NASA Scientific and Technical Aerospace Reports

NASA s Space Environments and Effects (SEE) Program and co-sponsored by the Air Force Research Laboratory (AFRL) and
the European Space Agency (ESA), the 2003 conference saw attendance from eleven countries with over 65 oral papers and
18 poster papers. Presentation topics highlighted the latest in spacecraft charging mitigation techniques and on-orbit
investigations, including: Plasma Propulsion and Tethers; Ground Testing Techniques; Interactions of Spacecraft and Systems
With the Natural and Induced Plasma Environment; Materials Characterizations; Models and Computer Simulations;
Environment Specifications; Current Collection and Plasma Probes in Space Plasmas; On-Orbit Investigations. A round-table
discussion of international standards regarding electrostatic discharge (ESD) testing was also held with the promise of
continued discussions in the off years and an official continuation at the next conference.
Derived from text
Spacecraft Charging; External Surface Currents
20040111032 NASA Marshall Space Flight Center, Huntsville, AL, USA
High Voltage Solar Array Arc Testing for a Direct Drive Hall Effect Thruster System
Schneider, Todd; Carruth, M. R., Jr.; Vaughn, J. A.; Jongeward, G. A.; Mikellides, I. G.; Ferguson, D.; Kerslake, T. W.;
Peterson, T.; Snyder, D.; Hoskins, A.; 8th Spacecraft Charging Technology Conference; March 2004; 15 pp.; In English; See
also 20040111031; No Copyright; Avail: CASI; A03, Hardcopy
The deleterious effects of spacecraft charging are well known, particularly when the charging leads to arc events. The
damage that results from arcing can severely reduce system lifetime and even cause critical system failures. On a primary
spacecraft system such as a solar array, there is very little tolerance for arcing. Motivated by these concerns, an experimental
investigation was undertaken to determine arc thresholds for a high voltage (200-500 V) solar array in a plasma environment.
The investigation was in support of a NASA program to develop a Direct Drive Hall-Effect Thruster (D2HET) system. By
directly coupling the solar array to a Hall-effect thruster, the D2HET program seeks to reduce mass, cost and complexity
commonly associated with the power processing in conventional power systems. In the investigation, multiple solar array
technologies and configurations were tested. The cell samples were biased to a negative voltage, with an applied potential
difference between them, to imitate possible scenarios in solar array strings that could lead to damaging arcs. The samples
were tested in an environment that emulated a low-energy, HET-induced plasma. Short duration trigger arcs as well as long
duration sustained arcs were generated. Typical current and voltage waveforms associated with the arc events are presented.
Arc thresholds are also defined in terms of voltage, current and power. The data will be used to propose a new, high-voltage
(greater than 300 V) solar array design for which the likelihood of damage from arcing is minimal.
Author
Hall Effect; High Voltages; Solar Arrays; Hall Thrusters; Spacecraft Charging; Arc Discharges
20040111035 NASA Marshall Space Flight Center, Huntsville, AL, USA
NASCAP-2K: An Overview
Mandell, M. J.; Davis, V. A.; Gardner, B. M.; Mikellides, I. G.; Cooke, D. L.; Minor, J.; 8th Spacecraft Charging Technology
Conference; March 2004; 14 pp.; In English; See also 20040111031; No Copyright; Avail: CASI; A03, Hardcopy
Nascap-2k is the modern replacement for the older 3-D charging codes NASCAP/GEO, NASCAP/LEO, POLAR, and
DynaPAC. Built on the DynaPAC kernel and incorporating surface charging, environment and space potential models from
the older codes, Nascap-2k performs charging calculations for a wide variety of space environments under control of a unified
graphical interface. In this paper we illustrate the use of Nascap-2k for spacecraft charging calculations. We touch on some
of the unique physical and mathematical models on which the code is based. Examples/demos include the use of Object
Toolkit, charging calculations in geosynchronous substorm, solar wind, low earth orbit, and auroral environments, and display
and analysis of surface potentials, space potentials and particle trajectories.
Author
Spacecraft Charging; Computerized Simulation; Space Environment Simulation
20040111039 Boeing Co., El Segundo, CA, USA
Plasma Phenomena Associated With Solar Array Discharges and Their Role in Scaling Coupon Test Results to a Full
Panel
Leung, Philip; Bodeau, Michael; 8th Spacecraft Charging Technology Conference; March 2004; 14 pp.; In English; See also
20040111031; No Copyright; Avail: CASI; A03, Hardcopy
On a solar array, different surface potential profiles could be developed under different environmental and spacecraft
operation configurations. These potential profiles were simulated in the laboratory with solar cell coupons, and the resulting
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