Coherently Cooperating Satellite Swarms for Autonomous In-orbit Operations
- Paper number
IAC-07-D1.4.04
- Author
Dr. Cristina Bramanti, European Space Agency (ESA), The Netherlands
- Coauthor
Dr. Dario Izzo, European Space Agency (ESA)/ESTEC, The Netherlands
- Coauthor
Dr. Jose Llorens, European Space Agency (ESA)/ESTEC, The Netherlands
- Year
2007
- Abstract
Recent trends in the space community for smaller, cheaper and more frequent space missions are driving the development of nano- and pico-spacecraft, which are considered for large constellations or swarm formations. In particular, the payload is distributed over multiple satellites belonging to the same mission. Swarms of separated elements cooperating coherently can be used to perform simultaneous scientific measurements of the space environment or implemented as large virtual, sparse apertures in space for high-resolution radar imagery of Earth, interferometry and high gain communications. Advantages of distributed constellations of micro-satellites over traditional single-satellite deployments include increased performance, redundancy and the possibility of reducing the overall cost, in term of launch cost and mission recovery by the substitution of a failed component. These improvements make the implementation of these swarm systems attractive as the functionality is spread over a number of cooperating satellites, thus enabling new missions which would not be possible with a single satellite. The challenges in controlling singularly a large number of elements are, though, enormous: the autonomy of the whole swarm is thus necessary. Swarm- intelligence is the scientific discipline that is expected to give an answer to this technological challenge. Multi-robot autonomous planetary exploration, on-orbit self-assembly, multiple coordinated observations (sensor-webs), are just examples of what could be achieved by the development of a flexible, robust, decentralised, and self-organized system exploiting collective emerging behaviours. The use of swarm robotics is also relevant for advanced mission architectures such as those recently studied by ESA (APIES mission) and NASA (ANTS mission) making use of satellite swarms to explore the asteroid belt or planetary surfaces. In the present paper we present the system design of a single collaborative -satellite swarm component and we analyse the various subsystems including power, propulsion, communication and the relative/absolute position sensors. We give a number of design options for the swarm element, associated to different performance levels, weights and dimensions. Possible in-orbit operations of the pico-satellite swarm architecture are then evaluated based on the Delta-V and the communications/sensing capabilities obtained as a result of the spacecraft system design. In particular, the operational phase is studied relying upon novel techniques based on swarm intelligence and behavioural robotics. These help to cope with the limited capabilities of a swarm element and thus to reach the required global swarm behaviour. Starting from the results achieved during the swarm element design and the in-orbit dynamical simulations, we critically argue on the feasibility of a number of applications recently proposed for in-orbit swarms.
- Abstract document