SpaceWire

Infobox Computer Hardware Bus
name = SpaceWire
fullname =


caption =
invent-date =
invent-name = European Space Agency
super-name =
super-date =
width =
numdev =
speed = 2 Mbit/s to 400 Mbit/s
style = s
hotplug = Yes
external = YesInfobox connector
name = SpaceWire
type = Data connector



caption =
designer = European Space Agency
design_date =
manufacturer =
production_date =
superseded =
superseded_by =
superseded_by_date =
external = Yes
hotplug = meter
length =
width =
height =
electrical =
ground =
maximum_voltage =
maximum_current =
audio_signal = No
video_signal = No
data_signal = Yes
data_bit_width =
data_bandwidth = 2 Mbit/s to 400 Mbit/s
data_devices =
data_style = Serial
cable =
physical_connector = DE-9
num_pins = 9
pinout_col1_name = Name
pinout_col2_name = Description
pinout_

pinout_caption =
pin1 = Data In
pin1_name = DIN+
pin2 = Strobe In
pin2_name = SIN+
pin3 = Ground
pin3_name = Inner Shield
pin4 = Strobe Out
pin4_name = SOUT-
pin5 = Data Out
pin5_name = DOUT-
pin6 = Data In
pin6_name = DIN-
pin7 = Strobe In
pin7_name = SIN-
pin8 = Strobe Out
pin8_name = SOUT+
pin9 = Data Out
pin9_name = DOUT+
pinout_notes =

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 Mb/s and 400 Mb/s. DS-DE is well-favored because it describes modulation, 8B/10B encoding 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. 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 and the Geostationary Operational Environmental Satellite (GOES-R). 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.

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:
* 1: Remote Memory Access Protocol (RMAP)
* 2: CCSDS Packet Transfer Protocol
* 238: Proposal for Reliable Data Delivery Protocol (RDDP) (used on GOES-R)
* 239: Serial Transfer Universal Protocol (STUP) (Used on SMCS-332 ASIC)

References

* [http://www.ecss.nl/forums/ecss/_templates/default.htm?target=http://www.ecss.nl/forums/ecss/dispatch.cgi/standards/docProfile/100654/d20080802144344/No/t100654.htm ECSS-E-ST-50-12C - SpaceWire - Links, nodes, routers and networks] , ESA-ESTEC.
* [http://www.ecss.nl/forums/ecss/_templates/default.htm?target=http://www.ecss.nl/forums/ecss/dispatch.cgi/standards/showFolder/100630 ECSS-E-50-12A (SUPERSEDED only document number has been changed to ECSS-E-ST-50-12C) SpaceWire - Nodes, links and networks] , ESA-ESTEC.
* [http://www.ecss.nl/forums/ecss/_templates/default.htm?target=http://www.ecss.nl/forums/ecss/dispatch.cgi/standards/docProfile/100654/d20080802144344/No/t100654.htm ECSS-E-ST-50-11C Draft 1.3 "Space engineering - SpaceWire protocols"]

External links

* [http://spacewire.esa.int/ SpaceWire Homepage]
* [http://www.ecss.nl European Cooperation for Space Standardisation - ECSS]
* [http://spacewire.computing.dundee.ac.uk International SpaceWire Conference 2007]
*http://www.interfacebus.com/SpaceWire_Avionics_Bus.htmlCommercial providers of SpaceWire equipment:
* [http://www.star-dundee.com STAR-Dundee]
* [http://www.4links.co.uk 4Links]
* [http://ams.aeroflex.com/ProductPages/RH_spacewire.cfm Aeroflex]
* [http://www.dyneng.com/spacewire.html Dynamic Engineering] NonCommercial providers of SpaceWire:
* [http://leventozturk.com/engineering/ Hardware RTL SpaceWire] SpaceWire IP Cores:
* [http://www.gaisler.com/cms/index.php?option=com_content&task=view&id=198&Itemid=141 Gaisler Research]
* [http://ipp.gsfc.nasa.gov/ft-tech-spacewire.html NASA Goddard - tech transfer]
* [http://www.opencores.org/projects.cgi/web/spacewire/overview OpenCores.org]
* [http://spacewire.cesr.fr/ CESR CNRS] Articles:
* [http://www.nasa.gov/vision/universe/watchtheskies/jwst_spacewired.html NASA article on SpaceWire used on JWST spacecraft]