SpaceFibre is a multi-Gbits/s, on-board network technology for spaceflight applications, which runs over electrical or fibre-optic cables. It complements the capabilities of the widely used SpaceWire on-board networking standard: improving the data rate by a factor of 10, reducing the cable mass by a factor of two and providing quality of service (QoS) and fault detection, isolation and recovery (FDIR) capabilities. Multi-laning improves the data-rate further to well over 20 Gbits/s. SpaceFibre is able to fulfil a wide range of spacecraft on-board communications applications because of its inbuilt QoS and FDIR capabilities.
SpaceFibre incorporates quality of service (QoS) using virtual channels to provide multiple independent communication channels over a single physical link. Each channel provides priority, bandwidth reservation and scheduled QoS. These QoS mechanisms operate together resulting in very versatile QoS and providing “babbling node” protection and scheduled, deterministic communication without wasting any network bandwidth.
Fault detection, isolation and recovery (FDIR) support is integrated in SpaceFibre, detecting, isolating and recovering from faults in the link where they occur, which prevents faults from propagating and causing further errors. The FDIR capability of SpaceFibre provides transparent recovery from transient errors.
Low latency broadcast messages are provided in SpaceFibre which enable the rapid signalling of events, reporting of errors, and distributing of system time information.
Very importantly SpaceFibre has been designed to be compatible with SpaceWire at packet level, which means that existing SpaceWire equipment can be readily integrated into a SpaceFibre network without modification to that equipment. A simple bridge connecting a SpaceWire interface to a SpaceFibre virtual channel is all that is necessary, and the SpaceWire traffic flowing over a SpaceFibre virtual channel gains the QoS and FDIR characteristics that SpaceFibre provides.
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Benefits of SpaceFibre
SpaceFibre brings many benefits to spacecraft on-board data handling systems:
- Very high data rates that meet the needs of very demanding instruments, mass-memory internal networks, and telecommunications systems;
- Reduction of harness mass by 33% and 50% when comparing the mass of a single SpaceWire cable to SpaceFibre electrical and fibre optic cables respectively, and by more than 90% when comparing per bit transferred;
- Simplification of redundancy though integration of several on-board communication functions into a single network, and through the carrying of the traffic of multiple SpaceWire links over a single SpaceFibre link;
- Increase in reliability by requiring one network rather than two or three to carry out the necessary on-board communication functions;
- Straightforward error recovery since transient errors are recovered on the link and do not need to be considered at the system level;
- Deterministic data delivery enabling AOCS/GNC and other control applications to be supported;
- Long distance communication enabling launcher application to be considered, where a single network can provide control, monitoring and video capture functions;
- Galvanic isolation improving system robustness by preventing fault propagation.
SpaceFibre enables a single, integrated network to be used which carries instrument data, configuration and control information, deterministic traffic, high-resolution time information, and event signals. This improves reliability, saves mass, and reduces cost.
SpaceFibre for Space
SpaceFibre IP cores for the Microsemi radiation tolerant RTG4 and RTAX FPGA are available from STAR-Dundee. SpaceFibre has been designed to have a small foot print, taking a minimum of FPGA or ASIC resources allowing multiple SpaceFibre interfaces and substantial user logic today’s radiation tolerant FPGA technology. SpaceFibre has also been implemented and tested in Spartan 6, Xilinx Virtex 4, Virtex 5 and Kintex 7 FPGA.
A complete range of SpaceFibre test equipment is available from STAR-Dundee.
The SpaceFibre Standard
The SpaceFibre standard was written by the University of Dundee and STAR-Dundee for ESA with contributions from many international spacecraft engineers including people from ESA, JAXA, NASA, Airbus DS, Thales Alenia Space, SubMicron, ELVEES, NEC Toshiba Space, Misubishi Heavy Industries, St Petersburg University of Aerospace Instrumentation and University of Pisa.
The SpaceFibre standard has been simulated, implemented and reviewed at all stages of its research, design and development. The physical, lane and QoS layers of SpaceFibre are fully defined and have been extensively tested with simulations by at least three independent organisations, and by implementation in FPGAs and an ASIC. The multi-lane layer has been designed and simulated, and is currently being tested in FPGAs implementations.
Read more about the SpaceFibre Protocol Stack.