Debris Avoidance through Autonomous Spacecraft Scattering

In recent years, a small but growing number of space missions have emerged utilizing distributed systems of satellites. It has been proposed that to both improve reliability and increase the return of scientific data, many near Earth and deep space missions could make use of multiple-use, low cost, cooperative spacecraft flying in formation. Examples of such missions include the TICS and F6 initiatives at DARPA. The former initiative envisions swarms of small satellites that can later combine in space to form larger systems capable of performing various sensing and servicing missions. The latter initiative seeks to distribute the function (payload) across a number of small spacecraft. Both approaches are currently considered as highly viable as they would enhance the robustness and survivability of space systems, while shortening development time. With the increase in space activity, the risk of collision with space debris is becoming a very significant issue. In this study, we present a method by which a cluster of spacecraft can perform an energy efficient scatter and re-gather manoeuvre to rapidly avoid collision with space debris. It is intended that this evasive action will be initiated without reference to any control external to the swarm making the threat response rapid and robust. The relative orbit dynamics are modelled as a discrete, linear time-invariant system. The avoidance manoeuvres are planned by using a mixed integer programming technique. Different spacecraft formation configurations, such as the elliptical formation and in-plane formation, are considered. The simulation results are validated using STK software.