NASA moving forward on return-to-flight plans
By Kate Tobin
(CNN) -- As NASA works to resume shuttle flights put on hold after the Columbia disaster, the space agency issued a self-report card Friday in a revision of its return-to-flight plan.
The revised plan paints a picture of a space agency with a number of challenging tasks remaining on its do-list before space shuttles can safely fly again. NASA plans to resume flights in March 2005.
"We have made significant progress across the board in all the items that we think are required for return to flight," Wayne Hale, space shuttle program deputy manager, said in a conference call with reporters.
"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 shuttle fleet has been grounded since the space shuttle Columbia broke apart over Texas while on approach to Florida's Kennedy Space Center on February 1, 2003.
In August, the Columbia Accident Investigation Board concluded that insulating foam flying off the shuttle's external fuel tank during lift off struck and cracked a panel on the orbiter's wing, leaving it vulnerable to the extreme heat of re-entry.
The major challenge for the space agency continues to be the elimination of so-called "critical debris sources," the insulating foam in particular.
"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.
Foam strikes had been observed on most shuttle launches, but before the Columbia disaster, engineers believed that the debris was not dense enough to cause damage.
To minimize the amount of foam and ice falling off the tank, NASA is redesigning the bipod area, where the tank attaches to the orbiter, and tweaking other systems where debris is most likely to build up or break loose.
NASA is studying more than 200 million computer simulated "debris transport cases" in order to better understand where, how and why they happen, and how to minimize damage to the shuttle.
Another hurdle is developing a means of repairing, in orbit, the tiles and panels that protect the shuttle from the intense heat of re-entry. The Thermal Protection System (TPS) previously could only be repaired on the ground.
NASA has designed a robotic boom tipped with cameras and other instruments to allow inspection of all shuttle surfaces, even the underside, for damage. Engineers are working on repair techniques, and on plans for the astronauts to take refuge at the international space station while repairs are made.
Also before returning to flight, NASA plans to:Refurbish the rudder speed brake, a flap in the tail that slows the orbiter on landing; a lack of parts is making these repairs slow work.Enhance "ascent imagery" capability by adding more high-resolution cameras to watch the launch.Develop a flight plan for "STS-300," an emergency rescue mission; NASA plans to have a second crew and orbiter on standby for every mission.