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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.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Surface phenomena in plasma environments

Plasma interactions and their effects on materials depend on a number of factors, including the pre-existing environment, the properties of surface materials and the characteristics of the system. An additional dimension is the question of mission: some payloads may be much more sensitive to plasma interactions than others. As an example, a payload whose objective is to measure the ambient environment will be more sensitive to any effects than will a power system. Material specific effects include charging and its associated effects, which can result in short- and long-term damage. Selection of materials for a particular application requires consideration of all factors and assessment of effects due to all causes. Proper selection and suitability determination requires analysis to identify the actual environment combined with testing under exposure to single and combined environment factors.

Purvis, C. K.↗
NASA NTRS2000

Charged Particle Environment Definition for NGST: L2 Plasma Environment Statistics

The plasma environment encountered by the Next Generation Space Telescope satellite in a halo orbit about L2 can include the Earth's magnetotail and magnetosheath in addition to the solar wind depending on the orbital radius chosen for the mission. Analysis of plasma environment impacts on the satellite requires knowledge of the average and extreme plasma characteristics to assess the magnitude of spacecraft charging and materials degradation expected for the mission lifetime. This report describes the analysis of plasma data from instruments onboard the IMP 8 and Geotail spacecraft used to produce the plasma database for the LRAD engineering-level phenomenology code developed to provide the NGST L2 environment definition.

Minow, Joseph I.↗
NASA NTRS1987

The geosynchronous plasma environment

The geosynchronous plasma environment in the 0 to 100 keV energy range as input in the modeling of spacecraft charging phenomena is summarized. Models for spacecraft design are reviewed, emphasizing practical tools for predicting the effects of spacecraft interactions on satellite systems.

Garrett, Henry Berry↗
NASA NTRS1990

The geosynchronous plasma environment

The geosynchronous plasma environment in the 0 to 100 keV energy range as input in the modeling of spacecraft charging phenomena is summarized. Models for spacecraft design are reviewed, emphasizing practical tools for predicting the effects of spacecraft interactions on satellite systems.

Garrett, Henry Berry↗
NASA NTRS2012

The Near-Earth Plasma Environment

An overview of the plasma environment near the earth is provided. We describe how the near-earth plasma is formed, including photo-ionization from solar photons and impact ionization at high latitudes from energetic particles. We review the fundamental characteristics of the earth's plasma environment, with emphasis on the ionosphere and its interactions with the extended neutral atmosphere. Important processes that control ionospheric physics at low, middle, and high latitudes are discussed. The general dynamics and morphology of the ionized gas at mid- and low-latitudes are described including electrodynamic contributions from wind-driven dynamos, tides, and planetary-scale waves. The unique properties of the near-earth plasma and its associated currents at high latitudes are shown to depend on precipitating auroral charged particles and strong electric fields which map earthward from the magnetosphere. The upper atmosphere is shown to have profound effects on the transfer of energy and momentum between the high-latitude plasma and the neutral constituents. The article concludes with a discussion of how the near-earth plasma responds to magnetic storms associated with solar disturbances.

Pfaff, Robert F., Jr.↗
NASA NTRS1987

The plasma environment during particle beam injection into space plasmas. I - Electron beams. II - Charge-neutral beams

A realistic electrostatic simulation model is used to investigate the plasma environment in the near vicinity of a spacecraft during the injection of electon beams from the spacecraft. The model is described, and the cases of injection into vacuum and into a low-density plasma are addressed. The relationship of the two-dimensional results to the purely field-aligned one-dimensional simulations is discussed. The dependence of the results on the ambient plasma density is investigated. Then, the properties of a charge-neutral beam and the plasma response are examined for the case where the beam has nonzero velocity components parallel and perpendicular to the magnetic field. The parameters used in the simulation are described, and the properties of the beam injection into the vacuum and in the case where a plasma is present are given.

Pritchett, P. L.↗
NASA NTRS1980

Preliminary results on the plasma environment of Saturn from the Pioneer 11 plasma analyzer experiment

The Ames Research Center Pioneer 11 plasma analyzer experiment provided measurements of the solar wind interaction with Saturn and the character of the plasma environment within Saturn's magnetosphere. It is shown that Saturn has a detached bow shock wave and magnetopause quite similar to those at earth and Jupiter. The scale size of the interaction region for Saturn is roughly one-third that at Jupiter, but Saturn's magnetosphere is equally responsive to changes in the solar wind dynamic pressure. Saturn's outer magnetosphere is inflated, as evidenced by the observation of large fluxes of corotating plasma. It is postulated that Saturn's magnetosphere may undergo a large expansion when the solar wind pressure is greatly diminished by the presence of Jupiter's extended magnetospheric tail when the two planets are approximately aligned along the same solar radial vector.

Wolfe, J. H.↗
NASA NTRS1979

Charge-exchange plasma environment for an ion drive spacecraft

The charge exchange plasma environment around a spacecraft that uses mercury ion thrusters for propulsion is described. The interactions between the plasma environment and the spacecraft are determined and a model which describes the propagation of the mercury charge exchange plasma is discussed. The model is extended to describe the flow of the molybdenum component of the charge exchange plasma. The uncertainties in the models for various conditions are discussed and current drain to the solar array, charge exchange plasma material deposition, and the effects of space plasma on the charge exchange plasma propagation are addressed.

