The Ultraviolet Limb Imaging (UVLIM) experiment flew on STS-39 in the spring of 1991 to observe the Earth's thermospheric airglow and included a far ultraviolet (1080-1800 ¿) spectrometer. We present first results from this spectrometer, including a spectroscopic analysis at 6-¿ resolution of H, O, N, and N2 dayglow emissions and modeling of the observed limb-scan profiles of dayglow emissions. The observed N2 Lyman-Birge-Hopfield (LBH) emission reflects a vibrational population distribution in the a1IIg state that differs significantly from those predicted for a direct electron excitation and excitation with cascade from the a' 1∑-u and w1Δu states. The vibrational population distribution and LBH brightness suggest a total cascade rate 45% that of direct excitation, in contrast to laboratory measurements. For the first time, pronounced limb brightening is observed in both the NI&lgr;1135 and NI&lgr;1200 limb emission profiles, as expected for emissions excited by N2 dissociation which produces kinetically fast N fragments; however, optically thick components of these features are also observed. Preliminary modeling of the OI&lgr;1356, HI&lgr;1216, and OI&lgr;1304 and OI&lgr;1641 emissions agrees to within roughly 10% of the observed limb-scan profiles, but the models underestimate the N2 LBH profiles by a factor of 1.4-1.6, consistent with the inferred cascade effect. Other findings include: an OI&lgr;1152/&lgr;1356 intensity ratio that is inconsistent with the large cascade contribution to OI&lgr;1356 from np 5P states required by laboratory and nightglow observations; nightglow observations of the tropical ultraviolet arcs exhibit a wide range of OI&lgr;1356/&eegr;1304 intensity ratios and illustrate the complicated observing geometry and radiative transfer effects that must be modeled; and we find a 3-&sgr; upper limit of 8.5 R to the total LBH vehicle glow emission. ¿ American Geophysical Union 1994