Astronuats Test Heat Shield Fix

JOHNSON SPACE CENTER, Texas, March 21, 2008 — -- Five years after the Columbia accident, NASA is still trying to perfect ways to repair a damaged space shuttle on orbit.

The question haunts many at NASA. What if anything, could they have done to save Columbia and its crew of seven?

Columbia broke apart over Texas after a hole, created when a piece of foam from the shuttle's tank hit the left wing of the shuttle, allowed the hot gases of re-entry to penetrate the shuttle and destroy it from within.

STS 123 astronauts Mike Foreman and Bob Behnken ventured out on the fourth spacewalk of their mission to search for answers to the question of how a shuttle could be repaired on orbit.

They tested some material designed to secure heat shield tiles while in space.

Their spacewalk had a serious purpose, but at times it seemed more like a cross between the TV comedy "Tool Time" and a cooking show on the Food Network.

Foreman joked that the stuff he was squirting into a test hole "looked like a loaf of bread with all the little bubbles in it." He and Behnken used a caulk gun and a foam brush to test a substance that looked much like cake batter. They pushed it into damaged heat tiles to see whether it could be used to repair damage to a shuttle on orbit -- a repair they hope they will never have to use.

Observers in Mission Control watched the process carefully from the Johnson Space Center.

"Endeavour, we are absolutely captivated by what you guys are doing here," said astronaut Steve Robinson to the space shuttle. "It's like brain surgeons up there."

Astronaut Rick Linnehan called out to his spacewalking colleagues, "You hear that, Mike? You're a brain surgeon."

Lead space station flight director Dana Weigel said she has confidence in the process: "I'm thrilled with what we saw today. The results based on testing we saw on the ground, we did a lot of testing in the vacuum chamber, the proof will come when the get this material back to the ground and cross section it, but, yes, it is behaving the way we expect it to behave but we have a lot of testing behind it."

NASA needs to know how to do this kind of repair before it launches a space shuttle flight later this year to service the Hubble Space Telescope for the last time.

Hubble is in a different orbit from the space station, and the Hubble crew would not be able to get to the space station for shelter if something damages its space shuttle.