Satellite dynamics about small bodies: Averaged solar radiation pressure effects

The effect of the solar radiation pressure force on a spacecraft orbiting a small body (asteroid or comet) is analyzed for the general case when the small body is in an elliptic orbit about the Sun and the spacecraft is in a relatively close orbit to the small body. The effect of this force is parameterized in terms of the spacecraft mass, spacecraft surface area. exposed to the Sun, the small body mass, and the small body orbit about the Sun. Constraints and general results on orbit dynamics are presented and discussed for the averaged solar radiation pressure effect. These solutions an seen to be integrable and a function only of the small body true anomaly. Four families of stable, frozen, Sun-synchronous orbits close to the small body are found, all for the case of elliptic motion of the small body about the Sun. Such orbits have applications for extended station-keeping at a small body or for mission operations when the solar radiation pressure effect is large. Specific results for the NEAR spacecraft at asteroid 433 Eros and the Rosetta spacecraft at comet Wirtanen are given.