Launch Lights Up The Florida Twilight Sky

ANN REALTIME UPDATE 03.15.09 1945 EDT: "Rock 'n roll, Discovery!" That message of encouragement from launch control came five seconds after the space shuttle Discovery cleared the launch tower, heading into orbit on a mission to deliver the last set of solar panels to the International Space Station.

Discovery rocketed off the pad at 1943 EDT, lighting the twilight sky over NASA's Kennedy Space Center. This is the 125th shuttle mission, and 36th for the oldest orbiter in NASA's shuttle fleet.

The STS-119 crew will rendezvous with the ISS Tuesday.

Earlier Reports

1820 EDT: It looks like we're gonna light this candle! The closeout crew has locked Discovery's hatch and is getting ready to leave Launch Pad 39A at NASA's Kennedy Space Center in Florida. The astronauts inside Discovery can open the hatch quickly in an emergency, but the countdown is moving along with no technical concerns.

The crew members are going through checklists and the launch team is watching over the systems and subsystems of the shuttle as launch time nears. Shuttle Weather Officer Kathy Winters has upgraded the launch forecast to 100 percent "go" for the 7:43 pm EDT liftoff of space shuttle Discovery.

The astronauts are strapped inside the shuttle, with four on the flight deck and three on the lower level of the crew compartment. Commander Lee Archambault and Pilot Tony Antonelli are seated in the front seats surrounded by the instrument panels and windows needed to control the shuttle. Steve Swanson will serve as flight engineer during ascent, so he is sitting behind and between Archambault and Antonelli. Joseph Acaba is in a seat behind Antonelli where he, too, can help out during launch.

On the lower deck, Richard Arnold is closest to the hatch. John Phillips is in the center seat and Japan's Koichi Wakata is in the right-most seat. Sandra Magnus will sit in his place during landing, after Wakata transfers to the International Space Station.

During Discovery's 13-day mission, the STS-119 crew members will deliver 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.

1415 EDT: The clock is ticking towards the scheduled launch of the space shuttle Discovery on its STS-119 mission to the International Space Station. NASA has completed the three-hour process to fuel the external tank, and there are no indications of the leak that scrubbed Wednesday's launch attempt.

T-minus zero is scheduled for 1943 EDT Sunday night. At the moment, the countdown clock has entered a planned hold at T-3 hours, and NASA says everything remains on schedule for the launch of space shuttle Discovery.

The weather forecast calls for an 80 percent chance of acceptable conditions at launch time, with negligible concern for the potential for low cloud ceilings in the area.

As ANN reported, NASA discovered a potentially catastrophic hydrogen leak while fueling the orbiter Wednesday morning. The leak developed on the piping that runs from the fixed service structure to a valve at the intertank section of the shuttle's external tank. The pipe moves hydrogen gas away from the shuttle and to a flare stack near the launch pad that burns it away safely.

Originally scheduled to liftoff February 12, Discovery was grounded for a month as NASA examined hydrogen flow control valves linking the external tank to the orbiter. One of those valves was found cracked after Endeavour returned from its mission in November; NASA opted to swap the valves originally installed on Discovery, with lower-time parts.

FMI: www.nasa.gov/shuttle