Upper-Atmosphere-Density Determination Using NRL Artificial Satellites

摘要

NRL has had several artificial satellites placed in orbit for various experimental purposes. By observing the changes in orbital elements, it has been possible to calculate the density at the altitude range of 950 to 1160 km for the past 3 years. Long- and short-term effects are noted and discussed. A cyclical variation of 27 days has been found. It is apparently due to the variation in solar activity with the sun's rotation. The centers of activity appear to be stationary on the sun's surface for months at a time. (Author)