The U.S. space shuttle Atlantis returned to Earth Friday after a week-long construction project at the international space station.

Atlantis landed at Cape Canaveral Florida, ending an 11-day mission to lengthen the space station's backbone.

The Kennedy Space Center control tower guided the touchdown.

"Welcome back to Earth, and congratulations on a truly spectacular mission expanding our new home in space," said the controller.

In their week at the station, the Atlantis crew mounted a 15-meter-aluminum girder, the second of 11 that will eventually span 100-meters to hold air conditioning, power, and data relay equipment for future research laboratories.

The effort required three spacewalks by two astronauts to connect kilometers of wires, optical fibers, and tubes carrying coolant through three large heat radiators.

A similar section is to be installed during the shuttle Endeavour's visit scheduled for November. That mission will also bring a fresh U.S. and Russian crew to the station.