Space shuttle charging or beam-plasma discharge: What can electron spectrometer observations contribute to solving the question?
Abstract
Several cooperative plasma experiments were carried out on board Spacelab-1, the ninth payload of the Space Transportation System (STS-9). Among them, the electron spectrometer 1ES019A was designed to observe 0.1-12.5 keV electron fluxes with high temporal and spatial resolution, while the SEPAC electron beam accelerator emitted electron beams with currents up to 280 mA and maximum energies of 5 keV. Since the question of orbiter charging to high voltages has controversially been discussed in several publications on STS-3 and STS-9 electron beam experiments, an attempt is made to relate information from the return electron flux observed during the SEPAC operations to the vehicle charging interpretation. A close examination reveals that most of our observations can be understood if the occurrence of a beam-plasma discharge is assumed at least for electron beam intensities above 100 mA. This would provide a substantial return current capability. High orbiter charging effects during electron beam accelerator electron emissions are consequently not supported by our observations.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- May 1988
- DOI:
- 10.1029/JA093iA05p04134
- Bibcode:
- 1988JGR....93.4134W
- Keywords:
-
- Space Plasma Physics: Active perturbation experiments;
- Space Plasma Physics: Spacecraft sheaths;
- wakes;
- charging;
- Space Plasma Physics: Wave/particle interactions