Nasa’s Challenger Tragedy

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NASA’s Challenger Tragedy

January 28, 1986 was marked as one of the darkest day of NASA’s history when Space Shuttle Challenger exploded 73 seconds after liftoff killing all seven crew members. It was NASA’s 25th, mission but unfortunately not a successful one. Challenger’s disaster appeared in a period of small budgets, workforce and a need for the space agency to confirm its successfully shuttle program. Pressures settled because of the need to meet client obligations, which transformed into a requirement to launch a certain number of flights per year at the scheduled time.

NASA was a government agency formed in 1958, a year after the launch of Soviet Union’s Sputnik. At the beginning NASA was created as a civilian space exploration programs but at actually it was an expression of a military culture having one goal to institute the U.S. dominance against the Soviet Union in space. In March 1970 President Nixon approved the Space Transportation System or Shuttle Program. The concept of the program was to build a fleet of reusable spacecraft and to service the yet-to-be-developed space station. To maintain Shuttle Program funding from Congress, NASA was required to make a series of major reductions. At the beginning, fronting an extremely controlled budget, NASA forfeited the investigation and development essential to produce a truly returnable shuttle. Instead they accepted a design which was only partially reusable, eliminating one of the structures which made the shuttle attractive in the first place. Solid rocket boosters (SRB’s) were used instead of safer liquid fueled boosters since they required a much smaller research and development effort. Various other design changes were made to reduce the level of research and development required.

In 1973 Morton-Thiokol a company from Utah won the contract of NASA to design and build the Solid Rocket Boosters (SRB). In 1977 the team of engineers from Morton-Thiokol, discovered at the analysis of a pre-flight hydrobust test a “joint rotation” which required a lot of pressure on the O-rings to seal the joint properly. Meanwhile, NASA and the team of engineers observed two conditions: erosion of the primary O-ring and blow-by, which will lower the integrity of the joint seal. In November 1982, the erosion of the primary O-ring on STS-5 flight pressed NASA to increase the critical rating of the primary O-ring, but this change was not communicated with Morton-Thiokol’s engineering team. Despite of the higher critically rating, NASA agreed with the expanding risk, rather than grounding the entire fleet of shuttles.

In March 1985, Roger Boisjoly a 27 years experienced engineer in booster joints seal, from Morton discovered a seal failure at the launch of flight 51-B, where both O-rings in the nozzle joint eroded. A preliminary test performed at Thiokol demonstrated that the O-rings do not work well in a low temperature. In august 1985, the team from Thiokol warned NASA about all joint seal problems, but their result was rejected by NASA who considered not being a big issue to determine grounding the entire fleet and advised the engineers from Thiokol to fix it as they go along.

Late January 1986, Challenger’s mission registered several delays because of the cold weather. NASA held many meetings to discuss the low temperature performance of the boosters before the decision to launch the Challenger was taken. With a night before the Challenger was launched, during a teleconference and Telefax systems that connected Kennedy Space Center in Florida, Morton-Thiokol in Utah and Marshall Space Flight Center in Huntsville Alabama, several engineers and managers discussed if it was safe to launch the shuttle at a predicted temperature of 19 degrees, temperature that was never experienced before.

Engineers involved in the presentation Roger Boisjoly and his supervisor Arnie Thompson point out the meeting as another opportunity to express their worries about the...
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