Search NASA⌕ Search

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.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

Spacecraft power system architecture to mitigate spacecraft charging effects

A power system architecture for a spacecraft and a method of a power supply for a spacecraft are presented which take advantage of the reduced plasma interaction associated with positive ground high voltage photovoltaic arrays and provide a negative ground power supply for electrical loads of the spacecraft. They efficiently convert and regulate power to the load bus and reduce power system mass and complexity. The system and method ground the positive terminal of the solar arrays to the spacecraft hull, and using a power converter to invert the electric sign, permit a negative ground for the electrical distribution bus and electrical components. A number of variations including a load management system and a battery management system having charging and recharging devices are presented.

Manner, David B.↗
NASA NTRS2004

Representation of the Geosynchronous Plasma Environment for Spacecraft Charging Calculations

Historically, our ability to predict and postdict surface charging has suffered from both a lack of reliable secondary emission and backscattered electron yields and poor characterization of the plasma environment. One difficulty lies in the common practice of fitting the plasma data to a Maxwellian or Double Maxwellian distribution function, which may not represent the data well for charging purposes. For 13 years Los Alamos National Laboratory (LANL) has been accumulating measurements of electron and proton spectra from Magnetospheric Plasma Analyzer (MPA) instruments aboard a series of geosynchronous satellites. These data provide both a plasma characterization and the potential of the instrument ground. We use electron and ion flux spectra measured by the LANL MPA to examine how the use of different spectral representations of the charged particle environment in computations of spacecraft potentials during magnetospheric substorms affects the accuracy of the results. We calculate the spacecraft potential using both the measured fluxes and several different fits to these fluxes. These flux measurements and fits have been corrected for the difference between the measured and calculated potential. The potentials computed using the measured fluxes, the best available material properties of graphite carbon, and a secondary electron escape fraction of 81%, are within a factor of three of the measured potential for nearly all the data. Using a Kappa fit to the electron distribution function and a Maxwellian fit to the ion distribution function gives agreement similar to the calculations using the actual data. Alternative spectral representations, including Maxwellian and double Maxwellian for both species, lead to less satisfactory agreement between predicted and measured potentials.

Davis, V. A.↗
NASA NTRS2000

Comparison of Spacecraft Charging Environments at the Earth, Jupiter, and Saturn

Studies of the Earth with the ATS-5, ATS-6, and SCATHA spacecraft led to the development of several simple tools for predicting the potentials to be expected on a spacecraft in the space environment. These tools have been used to estimate the expected levels of worst case charging at Jupiter and Saturn for the Galileo and the Cassini spacecraft missions. This paper reviews those results and puts them in the context of the design issues addressed by each mission including the spacecraft design mitigation strategies adopted to limit differential charging. The model shows that shadowed surfaces in Earth orbit can reach 25 kV or higher in worst case environments. For Galileo, spacecraft- to-space potentials of 900 V were predicted in shadow. Since such potentials could produce possible discharges and could effect low energy plasma measurements, the outer surface of Galileo was designed to rigid conductivity requirements. Even though the surface of Galileo is not entirely conducting, after 27 orbits no adverse effects due to surface charging aside from limited effects on low energy plasma measurements have been reported. The saturnian environment results in spacecraft potentials to space in shadow of 100 V or less. Although the overall surface of the Cassini spacecraft was not entirely conducting and grounded, it is shown that only in the most extreme conditions, is it expected that Cassini will experience any effects of surface charging at Saturn.

plasma environments↗
NASA NTRS1979

Secondary electron effects on spacecraft charging

Calculations were conducted to determine the effects of electron-produced secondary electrons on the net charging current and the equilibrium voltage of spacecraft surfaces immersed in hot (keV) plasmas. The effects of secondary electrons produced by the primary plasma electrons were examined for aluminum, Teflon, Mylar, and Kapton. The results indicate that it is the primary electron energy region over which the secondary electrons are emitted (rather than the ratio of secondary to primary electrons) which determines the effectiveness of the secondary electrons in limiting the net charging current. While the electron-produced secondary electrons decreased the charging current, they had little effect upon the equilibrium voltages attained.

Haffner, J. W.↗
NASA NTRS1979

Spacecraft Charging Technology, 1978

The interaction of the aerospace environment with spacecraft surfaces and onboard, high voltage spacecraft systems operating over a wide range of altitudes from low Earth orbit to geosynchronous orbit is considered. Emphasis is placed on control of spacecraft electric potential. Electron and ion beams, plasma neutralizers material selection, and magnetic shielding are among the topics discussed.

Source record↗
NASA NTRS2002

LEO Spacecraft Charging Guidelines

Over the past decade, Low Earth Orbiting (LEO) spacecraft have gradually required ever-increasing power levels. As a rule, this has been accomplished through the use of high voltage systems. Recent failures and anomalies on such spacecraft have been traced to various design practices and materials choices related to the high voltage solar arrays. NASA Glenn has studied these anomalies including plasma chamber testing on arrays similar to those that experienced difficulties on orbit. Many others in the community have been involved in a comprehensive effort to understand the problems and to develop practices to avoid them. The NASA Space Environments and Effects program, recognizing the timeliness of this effort, has commissioned and funded a design guidelines document intended to capture the current state of understanding. We present here an overview of this document, which is now nearing completion.

