Even as NASA marks the second anniversary of the Columbia accident, and the tragic loss of seven astronauts returning home after a successful flight, agency officials and astronauts are looking toward a return to space shuttle flights.
All the pieces for NASA's next shuttle launch, Discovery's STS-114 mission, sit at NASA's Kennedy Space Center (KSC), where engineers work to prepare them for flight with the lessons learned from the Feb. 1, 2003 loss of Columbia and its crew fresh in their mind.
"I think the agency is a different agency today than it was two years ago," said Jim Kennedy, director of the Kennedy Space Center -- NASA's Florida spaceport -- in a telephone interview. "We now have a really strong group of checks and balances, and we're a better agency for it."
Columbia was destroyed during reentry by a disaster precipitated days earlier during launch, when a chunk of foam from its external fuel tank gouged a hole in the shuttle's left wing. NASA has spent the two years since devising safer ways for humans to reach space.
In the meantime, the space agency's three remaining shuttles have been grounded, leaving only Russian Soyuz spacecraft to ferry new crews to the International Space Station (ISS).
"Because of the Columbia accident we are constantly, diligently, 24-7, working at fixing it so that we know that when it comes time to fly we have done our absolute best," said NASA chief Sean O'Keefe during a recent memorial service for the crew of Columbia, as well as the lost astronauts of the 1986 Challenger accident 1967 Apollo 1 fire. "We will never eliminate the inherent risk, though I know each of us will work to minimize that risk."
Among that work was the installation of new sensors along Discovery's wings to check for impacts, as well as an orbiter boom designed to scan the integrity of orbiter's underbelly in space and a redesigned external fuel tank that agency officials claim is the safest ever built.
But the agency has also worked to revamp its internal culture, which was cited by Columbia accident investigators as a contributor to the accident.
"For NASA, [return to flight] is a very important milestone," NASA's Lynn Cline, deputy associate administrator for space operations, told SPACE.com. "It's an indication that we have learned the lessons we've needed, fixed the problems and have a tangible demonstration that we're moving forward."
To test out those new technologies -- including a new flight maneuver expected to give space station astronauts a chance to photograph orbiters before docking -- shuttle officials have put two launches on the docket for this year. Discovery and the STS-114 crew is targeting a May-June liftoff, to be followed later by Atlantis. But agency managers are cautious to say that target dates are not binding.
"It's not in the bag and it's not a done deal," Kennedy said of Discovery's launch target. "We're committed to fly in May or June if we can, but we're not schedule-driven."
At KSC, engineers are preparing the Discovery and Atlantis orbiters for flight in tandem to prepare the off chance that something does go wrong with Discovery in flight and its crew left aboard the ISS, unable to return home. Atlantis would have to be ready to launch within about 33 days, the estimated time limit the ISS could support the addition of seven shuttle astronauts to its two-person crew, NASA officials have said.
"We don't want to launch the first one unless we have the second one close enough to launch to save the crew," Kennedy said.
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