Steered spacecraft deployment using interspacecraft Coulomb forces

Recent work has shown that Coulomb forces can be used to maintain fixed-shape formations of spacecraft at high Earth altitudes with practical charging requirements. These formations require a careful balance between the intercraft forces and the relative orbital dynamics. While nearly propellantless, the resulting dynamic equations are nonlinear, and result in a challenging control system design problem. This paper explores a different Coulomb force application where a chief satellite deploys deputy craft to specified end states. By using multiple charge surfaces on the chief, a linear control design approach can be used while guaranteeing reachability for one deputy. This is extended to simultaneous, multiple deputy deployment by modulating control authority across the formation. A 3 deputy example is presented to illustrate the approach where Debye length plasma shielding is considered. This example shows that 1 meter diameter craft can be deployed to a 30 meter, circular projected formation in geostationary orbit in approximately 2 orbits with a maximum of 20 kilovolts on the charge surfaces