Hillard, G. B.↗
NASA NTRS2020

Comparison of Extreme Value Distributions for Electrostatic Discharge Magnitudes in Spacecraft Charging Tests

Electrostatic Discharge (ESD) induced by the accumulation of charge in the space environment is known to cause spacecraft anomalies and failures. While it is critical to estimate the worst-case expected ESD, sensitive radar instruments can be impacted by high rates of occurrence of very small ESD. To estimate the correct extreme behavior, it is important to select the correct extreme value distribution for extrapolation of test results limited in time and sensitivity. Quantile-quantile (Q-Q) analysis is used to compare electron beam-induced ESD test data to several statistical distributions used in the published literature. The best-fit distribution is shown to vary from between tests on different materials; however, it is clear that power law distributions are not good approximations for low amplitude events. Q-Q analysis is a convenient graphical method for evaluating multiple theoretical extreme-value distributions simultaneously.

Kim, Wousik↗
NASA NTRS2004

Leo Spacecraft Charging Design Guidelines: A Proposed NASA Standard

Over the past decade, Low Earth Orbiting (LEO) spacecraft have gradually required ever-increasing power levels. As a rule, this has been accomplished through the use of high voltage systems. Recent failures and anomalies on such spacecraft have been traced to various design practices and materials choices related to the high voltage solar arrays. NASA Glenn has studied these anomalies including plasma chamber testing on arrays similar to those that experienced difficulties on orbit. Many others in the community have been involved in a comprehensive effort to understand the problems and to develop practices to avoid them. The NASA Space Environments and Effects program, recognizing the timeliness of this effort, commissioned and funded a design guidelines document intended to capture the current state of understanding. This document, which was completed in the spring of 2003, has been submitted as a proposed NASA standard. We present here an overview of this document and discuss the effort to develop it as a NASA standard.

Hillard, G. B.↗
NASA NTRS1981

Internal breakdown of charged spacecraft dielectrics

It is suggested that small energy discharges of low differential voltage that are associated with internal buried charge may be an important mechanism by which sorted electrostatic energy is released from dielectrics on board orbiting spacecraft. The evidence from space given by Stevens (1980) is noted, and the laboratory experimental evidence of Frederickson is cited to demonstrate that discharges occur under circumstances with no external potential drop. Previous calculations indicating that significant internal electric fields can exist in dielectrics charged with multiple-kilovolt electron beams under conditions involving little or no external potential drop are reviewed. Attention is given to the internal discharge mechanism of Meulenberg (1976), and new calculations suggesting that the space environment is conducive to the formation of the conditions required by this mechanism are presented. Experimental procedures for checking the suggestions made are developed.

Beers, B. L.↗
NASA NTRS1986

Numerical simulation of spacecraft charging by impact-induced plasmas during a cometary flyby

A numerical model is developed for the interaction of a cometary probe, such as Giotto, with its environment, i.e., dust particles and gas. The spacecraft was set on a course to pass the comet at a velocity of 69 km/sec, so a chance existed that a potential field would form around the spacecraft and block lower energy particles from reaching the spacecraft instruments. The motion of electrons and ions is traced as a function of time to examine the evolution of the electric field, electric potential and the total space charge distributions on the surface of the spacecraft and its environment. Account is taken of the density of the particles and gas molecules at various distances from the comet, the collision energies involved, and the Giotto geometry. A solution is defined for the Poisson equation to describe the evolution of the plasma around Giotto, including the effects of ion collisions with the Al bumper protecting the spacecraft. The simulation predicts formation of an ion wake behind Giotto and the evolution of a positive potential on the order of 10 V around the spacecraft, i.e., sufficient for a positive potential barrier near the surface of the spacecraft.

Thiemann, H.↗
NASA NTRS1981

Development and design of three monitoring instruments for spacecraft charging

A set of instruments which provide early detection of potentially dangerous geomagnetic substorm conditions and monitor the spacecraft response are discussed. The set consists of a sensor that measures the characteristic energy of collected electrons or ions from + 100 to - 20,000 V, a logarithmic current density sensor that measures local electron flux and a transient events counter that counts the spurious pulses from electrostatic discharges that couple into the spacecraft wiring harness. Design details and performance characteristics of the three instruments are given. Size, weight, and power requirements are minimized.

Sturman, J. C.↗
NASA NTRS1990

The interaction of an artificial electron beam with the earth's upper atmosphere - Effects on spacecraft charging and the near-plasma evironment

The ionization created in the earth's upper atmosphere by an electron beam emitted from a low altitude spacecraft is described by two coupled nonlinear differential electron transport equations for the up-going and down-going differential energy flux. The equations are solved numerically, yielding estimates of the differential electron energy flux density at the spacecraft location. At altitudes below 200-250 km and for beam energies around 1 keV, it is shown that secondary electrons supply a significant contribution to the return current to the spacecraft and thereby reduce the spacecraft potential. The numerical results are in good agreement with observations from the Charge 2 sounding rocket experiment.

Neubert, T.↗
NASA NTRS1972

Spacecraft charging at synchronous orbit.

Observation that ATS 5 can charge to potentials as high as 10,000 volts during eclipse, and as high as 200 volts in sunlight. This charging has been used to infer the presence of the plasmasphere at synchronous altitude in the midnight region, and its prompt disappearance when hot plasma is injected in association with substorms. Although injected plasma has a density of 1.0 per cu cm the remaining cold plasma (less than 50 eV) has a density of 0.01 per cu cm. A mathematical model of ATS 5 has been constructed that can be used to predict spacecraft potentials. In addition, parts of ATS 5 can charge to several hundred volts without affecting the overall spacecraft potential appreciably.

Deforest, S. E.↗
NASA NTRS1978

Spacecraft charging and plasma interaction implications for large space systems

Specific discharge mechanisms, plasma interactions, and scale effects associated with very large spacecraft are studied. The large area, low density character, and extensive use of non-conducting materials is thought to have a major impact on the performance and survivability of many large space systems.

Miller, E.↗