ANALYSIS OF RADIANCES FROM ORBITAL GAS RELEASES

We describe here the analysis of the optical emissions resulting from the sequential release of five gases (N2, Xe, CO, NO, and methylamine) from a remote canister as observed from a separate spacecraft by ultraviolet/visible array spectrometers and a pair of infrared circular variable filter spectrometers, These spectrometers provided continuous spectral coverage of the release event between 120 nm and 22-mu-m. The releases occurred at 260 to 300 km altitude under conditions of no solar illumination. No emissions were detected during the N2 and Xe releases, but bright infrared emissions in both fundamental and overtone vibrational bands observed for CO and NO resulted from the highly energetic interaction of the released gases with the residual atmospheric gases. Molecular internal distributions and collisional excitation cross sections were derived from the analysis. The collisional process creates highly rotationally and vibrationally excited CO and NO. The cross sections are determined with an order of magnitude uncertainty to be 10(-16) cm2 for O + CO --> CO(upsilon) + O and 10(-17) cm2 for O + NO --> NO(upsilon) + O. Methylamine (released as a liquid) exhibited both IR and UV emission features attributable to OH(upsilon), OH(A), and complex mid-IR emissions likely due to CH stretches and to NO and methylamine vibrational bands. This article reports our preliminary analysis and conclusions.