alt Hacker News>Camarda is an outlier. The engineers at NASA believe it is safe. The astronauts believe it is safe. Former astronaut Danny Olivas was initially skeptical of the heat shield but came around.
How do you explain so many people believing it is safe?
The problem is risks are far too easy to brainstorm, anyone can come up with endless risks that it takes endless time to mitigate.
If I were the manager for challenger, I would have run the o-ring experiment as soon as it was brought up as a concern. Put the fuel pumps in a freezer, test if they leak. Feynman famously demonstrated it with a glass of icewater. Experiment is what separates made up risks from real risks, I would have definitely told the engineers to take a hike and would have hit launch if they couldn't provide experimental evidence of o-ring failure in cold temps. (Spoiler alert: in that case they easily could have)
Replies
> How do you explain so many people believing it is safe?
The article itself answers this question: institutional incentives leading to heavy social pressure to agree with the groupthink and declare something is safe when it is not. And we know that the scenario it lays out is highly possible, because it has already destroyed two Space Shuttles. Now that this has happened twice, the burden of proof is on the people saying it's not happening again, especially when the OIG's report directly contradicted what NASA had been saying about the heat shield up to that point (indicating they were lying and had to hastily retcon their story).
No. That famous demonstration only touched on the real failure mode--the rings were covering up other failure and in the cold could not do so.
The real test was creating a full-scale test of ignition, an engine containing mostly inert filler (to occupy the fuel volume) and just enough fuel to reach stable burning.