Friday, June 15, 2007

ISS power problems

The Russian computer crash might be a power related problem from the new solar arrays installed on Monday. Today Atlantis crew will repair the thermal blanket.
HT Space Daily here:
"They had a problem with those computers going off-line overnight," NASA spokesman Bill Jeffs told AFP from Houston, Texas.

The first such mishap of its kind raised concerns the mission might have to be cut short.

But now "they have reestablished communications" with the module and Russian central computers, Jeffs said.

"The Russians report that they think it is a power problem and not a software problem" that triggered the potentially problematic glitch, Jeffs said.

Another NASA spokesman, John Ira Petty, said the problem had not been entirely fixed by 1255 GMT Thursday, but that restoring communictions was "certainly a step in that direction" after many hours of interruption.

"There is some cleaning up left to do after a situation like this as you can imagine. But we are optimistic," he added.

James Oberg over at MSNBC discusses the Russian's computer problem here.
Without the control computers, the Russian rocket thrusters — both on the station itself and on the unmanned Progress freighters that bring up supplies — cannot be activated to orient the station in space.

The main pointing control comes from a set of gyroscopic stabilizers on the U.S. segment that use electrical power to spin in directions that twist the station into desired turns. But this hardware — the "Control Moment Gyroscopes," or CMGs — need occasional assistance from rocket thrusters for more forceful turns and to "dump" excess angular momentum (which arises when the gyroscopes spin too fast).

As long as the computers are inoperable, other critical equipment in the Russian segment cannot function. The devices for producing oxygen, controlling humidity and scrubbing excess carbon dioxide were inoperable at first. However, during the brief time that the computers were operating Thursday morning, circuit breakers on the station were reconfigured to create a power pathway for some of that gear.

I'll blog the walk today.
Flame Trench will have NASA TV.

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