On Monday, engineers concluded that a finicky switch on Fincke's suit had caused oxygen to flow at too high a rate from his tank into his spacesuit.

Vera Medvedkova, a spokeswoman for Russian Mission Control, said in Moscow that the spacewalk was scheduled for 1:40 a.m. Moscow time on Thursday (2140 GMT Wednesday).

Flight controllers and the crew spent the weekend analyzing the problem and testing other Russian spacesuits. Everyone agreed that it was an isolated case and that with a little more attention, the same spacesuits can be used for Wednesday's outing, which is expected to last six hours.

The orbiting complex is limited to two full-time residents -- rather than three -- until NASA's shuttles begin flying again and provide badly needed spare parts and supplies. The shuttle fleet has been grounded ever since last year's Columbia tragedy.

As a result, the space station crew will leave the outpost vacant during a spacewalk for only the third time ever.

NASA wants the circuit breaker replaced as soon as possible in order to restore power to one of the gyroscopes that stabilize the station and keep it pointed in the right direction.

Every spacewalk is risky, but this one is especially so.

Because of problems with their U.S. spacesuits, Fincke and Padalka need to wear Russian spacesuits and go out the Russian hatch even though the repair work is on the distant U.S. side of the complex.

In addition, the two men will use a mishmash of Russian and U.S. gear and have a high probability of encountering communication blackouts, which will require them to use hand signals out in the void.

Fincke and Padalka are two months into a six-month space station stay.