The above 5-Why does not point to the root cause of the Challenger explosion. A 5-Why allows you to capture some of the cause-and-effect relationships within the incident. It is accurate, not complete. Another person analyzing the Challenger disaster may argue the 5-Why should look something like this:. Rather than argue the point, notice that both 5-Why examples above are accurate and based on evidence.
There is no right 5-Why. There is no right answer. The simple 5-Why Cause Map diagram allows us to incorporate multiple perspectives and gives us a place to start a more in-depth analysis. At first glance, it may appear that cause-and-effect analysis is too basic to adequately document an incident of this magnitude.
But as the investigation continues, we learn more details and collect more evidence to validate and understand what happened. Cause-and-effect relationships validated with evidence reveal why things are the way they are. For decades, conventional root cause analysis has defined a root cause as a special type of cause.
Cause and effect naturally splits into multiple causal paths when more than one cause is required to produce an effect. Here, we see that the straight-line 5-Why Cause Map diagrams shown above can combine into one larger, more detailed Map with multiple causal paths. As more evidence was collected, investigators learned there was a fundamental design flaw in the solid rocket booster to which engineers had grown accustomed. Here, we can ask why the flaw had not been corrected since its discovery in Because of the flaw, it was not uncommon for the booster casing to balloon under the stress of ignition, causing the metal parts of the casing to bend away from each other, creating gaps through which hot gases could leak.
In prior instances, the primary O-ring would shift out of its groove and form a seal. This process is called extrusion and the hot gases escaping is called blow-by. The evidence of previous issues with O-ring erosion and blow-by can be captured directly on the Cause Map diagram.
The more time it takes for extrusion to occur, however, the greater the damage to the O-rings. This brings us to the most immediate reason for the O-ring failure: the low temperatures at launch caused the O-rings to harden. On the morning of the launch, the cold weather lengthened the time of extrusion and hardened the O-ring, which could not form a seal in time. At the launch site, the fuel segments were assembled vertically. Field joints containing rubber O-ring seals were installed between each fuel segment.
The O-rings were never tested in extreme cold. On the morning of the launch, the cold rubber became stiff, failing to fully seal the joint. The fuel tank itself collapsed and tore apart, and the resulting flood of liquid oxygen and hydrogen created the huge fireball believed by many to be an explosion.
After the collapse of its fuel tank, the Challenger itself remained momentarily intact, and actually continued moving upwards. Without its fuel tank and boosters beneath it, however, powerful aerodynamic forces soon pulled the orbiter apart. The pieces—including the crew cabin—reached an altitude of some 65, feet before falling out of the sky into the Atlantic Ocean below. The five astronauts and two payload specialists that made up the STS L crew aboard the space shuttle Challenger in January of Crew members are left to right, front row astronauts Michael J.
Smith, Francis R. Dick Scobee and Ronald E. A presidential commission was convened to look into the incident, chaired by former Attorney General and Secretary of State William P. The commission report talked about the technical causes of the accident.
The entire failure could be traced to an O-ring, a rubber seal on the solid rocket boosters that degraded in the cold weather of the launch. But the O-ring would not have been a problem had NASA not chosen to launch on so cold a day -- the coldest launch yet, according to an NPR interview with one of the shuttle engineers. While the engineer blames himself for not convincing NASA and high-level managers of the danger the cold presented, a US House of Representatives report from the Committee on Science and Technology concluded that it was a long-standing failure in safety protocols, combined with an unsustainable launch rate that led to the disaster.
In the wake of what happened with Challenger, NASA made technical changes to the shuttle and also worked to change the safety and accountability culture of its workforce.
The shuttle program resumed flights in After the Challenger wreckage was examined, most of the pieces were buried and sealed in abandoned Minuteman missile silos at Cape Canaveral Air Force Station, where they remain today. Challenger's explosion changed the space shuttle program in several ways.
Plans to fly civilians in space such as teachers or journalists were shelved for the next 22 years, until Barbara Morgan , who was McAuliffe's backup, flew aboard Endeavour in Satellite launches were shifted from the shuttle to reusable rockets.
Additionally, astronauts were pulled off duties such as repairing satellites, and the Manned Maneuvering Unit was not flown again, to better preserve astronaut safety. Challenger has also left an educational legacy: Members of the crews' families founded the Challenger Center for Space Science Education program, which brings students on simulated space missions.
Visitors to the Kennedy Space Center can view debris from Challenger's last mission as well as Columbia at an exhibit called "Forever Remembered," which opened in The debris is on display at the visitor's center. Join our Space Forums to keep talking space on the latest missions, night sky and more!
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