The shuttle was designed to be a space truck; it's a multi-purpose vehicle. We've done a tremendous number of different things with it. It's the most versatile space vehicle that has ever been built. We've used it to launch satellites. We've used it to repair satellites in orbit and put them back into orbit. We've used it to capture satellites and bring them back to Earth for repair. We've outfitted it with the space lab built by our European partners and used it before the era of the space station to do scientific research. We used it as part of our partnership with the Russians, which is still continuing, first as part of the Mir space station, where we actually prolonged the useful life of Mir by several years through logistical supply visits with the shuttle. And now, of course, we're using it to build the new international space station, which is a… a huge international partnership.