Touchless Potential Sensing of Differentially Charged Spacecraft Using X-Rays

Abstract

A method has been proposed to estimate the electric potential of co-orbiting spacecraft remotely using x-rays that are excited by an electron beam. Prior work focused on the theoretical foundation and experimental validation of this approach using flat target plates. Although useful for concept validation, flat plates do not adequately represent the shape of spacecraft and the resulting complex particle dynamics. Additionally, all previous experiments employed fully conducting test objects, but it is not always possible to connect every spacecraft component to one common electric ground. This paper experimentally investigates the remote electrostatic potential estimation of objects with complex shapes and differentially charged components using x-rays. A particle tracing simulation framework is used to assist the interpretation of experimental results. The results show that the orientation of the target determines the areas irradiated by the electron beam and the detectability of different components. A new procedure is proposed to enable the simultaneous measurement of multiple potentials using a single x-ray spectrum, and dynamic experiments with a rotating target object are conducted to validate this method. The results of these dynamic experiments demonstrate that it is possible to estimate two potentials simultaneously with the support from theoretical x-ray models.