SpaceFibre:a very high speed network for space flight applications

SpaceWire has proved very successful since the release of the standard by ECSS. This success is due to the versatility of SpaceWire and its inherent simplicity and low implementation cost (low gate count). SpaceWire can be used as a simple point to point link to transfer data from an instrument to onboard memory or in a more sophisticated architecture using routers. The architecture can be tailored to suit the specific application, adding bandwidth and support for fault tolerance where it is needed. SpaceWire has a fairly high cable mass and uses a non DC balanced signalling technique that makes galvanic isolation difficult.SpaceFibre is a proposed very high speed serial data link intended to complement and extend the capabilities of SpaceWire: improving the data rate by a factor of 10, reducing the cable mass by a factor of four and providing galvanic isolation.SpaceFibre will operate over arbitrary networks of point-to-point links in a similar manner to SpaceWire, but at much higher speeds (1-10 Gbits/s) with a target of at least 2.5 Gbits/s initially. The highest speeds will be carried over optic fibre with lengths up to 100m. It will also be possible to operate over copper cable where the cable length does not exceed 5m. Galvanic isolation, not required over optic fibre, will be included in the copper version. Both versions will have a bit error rate of better than 10-12. Dedicated SpaceWire-SpaceFibre routers will allow a mixed SpaceWire-SpaceFibre network. The routers will multiplex a scalable number of SpaceWire links over the SpaceWire connection.This paper will give the background and requirements for SpaceFibre showing how the proposed standard builds on the existing SpaceWire standard. The technical background for SpaceFibre will be discussed, highlighting other high-speed networking standards and pointing out key similarities and differences. Although SpaceFibre shares a number of features with existing high-speed standards, the technical decisions made for SpaceFibre explicitly reflect the challenges posed by the application domain. The paper will then present the prototyping and demonstration work being carried out by the University of Dundee under ESA contrac