Extension of low-thrust propulsion to the autonomous coplanar circular restricted four body problem with application to future Trojan Asteroid missions

An Autonomous Coplanar Circular Restricted Four Body Problem (CRFBP) is considered, where the massless body is a low-thrust spacecraft. 'Natural' and 'artificial' (i.e. created with the use of continuous low-thrust propulsion) equilibrium solutions are identified, that have the potential to be exploited in future science missions. Results show that, with zero thrust, there are unstable equilibrium points close to the third primary. However, artificial equilibrium points, displaced from the natural ones, can be generated with the use of constant low-thrust. Furthermore, these points are proved to be stable in certain regions about the third primary mass. This is particularly advantageous since it means that it would be possible to continuously maintain a spacecraft about these strategic observation points, close to the smaller primary, without the need for state feedback control. The Sun-Jupiter-Trojan Asteroid-Spacecraft system is considered, as a particular case of the Autonomous Coplanar CRFBP. Curves of artificial equilibrium points are then identified. Furthermore, the stability analysis of these points reveals the region where they are stable. In this region four bounded orbits close to the Asteroid are proved to exist, that can be reached and maintained with a constant low-thrust lower than 10µN.