Optimizing orbital debris monitoring with optical telescopes

Continued growth in the orbital debris population has renewed concerns over the long-term use of space. Debris poses an increasing risk to manned space missions and operational satellites; however, the majority of debris large enough to cause catastrophic damage is not being tracked and maintained in a catalog. Passive optical systems hold great promise to provide a cost-effective means to monitor orbital debris. Recent advances in optical system design, detectors and image processing have enabled new capabilities. This work examines the performance of optical systems operating in a fixed or non-tracking mode for uncued debris detection. The governing radiometric equations for sensing orbital debris are developed, illustrating the performance dependencies according to the telescope optics, detector, atmosphere and debris properties. The governing equations are exercised by examining three debris monitoring scenarios: commonly used ground-based systems monitoring the geosynchronous orbit (GEO), a novel approach for using ground-based telescopes to monitor low earth orbit (LEO), and finally systems such as star trackers and small cameras hosted on GEObased satellites for monitoring GEO. Performance analysis indicates significant potential contributions of these systems as a cost-effective means for monitoring the growing debris population—this is particularly true for small aperture ground-based telescopes for monitoring LEO and GEO-based sensors monitoring GEO.