What was the fatal flaw that caused the Space Shuttle Challenger disaster?
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There is already the technical ELI5 commented, so let me offer the organizational ELI5:
You know how every January the President goes on TV and tells everyone how nice it is to live in America? Well that year when it was January, the President was going to say how great NASA is and how good spaceships they make. The Challenger spaceship was already delayed three times. If it was delayed again, the President’s friends would make fun of him because his spaceship doesn’t work. So NASA really made a pinky promise that this January they would fly the spaceship. The weather was very very icy that day and nobody was sure if the spaceship is safe to fly with that weather. Now, as people have doctors when they get sick from cold, there are some doctors for the machines. They are called engineers. NASA asked these machine doctors what to do. Because the machine doctors were afraid they would lose their job, they did not say that the spaceship will explode. They just said they are not sure what is happening. So NASA decided to pray very much to God that the spaceship will not explode the next day. But even if God wanted to help them, the spaceship was already damaged from the bad weather the previous day. So when they tried to fly the spaceship it exploded.
There’s a great book on this by Diane Vaughan, where she argues that the original fatal flaw was not the defective o-ring but actually how NASA was run at the time. She argues that some engineers knew the o-ring was an issue but that pressures to launch and weird internal hierarchy made it so that this issue when reported was deemed an “acceptable risk.” A good lesson for not just NASA but many companies and organizations charged with building things that can put human lives at risk. https://press.uchicago.edu/ucp/books/book/chicago/C/bo22781921.html
There is already the technical ELI5 commented, so let me offer the organizational ELI5:
You know how every January the President goes on TV and tells everyone how nice it is to live in America? Well that year when it was January, the President was going to say how great NASA is and how good spaceships they make. The Challenger spaceship was already delayed three times. If it was delayed again, the President’s friends would make fun of him because his spaceship doesn’t work. So NASA really made a pinky promise that this January they would fly the spaceship. The weather was very very icy that day and nobody was sure if the spaceship is safe to fly with that weather. Now, as people have doctors when they get sick from cold, there are some doctors for the machines. They are called engineers. NASA asked these machine doctors what to do. Because the machine doctors were afraid they would lose their job, they did not say that the spaceship will explode. They just said they are not sure what is happening. So NASA decided to pray very much to God that the spaceship will not explode the next day. But even if God wanted to help them, the spaceship was already damaged from the bad weather the previous day. So when they tried to fly the spaceship it exploded.
An underappreciated contributing factor in the pressure NASA felt to launch despite the dangerously low temperature comes from the origins of the shuttle program itself.
The military didn’t want to be dependent on the shuttle program to launch satellite payloads, they wanted their own dedicated system. But one of the selling points NASA used to secure funding from Congress was that the shuttle could carry military satellites into orbit, thus saving money– no need for a second expensive military system. The military expressed doubts about the shuttle’s reliability to launch regularly, especially in adverse weather conditions. But NASA won, the shuttle was funded, and the military did not get a new satellite booster (although they had older existing systems available for fallback).
And so NASA didn’t like canceling or rescheduling missions partly out of concern it would spur criticism of the program’s capabilities and reason for existence.
Hubris.
The people responsible for the start decided to ignore that the Space Shuttle wasn’t designed to start at temperatures this low. They even had their failure properly documented.
The chain of consequences of this failure is well known: because of the low temperature, a seal in one of the booster rockets failed soon after lift-off. This was because at this temperature, it wasn’t flexible enough to handle the stress of the start. Basically, it didn’t fill the gap it was intended to fill, because it wouldn’t expand quickly enough. This resulted in a flame that first further weakened the seal, and then damaged the main tank to the point where the fuel inside would gush out. That fuel caught fire. The tank ruptured, because the pressure inside was rising, and ultimately exploded.
There’s a great book on this by Diane Vaughan, where she argues that the original fatal flaw was not the defective o-ring but actually how NASA was run at the time. She argues that some engineers knew the o-ring was an issue but that pressures to launch and weird internal hierarchy made it so that this issue when reported was deemed an “acceptable risk.” A good lesson for not just NASA but many companies and organizations charged with building things that can put human lives at risk. https://press.uchicago.edu/ucp/books/book/chicago/C/bo22781921.html
An underappreciated contributing factor in the pressure NASA felt to launch despite the dangerously low temperature comes from the origins of the shuttle program itself.
The military didn’t want to be dependent on the shuttle program to launch satellite payloads, they wanted their own dedicated system. But one of the selling points NASA used to secure funding from Congress was that the shuttle could carry military satellites into orbit, thus saving money– no need for a second expensive military system. The military expressed doubts about the shuttle’s reliability to launch regularly, especially in adverse weather conditions. But NASA won, the shuttle was funded, and the military did not get a new satellite booster (although they had older existing systems available for fallback).
And so NASA didn’t like canceling or rescheduling missions partly out of concern it would spur criticism of the program’s capabilities and reason for existence.
Hubris.
The people responsible for the start decided to ignore that the Space Shuttle wasn’t designed to start at temperatures this low. They even had their failure properly documented.
The chain of consequences of this failure is well known: because of the low temperature, a seal in one of the booster rockets failed soon after lift-off. This was because at this temperature, it wasn’t flexible enough to handle the stress of the start. Basically, it didn’t fill the gap it was intended to fill, because it wouldn’t expand quickly enough. This resulted in a flame that first further weakened the seal, and then damaged the main tank to the point where the fuel inside would gush out. That fuel caught fire. The tank ruptured, because the pressure inside was rising, and ultimately exploded.
Look up Roger Boisjoly, he was one of the primary engineers trying to tell everyone who would listen to delay the launch because of the danger.
Utah Senators Jake Garn and Frank Moss Lobbying for the SRB to be built in Utah, which would require them to be transported in sections resulting in o-ring design that failed
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