Challenges Remain

"We have made significant progress across the board in all the items that we think are required for return to flight."

Those words come from Wayne Hale, NASA's deputy director for the space shuttle program. He says, after the February 1, 2003, Columbia disaster, the space agency is steadily approaching the day when the shuttles will fly again.

"We have a good schedule laid out, we have our arms around all the problems that we need to address, all the changes that are required to be made, and all the work that we have to do to get ready to fly," Hale said.

The shuttles are scheduled to return to flight next March, with a mission to the International Space Station.

But as it was last August, when the Columbia Accident Investigation Board ruled that foam debris from the shuttle's external fuel tank punched a hole in the space plane's wing, leading to the disastrous breakup of Columbia as it re-entered the atmosphere, "critical debris sources" continue to be the top focus at the Kennedy Space Center in Florida.

"The real restraint for return to flight is clearly, number one, fixing the external tank, and that has been the pacing item for return to flight from the very beginning," Hale said.

NASA is now looking over some 200 million computer simulations of debris strikes, trying to get a handle on how they happen and what damage they can do.

Another potential sticking point in the return to flight is the ability to repair the shuttle while it's in flight. As it stands now, the shuttle's critical heat tiles can only be repaired on the ground.

To fix it, you first have to find it. NASA has modified the Canadian-built robot arm to scour the surface of the shuttle's exterior, looking for just such damage.

Before the shuttles can return to flight, NASA also has to develop a plan to have a second space plane on standby for every mission. This potential rescue ship would be given the designation "STS-300." NASA also wants to put an eye on the shuttle much further through the ascent stage of each mission. That means more high-resolution cameras and sensors aimed at the shuttle during launch.

NASA is also rebuilding the speed brake, a split-rudder configuration on the shuttles. The problem there is availability of parts.

FMI: www.nasa.gov