A model developed for the aeronomy of odd nitrogen in the thermosphere is used to analyze rocket measurements of N(4S) NO densities. Data from Atmosphere Explorer were used to develop a consistent reaction kinetics model for odd nitrogen chemistry. We conclude that most NO dissociative recombination events must produce N(2D) is quenched by O at a rate of 1¿1012 cm3S-1, and that the atmospheric O2 quenching rate at N(2D) is consistent with the laboratory rate. The major quenching agent of N(2D) between 140 and 220 km is atomic oxygen, and this reaction is the major source of N(4S). We predict peak N(4S) densities of ? (2-6) ¿107 cm--3 140-150 km, with the variability being indicative of the model sensitivity to a factor of 2 change in the O/O2 ratio in the thermosphere.