Remember the floating sparring partner that darted about helping Luke Skywalker refine his lightsabre skills in Star Wars? Well, NASA is busy creating similar robots for its astronauts. Called personal satellite assistants, or PSAs, the tennis-ball-sized robotic helpers will float around spacecraft monitoring oxygen levels, taking snapshots and even fixing minor problems.
A roving PSA will be able to go where people can't. For example, astronauts could send it to investigate alarms. "When a fire broke out on the Mir space station," says the PSA project leader Yuri Gawdiak, "it would have been nice to have a PSA to send in to the area to see what was going on."
Suspended in microgravity, a PSA will need only tiny fans to move about. It will use range-finding sensors to detect objects-such as astronauts-that get in its way. The battery-powered device will be armed with sensors to detect changes in gas levels, temperature and atmos-pheric pressure.
Designed to work without human supervision, the PSA will communicate with the spacecraft's computers via a wireless network, shifting tougher tasks to the ship's computers to save power. It should also respond to human voice commands or be controlled using a hand-held remote control device, or even by crews on the ground.
Besides its monitoring duties, the PSA will serve as a communication port, equipped with microphones and video conferencing capabilities. It will act as a stand-in for scientists who send experiments up into space. Through the PSA, Earthbound researchers could watch procedures being carried out and communicate in real time with the astronauts. "The PSA will allow scientists to interact naturally with the crew," says Gawdiak.
"It's an exciting project that has great potential to enable the human exploration of space," said Ken Ford, head of the information technology unit at NASA's Ames Research Center in California. He introduced the PSA concept last week at a Silicon Valley conference on data fusion-which examined the integration of data from multiple sources into single, more manageable streams. The array of sensors used by the PSA will need just such a system to allow the device to make sense of the space it inhabits.
NASA scientists say it will be at least two years before the PSA is ready for use on the space shuttle or the International Space Station. "One of the major challenges of a device like this," says aerospace expert Jonathan How of Stanford University, "is how to keep the thing from running into people or doors." Another challenge is keeping its size down. "Small sensors tend to drift, that is, they lose their accuracy over time," he says.
The NASA team is now working on collision control software for the device, says Gawdiak. As for its size, Gawdiak says the team is working with the Jet Propulsion Laboratory in California to keep the unit's volume down-while keeping its productivity up.
Author: Catherine Zandonella, San Francisco
Issue: 17th July 1999
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