A LAN that's out of this world... literally
As Neil Woodbury can tell you, running a LAN in space poses some unusual challenges.
HOUSTON (IDG) -- At first, Neil Woodbury's networking challenge doesn't seem too tough: He needs to support a seven-person remote office 250 miles away.
But that's 250 miles straight up. And the office is moving at 17,000 miles an hour.
Woodbury is overseeing development of a local area network aboard the International Space Station now under construction.
As group head of the portable onboard computing and tools department at NASA's Johnson Space Center, he is responsible for the health of both the LAN and the applications that will run on it -- from e-mail to word processing, in addition to a few custom applications used for positional tracking.
One would think that Woodbury is employing high-tech, super-secret hardware and software in an effort to keep the ISS crew happily computing. But this is the new NASA.
"We try to use as much off the shelf stuff as possible," Woodbury says. "We like commercial folks to adopt things first because it is less we have to custom build."
To that end, the U.S. portion of the space station's LAN will be equipped with four IBM ThinkPad 760 laptops: three clients running Windows 95 and one NT server.
"It's a little less power than I would have liked, but it will do," Woodbury says. "We're only talking five clients when [everything is complete,] not like most systems with hundreds of users."
Everything will be connected to using standard Ethernet. Most of the PCs will be "hard lined" to the network using 10-base2 cable. 10-base2 is shielded and uses little power, allowing computers to be connected to one another directly, eliminating the need for a network hub.
Two separate ThinkPad 760s, running the Solaris version of Unix, will let the crew run the station.
Crew members will largely use off-the-shelf software, including Microsoft Office and Outlook for e-mail. They will also be equipped with custom software that displays the station's orbit position relative to the ground and show when the station will get communications again, similar to the big screen at the space shuttle control center in Houston.
"Whenever possible we try to use the same [commercial] software on station that the crew uses on the ground," Woodbury says. "This helps minimize training on new systems."
Still, running a LAN in space poses some unusual challenges.
The station will use an "orbiter communication adapter," similar to the ones now used by NASA space shuttles to handle data communications with the ground. The OCA is specially designed by NASA to accept all the delays and drop outs associated with space-to-ground communications. The device will attach to the network using proprietary Windows device drivers.
"E-mail is a bit of a challenge since we do not have a constant connection with the ground," he adds. To compensate, Outlook will run in pseudo offline mode and synchronize itself with the ground periodically.
The various modules that will make up the station cannot be hard-wired together -- running wires across the hatches that connect them would pose safety problems. To remedy that problem, the laptops will be equipped with Proxim RangeLAN 2 radio frequency Ethernet cards for inter-module communications.
The network itself will be simple once all the pieces are in place. The next flight after crew arrival will bring the U.S. Laboratory Module that will house the file and print server unit and a hard-line printer. The lab will have several physical network connection points for client machines. Crew members using laptops in other areas of the station will use the Proxim cards for their connection.
The crew will not have standard e-mail addresses, meaning the average Joe will not be able to e-mail them with the latest Clinton jokes. Most likely, the crew will be limited to sending and receiving e-mail to specific addresses. Anyone else wishing to send e-mail to the crew will be able to do so through a filtered drop address. "It's mainly for the families so they can stay in touch," Woodbury says.
Woodbury says he and his team have tried to anticipate any problems -- it's not like they can make a service call. The station will be stocked with spare computer gear, such as extra Ethernet cards, and Space Shuttle crews will arrive every few months with fresh supplies.
Woodbury does not want the astronauts pulling apart computers while in orbit to try and fix a broken hard drive. Replacement units will be available or shipped on the next returning shuttle flight should a laptop fail. Woodbury hopes that all that is needed from the crew perspective is to run backup routines every so often. "We just want to give the system a little care and feeding and hope that it stays up."
Looking ahead, Woodbury sees the day when the crew could surf the Internet from afar. Though it will soon be technically possible, there may be some official hesitation. "It makes some people nervous from a security standpoint," Woodbury says, adding he does not necessarily agree. "People also want the crew up there working, not surfing the Net."
Hey, who needs the Internet when you have one of the best views of the heavens and earth right outside your window?
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