Space shuttle Endeavour and its crew of seven returned to Earth, making a rare nighttime touchdown to wrap up "a two-week adventure" at the international space station. The shuttle swooped through the darkness and landed on NASA's illuminated runway at 8:39 p.m. Wednesday (0039 GMT Thursday), an hour after sunset. "Welcome home, Endeavour," Mission Control radioed. "Congrats to the entire crew." Replied Endeavour's commander, Dominic Gorie: "It was a super-rewarding mission, exciting from the start to the ending." Returning aboard Endeavour was French Air Force Gen. Leopold Eyharts, who spent 1 1/2 months aboard the space station, and Japanese astronaut Takao Doi, who accompanied his country's space station contribution to orbit. Raising the Kibo lab's storage compartment from Endeavour's payload bay for attachment to the space station "was a great moment not only for me, but for Japan," Doi said late Tuesday. It was concrete evidence, finally, of the Japanese Space Agency's partnership in the longtime station project. The shuttle's homecoming was a bit delayed. Endeavour was supposed to land before sunset, but at virtually the last minute, clouds moved in. As the astronauts took an extra swing around the planet, the sky cleared enough to satisfy flight controllers and - after asking Gorie for his opinion - they gave him the green light to head home. It was only the 22nd space shuttle landing in darkness. Less than one-fifth of all missions have ended at nighttime; the last one was in 2006. Endeavour blasted off March 11 - also in darkness - on an ambitious, intense space station construction mission that had even its commander wondering at times how everything would go. In the end, Gorie and his multinational crew accomplished everything they set out to do during their voyage, which spanned 16 days and 6.5 million miles. The astronauts installed the first piece of Japan's Kibo lab, put together a giant Canadian robot named Dextre, tested a shuttle repair technique and more. NASA Administrator Michael Griffin said he told Gorie after touchdown that "he had really flown two missions in one for us." "I can't imagine that the mission could have gone any better, and they made it look easy," Griffin said. The space station is now 70 percent complete, thanks to the latest additions, with a mass of nearly 600,000 pounds. Ten more shuttle flights to the space station - spread over the next two years - will round out the numbers. NASA hopes to have its share of the orbiting outpost finished in 2010 and its three shuttles retired, so it can focus on human expeditions to the moon. "This has been a two-week adventure," said Gorie's co-pilot, Gregory Johnson, before landing. "It's been a pleasure and an honor to be on it." Discovery is scheduled to fly to the space station in late May, carrying up Japan's enormous Kibo lab. The fuel tank for that mission arrived at Kennedy Space Center on Wednesday, later than planned, and Griffin said that almost certainly will mean a launch delay of at least a few days. Subsequent fuel tanks also could get backed up because of all the design changes necessitated by the 2003 Columbia disaster. NASA expects to have a better idea in another month whether it can keep the year's launches on track. Space shuttles are supposed to soar four more times in 2008, which would mean six missions for the year, a flight rate not seen since 2001. Up on the space station, meanwhile, the three occupants are gearing up for next week's arrival of the European Space Agency's supply ship, Jules Verne. The unmanned cargo carrier - the first of its kind - rocketed away from French Guiana this month with a load of food, water and clothes. Less than a week after that, on April 8, the Russians will launch a fresh space station crew from Kazakhstan.