Dynamics and control of electromagnetic satellite formations

Satellite formation flying is an enabling technology for many space missions, especially for space based telescopes. Electromagnetic formation flying (EMFF) is a novel concept that uses superconducting electromagnetic coils to provide forces and torques between different satellites in a formation. With EMFF the life-span of the mission becomes independent of the fuel. This comes at the cost of coupled and highly nonlinear dynamics of the formation and makes the control problem a challenging one. In this paper the dynamics for a general n-satellite electromagnetic formation (in 2D) is derived for deep space missions and then a non-linear control law using potential functions for the formation control and reconfiguration with collision avoidance is discussed. For EMFF formation reconfiguration problem is an optimal time problem as fuel cost for EMFF is zero. A framework for computing optimal time trajectories of electromagnetic formations is also presented. Specifically it is shown that an n-satellite electromagnetic formation can be stabilized under fairly general assumptions, therefore, showing the viability of this novel approach for satellite formation flying from dynamics and controls perspective.