Space shuttle Endeavour and seven astronauts, including the first Japanese to live on the International Space Station, landed in Florida today, capping a 16-day mission to complete construction of Japan's orbital laboratory.
Soaring over the Florida peninsula, Endeavour commander Mark Polansky gently circled the 100-ton ship to burn off speed, then nosed Endeavour to a Kennedy Space Center landing strip rimmed by swamps and palm trees at 1448 GMT.
"Welcome home Endeavour. Congratulations on a superb mission from beginning to end. Very well done," astronaut Alan Poindexter radioed to the crew from Mission Control in Houston.
"We're happy to be home," Polansky replied.
During an 11-day stay at the space station, Endeavour's crew installed the final segment of Japan's $2.4 billion Kibo laboratory, a platform for telescopes and other science experiments.
They also replaced batteries to keep the solar-powered station running during night-time passes around Earth and delivered spare parts.
NASA is stocking the $100 billion station, a project of 16 nations, in preparation for the shuttle fleet's retirement next year after seven more missions.
Using a Japanese-built robot arm for the first time, astronauts placed three devices on the new platform: an X-ray telescope, a monitor to measure electromagnetic fields around the station and a communications antenna for a Japanese satellite network.
One of the Endeavour astronauts, rookie Timothy Kopra, remained behind on the station, taking over the flight engineer's post previously held by Japan's Koichi Wakata, who returned home aboard the shuttle after 4 1/2 months in orbit.
"We miss Koichi already but we have a very good replacement on board," said space station crew member Frank De Winne, who watched Endeavour's landing with his crewmates on a live video feed.
Kopra may have a relatively short stay on the station. Endeavour's launch was delayed a month by weather and technical problems and his ride back to Earth is scheduled to launch on August 25.
NASA, however, is still working to understand why a large amount of foam fell off Endeavour's fuel tank during launch and will not clear Discovery, the next shuttle to fly, until it is sure the problem will not be repeated.
Endeavour was not damaged by falling debris, but foam shedding from the tank has been a serious issue since the 2003 Columbia accident.
Columbia was damaged by a piece of falling foam insulation during launch. It broke apart as it flew through the atmosphere for landing, killing all seven astronauts aboard.
Tests of Discovery's tank foam show it is properly bonded to the tank, said deputy shuttle program manager LeRoy Cain, although additional analysis is under way.
Engineers suspect Endeavour's tank was not properly cleaned before its foam insulation was sprayed on, or that there was some other type of contamination, Cain said.
"I think at this point it's going to be very, very difficult for us to positively get to (the) root cause," he said. "We don't have any reason to think that (Discovery's tank) has similar kinds of problems."
Also returning to Earth aboard Endeavour were pilot Doug Hurley, flight engineer Julie Payette, with the Canadian Space Agency, and spacewalkers David Wolf, Tom Marshburn and Chris Cassidy.