February 21, 2003
SPACE CENTER, Houston -- Just how the foam insulation was applied to the fuel tanks of NASA's space shuttles is getting special attention by the board investigating the Columbia accident, officials said Thursday.
One leading theory is that the insulation or the heavier material beneath may have damaged Columbia during liftoff, enough to trigger a deadly breach as the spaceship hurtled toward a Florida landing 21/2 weeks ago.
The foam insulation is applied at a Lockheed Martin plant in New Orleans. More of the foam is applied about a month before liftoff in several small areas of the tank needing touchup at NASA's Kennedy Space Center in Florida.
The investigation board has visited both sites and is going back for a harder look at the techniques -- and safeguards -- used.
"That is getting a good bit of attention by more than one of the groups," said NASA's Steve Nesbitt, referring to the board's three working groups. "A couple of the groups are looking at the thermal protection on the tank in this area, and some of them will be going back to see the manufacturing facilities, to talk to the people involved."
Nesbitt said the theories that focus on the left side of Columbia -- where all the overheating and other problems developed -- "will be getting the earliest attention."
The shuttle broke apart, killing all seven astronauts, as it re-entered Earth's atmosphere on its way home to Florida on Feb. 1, after a 16-day mission.
Air Force Maj. Gen. John Barry said this week he and other board members are reviewing NASA's history of foam coming off the so-called bipod area, where a pair of struts holds the tank to the upper belly of the shuttle.
That is the spot where a chunk of foam came off 81 seconds into Columbia's flight on Jan. 16; the debris slammed into the left wing during launch. An engineering analysis days later concluded that any damage was minimal and posed no safety threat.
NASA officials said that finding was based, in part, on the fact that previous foam impacts had not caused severe damage.
Barry said that four previous shuttle flights had foam falling from the bipod area: Challenger in 1983, Columbia in 1990 and again in 1992, and Atlantis in October. A 10-year gap exists between those two last flights, he pointed out, "so we've got some backtracking to do to be able to look at the history and make the analysis."
Last week, the board inspected Atlantis and its fuel tank at Kennedy and a completely assembled fuel tank at Michoud Assembly Facility in New Orleans that is identical to the one used by Columbia on its doomed flight. The Michoud tank has been impounded by the board for testing.
NASA estimates that the chunk of broken foam was 2.67 pounds and 20 by 16 by 6 inches. The weight would be more if ice were attached, a possibility under consideration by the board. The panel also is looking into whether the underlayer may have broken off.