accommodate the affects of solar variability in spacecraft and avionics design and operation. This will be accomplished by performing technology validation in space to enable routine operations, characterize technology performance in space, and improve and develop models, guidelines and databases. The anticipated result of the LWS/SET program is improved spacecraft performance, design, and operation for survival of the radiation, spacecraft charging, meteoroid, orbital debris and thermosphere/ionosphere environments. The program calls for a series of NASA Research Announcements (NRAs) to be issued to solicit flight validation experiments, improvement in environment effects models and guidelines, and collateral environment measurements. The selected flight experiments may fly on the SET experiment carriers and flights of opportunity on other commercial and technology missions. This paper presents the status of the project so far, including a description of the types of experiments that are intended to fly on SET-1 and a description of the SET-1 carrier parameters.

The space-age solar system

International Nuclear Information System (INIS)

Baugher, J.F.

1988-01-01

This book is a description of the sun, planets, moons, asteroids, and comets in the solar system. Discussion is based heavily on results obtained from recent space probes to Mercury, Venus, Mars Jupiter, Saturn, and Uranus. Offers detailed descriptions of the moons of Jupiter and Saturn, and the results of the recent probes of Halley's comet. A discussion of meteorites leads to a description of the current models of the solar system. Introductory chapters present theories of the solar system from the ancient Greeks to the present day. Other topics covered include the sun, its structure, and how it generates energy; the surfaces, internal structures, and histories of the planets, from innermost Mercury to farthest Pluto, and their moons

Design of Sail-Assisted Unmanned Surface Vehicle Intelligent Control System

Directory of Open Access Journals (Sweden)

Yong Ma

2016-01-01

Full Text Available To achieve the wind sail-assisted function of the unmanned surface vehicle (USV, this work focuses on the design problems of the sail-assisted USV intelligent control systems (SUICS and illustrates the implementation process of the SUICS. The SUICS consists of the communication system, the sensor system, the PC platform, and the lower machine platform. To make full use of the wind energy, in the SUICS, we propose the sail angle of attack automatic adjustment (Sail_4A algorithm and present the realization flow for each subsystem of the SUICS. By using the test boat, the design and implementation of the SUICS are fulfilled systematically. Experiments verify the performance and effectiveness of our SUICS. The SUICS enhances the intelligent utility of sustainable wind energy for the sail-assisted USV significantly and plays a vital role in shipping energy-saving emission reduction requirements issued by International Maritime Organization (IMO.

Space Flight Ionizing Radiation Environments

Science.gov (United States)

Koontz, Steve

2017-01-01

The space-flight ionizing radiation (IR) environment is dominated by very high-kinetic energy-charged particles with relatively smaller contributions from X-rays and gamma rays. The Earth's surface IR environment is not dominated by the natural radioisotope decay processes. Dr. Steven Koontz's lecture will provide a solid foundation in the basic engineering physics of space radiation environments, beginning with the space radiation environment on the International Space Station and moving outward through the Van Allen belts to cislunar space. The benefits and limitations of radiation shielding materials will also be summarized.

Modeling and nonlinear heading control for sailing yachts

DEFF Research Database (Denmark)

Xiao, Lin; Jouffroy, Jerome

2014-01-01

This paper presents a study on the development and testing of a model-based heading controller for a sailing yacht. Using Fossen’s compact notation for marine vehicles, we first describe a nonlinear four-degree-of-freedom (DOF) dynamic model for a sailing yacht, including roll. Our model also...

Modeling and nonlinear heading control for sailing yachts

DEFF Research Database (Denmark)

Xiao, Lin; Jouffroy, Jerome

2011-01-01

This paper presents a study on the development and testing of a model-based heading controller for a sailing yacht. Using Fossen's compact notation for marine vehicles, we first describe a nonlinear 4-DOF dynamic model for a sailing yacht, including roll. Starting from this model, we then design...

On public space design for Chinese urban residential area based on integrated architectural physics environment evaluation

Science.gov (United States)

Dong, J. Y.; Cheng, W.; Ma, C. P.; Tan, Y. T.; Xin, L. S.

2017-04-01

The residential public space is an important part in designing the ecological residence, and a proper physics environment of public space is of greater significance to urban residence in China. Actually, the measure to apply computer aided design software into residential design can effectively avoid an inconformity of design intent with actual using condition, and a negative impact on users due to bad architectural physics environment of buildings, etc. The paper largely adopts a design method of analyzing architectural physics environment of residential public space. By analyzing and evaluating various physics environments, a suitability assessment is obtained for residential public space, thereby guiding the space design.

Solar system for domestic hot water and space heating

Energy Technology Data Exchange (ETDEWEB)

Weiss, W. [Arbeitsgemeinschaf Erneubare Energie, Gleisdorf (Austria)

1997-12-31

The solar thermal markets, different types of solar systems for hot water and space heating, the dimensioning and the components of solar heating systems, the properties of the systems are reviewed in this presentation

Solar system for domestic hot water and space heating

Energy Technology Data Exchange (ETDEWEB)