SpaceWire

SpaceWire Specifications
Created by European Space Agency
Speed 2.0–400 Mbit/s
Style Serial
Hotplugging interface Yes
External interface Yes
SpaceWire Connector Specifications
Type Data connector
DesignerEuropean Space Agency
Hot pluggableYes
ExternalYes
Audio signalNo
Video signalNo
Pins9
ConnectorMicro-D
Data signalYes
Bitrate2.0–400 Mbit/s
ProtocolSerial
PinNameDescription
Pin 1DIN+Data In Pos.
Pin 2SIN+Strobe In Pos.
Pin 3Inner ShieldGround
Pin 4SOUT-Strobe Out Neg.
Pin 5DOUT-Data Out Neg.
Pin 6DIN-Data In Neg.
Pin 7SIN-Strobe In Neg.
Pin 8SOUT+Strobe Out Pos.
Pin 9DOUT+Data Out Pos.

SpaceWire is a spacecraft communication network based in part on the IEEE 1355 standard of communications. It is coordinated by the European Space Agency (ESA) in collaboration with international space agencies including NASA, JAXA and RKA.

Within a SpaceWire network the nodes are connected through low-cost, low-latency, full-duplex, point-to-point serial links and packet switching wormhole routing routers. SpaceWire covers two (physical and data-link) of the seven layers of the OSI model for communications.

Architecture

SpaceWire's modulation and data formats generally follow the data strobe encoding - differential ended signaling (DS-DE) part of the IEEE Std 1355-1995. SpaceWire utilizes asynchronous communication and allows speeds between 2 Mbit/s and 400 Mbit/s. DS-DE is well-favored because it describes modulation, bit formats, routing, flow control and error detection in hardware, with little need for software. SpaceWire also has very low error rates, deterministic system behavior, and relatively simple digital electronics. SpaceWire replaced old PECL differential drivers in the physical layer of IEEE 1355 DS-DE by low-voltage differential signaling (LVDS). SpaceWire also proposes the use of space-qualified 9-pin connectors.

SpaceWire and IEEE 1355 DS-DE allows for a wider set of speeds for data transmission, and some new features for automatic failover. The fail-over features let data find alternate routes, so a spacecraft can have multiple data buses, and be made fault-tolerant. SpaceWire also allows the propagation of time interrupts over SpaceWire links, eliminating the need for separate time discretes.

Uses

SpaceWire is used worldwide.[1] Its use began primarily in ESA projects, but it is currently used by NASA, JAXA, RKA, and many other organizations and companies. Some NASA projects using it include the James Webb Space Telescope, Swift's Burst Alert Telescope, the Lunar Reconnaissance Orbiter, LCROSS, the Geostationary Operational Environmental Satellite (GOES-R), and the SCaN Testbed, previously known as the Communications, Navigation, and Networking Reconfigurable Testbed (CoNNeCT). It has also been selected by the United States Department of Defense for Operationally Responsive Space. SpaceWire initiatives are being coordinated between several Space Agencies in the frame of CCSDS in order to extend its communication model to the Network and Transport Layers of the OSI model.

SpaceWire supports highly fault-tolerant networks and systems, which is one reason for its popularity.[2]

Protocols

The ESA has a draft specification in place for the Protocol ID.

The following Protocol ID's have been assigned in ECSS-E-ST-50-11:

References

  1. ↑ "Who Uses SpaceWire?".
  2. ↑ Dr Barry M Cook; Paul Walker. "Ethernet over SpaceWire - software issues". p. 2.

External links

Commercial providers of SpaceWire equipment:

SpaceWire IP Cores:

Articles: