231 results on '"Vaughn, Jason A."'
Search Results
2. Designing the PLANET Chamber for Lunar Environment Ground Testing
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Hayward, Erin G., primary, Nehls, Mary, additional, Schneider, Todd, additional, Lynn, Patrick, additional, Bertone, Peter, additional, and Vaughn, Jason, additional
- Published
- 2023
- Full Text
- View/download PDF
3. Spacecraft Charging Test Considerations for Composite Materials
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Andersen, Allen, primary, Kim, Wousik, additional, Dennison, J. R., additional, Wood, Brian, additional, Schneider, Todd A., additional, Vaughn, Jason, additional, Wright, Kenneth H., additional, Green, Nelson W., additional, Suh, Eric, additional, Schwartz, Joel, additional, and Azad, Abdul-Majeed, additional
- Published
- 2023
- Full Text
- View/download PDF
4. Internal Electrostatic Discharge Testing of Inert Solid Rocket Motor Materials
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Schneider, Todd A, Vaughn, Jason A, Hayward, Erin G, Phillips, Brandon S, Wright, Kenneth H., Jr, and Reynolds, Jason C
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Spacecraft Propulsion And Power - Published
- 2019
5. High-Frequency Density Oscillations from a Plasma Source Used for Simulating Low-Earth Orbit Plasma Environment
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McTernan, Jesse K, Williams, John D, Vaughn, Jason A, Schneider, Todd A, and Krause, Linda Habash
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Space Sciences (General) - Abstract
We present data from ground-based, vacuum-chamber tests demonstrating the ability to modulate the output of a plasma source capable of producing a low-Earth orbit (LEO) type plasma. We obtained plasma oscillations up to 2.5 kHz impingent on stationary test equipment, which corresponds to meter-level ionospheric structures in LEO. This plasma source is, therefore, suitable for developing scientific instruments that measure the LEO plasma environment, in situ, with meter-level spatial resolution. Measurements were made using a fixed-bias collector and an electrometer sampling at 40 kHz. A mechanical aperture was established at the output of the plasma source via two concentric grids. The outer grid was free to rotate in the azimuthal direction with respect to the fixed inner grid. An identical, alternating hole pattern in the two grids resulted in a variable aperture that cycles through 90 open/close cycles per revolution. The frequency of the plasma oscillations is limited by the mechanism used to spin the grids and the bearing assembly on which the grids rotate. Higher frequencies are obtainable by upgrading the drive mechanism, allowing the possibility of centimeter-level spatial resolution.
- Published
- 2019
6. Analyses and Methods of Solid Rocket Motor Material Irradiation at Marshall Space Flight Center
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Caffrey, Jarvis, Vaughn, Jason, Schneider, Todd, Willis, Emily, Soler-Luna, Adrian, Wiedow, Kathryn, Miloshevsky, Gennady, Phillips, Brandon, Hayward, Erin, and Norwood, Joey
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Nonmetallic Materials ,Space Radiation - Abstract
The search for life on other worlds is among humanity’s greatest endeavors. Europa represents the most probable location to discover extraterrestrial life in our solar system, owing to its surface composition of ice covering a liquid water ocean, warmed by the tidal forces of its orbit around Jupiter. Unfortunately, the Jovian system hosts the most intense planetary radiation environment in the solar system due to the charged particles, namely electrons and protons, trapped by Jupiter’s immense magnetic field. Any mission that attempts to approach or land on Europa must survive this radiation environment [Hand et al, 2017]. Radiation effects were identified as a priority risk to the successful development of a de-orbit stage and solid rocket motor (SRM) early in the Europa Lander De-orbit Stage project concept. The effects of primary concern tend to occur very near the outer surface of the SRM. The charged particles deposit their energy quickly and are mostly stopped in the outer metallic case, but a significant portion of radiation penetrates through the bondline and outer propellant regions. High doses of ionizing radiation are known to cause significant changes to mechanical properties of many materials, especially polymers. For polymers such as the rubber-like materials (elastomers) in a solid rocket motor, the primary damage mechanism is known as cross-linking, in which ionization causes the restructuring of the matrix of long polymer chains. Ionization energy breaks the long polymer chains and allows formation of new cross-linked bonding sites. This hardens and often strengthens the polymer, but at the cost of decreased flexibility (or modulus). Propellant, insulation, liner, and pyrotechnic materials were identified as higher risk items, and so were irradiated at Marshall Space Flight Center (MSFC) for investigation of changes in mechanical and ballistic properties. This process required significant levels of analysis to evaluate how the radiation environment evolves within the spacecraft during the mission, and also to evaluate how dose is delivered into test articles within the irradiating facilities.
