This paper models the fundamental vibration-rotation band emission from NO around 5.3 &mgr;m observed by the interferometer aboard the cryogenic infrared radiance instrumentation for shuttle (CIRRIS 1A) during the sunlit terrestrial thermosphere. The four dominant contributions to the 5.3 &mgr;m emission are solar pumping, the inelastic collisions with O of NO(&ngr;=0), the reactions of N(2D) with O2, and the reactions of N(4S) with O2. The contribution to the chemiluminescence due to the reaction of N(4S) with O2 is calculated using the energy distribution function (EDF) of these atoms obtained by solving the time dependent Boltzmann equation. The calculated radiance is derived using two model atmospheres: (1) the model atmosphere obtained from the atmospheric ultraviolet radiance integrated code (AURIC) [Strickland et al., 1998> and (2) the model atmosphere obtained from the thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) [Roble and Ridley, 1994>. The calculated results reproduce gross features of the CIRRIS 1A observations, and disagreement by a factor of ~2 in the total band radiance calls for a fine tuning of the model atmospheres and/or the underlying phenomenology. The cooling of the atmosphere at high altitudes due to chemiluminescence from the reaction of N(4S) with O2 is found to be comparable to that due to collisions of NO with O. ¿ 1998 American Geophysical Union