Seasonal Illumination of a Circumpolar Earth Satellite at its Extreme-Latitude Orbit Point

Abstract

OPTICAL tracking of Earth satellites is the only means of determining their motion with such precision as to render measurements of air density significant. This, however, can only be done when the satellite is sunlit, considering that a flashing beacon (which has been suggested) would relatively quickly run out of power. I shall discuss the insolation of Earth satellites revolving on orbits similar to those of the Russian Sputnik.