Space Debris - Propagation, Prediction and Removal

Since the launch of the first satellite (Sputnik 1) in 1957, humans have created a lot of objects in orbit around Earth. The number of space objects larger than 10 cm is presently approaching 21,000, the estimated population of objects between 1 and 10cm is about 500,000, and for objects smaller than 1cm the number exceeds 100 million. With the rush of global satellite communication companies into space, the technical advances of miniaturized satellites, and new concepts of satellites such as autonomous nanosatellite swarms, both the number of space objects and the number of conflicts between these objects are increasing exponentially. Our ability to generate accurate and timely predictions of the trajectory of a space object is the cornerstone of many current and future Space Situation Awareness (SSA) systems. In this talk, we will first discuss the space sustainability challenge raised by space debris. We will then use the 2009 collision of a U.S. Iridium communications satellite and a Russian Cosmos 2251 communications satellite as an example to illustrate the limitations of the existing methods for orbit propagation and prediction. Last, we will discuss a few proposed approaches for space debris removal.