Escape capsules are not used when the rocket is ok. So, 1 in 10 chance of failure would likely include dammage from an exploding rocket.
NASA's problem was their two failures did not result from any one component of the original design failing. One was used out of spec and the foam had been changed from the initial design.
>Escape capsules are not used when the rocket is ok. So, 1 in 10 chance of failure would likely include dammage from an exploding rocket.
I agree that a very effective escape system, as it appears the f9 has, makes the rocket far safer. However understanding failure probabilities is much complex than this thread is making it sound. For instance you could have a escape system failure that triggers the exploding rocket or a software system failure which causes both the rocket to explode and the escape system to fail. Take a look at 'Engineering a safer world' for an idea of how NASA and other parties actually calculate these probabilities: https://mitpress.mit.edu/books/engineering-safer-world
If you have the actual probabilities, which include cascade failures and one of the systems is a safety backup system not in normal use then multiplication is reasonably though not completely accurate. Though, you do need to consider the failure of the safety system when the normal system is operating correctly, but that's also much easier to avoid so likely very very low.
Cascade failures are a far more complex situation and thus harder to predict. So again, it depends on what the failure rate is describing not just what the number is.
NASA's problem was their two failures did not result from any one component of the original design failing. One was used out of spec and the foam had been changed from the initial design.