Cape Canaveral, Fla. NASA 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.
Tonight, 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 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 today'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.