Tapes show shuttle exploded 10 minutes before Houston knew

A chilling picture of events at mission control during the last minutes of Columbia was revealed by Nasa yesterday.

Conversations taped on 1 February show a team of highly trained scientists in Houston trying desperately to be rational and analytical even as disaster unfolded. The astronauts on the doomed shuttle huddled in near silence in the eight minutes before their craft started disintegrating around them. The shuttle commander, Colonel Rick Husband, managed only a perfunctory "Roger" to acknowledge a problem with tyre pressure before communication was lost.

The seven astronauts barely feature at all, following standard Nasa protocol that they only speak when they become aware of something going wrong. Clearly, they had only a glimmer of an idea of what was about to befall them.

Members of the ground team were so focused on their task that they took almost 10 minutes to realise what others knew from the terrible sonic booms and flashes above eastern Texas – that the shuttle was lost. Even when reality sank in, there was no room for emotion.

"OK, all flight controllers on page 9 of the FCOH procedure, you need to make sure you step through the actions required in Step 20. That's for your work station log's display printouts," the ground commander, Leroy Cain, tells his staff. "There's a whole list of data- collection items that we need to make sure we log through."

The first sign of trouble came from a mechanical officer called Jeff Kling. Eight minutes before the crash, he reported: "FYI I've just lost four separate temperature transducers on the left side of the vehicle." Mr Cain replied: "Is there anything common to them? I mean, you're telling me you lost them at exactly the same time." "No, not exactly," said Mr Kling. "They were within probably four or five seconds of each other."

A few minutes later, Mr Cain noticed that the shuttle was dragging but nobody thought this was more than a minor inconvenience. Slowly, the bad signs accumulated: sensor failures and then strange tyre pressure readings. There was little sense of foreboding, however, even after contact with Columbia was lost. Laura Hoppe, the communications officer, thought the blackout was surprising but also said she had expected radio contact to be "ratty" on re-entry.

The tape is the latest piece in the puzzle of the disaster to be made public. An inquiry is still hoping to recover wreckage from the early stages of Columbia's break-up, as it flew eastwards, but it has had no luck so far despite hundreds of reported sightings in California, Arizona and New Mexico.

A joint congressional committee met yesterday to ask some hard questions about Nasa and the future of space travel. The committee, chaired by Senator John McCain, will look at safety, budgets and shuttle technology. "If there's anything good to come out of this tragedy," he said, "it's that it has triggered a long-overdue discussion of policies regarding our role in space."