Performance of a Proposed Instrument for Space-Based Optical Observations of Space Debris

In 2003, the European Space Agency (ESA) initiated a study entitled "Space-Based Optical Observation of Space Debris" in order to investigat e means that would allow closing the knowledge gap for small-sized space debris objects. The study defined user requirements, developed an observation strategy for a space-based in trument capable of observing uncatalogued small-sized debris objects, and finally pres ented an instrument architecture and an operations concept for the passive optical observatio n of space debris objects in Low-Earth Orbit (LEO) and Geostationary Orbit (GEO). The object de ection will be carried out on-board, while the astrometric reduction, orbit determinatio n, and estimation of the size of objects are part of the on-ground processing. First orbits must be determined from a single observed crossing through the field of view. The proposed in strument combines a 20 cm aperture folded Schmidt telescope and a four megapixel, fast read-out camera using either a frametransfer charge coupled device or a hybrid visible silicon imager sensor. This paper focuses on the detailed estimation of the system performanc e of that proposed instrument. We discuss the observable objects using the statistical refere nce population from ESA's MASTER-2005 model, as well as the main parameters that limit th e possibility of the detection of objects. Based on simulations we evaluate the proposed objec t detection algorithm and the orbit determination. We conclude that in LEO ground-based r ada s are theoretically superior, but due to their limited availability a space-based system could still contribute significantly to the monitoring of the space debris environment. At GEO altitude the system could enhance the knowledge by decreasing the minimum object size fro m about 15 cm to less than 5 cm. The proposed instrument would allow improving the knowl edge of the uncatalogued small-sized space debris population in LEO and GEO by using a s imple instrument design and a straightforward processing strategy.