At that point Mr. McDonald, sitting in the back of the room, stood up. His hands shaking, he told the panel that Mr. Mulloy was not giving them the whole story; the engineers, he said, had been pressured and overruled.
Mr. Rogers immediately asked for the room to be emptied so the commissioners could discuss Mr. McDonald’s revelation. As the audience cleared out, Ms. Ride came over and hugged Mr. McDonald. Both of them had tears in their eyes.
“It was the turning point of the commission,” Alton G. Keel, its executive director, said in an interview, adding that Mr. McDonald’s statement, and subsequent public testimony, led Mr. Rogers to take a more focused, adversarial approach. The commission’s final report heavily criticized both the design of the rockets and NASA’s decision to ignore the engineers’ concerns.
“Allan McDonald was a hero in our eyes,” Mr. Keel said in an interview.
Allan James McDonald was born on July 9, 1937, in Cody, Wyo., and grew up in Billings, Mont. His father, John, ran a grocery; his mother, Eva Marie (Gingras) McDonald, was a homemaker.
He graduated from Montana State University with a degree in chemical engineering and immediately went to work for what was then called Thiokol, helping design the rocket systems for the Minuteman intercontinental ballistic missile. (The company became Morton Thiokol after it merged with Morton-Norwich, the maker of, among other things, Morton Salt.)
He later received a master’s degree in engineering administration from the University of Utah.
In 1962 he met Linda Rae Zuchetto at Sunday Mass; they married the next year. She and his daughter Ms. Goggin survive him, as do two other daughters, Lisa Fischer and Laura McDonald; a son, Gregory; and nine grandchildren.