Accession Number:

ADA036904

Title:

Pulsed Plasma Plume Studies.

Descriptive Note:

Final rept. Mar 75-Nov 76,

Corporate Author:

FAIRCHILD REPUBLIC CO FARMINGDALE N Y

Personal Author(s):

Report Date:

1977-03-01

Pagination or Media Count:

100.0

Abstract:

The exhaust plume of a millipound thrust level pulsed plasma thruster was studied in a vacuum chamber having all walls cooled by liquid nitrogen. This thruster has a propulsive performance capable of meeting North-South station-keeping requirements of satellites. The major source of contamination of a surface located in the facility was identified to be mainly due to mass being scattered off the walls of the test facility because the walls were incapable of absorbing the highly energetic plume of the first encounter with the wall. By means of a Langmuir probe, calorimetric discs, a collimated QCM and collimated glass capture cups it was found that the transient plume is fairly well collimated and that the outer extremities of the plume are located within or - 30 degrees to or - 40 degrees with respect to the geometric center line of the thruster that was studied. Whether or not major changes of the exhaust cone would change this location was not examined. Time resolved studies of the plume by a Langmuir probe and a photocell has shown the life of the plume at a region in space to be only a few tens of microseconds. This result reveals that a spacecraft surface exposed over a 5 to 7 year period to the plume of a North-South station keeping thruster will actually see an accumulated plume flow time for only about 5 minutes during that mission time.

Subject Categories:

  • Electric and Ion Propulsion
  • Unmanned Spacecraft

Distribution Statement:

APPROVED FOR PUBLIC RELEASE