Shuttle Atlantisdocked with the International Space Station today and prepared to hand over a 35,000-pound truss for attachment to the half-finished research outpost.
Flight commander Brent Jett linked the shuttle with the station 218 miles above Earth during the mission to restart space station assembly for the first time in three-and-a-half years, since the 2003 Columbiadisaster.
Less than two hours later, Mr Jett and his five crew mates floated aboard the station to greet commander Pavel Vinogradov, flight engineer Jeff Williams and the European Space Agency's Thomas Reiter.
Mr Vinogradov and Mr Williams are nearing the end of their six-month tenure in orbit. Reiter, who arrived in July, will stay on board until the next shuttle mission in December.
Before climbing into the station, the Atlantisastronauts prepared to deliver the structural truss to the outpost, used the shuttle's robot arm to latch onto the girder in the shuttle's cargo bay.
The 45-foot girder, which contains a new pair of power-providing solar arrays, will be passed over to the station's robot arm later on Monday.
It is to be latched to the station itself tomorrow. Shuttle crew members will then perform the first of three planned spacewalks to complete the installation, in what Nasa has said is one of its busiest, most complex shuttle missions.
The solar panels were to be unfolded later in Atlantis's planned week-long stay. The new solar arrays will double the amount of electricity for the expanding International Space Station. When the station is complete, it will have four sets of US-made arrays.
Nasa plans at least 14 more shuttle flights to complete the space outpost before the shuttle fleet is retired in 2010.