A DYNAMIC ATTITUDE TESTBED FOR CUBESATS

This work describes the development of a three degrees of freedom CubeSat attitude simulator testbed. To enable a reliable verification of attitude determination and control systems for nanosatellites, the environment of low Earth orbits with an almost disturbance-free rotational dynamics must be simulated. To this end, several subsystems have been developed and integrated: i) an air-bearing based, three degree of freedom platform with automatic balancing system ii) a Helmholtz cage for geomagnetic field simulation, iii) a Sun simulator, and iv) a metrology vision system for ground-truth attitude measurement. Apart of the Helmholtz cage, which is a COTS equipment, the other subsystems required substantial development effort, whose main outcome are: residual disturbance in the order of 10-5 Nm, attitude determination accuracy of the metrology system equal to 0.15° rms; divergence of the sun simulator light less than 0.2° in a 30cm diameter area. The commissioning phase of the facility is currently ongoing.