- Published
- 2019
7. Europa Lander Irradiation of Propellant at Marshall Space Flight Center
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Wiedow, Kathryn, Caffrey, Jarvis, Soler-Luna, Adrian, and Vaughn, Jason
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Spacecraft Design, Testing And Performance ,Propellants And Fuels - Published
- 2019
8. Electric Sail Tether Deployment System for CubeSats
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Tinker, Michael, Bryan, Thomas, Vaughn, Jason, Canfield, Steve, Hargis, Benjamin, Hunter, John Davis, and McArthur, Jonathan
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Spacecraft Design, Testing And Performance ,Engineering (General) - Abstract
An Electric Sail (E-Sail) propulsion system consists of long, thin tethers - positively-charged wires extending radially and symmetrically outward from a spacecraft. Tethers must be biased using a high-voltage power supply to ensure that the solar wind produces thrust. While the E-Sail concept shows great promise for flying heliopause missions with higher characteristic acceleration than solar sails, there are significant technical challenges related to deploying and controlling multiple tethers. A typical full-scale design involves a hub and spoke arrangement of 10 to 100 tethers, each 20 km long. In the last 20 years, there have been multiple space mission failures due to tether deployment and control issues, and most configurations involved a single tether. This paper describes an effort to develop and test a simple yet robust single-tether deployment system for a two-6U CubeSat configuration. The project included the following: a) Tether dynamic modeling/simulation b) E-Sail single-tether prototype development and testing c) Space environmental effects testing to identify best materials for further development. These three areas of investigation were needed to provide technical rationale for an E-Sail flight demonstration mission that is expected to be proposed for the 2022 time frame. The project team used an “agile” engineering approach in which E-Sail single-tether prototype designs were iteratively developed and tested to solve problems and identify design improvements. The agile approach was ideal for this low Technology Readiness Level (TRL) project because tether deployer development involved many unknowns in prototype development that could only be discovered through iterative cycles of construction and testing. Extensive modeling and simulation were accomplished for three types of tether deployment: a) Stage 1: propulsive separation with one 6U fixed b) Stage 2: propulsive spin-up with one 6U fixed c) Stage 3: propulsive spin-up with both 6Us free Simulation results were valuable for understanding the propulsive and braking forces needed for controlled tether deployment. This paper describes the evolution, insights, and test/ performance data related to the resultant single-tether two-6U E-Sail test article which has been demonstrated in a test laboratory. The development effort suggests near-term work needed to achieve a useful flight demonstration, and provides ideas for how multiple-tether deployment systems might evolve going forward. A planned next-generation E-Sail prototype will include autonomous propulsive tether deployment while monitoring tether tension, location on the floor, distance between tether ends, acceleration, velocity, and propellant used.
- Published
- 2019
9. Did You Know That Marshall Did That? Space Environmental Effects
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Nehls, Mary, Vaughn, Jason, Schneider, Todd, Finckenor, Miria, and Farr, Becky
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Ground Support Systems And Facilities (Space) - Published
- 2019
10. Nanoparticles: Biomaterials for Drug Delivery
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Gokhale, Abhijit, primary, Williams, Thomas, additional, and Vaughn, Jason, additional
- Published
- 2017
- Full Text
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11. The Development of Test Facilities for Induced, High-Frequency Plasma Instabilities
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McTernan, Jesse K, Leon, Omar J, Schneider, Todd A, Vaughn, Jason A, Bilen, Sven G, and Krause, Linda H
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Spacecraft Instrumentation And Astrionics - Abstract
We present results from modifications to test facilities equipped with a plasma source capable of producing a LEO-type environment. The modifications impose an oscillation to the output, thus simulating ionospheric disturbance. The frequency of the oscillations is adjustable as well as the base-line output of the source. Test results indicate that the density of the plasma can be varied with minimal impact on other plasma properties such as electron temperature. It is, therefore, possible to simulate realistic plasma environments such as day/night transitions or localized turbulence. The modified source is an effective tool for testing space instruments in a relevant environment increasing the instruments technology readiness level.
- Published
- 2018
12. Tor and Cor Ao-Vuv Resistant Polymers for Space
- Author
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Shepp, Allan, Haghighat, Ross, Lennhoff, John, Schuler, Peter, Connell, John, Clair, Terry St., Vaughn, Jason, Swiener, James, Kleiman, Jacob I., editor, and Tennyson, Roderick C., editor
- Published
- 1999
- Full Text
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13. Radiation Processing of Polycyclic Aromatic Hydrocarbons (PAHs) in Space: ICEE PoC
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Mattioda, Andrew, Cruz-Diaz, Gustavo, Barnhardt, Michael, Ging, Andrew, Schneider, Todd, Vaughn, Jason, Quigley, Emmett, and Phillips, Brandon
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Space Sciences (General) - Abstract
Small Polycyclic Aromatic Hydrocarbon molecules or PAHs (<30 carbon atoms) have been identified in comets, meteorites, asteroids, and interplanetary dust particles in our Solar System, while PAHs in the Interstellar Medium (ISM) tend to be much larger, usually between 50 to 100 carbon atoms in size. The cause of the size disparity between PAHs found in the ISM and Solar System as well as their influence on Solar System organics is not yet understood. Two chemical evolutionary paths have been proposed to explain the inventory of solar system organics. In one the prebiotic material was formed from the radiation induced modification of large pre-solar carbon-bearing species (e.g. ISM PAHs). The second path suggests that Solar System prebiotic matter is the result of bottom-up synthesis from small reactive molecules after the Solar System was formed. In this second scenario very few ISM PAHs survived the harsh pre-solar radiation as aromatic structures. ICEE PoC (ICEE Proof of Concept) investigated factors impacting the chemical evolution of large PAHs irradiated under conditions similar to the proto-solar nebula. Likewise ICEE PoC will refine the technical parameters of the proposed ICEE (Institute for Carbon Evolution Experiment) laboratory.
