How NASA Decided Not to Fix Shuttle

Aug. 17, 2007 — -- Shuttle Cmdr. Scott Kelly said he is confident Endeavour will land safely next week, after NASA decided it was safe to fly home "as is."

"We have had shuttles land with worse damage than this, and we gave this a very tough look and there will be no issue in my mind to worry about," Kelly said from orbit in an afternoon news conference.

The Mission Management Team overseeing this shuttle flight finally made the decision Thursday night to let Endeavour return home without repairs. The debate over repairing the hole in Endeavour's right wing consumed it for nearly a week.

In the end, engineers say it came down to an analysis that showed the heating in the inch-deep gouge on the bottom of Endeavour's right wing would not be enough to doom the shuttle on its return to Earth next week.

Endeavour's crew was told about an hour before it went to bed Thursday night.

"The decision came down," said astronaut Shane Kimbrough from Mission Control. "The MMT [Mission Management Team] has decided to fly the TPS [Thermal Protection System] as is. No repairs will be required."

Kelly said the gouge would not make him and his crew mates more tense at landing.

"We agree, absolutely, 100 percent with the decision to not repair the damage. There's a lot of engineering rigor put into making this decision, and it took some time, but that's because there was a lot of testing going on."

MMT Chairman John Shannon said there was some dissent among the 200-plus people who worked on the problem. An engineering group at the Johnson Space Center argued it would be "prudent" to send spacewalking astronauts to fill in the damage with a sealant that shuttle crews now routinely carry.

"It was not unanimous, but it was pretty overwhelming not to do the repair," said Shannon.

Shannon described the effort by hundreds of engineers working around the clock to come up with the analysis as very intense. In the end a spacewalk was determined to be riskier to the crew and orbiter than flying home with the damage.

"If we had a condition that I thought was a threat to crew safety, I would go execute this EVA [spacewalk] and feel pretty good about it," said Shannon. "Since that is not the case, there's no way I could justify sending the crew out on that EVA just because, just to go do something, and so it became, I think, a very simple decision once we got that analysis done."

A baseball-size piece of foam from Endeavour's external tank broke off and hit the shuttle's wing 58 seconds after launch Aug. 8. NASA, in all its previous testing, had never seen foam from that part of the tank hit the shuttle.

Before the Columbia accident, ignorance was bliss at NASA. If there was damage to a space shuttle, NASA usually didn't know about it until after the shuttle had landed. Damage to the tiles was considered a messy, time-consuming maintenance issue, but not a safety problem.