Troubleshooting faulty space robot 220 miles above Earth

NASA tries software patch when giant robot won't power up, suspects faulty cable

Computer programmers and engineers are troubleshooting a problem with a 3,400-lb. robot that is orbiting about 220 miles above Earth.

Earlier this week, the space shuttle Endeavour lifted off carrying nine robotic components -- the makings of Dextre, a 12-ft. tall robot with a wing span of 30 feet. The $200 million robot, built by the Canadian Space Agency in Saint-Hubert, Quebec, is designed to handle maintenance on the outer walls of the International Space Station. 

The problem started two nights ago, when astronauts went to fire up Dextre as part of a test to see how it fared during Endeavour's liftoff. The robot did not respond as required. Dextre was orbiting the Earth, 220 miles above its home and engineers, and it simply would not respond to commands.

"Power was reaching Dextre, but his computer wasn't acknowledging that it had received a command and start up," explained Michel Wander, a systems engineer who worked on Dextre at the Canadian Space Agency. "It's just not able to switch on the components."

The problem with not being able to power up the robot  -- other than having an unresponsive 3,400-lb., $2 million robot attached to the space station -- is that Dextre eventually will need to receive enough electricity to keeps its joints, cameras and sensors from freezing up in the harsh conditions of space. Wander said that the astronauts already have the robot covered with thermal blankets but in about a week, those blankets won't be enough to protect Dextre from the brutal cold.

"You just can't leave it without power," said Allard Beutel, a spokesman for NASA. "The system needs to be heated with electricity running through it. The longer things are in space without power and heat, you have problems. In theory, you'll start having mechanical problems. We don't want to start having parts not working."

The engineers at NASA and the Canadian Space Agency first suspected that the problem was a bug in the software. Canadian programmers immediately began building a patch that was sent to the space station via radio dishes. The software patch didn't fix the problem.

At this point, Wander said the engineers suspect that there's a configuration problem with the cable that links Dextre to the pallet that it's attached to. Electricity and software commands should be going to Dextre through the cable. If that's the case, the problem isn't with the robot itself and it should work as planned once it's off the pallet, fully assembled and permanently attached to the space station, he said.

To find out if the assumption is correct, Wander said around 10 p.m. EDT today, they'll grab hold of Dextre with a robotic arm that is already attached to the space station. Using the arm to bypass the potentially flawed cable, Dextre should be able to power up.

"It's not nerve wracking. We have an idea of what the problem is," said Wander. "If this doesn't work tonight, then yes, it will be more serious."

People can watch the astronauts and engineers troubleshoot Dextre tonight on NASA TV.

Copyright © 2008 IDG Communications, Inc.

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