The shuttle Endeavour descended safely to Earth on Friday, ending a successful 16-day assembly mission to the International Space Station (ISS) with the final piece of Japan's Kibo science laboratory.
The seven US, Canadian and Japanese astronauts aboard Endeavour touched down at NASA's Kennedy Space Center in Florida at 10:48 am (1448 GMT).
There were concerns that early morning thunder storms, coastal rain showers and fog near the Florida landing site might force shuttle commander Mark Polanski and his crew to postpone their return until Saturday.
However, the stormy conditions improved after daybreak, allowing Endeavour to begin its high-speed descent to Earth.
Endeavour's crew includes Koichi Wakata, Japan's first long-duration astronaut. He returned to Earth after 138 days in space, spent mostly aboard the space station carrying out experiments in Kibo.
"Welcome home, congratulations on a superb mission from beginning to end," said mission control, as the shuttle rolled to a stop on the Florida runway under sunny skies.
"That's what it's all about," said Polansky, who shared the controls with pilot Doug Hurley for the landing after a "fantastic mission."
"We are happy to be home," Polansky said.
Wakata, adjusting to Earth's gravity after more than four months of weightlessness, told reporters "I still feel a little shakey when I walk, but I'm feeling great."
The Japanese astronaut, who turns 46 on Friday, said he was hoped to celebrate by "having a lot of sushi and birthday cake."
The shuttle astronauts delivered and installed the last major piece of the one-billion-dollar Japanese research complex, the largest and most capable of the station's three primary science modules.
"Completing the assembly of all the Kibo elements makes possible various experiments," he said.
"It's extremely important to our country. In addition to gaining valuable knowledge from experiments, Wakata's mission advances our country's future manned space exploration."
The new open platform for external science experiments was fastened to the primary research enclosure and a equipment stowage chamber that were launched last year.
The astronauts also furnished the new platform with an X-ray telescope, an environmental monitor and a communications device to link the space station lab with Japan's mission control in Tsukuba.
Four of the astronauts carried out five long spacewalks in which they equipped the oldest of the station's outstretched solar power modules with new storage batteries and stowed away an assortment of large external spare parts.
Both activities were intended to ensure that the station functions beyond the planned retirement of NASA's space shuttle fleet, now planned for late 2010.
And with 13 astronauts on the ISS, it was the first time representatives from all of the station's partners have been on the spacecraft at the same time.
The large number of astronauts on the station became a challenge in and of itself. One of the station's two toilets broken during the mission, as did another device that cleans the breathing air of carbon dioxide.
"Though people think flying on a space station is maybe somewhat routine, it's tremendously challenging," said Polanski.
"You are in a very, very unforgiving environment. Seemingly innocuous things become huge impediments," he said.
Endeavour dropped off American astronaut Tim Kopra at the orbital outpost, where he joined five Russian, Canadian and European fliers.
Kopra, who is making his first trip to space, is scheduled to return to Earth aboard the shuttle Discovery in early September.
Meanwhile, NASA is preparing the shuttle Discovery for an August 25 mission scheduled to last 11 days.
Discovery's astronauts will deliver research equipment, medical gear and other supplies to the orbital outpost. With the looming retirement of NASA's shuttle fleet, seven missions remain.
Source: AFP Global Edition