Accession Number:

ADA199904

Title:

A Charge Control System for Spacecraft Protection

Descriptive Note:

Corporate Author:

AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA

Report Date:

1988-09-26

Pagination or Media Count:

16.0

Abstract:

An autonomous system to detect both absolute and differential spacecraft charging aboard high altitude satellites, and to reduce those potentials before hazardous arcing levels are reached, is now being developed. Operation of the system is based on the empirical results of the Space Test Program SCATHA p78-2 and NASA ATS-6 satellites, both of which successfully demonstrated the principle of safely reducing spacecraft charging levels by the emission of a low energy neutral plasma--effectively shorting the spacecraft and charged dielectric surfaces to the ambient space plasma. The Charge Control System will utilize a xenon-based plasma source capable of igniting within one second, and capable of emitting a quasi-neutral plasma containing more than 1 MA of ions. Satellite frame potential relative to the ambient space plasma will be determined by an electrostatic analyzer capable of detecting both ions and electrons in the energy range 50eV-20 kev. Automatic operation of the system will accomplished by microprocessor controller which will interpret the sensor data and activate the plasma source when predetermined threshold levels are exceeded. With a gas supply for more than 2000 hours of operation in space, the system may be expected to provide on-orbit spacecraft protection for up to 10 years.

Subject Categories:

  • Electricity and Magnetism
  • Astronautics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE