The upper atmosphere composition spectrometer (UACS) was flown on the Department of defense Space Test Program mission S85-1. UACS was designed to measure neutral composition, temperature, and the in-track wind component in the lower thermosphere. In the high inclination orbit of S85-1, UACS measured the meridional component of wind at all but the highest latitudes. While techniques to measure cross-track neutral wind have been successfully demonstrated by other investigators, in situ measurements of the in-track wind component have not been published before. UACS obtained a small but significant set of wind data for 2 days in July 1984 at altitudes between 200 and 235 km, at local solar times of 1030 and 2230 hours. The measured winds compare favorably with published results from ground-based incoherent scatter radar and Fabry-Perot interferometer experiments and with satellite-based cross-track measurements of the meridional wind. ¿ American Geophysical Union 1988