Perturbations of the Orbit of the Echo Balloon

Science  18 Nov 1960:
Vol. 132, Issue 3438, pp. 1484-1486
DOI: 10.1126/science.132.3438.1484


The motion of the Project Echo communications satellite during its first 12 days clearly confirms previous predictions of the influence of solar radiation pressure. During this time, solar pressure reduced perigee height by 44 km. The approximate value of 1.1 X 101 g/cm5 has been obtained for the average air density at the 1600-km altitude of the satellite.