NASA takes the wireless leap

NASA takes the wireless leap

A NASA ground support technician

City-sized LAN more than doubles accuracy of Kennedy' s inventory tracking

By Chris Driscoll

GCN Staff

NASA recently finished installing the world's largest wireless LAN as part of an inventory tracking system at Kennedy Space Center in Florida.

The wireless LAN covers 47 square miles, the size of San Francisco, and took six years to complete. It tracks and gives directions to 300,000 pieces of ground support equipment stored in 100 buildings. NASA's prime contractor for the space shuttle, United Space Alliance LLC of Houston, subcontracted the wireless LAN work to Intermec Technologies Corp. of Everett, Wash. NASA paid about $300,000, Intermec spokesman Jim Thebeau said.

The equipment being tracked ranges from torque wrenches to orbiter support braces that hold the space shuttles in place while machinists repair and refit them, said Mark Colborn, the NASA and Navy project manager for Intermec's government systems division.

NASA's previous inventory tracking system had about 40 percent accuracy at locating equipment, said Ed Venable, director of vertical processing for United Space Alliance. Now, using Intermec's radio frequency data collection units, the space center workers can pinpoint 98 percent of ground support items in a few seconds, Venable said.

He attributed the expected annual savings of nearly $1 million to reduced downtime from delays in locating specific equipment.'
Pat Carlton, United Space Alliance's line operations manager for the space center's Vehicle Assembly Building, said, 'This system saves me several hours each day looking for equipment.'

All the right moves''

Intermec built the handheld computers with built-in bar code scanners to register each time a piece of equipment moves. Ground support crews find the equipment again by typing in the model number. Or they can type in a room number and read a list of all the equipment there.''

'The handheld computers are very easy to use,' Carlton said. 'I can train a person in five minutes.'

RF data collection also lets NASA workers exchange information wirelessly with host computer databases. Colborn said it 'gives the handheld user immediate feedback on the work that's being done.'''

Information travels by radio signal from a handheld unit to a radio repeater or transceiver attached to a structure high above the ground. The repeater retransmits the message to another repeater until it reaches a token-ring network and an IBM ES/9000 mainframe. The token-ring network soon will be replaced by Ethernet, Colborn said.

For the RF signal relay, Colborn said, Yagi directional antennas were configured in a star pattern across the 47 square miles of land. A combination of Yagi and omnidirectional antennas covers building interiors.''

NASA specified a three- to five-second response time. To maintain signal strength over such a large wireless network, Colborn installed nine controllers, 65 repeaters and nine base radios, all built by Intermec. The RF system operates at 900 MHz; the transceivers repeat signals four times rather than the typical three times to get enough coverage breadth for the desired response time.

'We have 11 repeaters in the vehicle assembly building alone, which is where they stack the rockets,' Colborn said. Numerous repeaters were necessary because the 1.29- million-cubic-foot building covers eight acres and must have no dead spots where radio transmission would be lost.

'It's hard to explain what a big place this is,' Carlton said.

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