SEARCH · Search NASA
Results for “spacecraft charging”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Spacecraft Charging Current Balance Model Applied to High Voltage Solar Array Operations
No abstract available
Spacecraft Charging Considerations and Design Efforts for the Orion Crew Module
The Orion Crew Module (CM) is nearing completion for the next flight, designated as Exploration Mission 1 (EM-1). For the uncrewed mission, the flight path will take the CM through a Perigee Raise Maneuver (PRM) out to an altitude of approximately 1800 km, followed by a Trans-Lunar Injection burn, a pass through the Van Allen belts then out to the moon for a lunar flyby, a Distant Retrograde Insertion (DRI) burn, a Distant Retrograde Orbit (DRO), a Distant Retrograde Departure (DRD) burn, a second lunar flyby, an Earth Insertion (EI) burn, and finally entry and landing. All of this, with the exception of the DRO associated maneuvers, is similar to the previous Apollo 8 mission in late 1968. In recent discussions, it is now possible that EM-1 will be a crewed mission, and if this happens, the orbit may be quite different from that just described. In this case, the flight path may take the CM on an out and back pass through the Van Allen belts twice, then out to the moon, again passing through the Van Allen belts twice, then finally back home. Even if the current EM-1 mission doesn't end up as a crewed mission, EM-2 and subsequent missions will undoubtedly follow orbital trajectories that offer comparable exposures to heightened vehicle charging effects. Because of this, and regardless of flight path, the CM vehicle will likely experience a wide range of exposures to energetic ions and electrons, essentially covering the gamut between low earth orbit to geosynchronous orbit and beyond. National Aeronautical and Space Administration (NASA) and Lockheed Martin (LM) engineers and scientists have been working to fully understand and characterize the vehicle's immunity level with regard to surface and deep dielectric charging, and the ramifications of that immunity level pertaining to materials and impacts to operational avionics, communications, and navigational systems. This presentation attempts to chronicle these efforts in a summary fashion, and attempts to capture the results of that work as they pertain to the electrical and avionic systems on-board the Orion CM.
Spacecraft Charging and LESD Characterization of Carbon Composite Materials with Multiple Electron Beams
No abstract provided
New High-Throughput Dual-Electron Beam Spacecraft Charging Test Capability at JPL
No abstract provided
United States Spacecraft Charging Overview
Explore the source record for details and available documents.
Development and Use of Spacecraft Charging Flight Constraints
Explore the source record for details and available documents.
Development and Use of Spacecraft Charging Flight Constraints
Explore the source record for details and available documents.
Deep Dielectric Charging of Spacecraft Polymers by Energetic Protons
The majority of research in the field of spacecraft charging concentrates on electron charging effects with little discussion of charging by protons. For spacecraft orbiting in the traditional LEO and GEO environments this emphasis on electrons is appropriate since energetic electrons are the dominant species in those orbits. But for spacecraft in orbits within the inner radiation belts or for interplanetary and lunar space probes, proton charging (center dot) effects may also be of concern. To examine bulk spacecraft charging effects in these environments several typical highly insulating spacecraft polymers were exposed to energetic protons (center dot) with energies from 1 Me V to lO Me V to simulate protons from the solar wind and from solar energetic proton events. Results indicate that effects in proton charged dielectrics are distinctly different than those observed due to electron charging. In most cases, the positive surface potential continued to increase for periods on the order of minutes to a day, followed by long time scale decay at rates similar to those observed for electron charging. All samples charged to positive potentials with substantially lower magnitudes than for equivalent electron doses. Possible explanations for the different behavior of the measured surface potentials from proton irradiation are discussed; these are related to the evolving internal charge distribution from energy dependent electron and proton transport, electron emission, charge migration due to dark current and radiation induced conductivity, and electron capture by embedded protons.
Neutralizing charged-up spacecraft
The problem of spacecraft charging is examined. The mechanism by which a spacecraft acquires a charge with respect to the ambient space environment is discussed. Methods used to avoid spacecraft dysfunction due to charging, including the use of electron and ion emitters, adequately conducting surfaces, and dielectric materials with high secondary-emission coefficients, are described. Special attention is given to the development, in the context of the Scatha program, of a computerized model which will allow the calculation of spacecraft potential for a given set of conditions.
