CHALLENGER - John Wawrzonek



"Space Shuttle Challenger disaster

Date January 28, 1986; 32 years ago Time 11:39:13 EST (16:39:13 UTC)

Location Atlantic Ocean, off the coast of Florida

Outcome Grounding of the Space Shuttle fleet for nearly three years during which various safety measures, solid rocket booster redesign, and a new policy on management decision-making for future launches were implemented.

On January 28, 1986, the NASA shuttle orbiter mission STS-51-L and the tenth flight of Space Shuttle Challenger (OV-99)broke apart 73 seconds into its flight, killing all seven crew members, which consisted of five NASA astronauts and two payload specialists. The spacecraft disintegrated over the Atlantic Ocean, off the coast of Cape Canaveral, Florida, at 11:39 EST (16:39 UTC).

The disintegration of the vehicle began after a joint in its right solid rocket booster (SRB) failed at liftoff. The failure was caused by the failure of O-ring seals used in the joint that were not designed to handle the unusually cold conditions that existed at this launch.

The seals' failure caused a breach in the SRB joint, allowing pressurized burning gas from within the solid rocket motor to reach the outside and impinge upon the adjacent SRB aft field joint attachment hardware and external fuel tank. This led to the separation of the right-hand SRB's aft field joint attachment and the structural failure of the external tank. Aerodynamic forces broke up the orbiter.

The crew compartment and many other vehicle fragments were eventually recovered from the ocean floor after a lengthy search and recovery operation. The exact timing of the death of the crew is unknown; several crew members are known to have survived the initial breakup of the spacecraft. The shuttle had no escape system,[1][2] and the impact of the crew compartment with the ocean surface was too violent to be survivable.[3]

The Rogers Commission found NASA's organizational culture and decision-making processes had been key contributing factors to the accident,[4] with the agency violating its own safety rules. NASA managers had known since 1977 that contractor Morton-Thiokol's design of the SRBs contained a potentially catastrophic flaw in the O-rings, but they had failed to address this problem properly. NASA managers also disregarded warnings from engineers about the dangers of launching posed by the low temperatures of that morning, and failed to adequately report these technical concerns to their superiors.

The Challenger disaster has been used as a case study in many discussions of engineering safety and workplace ethics."

The Wikipaedia article is far longer than these brief excerpts, far more detailed, and quite frightening to read. The fright comes from descriptions of serious problems of the kind that caused the Challenger disaster clearly evident in the first flight and every subsequent flight. The acticle recounts the communication, or lack of it, between the various groups of engineers, managers and companies involved in the project.

The terrifying parts are two: failure of engineers to be absolutely explicit in communicating their judgments and the failure of managers to give full credence to what the engineers were saying, despite the fact that they were glossing over issues just as bit.

As I described in my early and simple lessons in risk assessment, managers have two things going against them: pressure from above to get on with the show because it is costing money and political capital and a lack of experience with the real thing, such as the smell of burning components or the evidendent violence when examining a crash or other kind of failure.

Engineers are at a disadvantage in not realizing the pressure on the managers and their own lack of experience in the real world. These are similar to the factors that come into play in global warming. Politicians and the public live in comfort and hear strangely vague language from scientists which may feel very explicit to the scientists.

There is one difference, however, between the space shuttle and the Earth. The shuttle has the same risk "rating," namely death, but it is clear, sudden and widely appreciated. The Earth's demise is slow, usually (at least in early stages) localized but of monumentally greater consequence. Nevertheless, the same failures of reasoning, communication and comprehension permeate both situations, as they do so many other human endeavors.

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