LEVEL 1 - 1 OF 1 STORY
Copyright 1986 The New York Times Company
The New York Times
February 23, 1986, Sunday, Late City Final Edition
SECTION: Section 4; Page 1, Column 1; Week in Review Desk
LENGTH: 457 words

HEADLINE: MAJOR NEWS; Shuttle Investigators Wonder Why Engineer's Warnings Went Unheeded



BODY:

What did NASA officials know, when did they know it and why did they not do more about it? Those questions were raised by a disquieting series of revelations last week concerning the launching of the ill-fated space shuttle Challenger.

As a Presidential panel pieced together the events that led to America's worst space tragedy, NASA documents showed that agency officials had during the last few years repeatedly discussed potential problems with the O rings, the seals in the shuttle's solid fuel booster rockets that are supposed to prevent explosive gas from leaking. The rings are prime suspects in the blast that killed all seven Challenger crew members Jan. 28. But yesterday, a former official of Morton Thiokol Inc., the company that built the boosters, said he thought the explosion may have been caused by a leak in the shuttle's huge external fuel tank.

Despite the discussions about the O rings, the National Aeronautics and Space Administration reached a consensus in August that the shuttle was safe to fly ''as is.'' There was no talk during that meeting about the effect cold weather might have on the seals.

But a day before the liftoff, as the orbiter sat on a frigid launching pad, an engineer from Morton Thiokol became worried that temperatures far lower than those prevailing at the time of any other launching would make a failure of the rubber rings more likely. Allan J. McDonald, an engineer for the subcontractor, said he and some colleagues at the company argued repeatedly with Lawrence C. Mulloy, head of NASA's solid fuel rocket project, and other officials to delay the flight. Mr. McDonald said he persisted even after a superior, Joseph Kilminster, transmitted to Cape Canaveral the company's written approval to proceed.

On Friday, three members of the Presidential panel interviewed employees at Morton Thiokol's Utah installation and said they found no immediate evidence that NASA had pressured the company to approve the launching. It looked, they said, like a ''professional engineers' disagreement.''

Still, nagging questions remained about NASA decision-making. Indeed, Jesse W. Moore, the official who gave the final go-ahead for the launching, said he had not been informed of the engineers' qualms.

Mr. Moore also said he was giving up his post as associate administrator in charge of the shuttle - Rear Adm. Richard H. Truly, a former astronaut, will take his place - but would continue to head the Johnson Space Flight Center in Houston.

According to a White House aide, another leadership change loomed: the agency's chief, James M. Beggs, who is on leave to fight an indictment unrelated to the space agency, will resign soon. The aide said that the job would go to an outsider.



GRAPHIC: Photo of a piece of right solidfuel rocket booster; Photo of a Navy research submarine (NASA via UPI; AP)