Shuttle Atlantis is ready to launch on a mission that should give the International Space Station (ISS) some "backbone" -- both from a hardware standpoint and as a way to shore up politics between the United States and the outpost's multi-national partners.

STS-110

For complete launch to landing coverage and the most up-to-date news about this assembly mission to the International Space Station click here.

Scheduled for liftoff between 2 and 6 p.m. EST Thursday, Atlantis is to haul into orbit the first segment of the ISS's crossbeam truss, designated S-Zero. To be installed by the astronauts -- who arrived at Kennedy Space Center on Monday -- the truss is the centerpiece to follow-on segments that, when linked, will stretch to 356 feet (109 meters).

Becoming the longest structure ever assembled in space; this essential hardware will house solar panels and cooling radiators to support yet-to-come European and Japanese research modules.

It will take four spacewalks spread out over six days to fully attach the $790 million assembly, which includes a moving base to which the station's Canadian robot arm will attach to facilitate additional construction work in space during the coming years.

But setting the stage for future international laboratories is one thing. Actually fulfilling that promise is another.

Straighten up and fly right

NASA's future space station work remains on "probation" -- a White House hand slapping in response to significant cost growth that has taken place in the ISS project.

According to a recent Congressional Research Service (CRS) review, the program already had experienced more than $7 billion in cost overruns above its original tally of $17.4 billion. Add on new cost-growth money, that estimate is now skyrocketing toward $30 billion. This price tag is well above a congressionally legislated cap of $25 billion, notes the CRS.

The Bush Administration has given NASA's space station program office some two years to straighten up and fly right. Cost estimating and program management of the ISS by the space agency is now undergoing a major overhaul, led by NASA's new chief, Sean O'Keefe.

Until the agency can tighten up the ISS project, NASA has been instructed to truncate construction of the space station. As of now, the end-of-the-road for ISS assembly is called "core complete." The facility would house only three individuals, instead of the seven planned.

That U.S. decision sparked a firestorm of criticism from the ISS partners. Cutting back on crew, they argue, also would cut back on research, affecting all the ISS partners -- Europe, Canada, Japan, and Russia, including the U.S. research community.

More power and plumbing

From the United States' perspective, a core complete ISS can house the hardware contributions of the European Space Agency's (ESA) Columbus module and Japan's Kibo facility. However, plugging in those labs to the growing orbiting complex demands more ISS power and plumbing,

With the flight of STS-110, putting the new truss in place is central to enabling future growth of the frontier complex, said Mike Raftery, ISS vehicle manager for Boeing, the prime contractor in building the sprawling outpost.

"The truss is really key. It's a crossroads part," Raftery said. "It is really a critical element. All the pieces are important. We understand the message from Washington. We're working hard to make sure that we meet the plan. The truss is an important element. There's no question about it," he said.

Meanwhile, while Atlantis sits on the pad ready to deliver the first station truss, the political scene between NASA and the ISS partners is one of discussion and wait-and-see wondering.

Next page: Truss but verify...