The Space Shuttle Endeavour's launch countdown operations continued without a hitch July 10, although predicted stormy weather continues to threaten the scheduled July 11 7:39 p.m. EDT liftoff. The mission, hauling the large, last pieces of the Japanese Kibo laboratory exposed complex to the International Space Station, was scratched twice in June due to a launch-pad hydrogen gas leak that NASA thinks it has successfully fixed.
NASA's latest weather forecast for the Endeavour's launch window gives the mission only a 40 percent chance of getting off the ground. NASA said Endeavour had until July 14 to blast off before having to stand down until July 27 to make way for a scheduled Russian Soyuz mission to the ISS.
"Everybody is 'go' for launch; we have no major issues at all," Mike Moses, chairman of the mission management team, said at a July 10 briefing. "I don't worry about things I can't control, and I can't control the weather."
Rollback of the rotating service structure at Launch Pad 39A at Cape Canaveral is set to begin July 10 at 11 p.m. EDT, setting the stage for the filling of Endeavour's external fuel tank July 11 at approximately 10:14 a.m. EDT.
If the liftoff is successful, Endeavour is scheduled to dock at the ISS July 13 with a cargo bay full of work that will require five spacewalks over the course of the 16-day mission. A "front porch" for the ISS, the Kibo laboratory complex will allow for space-exposed science experiments.
"It's a real exciting mission. We are the last mission that is taking up Japanese hardware on a space shuttle ... really big pieces of equipment that we're going to go ahead and leave behind on the space station for construction," Polansky said in a preflight interview.
Also inside Endeavour's cargo bay will be an integrated cargo carrier holding several pieces of spare equipment for the space station. Most of it-a spare space-to-ground antenna, a spare linear drive unit and a spare pump module-will be stored on an external storage platform on the station's truss. Six batteries for the station's oldest solar array will be installed.
Once the Endeavour reaches the ISS, things will be as busy inside the shuttle and space station as for the spacewalkers, with all three of the available robotic arms being put to use, sometimes all on the same day. The shuttle's Canadarm and the station's Canadarm2 will be put through their paces for surveys, unloading cargo and moving equipment and spacewalkers around, and a new Japanese robotic arm will be making its debut to transfer science experiments.
"It's certainly really exciting for JAXA [Japan Aerospace Exploration Agency]," said Polansky. "For them, this is the last of their hardware that's going to be permanently attached to the space station. This completes their series."
The mission also marks another milestone for JAXA with Japanese flight controllers on the ground operating their own berthing mechanisms for the first time. The Kibo external facility will never need to be connected to anything but a Japanese-built module, so JAXA was free to use any berthing mechanism.
"Before, even when we had pieces of hardware that were built by someone else, we have, here in the U.S. control center, still maintained a lot of the technical leadership," said ISS Flight Director Holly Ridings. "In this case, they truly have technical leadership for some of the things that must work to make the mission a success. It's unique."