Collisional desorption of NO by fast O atoms

Surface-adsorbed NO figures largely in the mechanism that produces visible glow around spacecraft in low Earth orbit (LEO). In view of the potential interference to optical observations such a glow represents, we have investigated the collision-induced desorption of NO from Al, Ni, and Z306 Chemglaze-coated surfaces at 96 K by hyperthermal (8 km/s) oxygen atoms. The removal of surface NO was followed by the monitoring of the visible fluorescence of electronically excited NO2 produced through the surface-mediated reaction O + NO. A variability in collisional desorption rate with material was observed. The limited data suggest a removal efficiency of 4 to 8% of the impinging O atom flux. Implications for the atmospheric scouring of contaminants from external surfaces of LEO spacecraft are discussed.