Friday the 13th was a good day as repairs began on the Ground Umbilical Carrier Plate (GUCP) interface, where gaseous hydrogen leaked during Wednesday's launch attempt. The interface then will be retested and leak checked before Sunday's 7:43 p.m. tentative launch attempt. The Mission Management Team (MMT)will meet on Saturday at 1 p.m. to review the data and the progress of the teams, and make a final determination on the launch. A Prelaunch News Conference will be held no earlier than 3 p.m. following Saturday's MMT. Image: A closeup of the 7-inch quick disconnect that will be replaced on the hydrogen vent line to the Ground Umbilical Carrier Plate of space shuttle Discovery's external fuel tank. Photos courtesy of United Space Alliance.

The weather forecast calls for an 80 percent chance of acceptable conditions at launch time. Meteorologists are watching for low cloud ceilings, Shuttle Weather Officer Kathy Winters said. The forecast deteriorates for potential Monday and Tuesday attempts.

The mission would last 13 days if Discovery launches Sunday, with the astronauts performing three spacewalks during the flight. Discovery's astronauts awoke at 9 a.m. and underwent standard medical exams at 10 a.m. Commander Lee Archambault and Pilot Tony Antonelli will practice landings in the Shuttle Training Aircraft at 7 p.m.

Commander Lee Archambault will lead Discovery's crew of seven, along with Pilot Tony Antonelli, and Mission Specialists Joseph Acaba, John Phillips, Steve Swanson, Richard Arnold and Japan Aerospace Exploration Agency astronaut Koichi Wakata on mission STS-119 to the International Space Station.

The Discovery crew members are set to fly the S6 truss segment and install the final set of power-generating solar arrays to the International Space Station. The S6 truss will complete the backbone of the station and provide one-fourth of the total power needed to support a crew of six.