Space Shuttle Endeavour Go for Friday Launch
The space shuttle Endeavour stands atop Launch Pad 39A for the planned Nov. 14, 2008 launch of its STS-126 mission to the ISS.
Credit: NASA/Troy Cryder.

CAPE CANAVERAL, Fla. - The shuttle Endeavour and seven NASA astronauts are cleared for their planned Friday night launch toward the International Space Station, mission managers said Tuesday.

Endeavour is poised to blast off from its seaside launch pad here at NASA?s Kennedy Space Center (KSC) on Nov. 14 at 7:55 p.m. EST (0055 Nov. 15 GMT) on a busy mission to prime the station for larger, six-person crews. The potential for thick clouds and nearby rain showers still plague the planned space shot, though Endeavour has a 60 percent chance of favorable launch weather.

"We're ready to go," said LeRoy Cain, chair of Endeavour?s mission management team, in a status briefing. "The vehicle and crew and ground teams have prepared very hard for this mission."

Commanded by veteran spaceflyer Chris Ferguson, Endeavour's STS-126 crew is preparing for a planned 15-day mission to the space station. Astronauts plan to swap out one member of the outpost?s three-person crew and perform four spacewalks to clean and grease up a damaged solar array joint during their orbital stay.

Endeavour is hauling a spare space toilet, second kitchen, new exercise equipment and a water recovery system designed to recycle urine into potable water. The first refrigerator to chill drinks and food for station crewmembers is also aboard the shuttle.

Set to launch toward the station with Ferguson are shuttle pilot Eric Boe and mission specialists Don Pettit, Steve Bowen, Heidi Stefanyshyn-Piper, Shane Kimbrough and Sandra Magnus. Magnus will replace NASA astronaut Greg Chamitoff aboard the station as part of the outpost?s Expedition 18 crew. The astronauts arrived at their launch site here late Monday after taking an aerial look at Endeavour atop the launch pad.

"It looks good on the pad and we?re very excited about getting up to orbit," Stefanyshyn-Piper said.

The weather forecast for the Friday night launch remains dicey, with nearby rain showers within 20 miles (32 km) of the launch site and thick clouds posing the only concerns, said Kathy Winters, NASA?s shuttle weather officer. A weather front is expected to arrive over the spaceport late this week, she added.

"Right now, weather is looking a little bit marginal with a 40 percent chance of KSC weather preventing launch," Winters said.

The weather on Saturday is even worse, with Endeavour sporting just a 40 percent chance of good launch weather, she added.

NASA must launch Endeavour by Nov. 25 to avoid unfavorable heating and sun angles at the International Space Station. Mission managers would prefer, however, to launch the shuttle by Nov. 21 to avoid docking conflicts with the unmanned Russian Progress 31 cargo ship, which is currently slated to arrive at the station on Nov. 30.

Endeavour?s STS-126 mission will mark NASA?s fourth shuttle flight of the year, the most in a single year since 2002. It is also the second night launch of 2008 for NASA?s shuttle fleet, and Endeavour in particular. The shuttle last lifted off in darkness during its STS-123 mission in March.

About 31 of NASA?s 123 shuttle missions to date have launched in darkness to light up the Florida sky.

"Night launches are special," said Mike Leinbach, NASA?s shuttle launch director. "They sure are."