An astronaut’s ripped glove forced an early end to a spacewalk and added to NASA’s headaches Wednesday as shuttle managers put off a decision on whether to order risky spacewalk repairs for a deep gouge on Endeavour’s belly.
After nearly a week of agonizing over the gouge, NASA indicated it was close to wrapping up tests and would decide Thursday whether repairs were needed.
Endeavour’s commander, Scott Kelly, asked Mission Control which way managers were leaning. The reply: “Unfortunately, we have no idea which way the wind is blowing at the moment.” Later, the chairman of the mission management team told reporters that he remained “cautiously optimistic” repairs would not be needed, based on preliminary test results.
One of the astronauts who would attempt those repairs, Rick Mastracchio, had to cut his latest spacewalk short after he noticed a hole in his left glove.
The quarter-inch-long (6-millimeter-long) rip in the thumb penetrated only the two outer layers of the five-layer glove, and he was never in any danger, officials said. Nevertheless, he was ordered back inside early as a precaution, and his spacewalking partner quickly finished what he was doing and followed him in.
NASA’s spacewalk office manager, Steve Doering, said he would not want to proceed with another spacewalk until the glove problem is better understood. He expected to gather more information over the coming day.
This is the second time in three shuttle missions that a glove has been damaged during a spacewalk at the international space station. Engineers are uncertain whether sharp station edges are to blame or whether it’s wear-and-tear.
John Shannon, the mission management team’s chairman, said the glove problem would not prevent him from ordering spacewalk repairs for the gouge.
“If we decided we needed to go do this, I would feel very comfortable doing it. We’ve done a lot of spacewalks without any glove problems,” Shannon said. He added that the repair job would not be anywhere near where Mastracchio was Wednesday.
The unprecedented patching job on Endeavour, if approved, would be performed on the next spacewalk, now set for Saturday, a day later than originally planned to give engineers more time to analyze the situation. That could keep Endeavour and its crew of seven, including teacher-astronaut Barbara Morgan, at the space station at least an extra day.
Two tiles affected
The 3.5-inch-long, 2-inch-wide (9-by-5-centimeter) gouge — the result of a debris strike at liftoff — is in two of the thousands of black tiles that cover Endeavour’s belly and guard against the 2,000-plus-degree Fahrenheit (1,100-degree Celsius) temperatures of atmospheric re-entry. Part of the gouge, a narrow one-inch (2.54-centimeter) strip, cuts all the way through the tiles, exposing the thin felt fabric that serves as the final thermal barrier to the ship’s aluminum frame.
The exposed area and the gouge itself are so small that NASA is not worried about a Columbia-type catastrophe at flight’s end. Rather, the concern is that if too much heat enters the crevice, the underlying aluminum structure might be damaged enough to warrant lengthy post-flight repairs. That, in turn, could lead to future launch delays and disrupt space station construction.
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NASA does not want the aluminum under the gouge to get hotter than 350 degrees F (177 degrees C). As of Wednesday, computer models put the maximum exposure at 325 degrees F (163 degrees C). Engineers believe the worst of the re-entry heat should skip right over the gouge. There might be some additional tile erosion around the damage, but nothing too bad, Shannon said.
Endeavour’s belly was smacked a minute after liftoff on Aug. 8 by a piece of debris about the size of a dishwashing sponge and weighing less than an ounce. NASA does not know if it was insulating foam or ice from the external fuel tank, or both. Whatever the material, the debris broke off a bracket on the tank, fell onto a lower tank strut, then shot up into the shuttle.
A redesign of these troublesome brackets, which support the fuel feed line on the tank, won’t be ready until spring. NASA is debating whether to implement a temporary solution before the next shuttle launch in October, which could well delay that flight.
Most chores completed
During Wednesday’s spacewalk — the third of the shuttle mission — Mastracchio and space station resident Clay Anderson moved two rail carts and an antenna base into new positions on the orbiting outpost. They also added new antenna parts to improve voice communications and completed most of their other chores before retreating inside because of Mastracchio’s ripped glove.
The spacewalk lasted 5½ hours, an hour shorter than planned.
Afterward, Mastracchio said he wasn’t sure how his left glove ended up being slit. His right glove had small puncture marks in the same place. His suit never leaked, and there was no excessive oxygen flow.
If the slit had pierced his entire glove, officials said, it’s difficult to know whether Mastracchio could have made it back into the station in time or whether he would have died outside. It would depend on the size of the hole and the distance the spacewalker had to go to get inside.
The next spacewalk will be trickier if shuttle repairs are ordered. Under the latest scenario, Mastracchio and another astronaut would apply black paint to the white gouge and squirt in a caulklike goo, while balancing themselves on the end of the shuttle’s 100-foot (30-meter) robot arm and extension boom.
As of now, Endeavour and its crew of seven are due to leave the space station Monday and land two days later.