The Triad Satellite is maintained in a purely gravitational orbit by the disturbance compensation system (Discos) on the central body of the satellite. Discos consists of small metal ball (the 'proof mass') surrounded by position sensors and an outer shell which holds fuel tanks and cold gas jets. The outer shell shields the proof mass from nongravitational forces. Whenever the outer shell is displaced in relation to the proof mass by 1 mm, the gas jets fire to recenter the outer shell. For 6 days during the period September 14--19, 1972, the position of the proof mass relative to the shell was telemetered to earth and recorded whenever the satellite was visible from the receiving station in Mayland. Local atmospheric densities near 800 km have been measured for the first time by using the ball position data. The observed accelerations have been corrected for the effects of solar radiation pressure. The measured densities reveal a greater dependence on latitude than the indicated by balloon satellites, whose measurements involve more averaging over latitude and longitude. The Triad results also exhibit a dependence on longitude in the limited number of measurements available. However only a small dependence on the index of geomagnetic activity Kp was observed in the localized region in which the measurements were made.