ABSTRACT
This chapter provides a summary of existing publications on satellite constellations and mega-constellations with their features and problems. These include proper management, using onboard intelligence, providing replacement, issues of effective communications which may be optical, complexity of ground antennas and gateways to monitor low orbit satellites, and also the increase of space debris by constellation units if not de-orbited at the end of service or after failure. The chapter briefs about some defense projects with multiple satellites in space such as Strategic Defense Initiative of the eighties, and the most recent SDA’s Next-Generation Space Architecture. Commercial activity and projects are reviewed too. A summary on the debris problems and existing solutions is provided with mention of legal questions of junk removal, debris surveillance and tracking, already existing removal contracts and techniques, as well as first removal missions. It also stresses the need for a unified system approach for dealing with different types of satellite constellations, especially in LEO orbits.
