Mitigation of scattered solar radiation from condensed attitude control jet plumes

Abstract

Introduction I a previous paper we reported on the observation and analysis of strong visible and ultraviolet signatures due to solar scattering by condensed argon attitude control system (ACS) jet plumes. In that paper, based on extrapolations of available laboratory jet condensation data and solid particle optical properties, we predicted that nitrogen ACS plumes would produce scattered solar signatures similar to those of argon. However, a review of the available laboratory jet condensation data and solid particulate optical properties of neon' led us to conclude that ACS jets utilizing neon as a propellant should exhibit solar scattering signatures more than two orders of magnitude smaller than those due to similar jets employing argon. * Neon was substituted for argon in the target module attitude control and settling jets for a flight of the U.S. Air Force's Multispectral Measurements Program (MSMP) subsequent to the flight report in our previous paper. This note reports that no observable solar scattered signals from the neon ACS jet exhaust plume were observed above the experimental background level. This lack of observed jet plume signatures is consistent with the predictions presented inRef. 1.