Spacewalk Will Be Riskiest Yet

The international space station's two residents were preparing for a riskier-than-usual spacewalk, fraught with an odd mishmash of Russian and U.S. gear and extra-stiff gloves never intended for the type of repair they hoped to accomplish.

They may be cut off at times from communications, and will be forced to alternately speak Russian and English and communicate with two different control centers during Thursday night's ordeal. They'll travel an unprecedented distance over dangerous terrain, about 45 minutes each way.

Why? Because there's no space shuttle to bring them the equipment they need.

The prolonged grounding of the fleet has NASA taking bigger chances — and more of them — even bending its own safety rules to keep the space station running with a two-man crew.

Astronaut Mike Fincke and cosmonaut Gennady Padalka say they're raring to go out and replace a fizzled circuit breaker. Fincke, a newcomer to spacewalking, is especially excited.

"This is going to be fun," Fincke told Mission Control on Wednesday. The time-saving ride on the end of an extendible boom "is going to be something to write home about."

That's for sure.

When the space shuttles were flying, NASA managers never would have considered a spacewalk requiring occasional hand signals and jury-rigged suits. But last year's Columbia disaster changed everything.

The Russians have been bailing out NASA with crew and supply drop-offs ever since the shuttle accident, and are demanding compensation for Thursday's six-hour spacewalk since it involves repairs to the U.S. section. They threatened to postpone the outing, but agreed Tuesday to worry about payment later.

The trouble in orbit began in April, just hours after Fincke and Padalka arrived at the space station for a six-month stay.

A critical circuit board failed, cutting power to a gyroscope, or spinning wheel. The breakdown left the station with just two functioning gyroscopes, the bare minimum needed to keep the complex stable and pointed in the right direction.

Then last month, Padalka could not get the water-cooling system of his U.S. spacesuit to work. The only option was to send Padalka and Fincke out in Russian spacesuits from the Russian side of the station, more than doubling their travel distance over a landscape of protruding metal parts.

The spacemen added American helmet lights and handcuff checklists to the brand new Russian suits, for extra safety.

Station operations manager Mike Suffredini said safety officials were in on the debate and stressed that this spacewalk "is one that we can go do and should go do." To put it off could jeopardize two spacewalks planned by the Russians later this summer for assembly chores, he said.

"We don't feel were cutting corners," Suffredini said. He noted there has been a heightened sensitivity to safety in the station program ever since the Columbia tragedy, and that he and others find themselves constantly asking, "What are we doing? Is it right to go do it? Are we taking unnecessary risks?"

But a retired agent in NASA's inspector general office, Joseph Gutheinz, wonders whether NASA and the Russian Space Agency are "sweeping any known risks under the table in an effort to keep the space station program alive." He said the agencies downplayed risks at Russia's Mir station during visits by U.S. astronauts in the 1990s.

Gutheinz also questions whether it's safe to send an entire crew out, with no one to monitor systems inside. The station has been empty during a spacewalk only once before, in February.

Although the station's U.S. pressure chamber was designed to accommodate Russian spacesuits, the parts needed for that are on the ground. So Fincke and Padalka will have to leave from the Russian hatch and travel between 80 feet and 100 feet to the repair site, using a 50-foot boom to swing themselves partway.

Exiting from the U.S. hatch would have put them 30 feet from the fried circuit breaker.

Because Fincke and Padalka will venture so far from the Russian antenna, they expect communication blackouts, not only with flight controllers but with each other. To get messages across, they've come up with hand signals: crossing their arms in front of their chests indicates an emergency, jutting a fist up means, 'hey, pay attention,' and a thumb-up means everything is OK.

If all else fails, they will hustle to a designated spot with a clear line of sight to the Russian antenna.

There's also the fatigue factor, and not just from all the extra scampering around.

Russian spacesuits are more pressurized than U.S. suits, and so it will be harder and take longer for Fincke and Padalka to undo American bolts, using American tools designed for American gloves.

Over the past few weeks, as the spacewalk has been bumped and repeatedly rescheduled, Fincke has kept a sense of humor and emphasized the need for flexibility.

At least the repair itself should be easy, says Fincke. He figures the tricky part will be the long trip over 45 minutes, at least and the long trip back. But, oh, the rewards.

"Boy, I can't wait to take a look at that view."