- Published
- 2017
14. Findings from NASA's 2015-2017 Electric Sail Investigations
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Wiegmann, Bruce M, Vaughn, Jason, Schneider, Todd, Bangham, Michael, and Heaton, Andy
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Electronics And Electrical Engineering - Abstract
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 approx. 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.
- Published
- 2017
15. The Heliopause Electrostatic Rapid Transit System (HERTS) - Design, Trades, and Analyses Performed in a Two Year NASA Investigation of Electric Sail Propulsion Systems
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Wiegmann, Bruce M, Scheider, Todd, Heaton, Andrew, Vaughn, Jason, Stone, Nobie, and Wright, Ken
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Spacecraft Propulsion And Power ,Energy Production And Conversion - Abstract
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.
- Published
- 2017
16. Flowing Plasma Interaction with an Electric Sail Tether Element
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Schneider, Todd A, Vaughn, Jason A, Wright, Kenneth H., Jr, Andersen, Allen J, and Stone, Nobie H
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Spacecraft Propulsion And Power ,Plasma Physics - Published
- 2017
17. Flowing Plasma Interaction with an Electric Sail Tether Element
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Schneider, Todd, Vaughn, Jason, Wright, Kenneth, Anderson, Allen, and Stone, Nobie
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Plasma Physics ,Spacecraft Propulsion And Power - Abstract
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.
- Published
- 2017
18. Simulated Space Environment Effects on a Candidate Solar Sail Material
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Kang, Jin Ho, Bryant, Robert G, Wilkie, W. Keats, Wadsworth, Heather M, Craven, Paul D, Nehls, Mary K, and Vaughn, Jason A
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Spacecraft Design, Testing And Performance - Abstract
For long duration missions of solar sails, the sail material needs to survive harsh space environments and the degradation of the sail material controls operational lifetime. Therefore, understanding the effects of the space environment on the sail membrane is essential for mission success. In this study, we investigated the effect of simulated space environment effects of ionizing radiation, thermal aging and simulated potential damage on mechanical, thermal and optical properties of a commercial off the shelf (COTS) polyester solar sail membrane to assess the degradation mechanisms on a feasible solar sail. The solar sail membrane was exposed to high energy electrons (about 70 keV and 10 nA/cm2), and the physical properties were characterized. After about 8.3 Grad dose, the tensile modulus, tensile strength and failure strain of the sail membrane decreased by about 20 ~ 95%. The aluminum reflective layer was damaged and partially delaminated but it did not show any significant change in solar absorbance or thermal emittance. The effect on mechanical properties of a pre-cracked sample, simulating potential impact damage of the sail membrane, as well as thermal aging effects on metallized PEN (polyethylene naphthalate) film will be discussed.
- Published
- 2017
19. Nanoparticles: Biomaterials for Drug Delivery
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Gokhale, Abhijit, primary, Williams, Thomas, additional, and Vaughn, Jason, additional
- Published
- 2015
- Full Text
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20. The Twin-Probe Method: Improving Langmuir Probe Measurements on Small Spacecraft
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Leon, Omar, primary, McTernan, Jesse, additional, Vaughn, Jason, additional, Schneider, Todd, additional, Miars, Grant C., additional, Hoegy, Walter R., additional, and Gilchrist, Brian E., additional
- Published
- 2022
- Full Text
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21. Big Business and the Blackboard: A Winning Combination for the Classroom.
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Vaughn, Jason
- Abstract
Reviews corporate involvement in education, highlighting partnership efforts of Channel One, Turner Communications, Pizza Hut, and School Properties, a professional fund-raising company. School can best utilize corporate America by refusing to become beggars. Instead, a system should be established (from the federal level down to individual classrooms) that allows schools to bargain efficiently for business services. (37 references) (MLH)
- Published
- 1997
22. Plasma Deflection Test Setup for E-Sail Propulsion Concept
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Andersen, Allen, Vaughn, Jason, Schneider, Todd, and Wright, Ken
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Spacecraft Propulsion And Power - Abstract
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.
