Accession Number : ADA325614

Title :   Gas Pressure Measurements on Space Shuttle Mission-39.

Descriptive Note : Interim rept.,

Corporate Author : PHILLIPS LAB HANSCOM AFB MA

Personal Author(s) : Denig, William F. ; Viereck, Rodney

PDF Url : ADA325614

Report Date : 09 APR 1996

Pagination or Media Count : 55

Abstract : During the STS-39 Space Shuttle Mission in April 1991 a Neutral gas pressure gauge was flown as part of the Infrared Background Signature Survey (IBSS) mission. This instrument provided gas pressure measurements within the Shuttle payload bay, on the Remote Manipulator System (RMS) arm, and as part of a deployed Shuttle PAllet Satellite (SPAS). The Pressure Gauge (PG) was found to be sensitive to payload bay outgassing, controlled gas releases, and geometry. During the 7-day mission the in-bay pressures decreased about an order of magnitude from 2 x 10(exp -6) to 3x10(exp -7) Torr. Local gas pressures were found to be dependent upon the availability of scattering surfaces within the field-of-view and the orientation of the Shuttle ram angle. On the other hand, SPAS pressures were consistent with background atmospheric levels near 10.8 Torr. At all time the local pressures were found to be sensitive to attitude control thruster operations and other controlled gas releases. The STS-39 pressure measurements indicate that the persistently high levels of contaminant gases within the cargo bay were larger than those measured on most earlier Shuttle missions and greater than NASA contaminant gas specifications.

Descriptors :   *PRESSURE MEASUREMENT, *GASES, *SPACE SHUTTLES, SCATTERING, DEPLOYMENT, PAYLOAD, ATTITUDE CONTROL SYSTEMS, INFRARED SIGNATURES, SPECIFICATIONS, NEUTRAL, PRESSURE GAGES, SURFACES, ARTIFICIAL SATELLITES, CARGO, CONTAMINANTS, INFRARED RADIATION, BACKGROUND RADIATION, MANIPULATORS, THRUST CONTROL, PALLETS, SPACE MISSIONS, REMOTE CONTROL, REMOTE SYSTEMS, BAYS, OUTGASSING.

Subject Categories : Physical Chemistry
      Manned Spacecraft
      Fuels

Distribution Statement : APPROVED FOR PUBLIC RELEASE