Allan McDonald, who directed the booster rocket project at NASA contractor Morton Thiokol, urged delaying the launch of the space shuttle before it exploded in 1986. He has died at age 83.

The focus of the commission’s investigation shifted to the booster rocket O-rings, the efforts of McDonald and his colleagues to stop the launch and the failure of NASA officials to listen. The company relented, and McDonald was promoted to vice president and put in charge of the effort to redesign the booster rocket joints that failed during the Challenger launch. In 2018, Allan McDonald reviewed the Challenger launch decision during a series of seminars about leadership and ethical decision-making to managers at U.S. Space Command. Blog this summary

Source: Remembering Allan McDonald: He Refused To Approve Challenger Launch, Exposed Cover-Up