- Published
- 2016
23. By-Pass Diode Temperature Tests of a Solar Array Coupon under Space Thermal Environment Conditions
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Wright, Kenneth H, Schneider, Todd A, Vaughn, Jason A, Hoang, Bao, Wong, Frankie, and Wu, Gordon
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Electronics And Electrical Engineering - Abstract
By-Pass diodes are a key design feature of solar arrays and system design must be robust against local heating, especially with implementation of larger solar cells. By-Pass diode testing was performed to aid thermal model development for use in future array designs that utilize larger cell sizes that result in higher string currents. Testing was performed on a 56-cell Advanced Triple Junction solar array coupon provided by SSL. Test conditions were vacuum with cold array backside using discrete by-pass diode current steps of 0.25 A ranging from 0 A to 2.0 A.
- Published
- 2016
24. By-Pass Diode Temperature Tests of a Solar Array Coupon Under Space Thermal Environment Conditions
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Wright, Kenneth H., Jr, Schneider, Todd A, Vaughn, Jason A, Hoang, Bao, and Wong, Frankie
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Electronics And Electrical Engineering - Abstract
Tests were performed on a 56-cell Advanced Triple Junction solar array coupon whose purpose was to determine margin available for bypass diodes integrated with new, large multi-junction solar cells that are manufactured from a 4-inch wafer. The tests were performed under high vacuum with cold and ambient coupon back-side. The bypass diodes were subjected to a sequence of increasing discrete current steps from 0 Amp to 2.0 Amp in steps of 0.25 Amp. At each current step, a temperature measurement was obtained via remote viewing by an infrared camera. This paper discusses the experimental methodology, including the calibration of the thermal imaging system, and the results.
- Published
- 2016
25. Bypass Diode Temperature Tests of a Solar Array Coupon Under Space Thermal Environment Conditions
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Wright, Kenneth H., Jr, Schneider, Todd A, Vaughn, Jason A, Hoang, Bao, Wong, Frankie, and Wu, Gordon
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Electronics And Electrical Engineering - Abstract
Tests were performed on a 56-cell Advanced Triple Junction solar array coupon whose purpose was to determine margin available for bypass diodes integrated with new, large multi-junction solar cells that are manufactured from a 4-inch wafer. The tests were performed under high vacuum with coupon back side thermal conditions of both cold and ambient. The bypass diodes were subjected to a sequence of increasing discrete current steps from 0 Amp to 2.0 Amp in steps of 0.25 Amp. At each current step, a temperature measurement was obtained via remote viewing by an infrared camera. This paper discusses the experimental methodology, experiment results, and the thermal model.
- Published
- 2016
26. Deep Charging Evaluation of Satellite Power and Communication System Components
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Schneider, Todd, Vaughn, Jason, Wright, Ken, Phillips, Brandon, Chu, Brian, Wong, Kit Frankie, and Gardiner, George
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Spacecraft Design, Testing And Performance - Published
- 2016
27. Space Environment Testing of Photovoltaic Array Systems
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Phillips, Brandon, Schneider, Todd A, Vaughn, Jason A, and Wright, Kenneth H
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Spacecraft Propulsion And Power - Abstract
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.
- Published
- 2015
28. Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center
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Phillips, Brandon S, Schneider, Todd A, Vaughn, Jason A, and Wright, Kenneth H., Jr
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Electronics And Electrical Engineering - Abstract
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.
- Published
- 2015
29. High Current ESD Test of Advanced Triple Junction Solar Array Coupon
- Author
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Wright, Kenneth H., Jr, Schneider, Todd A, Vaughn, Jason A, Hoang, Bao, and Wong, Frankie
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Electronics And Electrical Engineering - Abstract
A test was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by SSL. The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge testing at two string voltages (100 V, 150 V) and four array current (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micros to 2.9 ms. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission application.
- Published
- 2015
- Full Text
- View/download PDF
30. Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center
- Author
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Schneider, Todd A, Vaughn, Jason A, Wright, Kenneth H., Jr, and Phillips, Brandon S
- Subjects
Electronics And Electrical Engineering - Abstract
CubeSats, Communication Satellites, and Outer Planet Science Satellites all share one thing in common: Mission success depends on maintaining power in the harsh space environment. For a vast majority of satellites, spacecraft power is sourced by a photovoltaic (PV) array system. Built around PV cells, the array systems also include wiring, substrates, connectors, and protection diodes. Each of these components must function properly throughout the mission in order for power production to remain at nominal levels. Failure of even one component can lead to a crippling loss of power. To help ensure PV array systems do not suffer failures on-orbit due to the space environment, NASA's Marshall Space Flight Center (MSFC) has developed a wide ranging test and evaluation capability. Key elements of this capability include: Testing: a. Ultraviolet (UV) Exposure b. Charged Particle Radiation (Electron and Proton) c. Thermal Cycling d. Plasma and Beam Environments Evaluation: a. Electrostatic Discharge (ESD) Screening b. Optical Inspection and easurement c. PV Power Output including Large Area Pulsed Solar Simulator (LAPSS) measurements This paper will describe the elements of the space environment which particularly impact PV array systems. MSFC test capabilities will be described to show how the relevant space environments can be applied to PV array systems in the laboratory. A discussion of MSFC evaluation capabilities will also be provided. The sample evaluation capabilities offer test engineers a means to quantify the effects of the space environment on their PV array system or component. Finally, examples will be shown of the effects of the space environment on actual PV array materials tested at MSFC.
