Space shuttle Endeavourheaded for Earth today after delivering a Japanese module and a Canadian robot to the International Space Station.
Its 16-day mission was scheduled to end with a landing at Kennedy Space Center in Florida tonight.
Weather forecasts looked favourable and the shuttle was in good shape except for a small nick in the windshield, possibly caused by space debris, said flight director Richard Jones. The nick did not stop NASA officials from clearing Endeavourfor landing nor did it concern the seven astronauts on the shuttle, he said.
Endeavour'sreturn will cap one of Nasa's longest and busiest shuttle missions. The ship was docked at the space station for 12 days during which the crew performed five spacewalks.
The crowning achievement of the flight was delivery of the first segment of Japan's three-piece Kibo laboratory.
The module's installation finally gave Japan a presence on the station and meant that all 15 partner nations are now represented on the $100 billion outpost.
The main lab of Kibo, which means "hope" in Japanese, will be delivered in a May shuttle mission, followed by the final piece, an external platform, early next year.Kibo will be the largest lab on the station, which is now 70 per cent complete.
The other big task was delivery and assembly of Dextre, a Canadian-built robot with 11-foot-long arms to perform maintenance on the station exterior.
Nasa plans 10 more shuttle missions to construct and supply the station before the space shuttle fleet is retired in 2010. It also has a shuttle mission scheduled this year to update the Hubble Space Telescope.