Space-Object Charging and Its Effect on Orbit Evolution

Abstract

With the increasing number of uncontrolled objects in the space environment surrounding Earth, it has become important to keep track of the orbits of these objects so as to avoid collisions with active space assets. Because of the continuous bombardment of plasma particles, a space object is often subject to charging. One of the forces affecting the trajectory of a space object is the Lorentz force, which acts when a charged body moves through Earth’s magnetosphere. Correct modeling of Lorentz force requires correct modeling of magnetosphere and the body charge, which in turn depends on correct modeling of body currents, space plasma environment, and body capacitance. This research focuses on modeling of in-space charging for space objects, which are modeled as spherical conductors. Simulations incorporating Lorentz force as an additional perturbation force to Earth’s gravity have been run to evaluate the propagation of low-area-to-mass-ratio and high-area-to-mass-ratio objects in geosynchronous and low Earth orbits. Trends in the evolution of in-track, cross-track, and radial perturbations due to Lorentz force over a four-day period are investigated. It is found that, for a low-area-to-mass-ratio object in low Earth orbit, in-track perturbations due to Lorentz force can reach an order of decimeter in a mere four-day period under high-charge plasma conditions. A high-area-to-mass-ratio object in geosynchronous orbit can exhibit decimeter level in-track perturbations under high-charge plasma conditions during the same period.