Rendezvous Approach Guidance for Uncooperative Tumbling Satellites

The development of a Rendezvous and Proximity Operations (RPO) guidance algorithm for approaching uncooperative tumbling satellites has multiple purposes including on-orbit satellite servicing, space debris removal, asteroid mining, and on-orbit assembly. This paper develops a guidance algorithm within the framework of on-orbit satellite servicing, but is extendable to other mission scenarios. The author tests the algorithm in an RPO simulation with an uncooperative tumbling satellite near Geostationary Orbit (GEO) starting at a relative distance of 50 m and ending at a relative distance of 5 m. Due to the low Technology Readiness Level (TRL) of autonomous (RPO) missions, first missions prefer to use flight proven technologies. This paper implements a guidance algorithm based on the flight proven Clohessy-Wiltshire (CW) and space shuttle glideslope equations which command a sequence of burns to close the distance between the servicer and client while matching the client satellite's rotation rate. The author validates the guidance algorithm through Monte Carlo (MC) analysis in a Three Degrees of Freedom (3DOF) simulation. Fuel use metrics characterize the sensitivity of the algorithm. Fuel consumption is measured by the total velocity changes, or ΔV, needed to complete the maneuvers. Cumulative ΔV sensitivity is measured against navigational uncertainty in the rotational axis to summarize the key requirements and trade-offs associated with implementing this algorithm.