Initial Results from the GEM Challenge on the Spacecraft Surface Charging Environment
Spacecraft surface charging during geomagnetically disturbed times is one of the most important causes of satellite anomalies. Predicting the surface charging environment is one prevalent task of the geospace environment models. Therefore, the Geospace Environment Modeling (GEM) Focus Group "Inner Magnetosphere Crossenergy/Population Interactions" initiated a communitywide challenge study to assess the capability of several inner magnetosphere ring current models in determining surface charging environment for the Van Allen Probes orbits during the 17 March 2013 storm event. The integrated electron flux between 10 and 50 keV is used as the metrics. Various skill scores are applied to quantitatively measure the modeling performance against observations. Results indicate that no model consistently perform the best in all of the skill scores or for both satellites. We find that from these simulations the ring current model with observational flux boundary condition and Weimer electric potential driver generally reproduces the most realistic flux level around the spacecraft. A simple and weaker VollandStern electric field is not capable of effectively transporting the same plasma at the boundary toward the Earth. On the other hand, if the ring current model solves the electric field selfconsistently and obtains similar strength and pattern in the equatorial plane as the Weimer model, the boundary condition plays another crucial role in determining the electron flux level in the inner region. When the boundary flux spectra based on magnetohydrodynamics (MHD) model/empirical model deviate from the shape or magnitude of the observed distribution function, the simulation produces poor skill scores along Van Allen Probes orbits.
Charging of DMSP/F6 spacecraft in aurora on 10 January 1983
Spacecraft charging has been widely observed in geosynchronous orbit on the ATS-5 and ATS-6 pair and on the SCATHA spacecraft. An adequate theory for explaining the observations exist. Neither the data or theory can be exported to low polar orbit and its drastically different environment. Evidence of charging on the DMSP F6 spacecraft is presented. A simple model is set up explaining the observations. Two independent instruments on the spacecraft showed charging to a moderate (44 volts) negative potential. The selection spectrometer showed a flux of 2 billion electrons per sq. cm. sec. ster. peaked at 9.5 keV. This was marginally sufficient to overcome the flux of cold ambient ions. Charging calculations are presented showing where simplications are justified and where serious uncertainties exist. More serious charging is predicted for the Shuttle in polar orbit.
Effects of Low Temperature on Charging of Spacecraft Dielectrics
Spacecraft dielectric charging, sometimes called deep-dielectric-charging or bulk-charging, occurs when high energy electrons imbed themselves in dielectric materials, and the charge density builds up, sometimes to breakdown levels. Charges usually bleed off slowly due to material conductivity. At very low (cryogenic) temperatures, the dielectric conductivity decreases until charges may remain and build up over weeks, months, or years. In those cases, the guidelines given in NASA and industry documents for when dielectric charging may become important are misleading. Arcing tests of spacecraft cables at liquid nitrogen temperatures and very low flux levels have been done at NASA MSFC for the JWST Project. In this paper, we describe the results of those tests and analyze their important implications for cryogenic spacecraft cable design and construction.
Effects of Low Temperature on Charging of Spacecraft Dielectrics
Spacecraft dielectric charging, sometimes called deep-dielectric-charging or bulk-charging, occurs when high energy electrons imbed themselves in dielectric materials, and the charge density builds up, sometimes to breakdown levels. Charges usually bleed off slowly due to material conductivity. At very low (cryogenic) temperatures, the dielectric conductivity decreases until charges may remain and build up over weeks, months, or years. In those cases, the guidelines given in NASA and industry documents for when dielectric charging may become important are misleading. Arcing tests of spacecraft cables at liquid nitrogen temperatures and very low flux levels have been done at NASA MSFC for the JWST Project. In this paper, we describe the results of those tests and analyze their important implications for cryogenic spacecraft cable design and construction.
Numerical Simulations on the Effects of Positive Ion Beam Emissions from Negatively Charged
Spacecraft tend to charge negatively in space plasmas at night. Positive ions ejected from a.