Shuttle disaster tape released

The tape reveals how engineers monitoring the space shuttle's descent became aware of a succession of problems before they lost contact with the shuttle.

" We will find the problem that caused the loss of Columbia and its crew, we will fix it and we will return to flight operations that are as safe as humanly possible in pursuit of knowledge "
Sean O'Keefe
Nasa administrator

On Wednesday, Nasa's top official Sean O'Keefe told the first congressional hearing into the tragedy that throughout Columbia's 16-day mission there were "no indications" the disaster would occur.

It is still unclear what caused Columbia to disintegrate 40 miles (65 kilometres) above the Earth on 1 February.

The first pieces of debris have started to arrive at the Kennedy Space Center in Florida, where investigators hope to reconstruct the shuttle to look for clues for what caused it to break up.

Meanwhile, it has emerged that an obscure US law designed to curb Iran's military ambitions means the US cannot help Russia finance its struggling space programme.

Russian spacecraft remain the only option for moving crew out of the International Space Station (ISS) after the US shuttle fleet was grounded, but the US law forbids aiding Russia until it stops sharing military technology with Iran.

Sensors lost

The tape recording reveals the first hint of a problem with the shuttle when a technician reports: "I've just lost four separate temperature transducers on the left side of the vehicle, the hydraulic return temperatures."

SHUTTLE BREAK-UP

Flight Director Leroy Cain asks: "Is there anything common to them?"

"No, not exactly. They were all within four or five seconds of each other," comes the reply, suggesting a general failure.

The sensor readings were lost from the shuttle's left wing, which is suspected of having been damaged during lift-off.

Moments later, technicians report increased wind resistance and a loss of pressure in the shuttle's landing gear tyres.

Final contact is then made between Mission Control and the shuttle.

"Columbia, Houston, we see your tyre pressure messages and we did not copy your last."

Columbia commander Rick Husband replies: "Roger, buh -", and is cut off.

No signal

After contact is lost, flight controllers begin reporting a series of malfunctions.

Mr Cain asks when a radar signal was expected.

"One minute ago, flight," a flight officer replies.

A series of checks is made, followed by a long pause.

Finally, Mr Cain is heard to say "Lock the doors", an executive command to all staff at Mission Control not to leave the building.

Hours before the tape was released, investigators said they had identified part of the shuttle's left wing which was found near the town of Lufkin in Texas and could provide vital clues as to what caused the disaster.

'Continue support'

Mr O'Keefe was testifying before a joint House and Senate committee set up to examine the Columbia disaster and to consider the future of the national space programme.

He said the cause of the disintegration would be found and addressed.

But he called for continued support for the work of Nasa, including manned space flight as well as the use of machines.

"We know the lesson from this terrible accident is not to turn our backs on exploration simply because it is too hard or risky," he said.

"We will find the problem that caused the loss of Columbia and its crew, we will fix it and we will return to flight operations that are as safe as humanly possible in pursuit of knowledge."