Kaufman, H. R.↗
DOE OSTI2024

Overview, Progress and Next Steps for Our Understanding of the Near-Earth Space Radiation and Plasma Environment: Science and Applications

The Near-Earth Space Radiation and Plasma Environment falls within the realm of G3 Cluster (G3 refers to ‘Near-Earth Radiation and Plasma Environment’ of the ‘Coupled Geospace System’) under the COSPAR (Committee On Space Research) /International Space Weather Action Teams (ISWAT) Initiative. The diverse and dynamic particle populations from this region pose challenges from both science and space weather-impact perspectives. The G3 cluster has intimate connections with solar, heliosphere clusters, and the other Geospace ones (G1, G2) through a chain of physical processes. This paper reviews recent scientific advances in understanding this complex space environment, identifies gaps in research and space weather applications, and maps out our recommendations on priorities for the next 5-10 years.

Zheng, Yihua↗
NASA NTRS1979

Average plasma environment at geosynchronous orbit

The average plasma environment at geosynchronous orbit (GSO) is derived from a whole year's worth of plasma data obtained by the UCSD electrostatic electrometer on board ATS 5. The result is primarily intended for use as a general reference for engineers designing a large spacecraft to be flown at GSO. A simple mathematical formula using a 3rd order polynomial is found to be adequate for representing the yearly averaged particle energy spectrum from 70 to 41,000 eV under different geomagnetic conditions. Furthermore, correlation analyses with the geomagnetic planetary index Kp and with the auroral electrojet index AE were carried out in the hope that the ground observations of the geomagnetic field variations can be used to predict the plasma variations in space. Unfortunately, the results indicate that such forecasting is not feasible by use of these two popular geomagnetic parameters alone.

Su, S. Y.↗
NASA NTRS2010

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

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.

Minow, Joseph I.↗
NASA NTRS2005

Ion Composition in Saturn's Plasma Environment: Early Results from the Cassini Plasma Spectrometer

Prior to Cassini s arrival at Saturn, most of what was known about the composition of the plasma in Saturn s environment was derived from limited measurements by Pioneer 11 and Voyager 1 and 2 in 1979-1981[1-3]. The measurements reported here were made by the Cassini Plasma Spectrometer (CAPS) [4] during the first two Cassini orbits, including the closest approach to Saturn and the rings during the tour, and a close flyby of Titan. The CAPS instrument resolves ion energy/charge from 1 V to 50 kV and ion mass/charge from 1 to approx.100 amu/e, and it measures electron energy from 1 eV to 28 keV. Initial composition measurements of Saturn s magnetosphere show that protons dominate outside approx.8 R(sub s), while inside this radius the plasma is dominated by a mix of water-derived ions and N(+). Over the A and B rings a plasma layer is observed composed of O2(+) and O(+) . The close passage near Titan shows a rich network of both positive and negative molecular ions. We report preliminary analysis of these and other composition findings.

Reisenfeld, D. B.↗
NASA NTRS2006

Experimental Results of Thin-Film Photovoltaic Cells in a Low Density LEO Plasma Environment: Ground Tests

Plasma ground testing results, conducted at the Glenn Research Center (GRC) National Plasma Interaction (N-PI) Facility, are presented for a number of thin-film photovoltaic cells. The cells represent a mix of promising new technologies identified by the Air Force Research Laboratory (AFRL) under the CYGNUS Space Science Technology Experiment (SSTE-4) Program. The current ground tests are aimed at characterizing the performance and survivability of thin film technologies in the harsh low earth orbital space environment where they will be flown. Measurements of parasitic current loss, charging/dielectric breakdown of cover-slide coatings and arcing threshold tests are performed for each individual cell. These measurements are followed by a series of experiments designed to test for catastrophic arc failure mechanisms. A special type of power supply, called a solar array simulator (SAS) with adjustable voltage and current limits on the supply s output, is employed to bias two adjacent cells at a predetermined voltage and current. The bias voltage is incrementally ramped up until a sustained arc results. Sustained arcs are precursors to catastrophic arc failure where the arc current rises to a maximum value for long timescales often ranging between 30 to 100 sec times. Normal arcs by comparison, are short lived events with a timescale between 10 to 30 sec. Sustained arcs lead to pyrolization with extreme cell damage and have been shown to cause the loss of entire array strings in solar arrays. The collected data will be used to evaluate the suitability of thin-film photovoltaic technologies for future space operations.

