Accession Number : AD0766410

Title :   Ionization and Attraction of Neutral Molecules to a Charged Spacecraft.

Descriptive Note : Rept. Sep 72-Feb 73,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Cauffman,David P.

Report Date : 09 AUG 1973

Pagination or Media Count : 34

Abstract : Neutral molecules given off by spacecraft outgassing or thrusters may become ionized by solar uv radiation or ambient energetic electrons. These ions may be reattracted to the spacecraft and hence constitute a source of contamination for sensitive spacecraft surfaces. In this report, the magnitude of this effect is calculated. Using the best available outgas fluxes, it is predicted that the reattraction of outgas products will be a large contaminating effect during the initial several months of the spacecraft's orbital lifetime. The implications of assuming that this contamination mechanism is the dominant one during the early spacecraft lifetime are examined. In addition, a list of parameters that need to be measured more accurately is presented, and ways to combat contamination from this source are outlined. (Modified author abstract)

Descriptors :   (*SPACECRAFT, CONTAMINATION), (*EXHAUST GASES, GAS IONIZATION), (*SOLAR RADIATION, GAS IONIZATION), PHOTOCHEMICAL REACTIONS, ELECTRON IRRADIATION

Subject Categories : Physical Chemistry
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE