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Spaceguy5 t1_ivwy60i wrote

Reply to comment by mrgtiguy in NASA leaders recently viewed footage of an underwater dive off the East coast of Florida, and they confirm it depicts an artifact from the space shuttle Challenger by marketrent

The design wasn't bad, if it was used properly in the correct environment. The way they were using it is what was bad, because it wasn't designed to be used at those temperatures and they knew it but ignored the spec. And using stuff outside of spec without any kind of analysis nor investigation to confirm it won't be a problem is a lesson they learned in blood. It's something still taught to the current NASA work force (which I'm part of).

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isanameaname t1_ivx9d88 wrote

They had been partially failing since early testing but that partial failure was deemed acceptable because they failed in a way which was thought to be within acceptable levels of risk:

https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster?wprov=sfla1

Fun fact: it wasn't.

> Evaluations of the proposed SRB design in the early 1970s and field joint testing showed that the wide tolerances between the mated parts allowed the O-rings to be extruded from their seats rather than compressed. This extrusion was judged to be acceptable by NASA and Morton Thiokol despite concerns of NASA's engineers. A 1977 test showed that up to .052 inches (1.3 mm) of joint rotation occurred during the simulated internal pressure of a launch. Joint rotation, which occurred when the tang and clevis bent away from each other, reduced the pressure on the O-rings which weakened their seals and made it possible for combustion gases to erode the O-rings.

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intern_steve t1_ivy3wpw wrote

If you watch old slow motion footage of the boosters during launch you can actually see small puffs of smoke escaping from the seams between booster segments before the o rings extrude to fill the gap.

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