Sound waves may help investigators

Associated Press
Feb. 17, 2003

SPACE CENTER, Houston - Recordings made by instruments sensitive to sound below the threshold of human hearing may help investigators build a timeline of any uncharacteristic movements made by the space shuttle Columbia minutes before it broke apart, scientists say.

As parts of Columbia began to break off as the shuttle streaked across the West, the flight behavior of the normally streamlined spacecraft would have changed. Those changes would have generated distinctly different patterns of sound waves compared with previous shuttle flights.

The instruments also captured an explosion high over Texas that one scientist said could have been Columbia's cabin rupturing.

The patterns, recorded on the ground by instruments in Texas, Nevada and elsewhere in the West, are being examined as part of the Columbia disaster investigation.

One array of the sound-sensitive instruments near Big Bend National Park in southwest Texas, recorded sound waves from Columbia as it was over west Texas indicating an explosion equivalent to a few pounds of TNT, said Eugene Herrin, a geophysicist at Southern Methodist University.

"Our guess is that it could have been caused by a rapid decompression," Herrin said.