|Scott J. Kelly, Space shuttle Endeavour's commander, pointed to the damaged tiles on the underbelly of the spacecraft yesterday at Kennedy Space Center in Cape Canaveral, Fla. (STAN HONDA/AFP/Getty Images)|
Endeavour lands safely in Fla.; concern over foam tiles lingers
CAPE CANAVERAL, Fla. -- Even as the wounded space shuttle Endeavour brought seven astronauts safely home yesterday, NASA is looking ahead to three more launches at risk of the same kind of damage.
There is a striking parallel with the 2003 Columbia disaster in the space agency's failure to anticipate the harm from breaking ice or insulating foam, this time from a new area of the shuttle's fuel tank.
The 3.5-inch-long gouge in Endeavour's belly did not put the astronauts at risk. As soon as the damaged tiles are popped off, engineers will know whether repairs are needed to the underlying aluminum structure. The gash seemed to weather the return flight well, the National Aeronautics and Space Administration said.
But for the early part of Endeavour's 13-day mission, there was an eerie sense of déjà vu.
Back before Columbia flew its last mission four years ago, NASA knew it had a foam problem with its fuel tanks but never imagined a piece of the airy insulation could severely wound a space shuttle.
The result: Columbia shattered during reentry, just five days before engineers were to propose possible repairs.
This time, NASA knew it had a foam problem with brackets on its fuel tanks, but never imagined a stray piece would ricochet off the tank and smash into the shuttle.
Retired Navy Admiral Harold Gehman Jr., who headed the 2003 Columbia investigation, was reluctant to comment this week on the bracket problem. He said he didn't have enough information.
But he observed: "You have to assume things are going to happen, and you have to mitigate the consequences. That's what our report was all about."
Endeavour's gash, although deep, was too small for scorching atmospheric gases to penetrate and cause serious damage, mission managers said during the flight. It was also on the belly, a more benign area than the nose or wings, which are subjected to much higher heat. The platesize hole that brought down Columbia pierced the left wing.
Commander Scott Kelly said he was "a little bit underwhelmed" when he saw the gouge for himself after touchdown. "We knew how big it was conceptually," he told reporters. "We were told the dimensions. But to see it, it looked rather small."
After checking out Endeavour on the runway yesterday, officials said there was no apparent charring to the exposed felt fabric, the last barrier before the shuttle's aluminum frame.
But now NASA finds itself playing catch-up. It's analyzing a variety of temporary bracket solutions, which may or may not be in place before the next shuttle flight, in late October.
Making the brackets with titanium, which would require far less foam insulation than the aluminum version, is the permanent solution ordered after the problem first cropped up last summer. But that won't happen until next spring.
Engineers are considering a variety of short-term options: shaving some foam from the brackets or possibly applying an oil to the foam to reduce condensation and the buildup of ice.
Because the bracket problem has intensified for the launches since Columbia, engineers theorize it might be because of the one-hour earlier start of fueling -- a new rule intended to provide more time for ice checks.