A Robust Framework for Low-Cost Cubesat Scientific Missions

Cubesats have been effective at lowering the barriers for entry to space for educational institutions and small private players resulting in new and innovative missions and concepts. Novel, potentially powerful, space science projects such as QB50 can now be undertaken with limited budgets and resources. However, the failure rate of Cubesats has been quite high with many failing to establish any communications at all, leaving little opportunity for teams to debug and recover the satellite. Due to the time and cost restrictions faced by Cubesat projects, traditional verification and validation testing processes are not feasible, giving rise to the high failure rate. In this paper, we describe the experience gained during the development, launch and operation of the UNSW-EC0 Cubesat, which was deployed in 2017 as part of the QB50 mission. In particular, we present a robust framework derived from Failure Mitigation Effects and Criticality Analysis (FMECA) for Cubesat testing that is practical for typically resource and time constrained missions. We also describe robustness testing performed during development combined with additional functionality that was built into the satellite, which allowed in-orbit troubleshooting and mission recovery. Following its recovery, UNSW-EC0 was able to perform nominally for the remaining duration of its lifetime. Some preliminary in orbit mission results are also described in the paper. Two UNSW-built Single Event Upset (SEU) resistant experiments as well as the RAMSES payload successfully demonstrated long endurance operations in orbit.