- Published
- 2015
31. Testing the Solar Probe Cup, An Instrument Designed to Touch The Sun
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Whittlesey, Phyllis, Case, Anthony, Kasper, Justin, Wright, Kenneth, Alterman, Benjamin, Cirtain, Jonathan, Bookbinder, Jay, Korreck, Kelly, Stevens, Michael, Schneider, Todd, and Vaughn, Jason
- Subjects
Solar Physics ,Instrumentation And Photography - Abstract
Solar Probe Plus will be the first, fastest, and closest mission to the Sun, providing the first direct sampling of the sub-Alfvénic corona. The Solar Probe Cup (SPC) is a unique re-imagining of the traditional Faraday Cup design and materials for immersion in this high temperature environment. Sending an instrument of this type into a never-seen particle environment requires extensive characterization prior to launch to establish sufficient measurement accuracy and instrument response. To reach this end, a slew of tests are created for allowing SPC to see ranges of appropriate ions and electrons, as well as a facility that reproduces solar photon spectra and fluxes for this mission. Having already tested the SPC at flight-like temperatures with no significant modification of the noise floor, we recently completed a round of particle testing to see if the deviations in Faraday Cup design fundamentally change the operation of the instrument. Results and implications from these tests will be presented, as well as performance comparisons to cousin instruments such as those on the WIND spacecraft.
- Published
- 2014
32. Charging of the International Space Station as observed by the floating potential measurement unit: initial results
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Wright, Kenneth H., Jr., Swenson, Charles M., Thompson, Donald C., Barjatya, Aroh, Koontz, Steven L., Schneider, Todd A., Vaughn, Jason A., Minow, Joseph I., Craven, Paul D., Coffey, Victoria N., Parker, Linda N., and Bui, Them H.
- Subjects
Ionosphere -- Measurement ,Ionosphere -- Analysis ,Space stations -- Analysis ,Plasma diagnostics -- Analysis ,Business ,Chemistry ,Electronics ,Electronics and electrical industries - Abstract
The Floating Potential Measurement Unit (FPMU) is a multiprobe package designed to measure the floating potential of the International Space Station (ISS) as well as the density and temperature of the local ionospheric plasma environment. The purpose of the FPMU is to provide direct measurements of ISS spacecraft charging as continuing construction leads to dramatic changes in ISS size and configuration. FPMU data are used for refinement and validation of the ISS spacecraft charging models used to evaluate the severity and frequency of occurrence of ISS charging hazards. The FPMU data and the models are also used to evaluate the effectiveness of proposed hazard controls. The FPMU consists of four probes: a floating potential probe, two Langmuir probes, and a plasma impedance probe. These probes measure the floating potential of the ISS, plasma density, and electron temperature. Redundant measurements using different probes support data validation by interprobe comparisons. The FPMU was installed by ISS crew members during an extra-vehicular activity on the starboard (S1) truss of the ISS in early August 2006 when the ISS configuration included only one 160-V U.S. photovoltaic (PV) array module. The first data campaign began a few hours after installation and continued for over five days. Additional data campaigns were completed in 2007 after a second 160-V U.S. PV array module was added to the ISS. This paper discusses the general operational characteristics of the FPMU as integrated on ISS, the functional performance of each probe, the charging behavior of the ISS before and after the addition of a second 160-V U.S. PV array module, and initial results from model comparisons. Index Terms--Ionosphere, plasma measurements, spacecraft charging, space stations.
- Published
- 2008
33. Validation of the plasma densities and temperatures from the ISS floating potential measurement unit
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Coffey, Victoria N., Wright, Kenneth H., Jr., Minow, Joseph I., Schneider, Todd A., Vaughn, Jason A., Craven, Paul D., Chandler, Michael O., Koontz, Steven L., Parker, Linda N., and Bui, Them H.
- Subjects
Ionosphere -- Analysis ,Ionosphere -- Measurement ,Plasma physics -- Analysis ,Plasma physics -- Measurement ,Plasma diagnostics -- Usage ,Business ,Chemistry ,Electronics ,Electronics and electrical industries - Abstract
The validation of the floating potential measurement unit (FPMU) plasma density and temperature measurements is an important step in the process of evaluating International Space Station (ISS) spacecraft charging issues including vehicle arcing and hazards to crew during extravehicular activities. The highest potentials observed on the Space Station are due to the combined [V.sub.sp] x B effects on a large spacecraft and the collection of ionospheric electron and ion currents by the 160-V U.S. solar array modules. The ionospheric plasma environment is needed for input to the ISS spacecraft charging models used to predict the severity and frequency of occurrence of ISS charging hazards. The validation of these charging models requires the comparison of their predictions with measured FPMU values. The FPMU measurements themselves must also be validated for use in manned flight safety work. This paper presents preliminary results from a comparison of densities and temperatures derived from the FPMU Langmuir probes and plasma impedance probe with the independent density and temperature measurements from a spaceborne ultraviolet imager, a ground-based incoherent scatter radar, and ionosonde sites. Index Terms--Density measurement, ionosphere, plasma measurement, temperature measurement.
