Direct solar and earth-albedo radiation pressure effects on the orbit of Pageos 1

Abstract

The orbit of the Pageos 1 balloon satellite has been investigated in detail over the early part of the balloon's lifetime. The analysis herein focuses on how Pageos's orbit was affected by direct solar and albedo radiation pressure. Near the end of the second year of the satellite's lifetime, anomalous behavior was found in the orbital acceleration. This behavior may be the result of a change in the shape of the satellite: Pageos's original spherical shape had become slightly oblate, spinning about a minor axis and precessing about the direction to the sun. In fact, we have been able to represent this effect quite well by accounting for a small component of force in the plane perpendicular to the sun and allowing this component to rotate about the solar direction. By analyzing the balloon-inflation process, attained with sublimating compounds, and the consequent variation of the satellite's mass due to leakage through the holes caused by micrometeoroid bombardment, we have evaluated the near-earth micrometeoroid-particle flux, which turns out to be 5×10⁻⁸ cm⁻² sec⁻¹. With the assumptions we made for the satellite's area-to-mass ratio and reflection coefficient, we would need a solar constant of 1.95 cal cm⁻² min⁻¹ to give a best-fit to our data.