Weather Officer Kathy Winters now forecasts a slightly improved 40-percent chance that weather will allow an on-time liftoff this afternoon at 2:45 p.m. 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.

With all seven Atlantis astronauts strapped into their seats inside the crew compartment, the Closeout Crew members wished the STS-122 astronauts good luck and best wishes as they secured Atlantis' hatch for launch. The astronauts are now going through final checks inside the orbiter to prepare for their journey to the International Space Station.

During the last few minutes of the countdown, the access arm on the rotating service structure will swing away from the shuttle and the "beanie cap" covering the top of the external tank will lift up and move away.

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.

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.

News from Commercial Space Watch