NASA's shuttle Atlantis and its seven-astronaut crew are on track for launch to the international space station, mission managers said Friday.
Commanded by veteran shuttle flier Stephen Frick, Atlantis will launch at 4:31 p.m. ET Thursday to deliver the European-built Columbus laboratory to the ISS.
"Atlantis is on the pad ready to go, with no major issues or concerns regarding that vehicle," NASA shuttle program manager Wayne Hale said during a briefing at the agency's Kennedy Space Center in Cape Canaveral, Fla.
Atlantis' STS-122 mission will mark NASA's fourth shuttle flight of 2007, the most in a single year since the agency resumed orbiter flights after the 2003 Columbia tragedy, and comes after a packed month of construction work by the station's Expedition 16 astronauts. The three-person crew performed three spacewalks in 15 days and some tricky robotic arm work to ready the station and its new Harmony connecting module for the European Space Agency's Columbus lab.
"In my mind, it's been an unprecedented year for us," said Mike Suffredini, NASA's space shuttle program manager. "I will say, we always knew this particular moment was going to be a challenging moment for us."
Delivered by the shuttle Discovery last month, the Harmony module is designed to serve as the anchor for Europe's Columbus module and Japan's massive, three-segment Kibo laboratory, which will launch in stages next year to further expand the $100 billion space station.
Frick and his STS-122 crewmates will perform at least three spacewalks during their planned 11-day mission to install Columbus, replace station hardware and swap out one member of the station's Expedition 16 crew.
If Atlantis' power supplies hold out, NASA may extend the mission by two extra days and add a fourth spacewalk to take another look at a balky rotational joint designed to turn the station's starboard solar wings like a paddlewheel to track the sun. Previous limited inspections by spacewalkers found the joint to be contaminated with metallic grit, and engineers require additional data before they can decide on a repair plan.
"With some power downs, we can get a couple of extra days," Suffredini said. "During a [fourth spacewalk] we'd do some thorough inspections of the solar array joint."
But if Atlantis' power supplies can't support the extra spacewalk or its astronaut crew grows too fatigued, the inspection could be shifted to later in the Expedition 16 mission, he added.
NASA plans to launch some spare parts for the joint aboard Atlantis and another shuttle set to launch in February, to prepare for what could be a lengthy repair requiring multiple spacewalks, mission managers said.
Engineers also suspect that indications of a possible air leakin seals between the station's Harmony module and Destiny lab are the result of instrumentation error. A series of tests this week, some of which are continuing, have yet to turn up any sign of an actual leak.
"The data suggests this leak does not exist," Suffredini said.