That's because flight controllers and the science community will leave the Expedition Four crew little spare time for hobbies.

"During Expedition Four, we'll begin the busiest, most diverse and complex research program we've ever attempted on the international space station," said program scientist John Uri.

Through Expedition Three, 28 scientific payloads have been operated for 41 separate investigations requiring some 500 hours of crew time. More than 50,000 hours of experiment run time has been accumulated.

For Expedition Four, Uri said, "we'll have 26 different payloads that will be conducted - and seven of these are new to the ISS program - and they will be supporting 30 primary investigations to characterize the microgravity environment; to study human physiology; performing research in fundamental biology, which will be a first on this expedition; doing some materials processing as well as the exposure of materials to the space environment; biotechnology; (and) some very active commercial endeavors."

The space station as viewed by the last space shuttle crew. Photo: NASA

Onufrienko, Bursch and Walz will spend at least 300 hours doing hands-on research and 72 hours of work devoted to Russian research. They will accept delivery of some 1,650 pounds of experiment hardware from Endeavour and the next shuttle to visit in March. They also will stage two spacewalks and monitor a major software update for the station's command-and-control computers.

On top of all that, the crew will receive and unload an unmanned Progress supply ship in February and host a three-person crew delivering a fresh Soyuz lifeboat in April. Onufrienko and company will return to Earth in May aboard a shuttle ferrying up the Expedition Five crew.

"I'm proud that we can continue what we're doing," Walz said. "Hopefully, while we're up there we can remind the country that we are a space power, that we're keeping people aloft, that we're continuing to not only pursue our activities in Afganistan, but we continue to fly in space, that we fly in space with a consortium of nations and we are a visible symbol of how nations can work together harmoniously instead of having to fight with each other and do terrorist acts."

But a cloud of uncertainty hangs over the space station as NASA awaits the arrival of a new administrator - Sean O'Keefe - who has vowed to force the agency to live within its budget, even if that means indefinitely restricting station crew size to three.

NASA's longest-serving administrator, Daniel Goldin, resigned in October, just before the release of a critical report by a panel of outside experts that blamed projected space station cost overruns on poor management.

The panel said NASA must reorganize the space station program, redefine the project's science goals and sharply cut spending to keep even the current three-person lab financially feasible.

Those recommendations and others, if implemented, would reduce the shuttle flight rate to just four per year by 2003, eliminate hundreds, if not thousands, of contractor and civil service jobs across the nation and severely limit onboard research by Europe, Japan, Canada and other international partners.

Panel chairman Thomas Young said if these or similar measures are implemented, the agency probably could complete the space station's current three-person design and still meet, or come close to, an $8.3 billion spending cap set earlier by NASA and the Office of Management and Budget.

That spending cap covers station costs between fiscal 2002 and the completion of assembly, now stretched out to 2006. The overall cost of the station through assembly complete is roughly $25 billion by NASA's estimates, not counting shuttle transportation and other indirect costs.

NASA originally planned to build a crew habitation module and an emergency crew return vehicle that would support an on-board crew of six or seven. But earlier this summer, project managers discovered station costs would exceed the projected spending cap by $4.8 billion.

By eliminating work on the crew return vehicle, the habitation module and a multi-hatch node that would connect future modules, NASA reduced the projected overrun to around $480 million. That shortfall remains unresolved.

But loss of the crew return vehicle reduced the size of the station's eventual crew to just three, the number of astronauts that can fit inside a Russian Soyuz re-entry vehicle, the station's current lifeboat.

While three people can safely operate and maintain the station, there is little time for hands-on science operations: about 20 hours per week.

For the station's international partners, a three-person crew effectively eliminates any chance for European, Japanese or Canadian astronauts to carry out significant on-board research. For them, a six- or seven-member crew is essential.

But the Young panel recommended putting station expansion on hold until the agency can demonstrate more "credible" cost estimating and budgeting.

Sean O'Keefe is poised to become NASA's new leader. Photo: White House

With a clear mandate from the Bush administration to reign in the station program, O'Keefe, deputy director of the White House Office of Management and Budget, has vowed to implement the recommendations of the Young panel.

"The administration is very proud of the technical accomplishments of (the space station) program, as we all should be," O'Keefe said Nov. 7 in testimony before the House Science Committee.

"However, technical excellence at any cost is not an acceptable approach," he said. "Managing the program within cost and schedule must be elevated in importance - particularly within the culture of NASA's Human Space Flight activities - to be on a par with technical excellence."

Bill Gerstenmaier, deputy director of the station program at the Johnson Space Center in Houston, agreed NASA needs to improve its cost estimating techniques and predicted the agency will figure out ways to cut costs and still preserve a viable space station.

"Our problem is how we forecast costs and how we budget in the future," he said. "We definitely need to do some improvement there and we'll take some of the recommendations (the Young panel made) and figure out a way to put together a plan to satisfy what they need, run that through headquarters and up to OMB and Congress. I think we'll be able to get a plan that will satisfy where we want to go."

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