In the next eight days, crews will perform tasks to prepare for the installation of a European laboratory.
During the past several space-station construction missions, the phrase "most complex" has virtually become a cliché.
Yet, in the history of human spaceflight, no single building or patching job in space has ever been as complicated as the one confronting the crews of the shuttle Discovery and the International Space Station (ISS) during the next eight days. Nor are there likely to be any challengers over the shuttle program's remaining two years.
If all goes well, in a record five space-walks, the crews will have installed an Italian-built module on the station and rendered it fit for human occupancy. They will have used the shuttle's and station's robotic arms as an orbiting bucket brigade, gingerly passing an 18.5-ton set of solar panels from its current temporary location to a permanent spot at one end of the station's backbone, or truss. The distance covered: roughly half the length of a football field. And spacewalkers will have disconnected and reconnected various exterior power and cooling lines.
Once the tasks are finished – and the space-station crew conducts two additional spacewalks between now and December – the station will finally be fit to receive the first major laboratory built by the station's non-US partners: Europe's Columbus laboratory, slated for launch aboard Atlantis on Dec. 6.
The module being installed in the next week, dubbed Harmony by the United States and Esperia by the Italians, "is a gateway to the international partners' laboratories," says Derek Hassmann, NASA's lead flight director for the space station.
Little wonder, then, why the partners are eager to see it installed. "This is the start of a very exciting period for Europeans," notes Alan Thirkettle, space-station program manager for the European Space Agency (ESA). Yet he adds, "We can't get too excited. We're big enough and ugly enough to know we can be disappointed in this game. But we're getting there."