SpaceFibre
SpaceFibre is the successor of (and is compatible with) the very popular SpaceWire protocol but allows 15 times higher data rates per lane (up to 6.25 Gbps and beyond). It has fault detection and recovery as well as deterministic communication mechanisms built into the hardware and can operate via copper and optical fibre. The reduction of harness is high compared to SpaceWire, with 50% when using optical fibres and more than 90% when comparing per bit transferred. The SpaceFibre standard (ECSS-E-ST-50-11C) was published in 2019 and several Intellectual Property (IP) cores are readily available for the implementation into space-qualified FPGAs. Supported by two ongoing TRP activities, we also work actively towards a SpaceFibre router and interface ASIC.
The Standard
The ECSS standard ECSS-E-ST-50-11C is a key component for the successful deployment of SpaceFibre in future space missions. It has been written by the University of Dundee under ESA funding, with contributions from major international space agencies (NASA, JAXA) and prime contractors. The ECSS working group consists of members from: Airbus DS Germany & France, OHB Germany, Thales Alenia Space France, RUAG Space Sweden, STAR-Dundee UK, Cobham Gaisler Sweden, and IngeniArs Italy.
SpaceFibre is an open standard that is easy to understand and that allows everyone to implement SpaceFibre hardware and software without the need for relying on proprietary solutions.
The SpaceFibre standard is out now!
You can download the document at:
https://ecss.nl/standard/ecss-e-st-50-11c-spacefibre-very-high-speed-serial-link/
The Features
- Allows very high-speed streaming of data (many Gigabits per Second) with only minimum buffer requirements.
- Offers also deterministic communication through virtual channel isolation. This is fully implemented in hardware and extreme tight timing requirements can therefore be met.
- Provides very low latency and jitter (no store-and-forward, no embedded software).
- Has a low protocol overhead that is independent of packet size.
- Includes a mechanism to detect errors on the link and to recover from them automatically by re-transmitting of data. The re-transmission is on a point-to-point basis with extreme fast reaction time (< 1us).
- Has a flow-control mechanism built in.
- Does not restrict the sizes of packets.
- Simple networks are easily configured by hand, only larger networks might need specific software tools.
- Offers "broadcast messages", which have minimum latency due to being prioritized over other data traffic. This messages are used for time-synchronization, interrupts, error codes and similar tasks.
- SpaceFibre can easily be embedded into systems without the need for proprietary software.
The IP Cores
SpaceFibre protocol IP cores are available from several European companies (see links on the right-hand side). We can also provide IP cores through our own ESA IP Core Service to the European industry for a low administration fee (see here, please use the ESA IP Core Request Form to request a license). Target space-qualified FPGAs are Microsemi RTG4, the upcoming European BRAVE-Large, Xilinx Virtex-QV devices and Microsemi RTAX2000 (in combination with an external SerDes device such as TLK2711). Compared to other protocols, the IP cores have low implementation complexity (e.g. less than 5% of resources of a RTG4 are needed). IP cores are also developed in the US, in Russia, and in Japan.
Physical Layer Testing
SpaceFibre is based on modern high-speed serial communication using Serializer/Deserializer (SerDes) blocks at its physical layer. These blocks translate the digital parallel protocol data into a serial bitstream that is transmitted to the destination node via differential lines, often using Current Mode Logic (CML). Testing of this physical layer is required to minimize the risk of integration problems. This usually includes the testing of the transmitter by measuring eye diagrams with a high-performance oscilloscope and the testing of the receiver using dedicated Bit Error Ratio Test (BERT) hardware. Such test setups can quickly become very costly, especially for smaller companies. Therefore, we can offer the usage of our test equipment at ESA's premises to anyone interested in developing SpaceFibre hardware. Please contact us for more information.
Contact
The point of contact for SpaceFibre is Felix Siegle. Please get in touch if you need more information, either via phone: +31 71 565 4956 or email: spacefibre@esa.int.
