Discovery Comes Home
Frank Morring, Jr. morring@aviationweek.com 
The space shuttle Discovery landed safely at Kennedy Space Center, winding up a 13-day mission to give the International Space Station its fourth and final solar array wing and life support equipment needed when the crew doubles to six in May.
Discovery commander Lee Archambault and pilot Tony Antonelli flew Discovery over the Yucatan Peninsula, the Gulf of Mexico and Florida before executing a wide left turn to bring Discovery down to a 3:14 p.m. EDT landing on Runway 15 at the KSC shuttle strip.
The mission ended where it began March 15, bringing home seven NASA astronauts including Sandra Magnus, who spent 136 days in space as a member of the station's Expedition 18 crew. Left behind on the station was veteran Japanese astronaut Kioshi Wakata, his country's first space station crewman.
Landing came after Discovery completed almost 202 orbits, including an extra one at the end after the first landing attempt was waived off because of doubtful weather at the Florida landing site. The weather problems -- a cloud deck and crosswinds gusting into the unsafe zone -- improved enough during the final orbit for descent flight director Richard Jones to okay a 2-minute, 59-second deorbit burn that started at 2:08 p.m. EDT.
The STS-119/15A ISS assembly mission plugged in the final section of the station's main truss at the starboard end and unfurled its four big solar array blankets. Discovery also delivered a replacement distillation assembly that checked out before the orbiter undocked March 25, and brought home samples of water cleaned by the station's new water recycling system for safety analysis on the ground.
Recycled water and the power from the new solar arrays will be needed to support the station's six-person crew, particularly after the space shuttle fleet stops flying next year. Until then, station crews can continue to draw water from the orbiter's fuel cell power systems if necessary.
Discovery astronauts conducted three spacewalks during the mission, which was cut short by one spacewalk by a delayed launch and the need to leave the station before Soyuz TMA-14 arrived with a new station crew. That vehicle docked earlier today.
While the first extravehicular activity (EVA) went well, with spacewalkers Steve Swanson and Richard Arnold bolting on the new truss element and connecting its power and data cables, the next two EVA's had to be rechoreographed when a platform for spare-parts stowage failed to deploy properly. Ultimately Arnold and fellow EVA astronaut Joe Acaba had to tie the platform down securely with tethers until engineers can develop a plan for getting it into the proper position.
Despite the problem with the spare-parts platform, the mission accomplished its main objectives and left the way clear for the next shuttle visit in June to install an external experiment platform on Japan's Kibo laboratory module.
Photo credit: NASA TV
