CubeSat mission design based on a systems engineering approach

With the exception of the CubeSat specification, CubeSat design and development approaches have been mostly ad hoc, which has questioned their reliability. A systems engineering approach, based on the guidelines of NASA´s Systems Engineering Handbook has been developed for CubeSats to facilitate systematic design, development and address their reliability, traceability, and reusability. The CubeSat systems engineering approach, developed as a repeatable process, uses a top-down design methodology to translate mission definitions into basic building blocks, components, interfaces and tasks, that then facilitate a bottom-up development and fabrication process. Some of the design tools (e.g., N2 diagram) described in NASAs Systems Engineering Handbook are utilized early in the design phase to identify potential conflicts in the mechanical and electrical interfaces. A novel subsystem level flowdown, which transcribes the system level requirements into identifiable CubeSat subsystems, (i.e., building blocks) is described. Utilizing this approach yields full traceability from mission concept to subsystem component to flight software. Additionally, the approach facilitates the estimation of the mission overhead in terms of power, telemetry, and computation associated with each component, interface, and task.