Optimal Passive Formation Reconfiguration Using Attitude Control and Perturbing Forces

This paper examines a Spacecraft Formation Flying Configuration that utilizes active attitude control to achieve passive translational control which satisfies the formation constraints. The JC2Sat Formation Flying Mission provides the major inspiration and motivation for this study. The active control will reorient the space- craft to vary the effect of the external forces from natural perturbations and as such achieve passive translational control. These perturbing forces include atmospheric drag and solar radiation pressure. The formations considered include the Projected Circular Formation and the General Circular Formation. In particular, the feasi- bility and the analysis of a transition from the former to the latter will be studied with both theoretical investigations and numerical simulations. Gravity Gradient Torque will add fidelity to previous studies to determine refined reconfiguration, as it can affect the attitude maneuvers of the satellites. Minimum-time recon- figuration maneuvers will be considered, since perturbation forces have a small intensity compared to the gravitational field forces. The minimum-time planning guarantees to exploit the effect of the perturbation forces at the maximum extent and to obtain reasonable maneuver times. The Inverse Dynamics Particle Swarm Optimization provides a fast and validated optimization solution. It is particularly suitable for the proposed problem as it eliminates a costly integration process dur- ing the non-linear attitude dynamic simulation. A small number of optimization parameters are required, satisfy ed attitude boundary conditions are guaranteed and B-spline curves are used to model the attitude kinematics of the satellites. For terrestrial missions, a successful implementation of these formation reconfigura- tions will increase future missions’ lifetime, reduce fuel consumption and utilize natural resources and perturbing forces. Moreover, this study lay the foundation for formation of orbiters at other celestial bodies where the environment is more conducive to these maneuvers.