(AP) -- NASA zipped through the final hours of its countdown for space shuttle Endeavour, on track for a Saturday morning launch to the international space station.
Forecasters were sticking with their 90 percent "go" weather forecast.
NASA was to begin fueling the spaceship late Friday night, with the seven astronauts climbing aboard in the wee hours of Saturday. Launch time is 7:17 a.m., less than an hour after sunrise.
Endeavour and its crew will deliver the final segment of Japan's huge space station lab, along with some spare parts for the orbiting outpost and more than 600 pounds of food for the six men living at the orbiting outpost.
When Endeavour pulls up, there will be 13 people together in orbit for the first time.
Of the seven shuttle astronauts, only one is a woman, a Canadian. The rest of the crew are U.S. citizens. On board the space station, the crew is more international. The six occupants, all men, represent Belgium, Canada, Japan and Russia, as well as the United States.
"It's like having your family descend on you for the holidays, right? And they're going to stay for a very long time when they come and they're bringing all their stuff," observed Mike Moses, chairman of NASA's mission management team.
Endeavour and its crew will spend 11 1/2 days at the space station. Five spacewalks are planned.
"These crews have trained together quite a bit. They knew that they were going to be overlapping ... so they've gotten some good relationships with each other," Moses said Thursday.
The shuttle's arrival comes at a particularly busy time for the space station. The station crew doubled in size late last month; that's taken some adjustment for everyone involved. Then just a week ago, two of the crew went out on a spacewalk. Earlier this week, the two put their spacesuits back on and went into the air lock to work on a docking hatch.
NASA is pushing to launch Endeavour now because of the tight lineup of shuttle flights over the next 1 1/2 years. The space agency is under presidential direction to retire its three remaining shuttles and complete the station by the end of 2010 if possible.
Eight shuttle missions remain, including Endeavour's upcoming trip. Each one is dedicated to finishing the station, currently 81 percent complete, and hauling up supplies, spare parts and experiments.
The space station will be supplied over the long haul by unmanned Russian, European and Japanese craft, but none as big as the shuttle. That's why NASA needs to deliver large spare parts now, while the shuttles are still flying.
Until NASA's new spaceship is ready to carry passengers - which isn't expected to happen before 2015 - U.S. astronauts will hitch rides back and forth on the cramped Russian Soyuz spacecraft for up to $51 million a person.
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