THE SPACE SHUTTLE CHALLENGER AND COLUMBIA ACCIDENTS The NASA Space Shuttle Disasters The space shuttle is one of the most complex engineered systems ever built. The second O-ring was added to the booster for the shuttle to provide an extra margin of safety since, unlike the Titan, this booster would be used for a manned space craft. The Titan booster had only one O-ring in the field joint. To prevent the hot gases from damaging the O-rings, a heat-resistant putty is placed in the joint. The O-rings are made from a type of synthetic rubber and so are not particularly heat resistant. The O-rings are designed to prevent hot gases from the combustion of the solid propellant from escaping. The joints are sealed by two O-rings, a primary and a secondary. These are tang and clevis joints, fastened with 177 clevis pins. А key aspect of the booster design are the joints where the individual cylinders come together, known as the field joints, illustrated schematically in Figure 1.1a. But he was ready to speak publicly.Chapter 1 Introduction 7 8 1.8 Case Studies APPLICATION cylinders were then shipped to the Kennedy Space Center in Florida for assembly into a completed booster. He huddled in the corner of a couch, his arms tightly folded on his chest. When I visited him at his Utah home in April of 1987, he was thin, tearful and tense. The explosion of Challenger and the deaths of its crew, including Teacher-in Space Christa McAuliffe, traumatized the nation and left Boisjoly disabled by severe headaches, steeped in depression and unable to sleep. Until NPR's story, the special commission investigating the Challenger tragedy hadn't even interviewed all the engineers involved in the pre-launch debate. "Then, a few seconds later, the shuttle blew up. "And when we were one minute into the launch a friend turned to me and said, 'Oh God. So, when Challenger lifted off without incident, he and the others watching television screens at Thiokol's Utah plant were relieved. "We thought that if the seals failed the shuttle would never get off the launch pad," Boisjoly told Zwerdling. They overruled Boisjoly and the other engineers and told NASA to go ahead and launch. They told us that the NASA pressure caused Thiokol managers to "put their management hats on," as one source told us. These words and this debate were not known publicly until our interviews with Boisjoly and his colleague. "When do you want me to launch - next April?" "I am appalled by your recommendation."Īnother shuttle program manager, Lawrence Mulloy, didn't hide his disdain. "I am appalled," said NASA's George Hardy, according to Boisjoly and our other source in the room. But NASA officials on a conference call challenged that recommendation. At first, Thiokol managers agreed with them and formally recommended a launch delay. ![]() "We all knew if the seals failed the shuttle would blow up."Īrmed with the data that described that possibility, Boisjoly and his colleagues argued persistently and vigorously for hours. ![]() "We all knew what the implication was without actually coming out and saying it," a tearful Boisjoly told Zwerdling in 1986. I'm so torn up inside I can hardly talk about it, even now." ![]() Three weeks later, he told NPR's Daniel Zwerdling in an unrecorded and confidential interview, "I fought like Hell to stop that launch. NASA had never launched in temperatures that cold and Boisjoly and his four colleagues at Thiokol headquarters in Utah concluded it would be too dangerous too launch. On January 27, 1986, the forecast for the next morning at the Kennedy Space Center included a launch-time temperature as low as 30 degrees Fahrenheit. They tended to stiffen and unseal in cold weather and NASA's ambitious shuttle launch schedule included winter lift-offs with risky temperatures, even in Florida. ![]() The problem, Boisjoly wrote, was the elastic seals at the joints of the multi-stage booster rockets. Six months before the Challenger explosion, he predicted "a catastrophe of the highest order" involving "loss of human life" in a memo to managers at Thiokol. He found disturbing the data he reviewed about the booster rockets that would lift Challenger into space. Bulky, bald and tall, Boisjoly was an imposing figure, especially when armed with data.
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