Early this morning, the Mission Management Team met and gave the "go" for loading space shuttle Atlantis' external fuel tank with 500,000 gallons of liquid oxygen and liquid hydrogen. The first test of repairs on the wiring for the engine cut-off sensors will come when they are expected to give a "wet" reading as the tank fills.
There are four engine cut-off, or ECO, sensors inside the liquid hydrogen section of the tank. The sensors are part of several systems that protect the shuttle's main engines by triggering them to shut down if fuel runs unexpectedly low.
Liftoff is scheduled for 2:45 p.m. EST, which is the middle of the 10-minute launch window. The timing is precise so Atlantis can catch up and dock with the International Space Station.
Forecasters expect a cold front to move over Kennedy around launch time, bringing with it clouds and storms, resulting in only a 30 percent chance of good weather for liftoff. Further, there is a possibility that the front may stall over Central Florida, lowering the chances for acceptable weather for launch attempts on Friday or Saturday.
NASA has strict flight rules for weather that include limits on cloud height, storms in the area and clouds that could produce lightning. The criteria are set in part by the conditions a shuttle would need if it has to make an emergency landing soon after liftoff.
The good news for Atlantis and crew is that no technical issues are reported.
NASA astronaut Steve Frick commands a crew of six, including Pilot Alan Poindexter and Mission Specialists Leland Melvin, Rex Walheim, Stanley Love and the European Space Agency's Hans Schlegel and Leopold Eyharts. This is the first spaceflight for Poindexter, Love and Melvin.
During the 11-day mission, the crew's prime objective is to attach the European Space Agency's Columbus Laboratory to the International Space Station, adding to the station's size and capabilities.
Expedition 16 Flight Engineer Daniel Tani, who arrived at the station aboard Discovery in October, will return to Earth with the Atlantis crew as Eyharts takes his place on the station.
Shuttle mission coverage is available online at the
Image above: Space shuttle Atlantis is revealed on Launch Pad 39A after the rotating service structure, or RSS, at left of the pad was rolled back. Photo credit + text: NASA/Kim Shiflett