Accession Number:

ADA165223

Title:

A Neutral Plasma Source for Active Spacecraft Charge Control.

Descriptive Note:

Final rept. Jul 83-Aug 85,

Corporate Author:

JET PROPULSION LAB PASADENA CA

Personal Author(s):

Report Date:

1985-08-01

Pagination or Media Count:

137.0

Abstract:

The control of spacecraft charging is important since many satellite operating anomalies and systems malfunctions have been attributed to charging related phenomena. Overall spacecraft frame charging and differential surface charging can manifest themselves in many ways including electrostatic discharge, logic circuit upsets, space plasma measurement complications, enhancement of surface contamination and sputter erosion of surfaces. A prototype plasma source spacecraft discharge device has been developed to reduce overall and differential spacecraft surface charging and its effects. The plasma source is based on a hollow cathode discharge where the plasma generation process is contained completely within the cathode. The system operates on krypton gas and has cold start times of less than 4 seconds. A particle current control electrode just downstream of the cathode orifice can be used to enhance or inhibit electron flow from the cathode. The required inputs are power, telemetry line downlink, gas system latching valve openclose and control inputs from spacecraft potential monitors. A spacecraft discharge, net charge sensing circuit provides the ability to measure the polarity, magnitude, pulse shape and time duration of a discharge event. All system requirements have been met or exceeded. In ground simulation tests, the plasma source successfully discharged capacitivily biased plates, from as high as or - 2500V, to ground potential. Activily biased plates could be discharged and clamped at 5V with respect to ground.

Subject Categories:

  • Unmanned Spacecraft

Distribution Statement:

APPROVED FOR PUBLIC RELEASE