Challenger Booster Rocket Hit Fuel Tank, Panel Told

Investigators believe that the Challenger’s huge external fuel tank was hit during flight by its right booster rocket, part of a process that led to a “catastrophic in-flight breakup” of the shuttle, a presidential commission was told today.

Air Force Col. Edward O’Connor Jr. told the commission that based on debris already recovered, “there are places on the external tank where we can detect impact from the right” booster rocket. The tank is filled with volatile liquid fuels.

O’Connor said it might take up to three more months to raise enough pieces from the Atlantic Ocean bottom “to complete our analysis.”

O’Connor was the leadoff witness at the commission’s first public hearing in a week into the Jan. 28 loss of the Challenger and its seven crew members in the nation’s worst space disaster. The investigation to date has focused on the rupture on or near a seam, or joint, between the bottom and second segments of Challenger’s right booster rocket.

Photographs show a puff of black smoke emerging from that area at ignition and a flame spewing from the same spot 59 seconds later, 14 seconds before the explosion. Sources close to the investigation say a puff of steam has recently been discovered before the puff of smoke, leading to a theory that rainwater in the seam froze and the ice forced the seals open.

O’Connor said recovery officials believe they have located the areas where most pieces from the booster rockets are located, as well as sections of the external tank and the compartment that held Challenger’s crew. But he said that despite a seven-day-a-week salvage effort, the work has been “impeded by severe weather conditions” off the Florida coast.

In addition to the evidence that the external tank was struck during flight, O’Connor also said that a portion of the booster rocket just below the top showed damage.

These comments could confirm an earlier theory about the accident--that the right booster rocket became loose at the bottom and pivoted into the external tank near the top, triggering the explosion that tore apart the shuttle.

O’Connor said that based on debris recovered to date, there is no evidence of an internal explosion within the space orbiter itself. Rather, he said the destruction of the $1.2-billion Challenger was a “catastrophic in-flight breakup” caused by the blast of another explosion and abnormal aerodynamic forces.