Galofaro, Joel T.↗
NASA NTRS2004

Specification of ISS Plasma Environment Variability

Quantifying spacecraft charging risks and associated hazards for the International Space Station (ISS) requires a plasma environment specification for the natural variability of ionospheric temperature (Te) and density (Ne). Empirical ionospheric specification and forecast models such as the International Reference Ionosphere (IRI) model typically only provide long term (seasonal) mean Te and Ne values for the low Earth orbit environment. This paper describes a statistical analysis of historical ionospheric low Earth orbit plasma measurements from the AE-C, AE-D, and DE-2 satellites used to derive a model of deviations of observed data values from IRI-2001 estimates of Ne, Te parameters for each data point to provide a statistical basis for modeling the deviations of the plasma environment from the IRI model output. Application of the deviation model with the IRI-2001 output yields a method for estimating extreme environments for the ISS spacecraft charging analysis.

Minow, Joseph I.↗
NASA NTRS2002

Specification of the ISS Plasma Environment Variability

Quantifying the spacecraft charging risks and corresponding hazards for the International Space Station (ISS) requires a plasma environment specification describing the natural variability of ionospheric temperature (Te) and density (Ne). Empirical ionospheric specification and forecast models such as the International Reference Ionosphere (IRI) model typically only provide estimates of long term (seasonal) mean Te and Ne values for the low Earth orbit environment. Knowledge of the Te and Ne variability as well as the likelihood of extreme deviations from the mean values are required to estimate both the magnitude and frequency of occurrence of potentially hazardous spacecraft charging environments for a given ISS construction stage and flight configuration. This paper describes the statistical analysis of historical ionospheric low Earth orbit plasma measurements used to estimate Ne, Te variability in the ISS flight environment. The statistical variability analysis of Ne and Te enables calculation of the expected frequency of Occurrence of any particular values of Ne and Te, especially those that correspond to possibly hazardous spacecraft charging environments. The database used in the original analysis included measurements from the AE-C, AE-D, and DE-2 satellites. Recent work on the database has added additional satellites to the database and ground based incoherent scatter radar observations as well. Deviations of the data values from the IRI estimated Ne, Te parameters for each data point provide a statistical basis for modeling the deviations of the plasma environment from the IRI model output. This technique, while developed specifically for the Space Station analysis, can also be generalized to provide ionospheric plasma environment risk specification models for low Earth orbit over an altitude range of 200 km through approximately 1000 km.

Minow, Joseph I.↗
NASA NTRS2003

L2 Plasma Environments

The second LaGrange point, 1.5 million miles from the Earth in the anti-solar direction, is becoming an important destination for scientific spacecraft. The quasi-stable gravity field requires little energy resources for station keeping and astronomical missions-infrared and microwave in particular-find the minimal impact from Earth albedo radiation and limited restrictions on viewing directions a tremendous advantage in their mission design. Spacecraft design for L2 missions will have to consider the plasma environments of the ambient solar wind, magnetosheath, and magnetotail from energies of a few 10s of an eV through 10s of keV in addition to enhanced energetic particle populations from 10s to 1000 keV during solar energetic particle events. This presentation will provide a background on the appropriate L2 charged particle environments at L2 and describe modeling efforts at MSFC to develop environment specification tools for the L2 plasma environment.

Minow, Joseph I.↗
NASA NTRS2003

L2 Plasma Environments

The second LaGrange point, 1.5 million miles from the Earth in the anti-solar direction, is becoming an important destination for scientific spacecraft. The quasi-stable gravity field requires little energy resources for station keeping and astronomical missions-infrared and microwave in particular-find the minimal impact from Earth albedo radiation and limited restrictions on viewing directions a tremendous advantage in their mission design. Spacecraft design for L2 missions will have to consider the plasma environments of the ambient solar wind, magnetosheath, and magnetotail from energies of a few 10s of an eV through 10 s of keV in addition to enhanced energetic particle populations from 10s to l000 keV during solar energetic particle events. This presentation will provide a background on the appropriate L2 charged particle environments at L2 and describe modeling efforts at MSFC to develop environment specification tools for the L2 plasma environment.

Minow, Joseph I.↗
NASA NTRS2002

Specifying the ISS Plasma Environment

Quantifying the spacecraft charging risks and corresponding hazards for the International Space Station (ISS) requires a plasma environment specification describing the natural variability of ionospheric temperature (Te) and density (Ne). Empirical ionospheric specification and forecast models such as the International Reference Ionosphere (IN) model typically only provide estimates of long term (seasonal) mean Te and Ne values for the low Earth orbit environment. Knowledge of the Te and Ne variability as well as the likelihood of extreme deviations from the mean values are required to estimate both the magnitude and frequency of occurrence of potentially hazardous spacecraft charging environments for a given ISS construction stage and flight configuration. This paper describes the statistical analysis of historical ionospheric low Earth orbit plasma measurements used to estimate Ne, Te variability in the ISS flight environment. The statistical variability analysis of Ne and Te enables calculation of the expected frequency of occurrence of any particular values of Ne and Te, especially those that correspond to possibly hazardous spacecraft charging environments. The database used in the original analysis included measurements from the AE-C, AE-D, and DE-2 satellites. Recent work on the database has added additional satellites to the database and ground based incoherent scatter radar observations as well. Deviations of the data values from the IRI estimated Ne, Te parameters for each data point provide a statistical basis for modeling the deviations of the plasma environment from the IRI model output.

Minow, Joseph I.↗