SPACE CENTRE, Houston (AP) – NASA said it would release videotape shot by Columbia’s astronauts in the final minutes of their lives – but before any hint of trouble – three weeks after the cassette was found among shuttle wreckage.

The 13 minutes of tape show four crew members, clad in orange flight suits, going through routine checklist activities in the shuttle’s cockpit. The other three astronauts were seated on the lower deck.

The space agency said it would broadcast the tape on its television service early yesterday afternoon.

The digital tape was discovered February 6 near Palestine in East Texas. It ends four minutes before the first sign of trouble, because of heat damage to the tape, said an official close to the accident investigation.

NASA acknowledged the existence of the tape on Tuesday; officials wanted to make sure all the astronauts’ families saw it before broadcasting it to the public. It holds no investigative value, officials said.

The tape shows flight-deck activity beginning around 8:35 am February 1, as Columbia soared 500,000 feet (150,000 metres) above the south-central Pacific Ocean, and continues until 8:48 am, when the shuttle was over the eastern Pacific, southwest of San Francisco, at an altitude of less than 300,000 feet (90,000 metres).

On the tape, Commander Rick Husband, co-pilot William McCool, flight engineer Kalpana Chawla and Laurel Clark are heard chatting among themselves.

Eleven minutes later, Mission Control lost contact with Columbia. And 32 seconds after that, all communication ceased as the spaceship shattered over Texas. All seven astronauts were killed.

The video was shot with a small onboard camera mounted to the right of McCool, at the front of the cockpit, NASA said. He removes the camera at one point and hands it to Clark to continue filming.

It is clear that none of the astronauts had a clue about their impending doom. NASA officials said Husband was notified about the tank debris that smacked into the left wing barely a minute after liftoff on January 16 and also the results of the engineering analysis that concluded any damage to the thermal tiles was minimal and posed no safety threat.

Flight controller Jeffrey Kling, who was the first one in Mission Control to report problems in the left wing during Columbia’s plunge through the atmosphere, said earlier this week that Husband seemed to be satisfied with the engineering results that were relayed to him.

Columbia was just 16 minutes away from landing in Florida when it disintegrated in the sky. The investigation board suspects a breach somewhere in the wing let in superheated gases.

The astronauts seated in Columbia’s lower deck were Michael Anderson, David Brown and the first Israeli in space, Ilan Ramon.