Simulation of resident space objects detection from space-based optical imaging

Abstract

The United States Space Surveillance Network catalogs around 23,000 Resident Space Objects (RSOs). The completeness of their coverage of the true RSO population decreases gradually with object size and radar reflectivity. While the population of cm level space debris is poorly represented in the catalogs these space bullets can cause severe damage to satellites and spacecrafts in addition to being likely much more numerous than larger pieces. This research project focuses on the ability to peek into this debris population using space-based high sensitivity, fast frame rate, wide field visible imaging from low Earth orbit. The simulator developed focuses on a LEO to LEO (sensor to RSO) scenario and the capacity to constrain their orbit trajectory. In the Matlab simulator, a simple specular/diffuse sphere model is used for the debris in order to generate the object’s apparent magnitude for any sun-debris-observer arrangement. Satellite and debris relative velocities and orbits are also considered in order to determine the length of the streak left by the debris on any given exposure sequence and the number of photons per pixel. The exact timing, position, length and orientation of the streak contains information constraining the object’s orbit. The generation of representative star backgrounds matched to the sensor high sensitivity is also an important part of the simulator since it affects the effective limiting sensitivity to faint transiting source. This simulator allows us to trade various sensor parameters in order to optimize the camera design. The conclusion from this work contribute to the global effort in Space Situational Awareness (SSA) by assessing the impact of including space based optical imagery in the detection mix.