An approaching cold front could thwart NASA’s plans to launch the space shuttle Endeavour on Friday on a flight to the international space station.
But the seven astronauts arrived Tuesday ahead of the countdown start and hopeful for an on-time liftoff.
“This mission is all about home improvement, home improvement both inside and outside of the international space station,” shuttle commander Christopher Ferguson said after arriving from Houston with his crew.
During the 15-day mission, the astronauts will deliver a new bathroom, kitchenette, two bedrooms and exercise machine, as well as a water recycling system. They'll also deliver a new resident for the space station, Sandra Magnus, who will replace her NASA colleague Gregory Chamitoff as one of the station's three crew members.
The plan is to expand the living quarters of the space station so the crew can be doubled to six by next June.
"On the inside of the space station, the walls are largely up," Ferguson said. “We've had some large modules delivered in the last year. Well, it’s moving day. It’s time to fill them up.”
He also noted the never-before-attempted repairs that are planned for outside the space station. Three of the crew will take turns going outside to clean and lubricate a clogged joint that is preventing one set of solar wings from turning automatically toward the sun, and they’ll replace its bearings.
Ferguson, a Navy captain and former test pilot, paid tribute to his fellow military service members on Veterans Day. "We have five active-duty members on this fine space shuttle crew," he said, "and we know what it means to serve."
This will be NASA’s first shuttle launch since the end of May.
“We haven’t had a launch for a while, so we’re really excited to be back in the saddle again,” said test director Jeff Spaulding.
The threatening cold front was moving across the central part of the nation Tuesday and was expected to bring rain and thick clouds to the launch site by week’s end.
Shuttle weather officer Kathy Winters said there was a 60 percent chance of acceptable conditions at the 7:55 p.m. ET Friday liftoff time and only a 40 percent chance on Saturday.
“The timing of the front will be critical,” she said.
NASA has a shuttle launch window until Nov. 25.
This report was supplemented by msnbc.com.