Adam Reynolds wrote:
Simon_Jester wrote:The real problem is that with a 90% reliability rate, you can't plan on Falcon launches actually working. You certainly can't put a human being on the rocket. Nor can you put a cargo on the rocket that is mission-critical for a manned mission, unless you have a duplicate cargo standing by to launch on another Falcon 9 in case the first one explodes.
That is what launch escape systems are for. SpaceX has one for their potential Dragonn manned capsule, and it would have certainly saved the crew if this were a failure on a manned mission. Assuming it is more reliable than the second stages, which I certainly hope it is.
On one level it doesn't matter. If you have to use a launch escape mechanism you've already lost in a lot of ways. If you're sending up a mission-critical unmanned payload, that payload will almost certainly NOT be serviceable and ready to be reused on another rocket any time soon, and you'll miss your launch window if you're dealing with any kind of interplanetary or timed operation. At best it's a "try again next year" situation, at worst it's a "we don't have the budget to launch your space probe to Jupiter again, so much for that idea" situation. You can't just shrug, say "oh well," and climb in another rocket for another try; this isn't Kerbal Space Program.
Moreover, that is precisely the question. Space-X is having a 10% or so failure rate in their actual rockets, which are tested frequently, and which is so critical to their success because nothing good can possibly happen for them if the rocket fails. What are the odds that a piece of equipment like the escape tower is MORE reliable, when it rarely or never actually gets used for anything during a mission?
If you're the kind of person who skimps on safety checks for the thing that can make the whole satellite launch fail and explode (the second stage of the rocket), you're also going to skimp on checking the reliability of things that might not get used at all.
Bluntly, Falcon 9 is not a man-rated rocket, and at this rate it never will be. You could probably find astronauts mad enough to fly it, but that doesn't make it a good choice for space exploration.
Sea Skimmer wrote:Thing to remember also is NASA's own work indicates that you need to aim for, design for, condition for and then test for at least a 1:100,000 failure rate if you want to even think about getting a 1:100 failure rate in actual service conditions.
One interesting bit I recall from Richard Feynman's account of his service on the Rogers commission that investigated the Challenger disaster was that the managers tended to use the testing rate and the engineers tended to use the service rate when he interviewed both. Which is why managers sat before Congress and claimed the former failure rate, even though engineers recognized the difference.
The underlying problem when the space shuttle was built was that NASA could only fund it by outright lying to Congress so that it would be initially funded, then use the sunk cost in order to fund the rebuild cycles.
The underlying problem is that Congress went "okay, we put a man on the moon, time to stop thinking about space exploration ever," and the funding dried up almost instantly. NASA has spent literally the entire time since struggling to get enough funding to accomplish anything other than its quite impressive unmanned exploration program, while everyone gets more and more disappointed in them about "why haven't we done anything awesome like the moon landings in fifty years?" 
Statistics: Posted by Simon_Jester — 2016-09-05 02:26pm