Sweden's formation-flying satellite technology mission, Prisma, has passed its critical design review, but still faces the possibility of delays. To be launched in 2008 or 2009, probably by a Russian Kosmostras Dnepr rocket, Prisma will use two spacecraft to test guidance, navigation and control for rendezvous and formation flying.

The two small satellites are the 140kg (310lb) Main spacecraft and 40kg Target vehicle. Main will manoeuvre to dock with Target, although they will be launched in a docked configuration. Prisma technology will be useful for future missions such as ESA's extraterrestrial planet finder Darwin.

Although the review concluded that Prisma's overall design was mature, its programme management expects an Alcatel-developed radio-frequency instrument funded by French space agency CNES to be a potential source of delay. Other possible sources of delays are radio and software issues.

"We have not defined all the software requirements [and] the inter-satellite radio link for formation flying. We have not tested it and that is a weak point," says Swedish Space programme manager Staffon Persson. Swedish Space is Prisma prime contractor for the Swedish National Space Board. He expects the software issues to be dealt with in the second quarter, and for the team to begin mechanical integration of the Prisma flight unit by June, with the electronics to be added in September.

UK company Surrey Satellite Technology (SSTL) has won a €2.28 million ($3 million) Advanced Research in Telecommunications Systems-4 contract from the European Space Agency to progress its Geostationary Minisatellite Platform, which began under the British National Space Centre's (BNSC) Micro Satellite Applications in Collaboration programme. That BNSC programme enabled SSTL to develop the successful Galileo In-Orbit Validation-A satellite.

Source: Flight International