Shuttle investigators focus on heat rise

The investigation into the Columbia space shuttle disaster was intensifying today, as Nasa engineers focused on whether a piece of peeling insulation had caused damage to crucial heat-protection tiles.

More details have been emerging of conditions before Columbia broke up on its way to landing in Florida on Saturday. All seven astronauts aboard died in the disaster.

Nasa scientists at the Johnson space centre in Houston have been poring over data for clues, looking at a sharp heat rise along Columbia's left side, both in the wheel well and on the fuselage.

The conditions prompted an unusually sharp automatic corrective move by the autopilot, which was recorded just before the vehicle disintegrated over Texas.

So far, more than 500 pieces of the shuttle have been recovered in Nacogdoches county, Texas, and searchers have been using horses and four-wheel-drive vehicles to scour rugged wooded areas.

The debris is being catalogued and trucked to a US air force base in Louisiana, where the painstaking task of trying to arrange it into an outline of the shuttle is beginning.

Some crew body parts have been recovered, and it is understood that they will be sent to a military morgue at Dover US air force base, in Delaware.

The families of Columbia's crew members say they want their legacy to continue. In a statement read on the NBC US television network by Evelyn Husband, wife of shuttle commander Rick Husband, they said: "Although we grieve deeply, as did the families of Apollo I and Challenger before us, the bold exploration of space must go on.


A further front in the investigation was also opening today as an independent inquiry board appointed by Nasa met for the first time.

The Nasa administrator, Sean O'Keefe, chose a former navy admiral to oversee the independent review of the accident. Mr O'Keefe was today meeting with the US president, George Bush, to discuss the accident.

Mr O'Keefe said investigators would initially focus on whether the piece of insulation caused the damage that brought down the shuttle. He stressed that the space agency was not looking into a single scenario of what could have caused the crash, saying that the insulation was "one of the areas we're looking at first, early".

Computer data showed temperatures rising markedly on the shuttle's left side moments before it disintegrated: the same side of the craft hit by peeling fuel-tank insulation during its January 16 launch, Nasa engineers said.

The exteriors of all space shuttles are covered with thousands of tiles, designed to protect the craft from the extreme heat of re-entry. Shuttle programme manager Ron Dittemore told a news conference that Nasa engineers had seen the peeling fuel tank insulation on high speed cameras recording the launch of Columbia.

The possible effects on the tiles from the insulation were studied while the shuttle was still aloft, but engineers concluded that "it did not represent a safety concern".

Mr Dittemore said engineering data shows a rise of 20-30F (11-17C) in the left wheel well about seven minutes before the spacecraft's last radio transmission. There was then a rise of about 60F (32C) over five minutes in the left hand side of the fuselage above the wing, he said.

The shuttle temperature rose the normal 15F (eight degrees C) on the right side over the same period. All the readings came from sensors underneath the thermal tiles, on the aluminium hull of the craft.

The temperature rises were accompanied by increased drag, or wind resistance, which forced Columbia's automated flight control system to make rapid adjustments to maintain stability.

The corrections were the largest ever for a shuttle re-entry, but Nasa said they were still within the craft's capability. "We've got some more detective work to do," Mr Dittemore said. "But we're making progress inch by inch."

Lockheed, the maker of the fuel tank under scrutiny, said yesterday that Nasa used an older version of the tank, which the space agency began phasing out in 2000. Nasa's pre-flight press information stated that the shuttle was using one of the newer super-lightweight fuel tanks.