What is Low Earth Orbit

This chapter introduces the challenge of space debris and the concepts of on-orbit servicing and active debris removal. The evolution of the debris population is put into a historical perspective, observation and modelling methods are described, and internationally agreed mitigation strategies are briefly introduced. Proposed mission types and the required technologies for servicing and removal activities are detailed and their challenges explained. Where applicable, past, current, and proposed activities are summarized to illustrate the concepts.