CAPE CANAVERAL, Fla. – NASA (search) is taking bigger chances and more of them -- even bending its own safety rules -- to keep the international space station running with a two-man crew and no shuttle visits.
On Thursday night, both astronauts will take a riskier than usual spacewalk, wearing an odd mishmash of Russian and U.S. gear, cut off at times from communications, and struggling with tools in extra-stiff gloves never intended for the repairs they will make.
They'll be forced to alternately speak Russian and English and communicate with two different control centers. They'll travel an unprecedented distance over dangerous terrain, about 45 minutes each way.
Why? Because there's been no space shuttle to bring them the equipment they need. Russian spacecraft are too small to carry large replacement parts.
Despite the added risks, astronaut Mike Fincke and cosmonaut Gennady Padalka said Wednesday they're excited and ready.
"We're all in this together," Fincke told Mission Control. "This is going to be fun."
Their task will be replacing a fizzled circuit breaker.
When the space shuttles were flying, managers never would have considered a spacewalk requiring occasional hand signals and jury-rigged suits. But last year's Columbia disaster (search) 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 we're cutting corners," Suffredini said. He said 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 (search) 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 crane 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, a newcomer to spacewalking. He figures the tricky part will be the long trip over -- 45 minutes, at least -- and the long trip back. But, oh, the rewards.
Riding on the end of the extendible boom will be "something to write home about."
"And boy, I can't wait to take a look at that view."