Films Reportedly Point to Seals as Shuttle Blast Cause

Presidential investigators received “considerable confirmation” from new film studies shown in a private meeting Friday that safety seals on the Challenger’s right booster rocket caused the shuttle to explode in flight, a source close to the inquiry said.

This source, who asked not to be identified by name, said that “for the first time, the commission saw enhanced film analysis coordinated with a time line” of the accident. “It provided considerable confirmation of our view on the place and timing of the fire” that caused the Jan. 28 explosion that killed all seven crew members.

The source added that the panel is still trying to determine what caused the failure of the seam that is designed to contain hot gases inside the solid fuel booster rocket. Leading theories are that cold weather reduced the effectiveness of rubber-like O-ring seals, or that the seals were harmed by the normal motion of the rocket, or were defective on manufacture, the source said.

The investigative source said that commission Chairman William P. Rogers and Executive Director Alton G. Keel Jr. reported on their talks during the week with Martin Marietta, manufacturer of the shuttle’s external fuel tank--the only element of the shuttle other than the booster rocket not yet ruled out as a cause of the accident.

“The tank’s never been a high priority suspect and their presentation did nothing to change that,” the source said.

Outside Experts

The commission issued a statement saying that it had agreed to appoint a group of four to six outside experts to monitor testing of the booster rocket that is designed to pinpoint the precise cause of the accident.

A source said the group would probably include representatives of private aerospace firms, the Air Force and the National Transportation Safety Board.

Meanwhile, stormy seas off Cape Canaveral, Fla., on Friday kept salvage ships in port and interrupted the search for Challenger wreckage.