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Pancake flips are the key to spacewalkers' repair job

By ASSOCIATED PRESS
Published July 13, 2006

HOUSTON - Two spacewalkers sheepishly lost a spatula in orbit Wednesday. But NASA engineers didn't mind much, because the two accomplished their main task of testing a method to apply emergency patches to a shuttle heat shield - and then some.

Discovery spacewalkers Piers Sellers and Michael Fossum improved on the method of applying a special mixture to repair the reinforced carbon leading edges of a space shuttle, using mock-ups in a suitcase in Discovery's payload bay.

A crack allowed fiery gases to penetrate space shuttle Columbia's reinforced carbon wing during re-entry to Earth's atmosphere in 2003, destroying that shuttle and killing its seven astronauts.

The same peanut butter-like repair goo was used a year ago in a first test of the system, with mixed results. That test produced many bubbles that could allow killer heat to penetrate on re-entry. This time, initial results showed that some bubbles formed, but they didn't join to become big, dangerous ones, said lead spacewalk officer Tomas Gonzalez-Torres.

The key difference? Pancakes, Gonzalez-Torres said.

Fossum and Sellers used a technique similar to flipping pancakes. They spread a thin layer of the mixture, then kept flipping it, Gonzalez-Torres.

At first, astronauts said the bubbles kept forming, but they were able to keep them to a minimum.

"It's bubbling," Sellers said at one point. "It's growing. It's scary-looking."

The goo was messy, spattering the spacewalkers to the extent that Sellers told Fossum: "Mike, you look like a panda. You've got a few little spots."

There was only one thing missing from the spacewalk: Sellers' spatula.

It flew overboard, off the right side of the shuttle's payload bay.

"No sign of the spatula. I think it's gone, gone, gone," Sellers said of the kitchen appliance, 14 inches long and 2 inches wide.

When Sellers was nearing the finish of his extended seven-hour, 11-minute spacewalk, mission control teased him by making him count his spatulas. He still had five left, from a total of 6.

"Rub it in, rub it in," Sellers said.

It is rare for spacewalkers to lose such a tool, but "it is no hazard to us," Gonzalez-Torres said. Nonetheless, military monitors of space debris were notified of the new hazard to track.

[Last modified July 13, 2006, 06:39:57]