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https://www.space.com/8193-caused-apollo-13-accident.html https://www.space.com/8193-caused-apollo-13-accident.html >In October 1968, the Number 2 tank eventua

https://www.space.com/8193-caused-apollo-13-accident.html https://www.space.com/8193-caused-apollo-13-accident.html >In October 1968, the Number 2 tank eventually used on Apollo 13 was at the North American Aviation plant in Downey, California. There, technicians who were handling the tank accidentally dropped it about two inches. After testing the tank, they concluded the incident hadn't caused any detectable damage. >The dropped tank was eventually cleared for flight and installed in Apollo 13. The tank passed all of its routine prelaunch tests. But at the end of March 1970, after a practice session called the Countdown Demonstration Test, ground crews tried to empty the tank -- and couldn’t. >The small tube used to fill and empty the tank of its super-cold contents had been damaged by the mishandling almost two years earlier. Looks like it was two problems that came together. The heating insulation / voltage-change oversight wouldn't have triggered unless they also had to work around the jammed pipe.

monocasa 9y ago
That's more or less consistent with what I've heard, with the added part that the Beech Aircraft engineers who designed the thing never wanted it to make it's way into a spacecraft. Their opinion was there was no way to certify the thing again; it wasn't designed to be serviced, so NASA would just have to wait for the next tank and delay the Apollo program. The stupid hacks all pointed to finding existing damage from the drop that had been missed when NASA's engineers tried to re-cert the tank that Beech wouldn't. But hey PMs feeling pressure on timelines will ignore engineers' recommendations, roll the dice and just push to prod anyway. And find some engineers who'll back them up who had nothing to do with the original design. Some things never change.
- digi_owl 9y ago
  Seems very similar to why Challenger blew up as well. Engineers felt unease about launching in such cold weather, but management rammed approval through.
  - gknoy 9y ago
    I read a really interesting article on this in my undergraduate software engineering course (an excerpt from Tufte's excellent "Visual Explanations" book dealing with the shuttle Challenger mishap). The main takeaway was not that it was malicious management, but rather that the _way the information was portrayed_ (slides) did a remarkably poor job of showing the relationship between temperature and booster failure. No one showed management a graph of, _"Here's a chart of failures vs temperature, and this is how cold is is today ..."_ Looking at the memos and slides that were presented up the chain, it's not very surprising that the correlation between temperature and failure was lost on its way up the bureaucracy.
    - LeifCarrotson 9y ago
      Engineering says "This is a bad idea". Management says "We want this regardless." The problem is not that the engineers didn't convey what they wanted to say clearly, it's that management did not want to listen.
      - mrisoli 9y ago
        Exactly this, speaking from personal experience, a PM's job is to make sure things are shipped, not escalate Engineering problems to increasingly non-technical people up in the chain. If engineering says "This is a bad idea", PMs will say "It's not perfect", for management that means "ship it".
    - pdonis 9y ago
      Any reading of Tufte's claims about the Challenger launch decision should be accompanied by reading this article, one of whose authors is Roger Boisjoly, one of the Thiokol engineers who recommended against the launch: https://people.rit.edu/wlrgsh/FINRobison.pdf https://people.rit.edu/wlrgsh/FINRobison.pdf tl/dr: Tufte's analysis itself exemplifies the charge Tufte makes. Tufte presents the wrong information about the way the decision was made, in the wrong way, and that is what drives his conclusions. When the right information is presented in the right way, it is clear that the Thiokol engineers did everything they possibly could, and that it was indeed a case of management overruling good recommendations by engineers. The article also gives very important background information: Thiokol had previously recommended grounding the Shuttle until issues with the O-rings that had surfaced on previous flights could be understood. NASA refused. So during the discussion the night before the Challenger launch, Thiokol could not make a number of arguments that would have seemed simpler and easier, taken in isolation--because they had already made those arguments and had them rejected.
- closeparen 9y ago
  If project management honored every engineer's every desire to delay the project out of an abundance of caution, would it have launched at all? It seems doubtful that this was the only case in which they had to choose between delaying the project and accepting risk.

monocasa 9y ago

That's more or less consistent with what I've heard, with the added part that the Beech Aircraft engineers who designed the thing never wanted it to make it's way into a spacecraft. Their opinion was there was no way to certify the thing again; it wasn't designed to be serviced, so NASA would just have to wait for the next tank and delay the Apollo program. The stupid hacks all pointed to finding existing damage from the drop that had been missed when NASA's engineers tried to re-cert the tank that Beech wouldn't. But hey PMs feeling pressure on timelines will ignore engineers' recommendations, roll the dice and just push to prod anyway. And find some engineers who'll back them up who had nothing to do with the original design. Some things never change.

digi_owl 9y ago
Seems very similar to why Challenger blew up as well. Engineers felt unease about launching in such cold weather, but management rammed approval through.
- gknoy 9y ago
  I read a really interesting article on this in my undergraduate software engineering course (an excerpt from Tufte's excellent "Visual Explanations" book dealing with the shuttle Challenger mishap). The main takeaway was not that it was malicious management, but rather that the _way the information was portrayed_ (slides) did a remarkably poor job of showing the relationship between temperature and booster failure. No one showed management a graph of, _"Here's a chart of failures vs temperature, and this is how cold is is today ..."_ Looking at the memos and slides that were presented up the chain, it's not very surprising that the correlation between temperature and failure was lost on its way up the bureaucracy.
  - LeifCarrotson 9y ago
    Engineering says "This is a bad idea". Management says "We want this regardless." The problem is not that the engineers didn't convey what they wanted to say clearly, it's that management did not want to listen.
    - mrisoli 9y ago
      Exactly this, speaking from personal experience, a PM's job is to make sure things are shipped, not escalate Engineering problems to increasingly non-technical people up in the chain. If engineering says "This is a bad idea", PMs will say "It's not perfect", for management that means "ship it".
  - pdonis 9y ago
    Any reading of Tufte's claims about the Challenger launch decision should be accompanied by reading this article, one of whose authors is Roger Boisjoly, one of the Thiokol engineers who recommended against the launch: https://people.rit.edu/wlrgsh/FINRobison.pdf https://people.rit.edu/wlrgsh/FINRobison.pdf tl/dr: Tufte's analysis itself exemplifies the charge Tufte makes. Tufte presents the wrong information about the way the decision was made, in the wrong way, and that is what drives his conclusions. When the right information is presented in the right way, it is clear that the Thiokol engineers did everything they possibly could, and that it was indeed a case of management overruling good recommendations by engineers. The article also gives very important background information: Thiokol had previously recommended grounding the Shuttle until issues with the O-rings that had surfaced on previous flights could be understood. NASA refused. So during the discussion the night before the Challenger launch, Thiokol could not make a number of arguments that would have seemed simpler and easier, taken in isolation--because they had already made those arguments and had them rejected.
closeparen 9y ago
If project management honored every engineer's every desire to delay the project out of an abundance of caution, would it have launched at all? It seems doubtful that this was the only case in which they had to choose between delaying the project and accepting risk.