Delfi-C³ Autonomous Wireless Sun Sensor Payload

Delfi-C³ houses two sun sensors from TNO (www.tno.nl) which are fully autonomous and wireless. With the typical internal volume of a nanosatellite already being quite limited, reducing wiring is an important challenge. The sensors have a half-sized GaAs solar cell as an independent power supply. This autonomy is accompanied by a wireless radio frequency link. This link is an adapted commercial off-the-shelf transceiver, operating in the 915 MHz band.

Although wireless data communication on board such small satellites might seem a bit superfluous in itself, implementing this technology adds to modularity and results in a flexible “plug and play” system. The autonomous sensor unit, in this case measuring approximately 60x40x20 mm, is a predecessor of an even smaller digital version that can be mounted on e.g. a solar panel.

The in orbit experiment concentrates on demonstrating the feasibility of the wireless link (immunity for disturbances; no interference with other equipment) and the operation of the sun sensor under variable power supply. Of one sensor many data has been gathered and analysed. It has proven to work as expected, demonstrating the feasibility of this concept. As such, the experiment is succesfull. The other sensor has never been heard, also during exciting and unique attempts to listen to it directly using high end space telescopes as described in a paper.

Key results have been published in a paper: C.W. de Boom, et. al., In Orbit Experience of TNO Sun Sensors, Proceedings of the 8th ESA Conference on Guidance, Navigation and Control Systems, Carlsbad, Czech Republic, 2011.