The Atlantis and its seven-member crew are to take off from the Kennedy Space Center in Florida Thursday  at 2:45 p.m. Eastern time on an 11-day mission that will attach the European Space Agency’s new Columbus science laboratory to the station.

The biggest potential obstacles to a Thursday launching are rain, low clouds and winds expected around liftoff time, Air Force weather forecasters said. The Atlantis has only a narrow launching window each day to reach the station since it must lift off at roughly the time the earth’s rotation lines up the launching pad with the plane of the station’s orbit.

Two attempts to fly the mission in early December were thwarted by irregular readings from four sensors at the bottom of the shuttle’s large external fuel tank N. Wayne Hale Jr., director of the space shuttle program, said tests showed the problem was in temperature-induced gaps where sensor wires attached to a connector when super-cold liquid hydrogen fuel filled the tank. Soldering the wires to the connector solved the problem, he said,

The last remaining technical issue, a bent radiator hose, also was resolved, officials said. Flexible metal hoses carry Freon coolant to radiators in the shuttle’s cargo bay doors that dissipate heat from the electronics.