NASA Scientific and Technical Aerospace Reports

which are particularly well suited to study electron emission as related to spacecraft charging. These measurements include
electron-induced secondary and backscattered yields, spectra, and angular resolved measurements as a function of incident
energy, species and angle, plus investigations of ion-induced electron yields, photoelectron yields, sample charging and
dielectric breakdown. Extensive surface science characterization capabilities are also available to fully characterize the
samples in situ. Our measurements for a wide array of conducting and insulating spacecraft materials have been incorporated
into the SEE Charge Collector Knowledge-base as a Database of Electronic Properties of Materials Applicable to Spacecraft
Charging. This Database provides an extensive compilation of electronic properties, together with parameterization of these
properties in a format that can be easily used with existing spacecraft charging engineering tools and with next generation
plasma, charging, and radiation models. Tabulated properties in the Database include: electron-induced secondary electron
yield, backscattered yield and emitted electron spectra; He, Ar and Xe ion-induced electron yields and emitted electron spectra;
photoyield and solar emittance spectra; and materials characterization including reflectivity, dielectric constant, resistivity,
arcing, optical microscopy images, scanning electron micrographs, scanning tunneling microscopy images, and Auger electron
spectra. Further details of the instrumentation used for insulator measurements and representative measurements of insulating
spacecraft materials are provided in other Spacecraft Charging Conference presentations. The NASA Space Environments and
Effects Program, the Air Force Office of Scientific Research, the Boeing Corporation, NASA Graduate Research Fellowships,
and the NASA Rocky Mountain Space Grant Consortium have provided support.
Author
Spacecraft Charging; Electrical Properties; Spacecraft Construction Materials; Insulators; Universities; Utah; Knowledge
Bases (Artificial Intelligence)
20040111059 Aerospace Corp., Los Angeles, CA, USA
An Empirical Low-Energy Ion Model of the Inner Magnetosphere
Roeder, J. L.; Chen, M. W.; Fennell, J. F.; Friedel, R.; 8th Spacecraft Charging Technology Conference; March 2004; 15 pp.;
In English; See also 20040111031
Contract(s)/Grant(s): GC131165NGD; No Copyright; Avail: CASI; A03, Hardcopy
Ion flux measurements by the CAMMICE/MICS and Hydra instruments on the NASA Polar satellite have been used to
build empirical models of the ion environment at low energies in the Earth s inner magnetosphere. These models may be used
to develop design and test specifications for spacecraft surface materials, which are susceptible to damage by the ions. The
combination of the CAMMICE/MICS and Hydra models provide the ion flux at energies in the range 20 eV 200 keV as a
function of position in the magnetosphere. For the 1 200 keV energy range, the H+ and O+ ion flux is estimated separately
using the CAMMICE/MICS data. Average environments have been calculated for several sample orbital trajectories: a
geosynchronous orbit and the orbits of several satellites in the Global Positioning System (GPS) constellation. At high energies
(~100 keV) the flux estimates agree with corresponding estimates from the NASA AP-8 model, but the fluxes at low energies
are larger than those extrapolated simply from AP-8. The CAMMICE/MICS model shows that H+ dominates the \g2 keV ion
populations, but that the O+ flux becomes comparable to the H+ flux at ~1 keV. The standard deviation of both the ion and
electron flux was found to be 100 200% of the average value over the entire considered energy range. The average 1 200 keV
O+ flux estimates for GEO appear very similar to the averages for GPS orbit, so that any material damage due to O+ ions in
this energy range should be the same for the two orbits.
Author
Ions; Flux (Rate); Earth Magnetosphere; Design Analysis; Surface Properties; Geosynchronous Orbits
20040111061 Kyoto Univ., Japan
Feasibility Study of an Experimental Platform With Active Plasma Emission for Japan Experimental Module Onboard
ISS
Usui, Hideyuki; Funaki, I.; Nakayama, Y.; Tashima, H.; Kuninaka, H.; Okada, M.; 8th Spacecraft Charging Technology
Conference; March 2004; 11 pp.; In English; See also 20040111031; No Copyright; Avail: CASI; A03, Hardcopy
A Japanese experimental module (JEM) onboard the international space station (ISS) is directly exposed to space, hence
if a plasma device is equipped to the exposed facility of JEM, many kinds of new plasma experiment become possible.
However, there is a concern that by emitting plasmas, spacecraft charging and corresponding discharge will severely damage
JEM and even ISS. We are proposing an experimental module for JEM in order to clarify such spacecraft-plasma interaction
by operating a sub-scaled plasma-emitting floating body that can be deployed from JEM with some diagnostic equipment.
Prior to the design of such a plasma experimental facility, strict assessment on the plasma environment around the plasma
emitting device should be finished. We particularly focus on the transient response to the plasma emission. In this paper, the
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