Fault-Tolerant and Deterministic Flight-Software System For a High Performance CubeSat

We describe the design and implementation of a complete flight-software operating system (OS) for a high-performance CubeSat carrying a third-party payload. This CubeSat's mission is to carry out research experiments on this payload while in low earth orbit. These experiments may be specified and prepared on the ground while the CubeSat is already in flight, and later uploaded via communication link. Experimental results collected by the CubeSat may likewise be downloaded to the ground. The CubeSat must collect and respond to sensor telemetry every second, and respond to ground communication on demand. To survive an adversarial space environment, the CubeSat OS is implemented as a deterministic state machine, storing state in a fault tolerant global memory structure. We validate our system via an end to end test of the CubeSat with its ground station, and demonstrate its capability to tolerate and even actively mitigate potential faults resulting from space radiation.