ORBITAL EVOLUTION OF HIGH-ALTITUDE BALLOON SATELLITES

We investigate the motion of artificial satellites with large area-to- mass ratios in high-altitude low inclined orbits, perturbed simultaneo usly by solar radiation pressure and Earth's oblateness. Our study is based on recent theoretical advances in circumplanetary dust dynamics (Hamilton & Krivov 1996). Applying these methods to the motion of ball oon satellites, we write down and analyze the orbit-averaged equations of motion in planar approximation. Contrary to many previous works, o ur consideration imposes no restrictions on eccentricities and radiati on pressure strengths. The results show how the eccentricity and apses line of a satellite orbit evolve with time for various area-to-mass r atios, geocentric distances, and initial data. Our special interest is with complicated dynamical effects arising from the two perturbing fo rces above. We demonstrate the possibility of dramatic orbital changes under small variations of initial data and force parameters. For typi cal balloon satellite parameters, these unusual effects may take place at altitudes between one and two Earth's radii.