Nasa Releases Final Transmissions of Doomed Shuttle

Transcripts of the final radio transmissions made from the doomed space shuttle Columbia have been released by Nasa.

The transmissions chronicle the efforts of mission control engineers as they became painfully aware of the destruction that was unfolding in the skies above them.

In the conversations, released yesterday, mission control reports a litany of problems that worsen by the minute as the shuttle breaks into pieces, killing all seven astronauts aboard.

The first bad news came when Jeff Kling, the maintenance, mechanical arm and crew systems officer, reported a sudden and unexplained loss of data from spacecraft sensors. The assessment came in the final six or seven minutes of the flight.

"I just lost four separate temperature transducers on the left side of the vehicle, the hydraulic return temperatures," Kling said.

Flight director Leroy Cain quickly asked if there was anything common to the sensors and got bad news in reply. Kling said there was no commonality, suggesting there was a general failure instead of a single system.

Moments later, more bad news. Mike Sarafin, the guidance and navigation officer, announces Columbia's wing is encountering drag, or increased wind resistance.

Cain, still hopeful, asks if everything else is normal and Sarafin assures him, "I don't see anything out of the ordinary."

Soon, flight controllers begin reporting a string of more problems. There is evidence of small collisions on the tail, and signals are cut off from the nose landing gear and the right main landing gear. Then more sensors are lost and the drag increases to the left.

Hobaugh begins a series of radio calls to the shuttle, but there is no response as the minutes tick down toward the planned landing at the Kennedy Space Center.

"MILA [the Kennedy spacecraft communication center] is not reporting any RF [radio frequency] at this time," says Bill Foster, a ground controller.

"OK," says Cain, who then asks hopefully when a radar signal was expected.

"One minute ago, flight," comes the response from Richard Jones, flight dynamics officer. The communication checks continue. So does the silence. A radar station near the Kennedy center then says it is putting its radar in a "search mode."

"We do not have any valid data at this time," said Jones. He said there was a "blip" but it was bad data.

Then a long pause, a silence of despair. Then Cain says the final words, the phrase that marked the lack of hope: "Lock the doors."

This meant nobody could leave Mission Control or even make phone calls. For the next several hours, the engineers have to ignore the certain loss of the crew and store the data in their computers, finish reports and then write personal accounts of what they saw, heard and did on February 1.