Today in History – January 28, 1986 – Space Shuttle Challenger explodes after launch, killing the entire crew. American’s stared in shock at their televisions watching the Challenger accident in full motion video. The 35th Challenger’s flight had been previously scheduled for January 22, but delayed because of bad weather, high winds and icicles on the launch apparatus. Never had there been a launch approved in freezing weather conditions, but NASA had assured the public that the conditions were safe. They were anxious to launch due to economic considerations and scheduling backlogs. Political pressure has been suggested as well due to NASA’s heavy publicizing of Christa McAuliffe as the first school teacher in space. She had been selected under a highly competitive process from among 10,000 entries for the opportunity. The Challenger disaster was a severe blow to the American space program, bringing manned flights to a halt for many years. It was also a blow to the American public who had come to think of the Space Shuttle as an important symbol of national identify.

Speaking before the launch, Christa McAuliffe said: “One of the things I hope to bring back into the classroom is to make that connection with the students that they too are part of history, the space program belongs to them and to try to bring them up with the space age.”

Morton-Thiokol, one of the contractors for the Solid Rocket Motor was convinced that the cold weather would cause problems and had briefed NASA about their concerns. Two engineers, Robert Ebeling and Roger Boisjoly had previously urged a redesign on the booster rockets due to O-ring erosion in the booster field joints. The lowest temperature experienced by the O-rings in any previous mission was 53°F in the January 24, 1985 flight; the temperature predicted for Florida on January 28th was much lower, in the low 20′s °F.

The Rogers commission confirmed the cause of the Challenger disaster explosion to have been caused by a leak through the faulty O-ring seal in one of the solid rocket boosters. According to testimony by Morton-Thiokol engineer Boisjoly, management put pressure on the engineers to OK the launch saying: “Take off your engineering hat and put on your management hat.” The recommendation was reversed, discounting the concern about the O-rings as being “inconclusive” and launch was recommended, “based on their engineering assessment”, even though the engineers had no part in this recommendation. In spite of concerns expressed by others, NASA managers decided to approve the boosters for launch despite the fact that the predicted launch temperature was outside of their operational specifications and any test conditions.

Engineers must learn from both the technical and organizational failures that led to the tragic Challenger accident. The Engineering Pathway digital library has information on several excellent case studies, lesson plans and other curricular materials that can be used in the classroom. The Texas A&M case, for example, leads to these discussions questions:

• “What could NASA management have done differently?
• What should Roger Boisjoly have done differently (if anything)? In answering this question, keep in mind that at his age, the prospect of finding a new job if he was fired was slim. He also had a family to support.
• What do you (the students) see as your future engineering professional responsibilities in relation to both being loyal to management and protecting the public welfare?”

For more information, see the Engineering Pathway’s resources on the Challenger accident or engineering ethics.