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THE NATION

Computers restored aboard space station

A system that controls oxygen manufacture had been down 2 days.

June 16, 2007|Thomas H. Maugh II | Times Staff Writer

Bypassing a power switch manually, Russian cosmonauts were able to restore two-thirds of the computer functions on the International Space Station on Friday, offering hope that they will be able to restore the system completely.

At the same time, spacewalking astronauts repaired the shuttle Atlantis, installed a hydrogen vent on one of the station's laboratories and continued folding an old pair of solar panels that are not being used.

The two main computers on the space station crashed Wednesday for reasons that are not yet clear. Ground controllers and cosmonauts tried rebooting them several times, but the system could not restored, potentially endangering the status of the station.

The German-built computers control the manufacture of oxygen, the removal of carbon dioxide and the orientation of the station in orbit. If the computers could not have been restored, their loss might have led to the evacuation of the station, although that was never considered a serious possibility.

Friday afternoon, cosmonauts Fyodor Yurchikhin and Oleg Kotov used essentially a pair of alligator clips to bypass the main power switch on the computers. When they attempted to reboot the system then, two of the three data channels on each of the two computers were restored.

When the system appeared to be stable, the computers were shut down again, the external connections stabilized mechanically and the panel doors enclosing them shut to prevent their being jostled.

The computers were restarted again at 2:09 p.m. PDT and have been running since.

"Both computers are working right now, and the plan is to continue monitoring them for several hours," said NASA spokeswoman Lynette Madison.

Russian engineers also determined that backup power supplies for the computers had failed. The Russian space agency said it would move up a resupply launch of a Soyuz spacecraft by two weeks to July 23 to replace the faulty equipment.

While engineers were struggling with the malfunctioning computer system, astronauts Jim Reilly and John "Danny" Olivas made the third of four scheduled spacewalks.

While Reilly installed a hydrogen vent on the station's Destiny laboratory for a new oxygen-generation system, Olivas repaired a 4-by-6-inch piece of thermal blanket on the shuttle's left orbital maneuvering system pod that had come loose during the launch.

The loose blanket was not considered a threat to the safety of Atlantis because it covers an area that is not exposed to the highest temperatures during reentry. But the temperatures could have damaged the shuttle, necessitating repairs that would delay other missions scheduled for this year.

Working from the end of the shuttle's robotic arm, Olivas tucked the loose piece of blanket back into place, then attached it to the adjacent blanket using a medical stapler.

The two astronauts then continued the job of folding the old solar panels. The panels must be retracted so the new ones installed on this mission can open and rotate properly.

The old panels will be moved to a different location on the station during a subsequent mission.

There had been the possibility that Reilly and Olivas would unhook an electrical connection between the new solar panels and the station during their spacewalk.

The computer malfunction had occurred about the same time Wednesday that the connection was made, and engineers had speculated that a power surge or magnetic field from the line had affected the computers.

But with the computers operating again, there was no need to disconnect the line, Madison said.

thomas.maugh@latimes.com

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