Cape Canaveral, Fla. ? An approaching cold front could thwart NASA’s plans to launch 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,” shuttle commander Christopher Ferguson said after flying in 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 – and a new resident for the space station. Astronaut Sandra Magnus will replace one of the three space station residents.

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. “Well, it’s moving day. It’s time to fill them up.”

Ferguson 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.

This will be NASA’s first shuttle launch since the end of May.