Satellite formation flying

Systems of satellites orbiting in formation benefit from being more robust, simpler and cheaper to implement, because the functionality of a satellite's systems can be distributed amongst small, redundant members that can (if necessary) be progressively launched and assembled.
The A-Train
Credit: NASA

Simultaneously, the capability of tiny satellites is rapidly increasing. Cubesats (small 10x10x10 cm 1+ kg, or multiples thereof) are inexpensive to acquire/build/launch, and are being routinely flown in Low Earth Orbit. They are moving from educational “toys” – the domain of student groups – to accepted options for both the scientific and commercial sectors for conducting space activity. The challenge is now to develop capability to fly such tiny satellites in formations or swarms, with sensors distributed across the multiple platforms, enabling remote sensing, Space Situational Awareness, astronomy, space science, and other activities to be achieved with greater agility and at a fraction of the cost of traditional large satellite platforms. UNSW Canberra will tackle this challenge of moving into top-level space-based research and engineering, and in so doing play a leading role worldwide in the future of space technology.

In particular, alongside capability-building for acquiring, adding innovation to, testing and (post-launch) operating cubesats, UNSW is developing algorithms for formation flying guidance, navigation and control (GNC); inter-satellite communications; data fusion from on-board sensors across formations; and capability to develop and test such technologies in the context of the inaccuracies, biases and potential failures (in the space environment) inherent in real sensors and systems.

For the SSA formation flight, in which different aerodynamic shapes will be deployed and their relative motion accurately measured, formation control (via onboard position control) may be beyond the scope of the mission other than through control via differential drag. However, that flight will offer the opportunity for flight-testing aspects of GNC algorithms, inter-satellite communications and on-board processing for data fusion from distributed sensors.