Shuttle in a hurry to space station, now and in future

The space shuttle Discovery is rushing to catch up with the international space station for a Thursday rendezvous. The chase mirrors what has been going on down on Earth for the past few years.

Just about every decision about the space shuttle  including the controversial call to launch now instead of waiting until the chronic foam problem is fixed is tied to the space station's construction deadline.

The sole reason for the aged shuttle fleet's continued existence before the three remaining spacecraft are retired in 2010 is to finish up the construction of the half-built space station, NASA Administrator Michael Griffin told The Associated Press in a June interview.

The shuttle "will be employed, if employed at all, for purposes of completing the international space station project," Griffin said. "So all of our decisions on shuttle are really being made with an eye to how to how does this help us achieve our larger goal, which is not one shuttle flight or two shuttle flights, but 16 flights to finish the assembly of the space station.

"We're looking at the package of flights, we're looking at the big picture," Griffin said. "Because if we don't think we can get to the end of the project, then frankly, there's no need to go halfway."

The United States has treaty obligations that keep it from abandoning the massive outpost 212 miles (341 kilometers) above Earth.

The 2010 deadline is there because after the Columbia accident 3 1/2 years ago, President George W. Bush came up with a plan to send astronauts to the moon and then Mars. NASA said it would retire the shuttle and spend its money on a new ship, aiming for the moon by 2020.

The space station will give NASA an off-Earth training station to learn how to live in space for months on end, because a trip to Mars would take six months each way, reports AP.