SpaceFibre is a high-speed data-link technology being developed by the University of Dundee for ESA to support spacecraft onboard data-handling applications. SpaceFibre operates at 2.5 Gbits/s, can run over fibre optic or electrical media, provides galvanic isolation, includes Quality of Service (QoS) and Fault Detection Isolation and Recovery (FDIR) support, and provides low-latency signalling. It operates over distances of 5m with copper cable and 100 m or more with fibre optic cable. SpaceFibre supports multiple virtual channels running over a single physical link. QoS capabilities built into the SpaceFibre hardware allow the bandwidth and priority of each virtual channel to be specified. Traffic flow over each virtual channel then adapts automatically taking into account virtual channels that have data ready to send and available buffer space at the far end of the link, along with link bandwidth and priority allocation. The novel QoS mechanism is simple but powerful and also allows the automatic detection of “babbling idiots” and virtual channels that are sending much less data than expected. After a brief introduction the SpaceFibre QoS and FDIR capabilities are explained. The approach taken in validating the SpaceFibre protocols and current status of the SpaceFibre development activities are then described.