If you are a router company with as much as 80 percent market share and a $3.2 billion R&D budget to play with, why not bolt a router to a rocket and shoot it into orbit?
That is what a group of engineers at Cisco did as part of the Cisco Low Earth Orbit (CLEO) project, which recently completed its second year orbiting Earth. CLEO is a modified version of Cisco's Mobile Access Router, typically used to connect computer equipment in police cars, ambulances, aeroplanes and other vehicles to an IP network.
Cisco says the project is a proof-of-concept exercise designed to show the aerospace industry that commercial IP technology is space-worthy.
"We needed to put a stake in the ground and have something to talk about from a technology perspective," says Rick Sanford, director of Cisco's Global Space Initiatives group.
Routers in space hold promise for future satellite-based broadband technologies, which could make wide-area data network services ubiquitous and more robust than current satellite data services, Sanford says. The use of commercial off-the-shelf (COTS) computing and network technology is also of interest to the government and aerospace industry.
"NASA and the Department of Defense are currently involved in defining the next-generation network architecture for space. This new architecture will utilise Internet Protocols to ensure interoperability between terrestrial (land, sea and air) and satellites," wrote Phillip Paulsen, space Internet technology project manager for NASA's Glenn Research Centre, in a report. The centre, in Cleveland, has been involved in the development of Internet technologies for space applications since the mid-1990s.
"The current development activities are all co-operative in nature and utilise commercial-off-the-shelf network equipment that has been designed to open standards, helping to reduce costs and ensure compatibility with future commercial systems," Paulsen wrote.
CLEO is born
Working with Surrey Satellite Technology, Cisco made CLEO available for launch in 2003 as piggyback cargo on the UK Disaster Monitoring Consortium satellite, part of a satellite network used to photograph hurricanes, wildfires and earthquakes from space.
Last year, CLEO was put to its big test, executed by the Air Force, Army and NASA's Glenn Research Centre at Vandenberg Air Force Base in California. In this test, military personnel sitting in a jeep used a laptop running special General Dynamics software to make IP-based contact with CLEO. From this Virtual Mission Operations Centre, laptop operators were able to download images from the satellite and send command-and-control signals to the device over IP. This pure-IP link to a router in space was a first, Sanford says.
Satellite communication signals traditionally have been sent and received using what's known as a bent-pipe method. A signal is sent up from a fixed point on Earth, received by the satellite and amplified, then sent back down to a predetermined point. With all traffic routing decisions made on the ground, the satellite link is basically a Layer 1 connection technology.
"Satellites can be sort of a fixed infrastructure, always over a point of the globe - not dissimilar to a fibre network in the ground," says Lloyd Wood, space initiatives manager at Cisco. "So getting more networking into space is of interest to us."
Having a router onboard a satellite changes everything, Wood says.
"Satellites are becoming more computationally smart. But the trend is to move toward doing more digital signal processing - cleaning up the signals electronically before amplifying and shoving them back down. If you're willing to do the electronics and processing, actually going another step to look at what you're carrying, to look at the signal and do packet processing isn't much of a stretch," he says.
Having a router on a satellite dynamically move packets to different nodes could make satellite signals harder to jam, allowing satellites to route signals to each other in the air or on the ground. Space-born routers also could lead to higher-bandwidth satellite data and voice services that have less latency and more resiliency.
Satellite makers such as Boeing and Lockheed Martin are working on on-board processing technology that allows for more advanced communication beyond the bent-pipe method, says Max Engle, aerospace and telecom analyst for Frost and Sullivan. But COTS network gear, such as industry-standard routers, IP stacks and protocols, is still not widely used.
"The big satellite companies are not using anything even approaching off-the-shelf technology for that," Engle says. The reason is the demanding environment of space - extreme temperatures, radiation, vacuum, and no ability to send up a technician to fix things if they break, he says.
"One of the things with on-board processing is a communications satellite that has dumb transponders is pretty robust," Engle says. "There is not a single point of failure in the communication system. Once you put more processing up there, you run the risk of having one failure in your communication system propagate to your whole satellite."
With the environment of space in mind, CLEO wasn't built like other routers. To get the device ready for space travel, Cisco engineers had to make some unique modifications.
Its circuits are soldered not with standard tin, but with lead, which can be health hazard for electronics sold on Earth. Tin solder also isn't without its shortcomings, as it is susceptible to flakes of metal that form and can short out circuitry.
Cisco also built the router without internal clock batteries, which could explode in space. Instead of fans, heat sinks push heat generated by the electronics out toward the casing of the device. Acid-based or "wet" capacitors in the circuitry are swapped for dry capacitors.
Otherwise, CLEO was kept to industry standards and COTS-based technology, Sanford says. For instance, the device has no radiation shielding, which would have subjected CLEO to the US International Traffic and Arms Regulations, which prevent technology specifically designed for space and weapons systems to be released outside the US.
"This allowed us to represent what's possible by leveraging commercial capabilities in partnership with the space community," Sanford adds.
Not coming home
As for when CLEO will come down, a timetable has not been established.
"The design life of the spacecraft is 20 years," Wood says. But because the router has no radiation shielding, "we don't know how long it will last."
If or when CLEO or the satellite does fail, the satellite can be de-orbited to keep paths clutter free. But Cisco won't be able to recover its first space-travelling product for posterity.
"We would use the remaining propulsion to put it into an orbit to burn up in the atmosphere," Wood says. "Unfortunately, we won't be able to get CLEO back."
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