- Published
- 2008
34. High Current ESD Test of Advanced Triple Junction Solar Array Coupon
- Author
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Wright, Kenneth H., Jr, Schneider, Todd A, Vaughn, Jason A, Hoang, Bao, and Wong, Frankie
- Subjects
Spacecraft Propulsion And Power ,Electronics And Electrical Engineering - Abstract
Testing was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by Space Systems Loral, LLC (SSL). The ATJ coupon was a small, 4-cell, two-string configuration of flight-type design that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge (ESD) testing at two string voltages (100 V, 150 V) and four string currents (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micro-seconds to 2.75 milli-seconds. All TSAs occurred at a string voltage of 150 V. Post-ESD functional testing showed that no degradation occurred due to the TSA events. These test results point to a robust design for application to a high-current, high-power mission.
- Published
- 2014
35. Targeted High Lung Concentrations of Itraconazole Using Nebulized Dispersions in a Murine Model
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McConville, Jason T., Overhoff, Kirk A., Sinswat, Prapasri, Vaughn, Jason M., Frei, Bradi L., Burgess, David S., Talbert, Robert L., Peters, Jay I., Johnston, Keith P., and Williams, III, Robert O.
- Published
- 2006
- Full Text
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36. Murine airway histology and intracellular uptake of inhaled amorphous itraconazole
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Vaughn, Jason M., Wiederhold, Nathan P., McConville, Jason T., Coalson, Jacqueline J., Talbert, Robert L., Burgess, David S., Johnston, Keith P., Williams, Robert O., III, and Peters, Jay I.
- Published
- 2007
- Full Text
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37. NASA GRC and MSFC space plasma arc testing procedures
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Ferguson, Dale C., Vayner, Boris V., Galofaro, Joel T., Hillard, G. Barry, Vaughn, Jason, and Schneider, Todd
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Space plasmas -- Research ,Environmental testing -- Analysis ,Plasma physics -- Research ,Business ,Chemistry ,Electronics ,Electronics and electrical industries - Abstract
Tests of arcing and current collection in simulated-space-plasma conditions have been performed at the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) in Cleveland, OH, for over 30 years and at the Marshall Space Flight Center (MSFC) in Huntsville, AL, for almost as long. During this period, proper test conditions for an accurate and meaningful space simulation have been worked out, comparisons with actual space performance in spaceflight tests and with real operational satellites have been made, and NASA has achieved the authors' own internal standards for test protocols. It is the purpose of this paper to communicate the test conditions, test procedures, and types of analysis used at the NASA GRC and MSFC to the space environmental testing community at large, to help with international space-plasma arcing-testing standardization. Discussed herein are the neutral gas conditions, plasma densities and uniformity, vacuum chamber sizes, sample sizes and Debye lengths, biasing samples versus self-generated voltages, floating samples versus grounded samples, test electrical conditions, arc detection, preventing sustained discharges during testing, real samples versus idealized samples, validity of low Earth orbit tests for geosynchronous Earth orbit samples, extracting arc threshold information from an arc rate versus voltage tests, snapover, current collection and glows at the positive sample bias, Kapton pyrolysis, thresholds for trigger arcs, sustained arcs, dielectric breakdown and Paschen discharge, tether arcing and testing in very dense plasmas (i.e., thruster plumes), arc mitigation strategies, charging mitigation strategies, models, and analysis of test results. Finally, the necessity of testing will be emphasized, not to the exclusion of modeling, but as part of a complete strategy for determining when and if arcs will occur, and preventing them from occurring in space. Index Terms--Aerospace simulation, arc discharges, environmental testing, plasma measurements.
- Published
- 2006
38. Putinomics: power and money in resurgent Russia
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Vaughn, Jason C., primary
- Published
- 2021
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39. Single dose and multiple dose studies of itraconazole nanoparticles
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Vaughn, Jason M., McConville, Jason T., Burgess, David, Peters, Jay I., Johnston, Keith P., Talbert, Robert L., and Williams, Robert O., III
- Published
- 2006
- Full Text
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40. Cryogenic liquids, nanoparticles, and microencapsulation
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Purvis, Troy, Vaughn, Jason M., Rogers, True L., Chen, Xiaoxia, Overhoff, Kirk A., Sinswat, Prapasri, Hu, Jiahui, McConville, Jason T., Johnston, Keith P., and Williams, Robert O., III
- Published
- 2006
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41. NASA's New High Intensity Solar Environment Test Capability
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Schneider, Todd A, Vaughn, Jason A, and Wright, Kenneth H
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Solar Physics - Abstract
Across the world, new spaceflight missions are being designed and executed that will place spacecraft and instruments into challenging environments throughout the solar system. To aid in the successful completion of these new missions, NASA has developed a new flexible space environment test platform. The High Intensity Solar Environment Test (HISET) capability located at NASA fs Marshall Space Flight Center provides scientists and engineers with the means to test spacecraft materials and systems in a wide range of solar wind and solar photon environments. Featuring a solar simulator capable of delivering approximately 1 MW/m2 of broad spectrum radiation at maximum power, HISET provides a means to test systems or components that could explore the solar corona. The solar simulator consists of three high-power Xenon arc lamps that can be operated independently over a range of power to meet test requirements; i.e., the lamp power can be greatly reduced to simulate the solar intensity at several AU. Integral to the HISET capability are charged particle sources that can provide a solar wind (electron and proton) environment. Used individually or in combination, the charged particle sources can provide fluxes ranging from a few nA/cm2 to 100s of nA/cm2 over an energy range of 50 eV to 100 keV for electrons and 100 eV to 30 keV for protons. Anchored by a high vacuum facility equipped with a liquid nitrogen cold shroud for radiative cooling scenarios, HISET is able to accommodate samples as large as 1 meter in diameter. In this poster, details of the HISET capability will be presented, including the wide ]ranging configurability of the system.
