3 ms·

With the addition of the crew escape system plus nailing down the causes of their last failure, very much safer than any other manned launcher the US has had in

With the addition of the crew escape system plus nailing down the causes of their last failure, very much safer than any other manned launcher the US has had in service.

lutorm 11y ago
That's a hope though, not a fact...
- InclinedPlane 11y ago
  That's an estimate based on engineering analysis and statistics, just like any estimate of reliability.
  - lutorm 11y ago
    It's not an estimate based on statistics, because there are no statistics for the system you are talking about. It is a prediction based on engineering analysis, and the prediction for space shuttle reliability was quite a bit better than the actual record turned out to be. I want SpaceX to succeed as much as anyone (probably more since I work there), but one should not delude oneself into thinking that predictions are fact.
avmich 11y ago
You think it's going to be more reliable than Saturn-V manned stack? Why?
- Already__Taken 11y ago
  I don't agree with the premise but as I understand it the crew escape system can work for the entire preflight+flight not just a certain window on the ascent.
- dunmalg 11y ago
  Cherry picking the MANNED Saturn V missions conveniently leaves out the unmanned Apollo 6 test where pogo vibrations borked two of the second stage engines and caused third stage relight to fail. And if you want to consider the whole Saturn V STACK then you're going to have to consider counting Apollo 13 as a failure. The "payload" for Apollo is, in the end, really just the Command Module.
  - avmich 11y ago
    We're a bit offtopic here :) but let me respectfully disagree. The whole point of doing testing with rockets is to find what you don't know, validate your assumptions... What you usually don't know is when a thing will fail - and you don't want to learn that in a real mission, so you push the test article to extreme. Another reason to do tests is something which should work - and shouldn't fail - but you can't test that without actually doing a flight test. So, in my opinion, cherry picking test flights - where things fail routinely, otherwise why testing? - doesn't show you the designed - and updated, with test data - reliability of the system. Regarding whole stack - I meant the whole thing which lifted off and the part of which reached low Earth orbit. That stack had the pulling safety tractor rocket. But frankly, if I'd consider Apollo-13 flight, I'd assume we have the case of mission abort in a later stage of flight, after which the existing measures were taken to bring back the craft safely. So mission was aborted - just as it would be if, say, Saturn-V grossly misbehaved on 30th second of flight - and the systems worked on safe return.

With the addition of the crew escape system plus nailing down the causes of their last failure, very much safer than any other manned launcher the US has had in service.

lutorm 11y ago

That's a hope though, not a fact...

InclinedPlane 11y ago
That's an estimate based on engineering analysis and statistics, just like any estimate of reliability.
- lutorm 11y ago
  It's not an estimate based on statistics, because there are no statistics for the system you are talking about. It is a prediction based on engineering analysis, and the prediction for space shuttle reliability was quite a bit better than the actual record turned out to be. I want SpaceX to succeed as much as anyone (probably more since I work there), but one should not delude oneself into thinking that predictions are fact.

avmich 11y ago

You think it's going to be more reliable than Saturn-V manned stack? Why?

Already__Taken 11y ago
I don't agree with the premise but as I understand it the crew escape system can work for the entire preflight+flight not just a certain window on the ascent.
dunmalg 11y ago
Cherry picking the MANNED Saturn V missions conveniently leaves out the unmanned Apollo 6 test where pogo vibrations borked two of the second stage engines and caused third stage relight to fail. And if you want to consider the whole Saturn V STACK then you're going to have to consider counting Apollo 13 as a failure. The "payload" for Apollo is, in the end, really just the Command Module.
- avmich 11y ago
  We're a bit offtopic here :) but let me respectfully disagree. The whole point of doing testing with rockets is to find what you don't know, validate your assumptions... What you usually don't know is when a thing will fail - and you don't want to learn that in a real mission, so you push the test article to extreme. Another reason to do tests is something which should work - and shouldn't fail - but you can't test that without actually doing a flight test. So, in my opinion, cherry picking test flights - where things fail routinely, otherwise why testing? - doesn't show you the designed - and updated, with test data - reliability of the system. Regarding whole stack - I meant the whole thing which lifted off and the part of which reached low Earth orbit. That stack had the pulling safety tractor rocket. But frankly, if I'd consider Apollo-13 flight, I'd assume we have the case of mission abort in a later stage of flight, after which the existing measures were taken to bring back the craft safely. So mission was aborted - just as it would be if, say, Saturn-V grossly misbehaved on 30th second of flight - and the systems worked on safe return.