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Venus is about to be ousted as the brightest star-like object in the night sky. The next space shuttle mission, STS-119 is slated to launch on Wednesday night, March 11 at 9:20 p.m. EDT (1:20 a.m. Thursday March 12 GMT), and astronauts will deliver and install the fourth and final set of solar array wings to the International Space Station. Once the array is deployed, the station will surpass Venus as the brightest object in the night sky, second only to the Moon. The new array will increase the amount of electricity available for science experiments by 50%, providing the power needed for the ISS to house a crew of 6 astronauts instead of the current 3.



The solar array truss segment, known as Starboard 6 or S6 for short, weighs 14,000 kilograms (31,060 pounds) and measures 5 meters (16.3 feet) wide, 13.8 meters (45.4 feet) long in the shuttle’s cargo bay. Once deployed, the ISS will then have four panels on each end of its power truss. Total surface area of all the arrays will be roughly one acre, generating 84 to 120 kilowatts of useable power, depending on the time of year and angle to the sun.

“It takes up the entire payload bay, so unlike the last flight (in November), this is pretty much what our focus will be on the mission, getting the element installed and activated and the wings deployed,” said ISS program manager Mike Suffredini.

There are a few interesting aspects to this mission. Two teachers are part of the crew, but they won’t be teaching from space. Both Richard Arnold and Joe Acaba, who were selected by NASA as part of the educator astronaut initiative, will be conducting two spacewalks each – one of those together –to help outfit the S6 truss, preparing it for deploy.

“As an educator,” Arnold said, “you presumably believe in the notion that education can take you anywhere. Here we are. We’re knocking on the door. We’re about to go to space.”

They hope to demonstrate that educators can contribute as astronauts, just as well as military pilots, engineers and scientists. “Teachers have to think on their feet and be at their absolute best all the time,” Acaba said. “Our performance will speak a lot for the profession.”



STS-119 also will bring up Japan’s first long-duration resident of the ISS station flier, veteran Koichi Wakata, who has flown on the shuttle twice previously. He’ll be taking the place of Sandy Magnus who has been on board the station for the past four months.

Other crew members are Commander Lee Archambault, pilot Tony Antonelli, and Mission Specialists John Phillips, and Steve Swanson.

This mission has been delayed because of concerns about possible cracks in the three hydrogen flow control valves used to pressurize the hydrogen section of the external fuel tank. But the valves have now been replaced and so far, the weather looks favorable for Wednesday night’s launch.



By the time Discovery leaves the station, the mass of the ISS will increase to 669,291 pounds – 335 tons – and construction of the station be 81% complete. S6 is the last US-built piece of the station.

Despite the delay getting Discovery off the ground, NASA still hopes to launch five missions this year.

The Hubble repair mission is scheduled for launch May 12, and Endeavour returns to space around June 13 for a mission to attach an external experiment platform on the space station’s Japanese Kibo lab module. Atlantis is scheduled to fly again in late August, followed by Discovery in November or December.

Sources: CSA, CBS Space Place