Collective Systems in Space and for Planetary Explorations

In an issue of the Wireless World magazine, back in 1945, A. C. Clarke on a letter to the editor wrote " However, I would like to close by mentioning a possibility of the remote future-perhaps half a century ahead... Three repeater stations, twelve degrees apart in the correct orbit, could give television and microwave coverage to the entire planet. " These words envisioned, before the space era even started, the now overcrowded geostationary orbit, while also introducing one of the most lucrative commercial applications of the space business: telecommunications. It is worth noting in this context, how this early space mission concept made use of multiple satellites to achieve its goal. Twenty years later, the space era actually begun with the successful launch of the Russian satellite Sputnik I. In the following years, many missions have been proposed, designed and realized that make use of multiple satellites, probes, planetary rovers, robots or, in general, of what can be called " space agents " to underline the connection to multi-agent-systems research. The European Space Agency (ESA) mission named Cluster II, currently orbiting around our planet, is made of four identical satellites that need to accurately fly in a tetrahedron formation during part of their orbit. This particular geometry allows for the determination of three-dimensional and time-varying phenomena related to the Earth's magnetic field. Several satellite constellations, among which the currently active GPS, Globastar and Iridium, but also the planned European Galileo and Swarm constellation are formed of many identical spacecrafts (up to 50) that achieve a common overall objective thanks to complex orbital and communication strategies. The Teledesic innovative and ambitious project (involving contributions from Bill Gates and Paul Allen, but canceled in 2001) considered, at a certain point, to employ 840 active identical satellites orbiting around the Earth