High-Voltage Charging of Spacecraft in Low Polar Orbit: A Study of Physical Effects Involved
Abstract
The work first reviews the main differences between the plasma environments in geostationary orbit and low polar orbit with regard to high- voltage charging situations. Section 2 develops a simple rough estimate of the required conditions for overall charging of a large spacecraft in low-orbit auroral-zone conditions. The results indicate that for any given spacecraft, surface potentials are likely to depend more strongly on the ratio of ambient flux of high-energy electrons to that of all ions than on any other environmental parameter, and this prediction has been corroborated by results of Gussenhoven et al for the DMSP satellites. Section 3 presents results from a calculation of escape currents of electrons emitted from negatively-charged spacecraft surfaces having various orientations relative to the direction of the local magnetic field B. The suppression of such currents by B effects indicates that on mostly-dielectric large spacecraft such as the Shuttle Orbiter, local charging, especially on surfaces nearly parallel to B, may occur in ionospheric conditions which do not produce overall charging. Section 4 proposes a wake- induced-barrier-effect mechanism which also suppresses escape of emitted electrons. This effect appears to permit beam-induced as well as polar-orbit high-voltage charging to occur. Section 5 presents preliminary results of numerical simulation work directed toward making detailed tests of these predictions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 04, 1988
- Accession Number
- ADA213809
Entities
People
- J. G. Laframboise
- Jiangyi Luo
- L. W. Parker
Organizations
- University of York