Challenging Spacewalk On Tap

Russian cosmonaut Gennady Padalka, left, and NASA astronaut Michael Fincke 2004/3/1
The astronauts at the international space station got gentle reminders and best-of-luck wishes as they prepared to take another stab at an unusually risky spacewalk ordered up for critical repairs.

"We have absolutely no question in our minds what we're supposed to do and what you guys will be doing in return," American spaceman Mike Fincke told Mission Control on Tuesday, "and I think this will go nice and smooth."

Fincke and Russian Gennady Padalka will open the hatch late Wednesday afternoon and float outside with a spare circuit board to replace one that stopped working and cut power to a crucial steering device in April.

They scrubbed last Thursday's spacewalk after less than fifteen minutes, reports CBS News Correspondent Peter King. Mission Control saw the oxygen pressure in Fincke's main tank was dropping and ordered him back inside.

The problem turned out to be a stuck switch.

The spacemen will wear the same Russian suits again, but pay greater attention to the switches and oxygen flow.

The spacewalk is seen as a challenge. First, Fincke and Padalka have to climb from the Russian airlock to the American side of the space station, 80 to 100 feet from the fried circuit breaker on the U.S. side, which could take almost an hour. And once they get there, they may have trouble talking to Mission Control and each other, because the relay antennas for their Russian suits are on the other side of the station. They've worked out hand signals, and a nearby place they can go to for quick communication with the ground.

In addition, the spacewalk will require switching between Russian and English, and between control centers in Moscow and Houston.

They should be wearing NASA spacesuits for the excursion, but two of the three on board are unusable and no more can be sent up until shuttle flights resume.

It will be only the third time that the station is left empty during a spacewalk, a situation necessitated by the diminished crew size — a direct result of the Columbia accident and subsequent grounding of the shuttle fleet.

The station can operate with two working gyros, reports King, but if another goes down, that means using the station's limited supply of fuel to keep it aimed correctly.