Plume Characterization of a One-Millipound Solid Teflon Pulsed Plasma Thruster
Abstract
To provide information necessary for an evaluation of the spacecraft contamination due to the one millipound pulsed plasma thruster (PPT) plume, studies of the plume mass flow distribution were carried out, with an emphasis on the flow into regions upstream of the thruster. Through an examination of the deposits on a large aluminized mylar sheet placed perpendicular to the primary PPT plume flow, 70 cm downstream of the PPT nozzle, the axisymmetry of the plume was confirmed. Using a special double quartz crystal microbalance (QCM) probe, the radial mass flux profile of the primary plume mass was found to drop off along a Gaussian bell curve to 10% of its centerline value at a radius corresponding to a plume expansion half angle of about 40 deg. High speed photography was used to confirm that the primary plume is composed of a high energy plasma moving at over 30 km/sec and low energy, presumably neutral, gas moving considerably slower (less than or equal to 17 km/sec). Measurements of the PPT plume upstream mass flux were made in the Molecular Sink (MOLSINK) vacuum facility in order to minimize the plume-tank wall reflected mass flux. Using specially designed collimators on 4 rows of QCMs mounted on a support extending radially away from the plume axis, measurements were made of the mass flux originating in a thin slice of the PPT primary plume at an arbitrary 'dip' angle with respect to the thruster axis.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1979
- Accession Number
- ADA087713
Entities
People
- K. G. Harstad
- L. C. Pless
- L. K. Rudolph
- R. M. Jones
Organizations
- California Institute of Technology