During a review of space shuttle Discovery's readiness for flight, NASA managers decided Tuesday to plan a launch no earlier than Feb. 19. The new planning date is pending additional analysis and particle impact testing associated with a flow control valve in the shuttle's main engines. Discovery's STS-119 mission to the International Space Station originally had been targeted for Feb. 12. The valve is one of three that channels gaseous hydrogen from the engines to the external fuel tank. One of these valves in shuttle Endeavour was found to be damaged after its mission in November.

As a precaution, Discovery's valves were removed, inspected and reinstalled. The Space Shuttle Program will convene a meeting on Feb. 10 to assess the analysis. On Feb. 12, NASA managers and contractors will continue the flight readiness review, which began Tuesday, to address the flow control valve issue and to select an official launch date.

Space shuttle Discovery's STS-119 crew is 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, with its set of large U.S. solar arrays, will complete the backbone of the station and provide one-fourth of the total power needed to support a crew of six.

The two solar array wings each have 115-foot-long arrays, for a total wing span of 240 feet. They will generate 66 kilowatts of electricity -- enough to provide about 30 2,800-square-foot homes with power.

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.

What is the Flight Readiness Review?

Approximately two weeks prior to the opening of the launch window for each space shuttle, the Shuttle Mission Management Team meets at Kennedy Space Center for a thorough review of the next mission. Also in attendance are other top-level NASA officials, Space Shuttle Program managers, engineers and contractors. The group conducts a comprehensive evaluation of all activities and elements necessary for the safe and successful performance of shuttle mission operations -- from the prelaunch phase through post-landing. They also examine the readiness of the space shuttle, flight crew and payloads to determine if everything is set to proceed with launch.

At the conclusion of the review, the chairman of the Mission Management Team conducts a poll of the team members. If there are no unresolved issues, the members then sign a "Certification of Flight Readiness" to verify that all flight preparation processes to that date have been successfully completed. The official launch date is then set and announced, and shuttle processing continues toward the projected liftoff date.

Wakata will replace Expedition 18 Flight Engineer Sandra Magnus, who will return to Earth with the STS-119 crew. Wakata will serve as a flight engineer for Expeditions 18 and 19, and return to Earth with the STS-127 crew.

Discovery's STS-119 mission to the International Space Station is targeted to lift off no earlier than Feb. 19.

Additional Resources
› STS-119 Mission Summary (562 Kb PDF)
› STS-119 Press Kit (4.9 Mb PDF)