Prisma

From 2010 to 2012, the two satellites on the PRISMA orbital technology demonstrator mission tested a range of autonomous formation-flying and rendezvous technologies.

Funded by the Swedish National Space Board (SNSB), the PRISMA mission was conducted in partnership with Denmark, France and Germany. Its 2 satellites, named Mango and Tango, were launched on 15 June 2010 by a Dnepr vehicle from the Yasny launch base in Russia. For 2½ years, the 140-kg Mango principal satellite repeatedly approached and receded from the 40-kg Tango target satellite.

From 28 October 2010, CNES took control of Mango for a total of 30 days to perform the FFIORD experiment (Formation Flying In Orbit Ranging Demonstration), designed to validate manoeuvres for satellite separation distances from 10 km down to 50 m. The relative position of the 2 satellites was measured by radiofrequency sensors developed by Thales Alenia Space and GMV with funding from CNES and Spain. Mango’s autonomous movements were controlled by navigation and guidance algorithms developed by CNES.

From November 2011 to September 2012, CNES performed a series of additional experiments, including vision-based rendezvous, short-distance transitioning from radiofrequency control to close optical control, and reconfiguration and formation-maintaining manoeuvres representative of a Universe science mission. The last experiment—to rendezvous with a non-cooperative target, the PICARD satellite—unfortunately had to be scrubbed before final approach when fuel ran out.

The diverse range of operations performed by PRISMA and the FFIORD experiment has significantly advanced in-orbit validation of formation flying and orbital rendezvous techniques, working within very tight schedule and cost constraints