SpaceWire communications in power over ethernet environment

Abstract

This is a high-level study into the validation of a unified electric power and communications architecture for modern spacecraft systems. We leverage from blending the European Cooperation for Space Standardisation (ECSS) SpaceWire and the IEEE 802.3 Power over Ethernet (PoE) standards for a common onboard power and communications interface. The focus of the work has been communication performance. The requirements from the protocols of both standards were analysed and combined to create a full protocol stack for SpaceWire PoE. The stack is implemented on an embedded platform represented as a proof-of-concept SpaceWire PoE system. The results of functional testing demonstrate SpaceWire PoE as a valid solution that meets the requirements of both protocols. For the 100 Mb/s links, the SpaceWire PoE throughput is on a par (97.39%) with Ethernet (97.52%) and SpaceWire (99.2%). Shared communication and power architecture is intended for decentralised operation achieving greater autonomy of the integrated subsystems. This potentially may lead to standardisation of electrical, mechanical and communication interfaces across spacecraft subsystem manufacturers, easing harness complexity and routing during the assembly, integration and test (AIT) phase of the spacecraft as well as saving mass and launch cost.