- Published
- 2012
42. Formation of Complex Organic Molecules (COMs) from Polycyclic Aromatic Hydrocarbons (PAHs): Implications for ISM IR Emission Plateaus and Solar System Organics
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Mattioda, Andrew L., primary, Cruz-Diaz, Gustavo A., additional, Ging, Andrew, additional, Barnhardt, Michael, additional, Boersma, Christiaan, additional, Allamandola, Louis J., additional, Schneider, Todd, additional, Vaughn, Jason, additional, Phillips, Brandon, additional, and Ricca, Alessandra, additional
- Published
- 2020
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43. Defense policies of east-central European countries after 1989: creating stability in a time of uncertainty
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Vaughn, Jason, primary
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- 2020
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44. Putinomics: power and money in resurgent Russia: by Chris Miller, Chapel Hill, USA, University of North Carolina Press, 2018, 240 pp., $28.00 (Hardcover), ISBN 978-1-4696-4066-2; $22.95 (Paperback), ISBN 978-1-4696-6391-3; $16.99 (Ebook), ISBN 978-1-4696-4067-9
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Vaughn, Jason C.
- Subjects
- *
ELECTRONIC books , *FINANCIAL policy - Abstract
The nexus of power and money in Russia after the fall of the Soviet Union is an often-studied subject over the past 25-plus years. Few other books of such substance put the idea of Putinomics in its proper place and this is an issue of some importance when looking at late Putin-era protests, the as-of-2020 recent poisoning of opposition leader Alexei Navalny, and the inevitable development of Putin's regime into whatever may come next. In his unique way, Chris Miller does an admirable job and, perhaps most importantly, avoids repetitive theories based on other authors and eschews boring assessments of Russia's economic past, present, and future in the Putin era. [Extracted from the article]
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- 2022
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45. Space Environmental Effects (SEE) Testing Capability: NASA/Marshall Space Flight Center
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DeWittBurns, H, Crave, Paul, Finckenor, Miria, Finchum, Charles, Nehls, Mary, Schneider, Todd, and Vaughn, Jason
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Ground Support Systems And Facilities (Space) - Abstract
Understanding the effects of the space environment on materials and systems is fundamental and essential for mission success. If not properly understood and designed for, the space environment can lead to materials degradation, reduction of functional lifetime, and system failure. Ground based testing is critical in predicting performance NASA/MSFC's expertise and capabilities make up the most complete SEE testing capability available.
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- 2012
46. Space Environmental Effects Testing Capability at the Marshall Space Flight Center
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DeWittBurns, H, Craven, Paul, Finckenor, Miria, Nehls, Mary, Schneider, Todd, and Vaughn, Jason
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Space Sciences (General) - Abstract
Understanding the effects of the space environment on materials and systems is fundamental and essential for mission success. If not properly understood and designed for, the effects of the environment can lead to degradation of materials, reduction of functional lifetime, and system failure. In response to this need, the Marshall Space Flight Center has developed world class Space Environmental Effects (SEE) expertise and test facilities to simulate the space environment. Capabilities include multiple unique test systems comprising the most complete SEE testing capability available. These test capabilities include charged particle radiation (electrons, protons, ions), ultraviolet radiation (UV), vacuum ultraviolet radiation (VUV), atomic oxygen, plasma effects, space craft charging, lunar surface and planetary effects, vacuum effects, and hypervelocity impacts as well as the combination of these capabilities. In addition to the uniqueness of the individual test capabilities, MSFC is the only NASA facility where the effects of the different space environments can be tested in one location. Combined with additional analytical capabilities for pre- and post-test evaluation, MSFC is a one-stop shop for materials testing and analysis. The SEE testing and analysis are performed by a team of award winning experts nationally recognized for their contributions in the study of the effects of the space environment on materials and systems. With this broad expertise in space environmental effects and the variety of test systems and equipment available, MSFC is able to customize tests with a demonstrated ability to rapidly adapt and reconfigure systems to meet customers needs. Extensive flight experiment experience bolsters this simulation and analysis capability with a comprehensive understanding of space environmental effects.
