Impact of Electrostatic Perturbations on Proximity Operations in High Earth Orbits

Abstract

A range of upcoming missions propose to rendezvous in high Earth orbits, including the geostationary orbit region. This region is known to periodically experience high levels of electrostatic charging, which can result in perturbing intercraft forces and torques during close-proximity operations on the order of tens of meters. A range of proximity operations with a nonoperational target are modeled to evaluate the impact of electrostatic force and torque perturbations as a result of spacecraft charging. Perturbing electrostatic torques are evaluated using the multisphere method and result in the target body rotating, requiring the servicer to maintain its relative position by translation. Electrostatic perturbations are found to be significant, with potentials on the order of 1000 V resulting in larger perturbing torques than solar radiation pressure for this model. Electrostatic perturbations exist even in cases where both spacecraft are at the same potential. Record charging conditions lead to target rotational rates over during a nominal rendezvous. Target rotations require increases in fuel consumption for rendezvous and proximity operations, over 10 times more than a solar radiation pressure-induced torque, and present additional challenges associated with maneuvering in proximity to a tumbling target in a highly coupled and nonlinear dynamic environment.