Space Shuttle Discovery to Launch Tonight

CAPE CANAVERAL, Fla. - The space shuttle Discovery is poised to launch into orbit under a full moon tonight on a delivery mission to the International Space Station (ISS).

Discovery and her seven crewmembers are scheduled to blast off from a seaside launch pad at NASA?s Kennedy Space Center here at 9:20:10 p.m. EDT (0120:10 March 12 GMT) to begin their two-week construction flight.

Packed aboard the spacecraft is a new set of solar panels to be installed on the station, as well as the final stretch of the ISS's massive backbone-like girder. Discovery is also due to deliver even more precious cargo: Koichi Wakata, a Japan Aerospace Exploration Agency (JAXA) astronaut, who is to become his nation's first long-duration spaceflyer when he joins the station's Expedition 18 crew as a flight engineer for a six-month stay.

"I feel just lucky to be able to serve as a crew member to complete the assembly of the International Space Station," Wakata said in a NASA interview. While onboard the orbiting laboratory, he will devote much of his time to working in Japan's Kibo module, which was launched into space last year.

Clear skies

The weather appears to be cooperating for tonight's planned launch, with shuttle weather officer Kathy Winters estimating a 90 percent chance of "go" weather conditions.

Ground crews plan to begin filling the space shuttle's giant orange fuel tank with its liquid oxygen and liquid hydrogen propellant at 12:05 p.m. EDT (1605 GMT).

If for some reason Discovery is unable to launch tonight, mission managers have said they can try again up until March 16, though pushing the liftoff that late would mean cutting a few days off the planned 14-day flight.

This mission has been delayed for nearly a month because of concerns over suspect fuel control valves in the shuttle's main engines. During the last shuttle launch, Endeavour's November 2008 liftoff, a valve on that orbiter cracked, though it did not affect the flight. To be on the safe side, engineers replaced all three valves on Discovery with a new set known to be damage-free. Mission managers said they feel confident the issue poses no threat to the shuttle or its crew.

Teacher astronauts

Discovery?s STS-119 crew, commanded by Lee Archambault, also includes pilot Tony Antonelli and mission specialists Joseph Acaba, Steve Swanson, Richard Arnold, and John Phillips.

First-time spaceflyers Acaba and Arnold are both educator astronauts. Before joining NASA, the two men taught math and science. They have said they hope their trip to space will serve as an inspiration to students.

"If you look at our crew, we all come from very diverse backgrounds, different parts of the country, different experiences professionally, different family experiences," Arnold said in a preflight interview. "Yet, the one thing we do have in common is that education was a really important part of who we were growing up and even as adults. Those dreams are all out there for these kids that are sitting in school today to realize."

Acaba and Arnold are set to be the first teacher astronauts to walk in space when they help install the new hardware on the station during the mission's four planned spacewalks.

Home improvements

Discovery's payload represents the last major U.S. contribution to the space station, which will be 81 percent complete after the installation of the new girder. The $298 million Starboard-6 (S6) truss will finish the backbone of the station, extending it to the length of an American football field.

Once installed, the new solar array panels should boost the space station's power generating ability by 25 percent - an important step toward expanding the station's crew size from three to six, planned for this summer.

Discovery is also ferrying up a replacement part for a failed processor in the station's urine recycling system. The machine, which was delivered to the ISS in November 2008, was designed to turn the astronaut's pee into drinkable water, though it has been malfunctioning since the start. Mission managers said they hope the spare part being carried up by Discovery will do the trick to fix the system, which is also essential for hosting double-sized crews on the space station.

SPACE.com is providing continuous coverage of STS-119 with reporter Clara Moskowitz at Cape Canaveral and senior editor Tariq Malik in New York. Click here for mission updates and SPACE.com's live NASA TV video feed. Live launch coverage begins at 4:00 p.m. EDT (2000 GMT).

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