- Published
- 2012
47. Test Before You Fly - High Fidelity Planetary Environment Simulation
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Craven, Paul, Ramachandran, Narayanan, Vaughn, Jason, Schneider, Todd, and Nehls, Mary
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Ground Support Systems And Facilities (Space) - Abstract
The lunar surface environment will present many challenges to the survivability of systems developed for long duration lunar habitation and exploration of the lunar, or any other planetary, surface. Obstacles will include issues pertaining especially to the radiation environment (solar plasma and electromagnetic radiation) and lunar regolith dust. The Planetary Environments Chamber is one piece of the MSFC capability in Space Environmental Effects Test and Analysis. Comprised of many unique test systems, MSFC has the most complete set of SEE test capabilities in one location allowing examination of combined space environmental effects without transporting already degraded, potentially fragile samples over long distances between tests. With this system, the individual and combined effects of the lunar radiation and regolith environment on materials, sub-systems, and small systems developed for the lunar return can be investigated. This combined environments facility represents a unique capability to NASA, in which tests can be tailored to any one aspect of the lunar environment (radiation, temperature, vacuum, regolith) or to several of them combined in a single test.
- Published
- 2012
48. The PROPEL Electrodynamic Tether Mission and Connecting to the Ionosphere
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Gilchrist, Brian, Bilen, Sven, Hoyt, Rob, Stone,Nobie, Vaughn, Jason, Fuhrhop, Keith, Krause, Linda, Khazanov, George, and Johnson, Les
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Spacecraft Propulsion And Power - Abstract
The exponential increase of launch system size.and cost.with delta-V makes missions that require large total impulse cost prohibitive. Led by NASA's Marshall Space Flight Center, a team from government, industry, and academia has developed a flight demonstration mission concept of an integrated electrodynamic (ED) tethered satellite system called PROPEL: "Propulsion using Electrodynamics". The PROPEL Mission is focused on demonstrating a versatile configuration of an ED tether to overcome the limitations of the rocket equation, enable new classes of missions currently unaffordable or infeasible, and significantly advance the Technology Readiness Level (TRL) to an operational level. We are also focused on establishing a far deeper understanding of critical processes and technologies to be able to scale and improve tether systems in the future. Here, we provide an overview of the proposed PROPEL mission. One of the critical processes for efficient ED tether operation is the ability to inject current to and collect current from the ionosphere. Because the PROPEL mission is planned to have both boost and deboost capability using a single tether, the tether current must be capable of flowing in both directions and at levels well over 1 A. Given the greater mobility of electrons over that of ions, this generally requires that both ends of the ED tether system can both collect and emit electrons. For example, hollow cathode plasma contactors (HCPCs) generally are viewed as state-of-the-art and high TRL devices; however, for ED tether applications important questions remain of how efficiently they can operate as both electron collectors and emitters. Other technologies will be highlighted that are being investigated as possible alternatives to the HCPC such as Solex that generates a plasma cloud from a solid material (Teflon) and electron emission (only) technologies such as cold-cathode electron field emission or photo-electron beam generation (PEBG) techniques.
- Published
- 2012
49. Age Induced Effects on ESD Characteristics of Solar Array Coupons After Combined Space Environmental Exposures
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Wright, Kenneth H, Schneider, Todd A, Vaughn, Jason A, Hoang, Bao, Funderburk, Victor V, Wong, Frankie, and Gardiner, George
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Electronics And Electrical Engineering - Abstract
A set of multi-junction GaAs/Ge solar array test coupons provided by Space Systems/Loral were subjected to a sequence of 5-year increments of combined space environment 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 performing electrostatic discharge (ESD) tests in the inverted gradient mode. The protocol of the ESD tests is based on the ISO standard for ESD testing on solar array panels [ISO-11221]. 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 four cells constructed to form two strings. The ESD tests were performed at the beginning-of-life (BOL) and at each 5-year environment exposure point until end-of-life (EOL) at 15 years. The space environmental exposure sequence consisted of ultra-violet radiation, electron/proton particle radiation, thermal cycling, and Xenon ion thruster plume erosion. This paper describes the ESD test setup and the importance of the electrical test design in simulating the on-orbit operational conditions. Arc inception voltage results along with ESD test behavior from the BOL condition through the 15th year age condition are discussed. In addition, results from a Xenon plasma plume exposure test with an EOL coupon under the full ESD test condition will be discussed.
- Published
- 2012
50. Comparison of powder produced by evaporative precipitation into aqueous solution (EPAS) and spray freezing into liquid (SFL) technologies using novel Z-contrast STEM and complimentary techniques
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Vaughn, Jason M., Gao, Xiaoxia, Yacaman, Miguel-Jose, Johnston, Keith P., and Williams, Robert O., III
- Published
- 2005
- Full Text
- View/download PDF
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