NASA is considering sending two astronauts on an unprecedented spacewalk to the belly of space shuttle Discovery to smooth out rough spots in the ship's heat shield, U.S. space agency officials said on Sunday.
NASA managers are concerned that two protruding bits of material known as "gap fillers" could overheat Discovery as it plunges through Earth's atmosphere for landing.
Heat shield damage was responsible for the loss of shuttle Columbia and its seven astronauts during NASA's last shuttle mission more than two years ago.
"My immediate knee-jerk reaction was that we could live with this," said deputy shuttle program manager Wayne Hale. "On the other hand, if the (spacewalk repair) plan is relatively simple, why worry? Why would you not just go take care of it?"
Thousands of gap fillers are tucked between the black heat-resistant ceramic tiles on the shuttle's belly, which typically experiences temperatures of about 2,500 degrees Fahrenheit (1,370 Celsius) as the shuttle re-enters the atmosphere.
Two gap fillers on Discovery are sticking up about an inch (2.5 cm) from the tiles, a protrusion that could trigger a 15 percent to 25 percent temperature spike, said orbiter projects manager Steve Poulos.
NASA has successfully landed space shuttles 112 times previously, despite sometimes extensive heat shield damage.
"The Columbia accident made us realize that we had been playing Russian roulette with the shuttle crews," Hale said.
"I think the jury is out at this point on whether we'll do anything," Hale said.
With the next space shuttle mission to the International Space Station on hold, NASA has extended Discovery's mission by one day and rescheduled landing for Aug. 8.
If the Discovery crew is asked to remove or trim gap fillers, the work could be added to a previously scheduled spacewalk on Wednesday. Managers also could order a fourth spacewalk on Friday.
The second spacewalk of the mission, which is devoted to replacing a failed space station gyroscope, was scheduled to begin early on Monday.
I hope everything goes well with the Discovery's flight home. All decent people do.
But in light of the fact that we have spent over two years and hundreds of millions of dollars, and we are still having to deal with the same basic problems that doomed the Columbia, this is highly frustrating for people like me who strongly support manned space-flight.
Let's get our act together, NASA. How in the hell are we supposed to be able to get back to the moon, and then to Mars, if we can't even get a shuttle off the ground without there being potentially-catastrophic damage?
JFK must be doing fuckin' backflips in his grave right about now...