Design of Command, Data and Telemetry Handling System for a Distributed Computing Architecture CubeSat

Among the size, weight and power constraints imposed by the CubeSat specification, the limitation associated with power can be addressed through a distributed computing architecture. This paper describes such a distributed computing architecture and its operational design in the form of command and data handling system and telemetry formulation, adapted for a CubeSat whose power requirements for proving the mission are significantly larger than the on-orbit average power generated. The 1U CubeSat with the mission objective of precision three axes attitude control is composed of a low power flight computer and a high power, high speed auxiliary processor (CMG controller), along with a high capacity battery. The precision sensors, actuators and complex computing algorithms, are interfaced and implemented on the high speed auxiliary processor, which is operated intermittently. Health monitoring sensors, transceiver and other housekeeping tasks are interfaced and implemented on the flight computer, which is in continuous operation. To facilitate effective operation and telemetry packaging, each computing unit is designed to host a storage device. The flight software, designed as operating modes, is distributed across the two computing platforms. Distributed operations are initiated through the flight computer and executed on the auxiliary processor. The paper describes in detail the distributed design of these operating modes as flowcharts and the associated telemetry budget as tables.