> The timing mechanisms have to execute perfectly to get a full power detonation and should be designed to become inert in a catastrophic breakup anyway. Shoul

> The timing mechanisms have to execute perfectly to get a full power detonation and should be designed to become inert in a catastrophic breakup anyway. Should assumes particular goals, and with almost any system you're looking at a trade off between safety and reliability. Like the sensors on a modern car; some cars refuse to start these days if the sensor's out. The military's perspective is likely to be something like: We press a button, we want a mushroom cloud. Thank you very much. They're unlikely to want to introduce unnecessary points of failure in their system. Timing systems, trigger mechanisms and the like will break, or be manufactured incorrectly. Nothing's perfect. Especially when you're designing something that's going to be thrown around a bit (slimmer margins.) Which then gets weighed against the concern that that thing better not go off by itself. I would imagine that the latter is why there were multiple safety devices on the weapon - reasoning that the chance of them all failing concurrently was very low. Either way you do it, you're taking on some degree of risk of something - even if you make a system with a single point of failure, and make it fail safe as far as possible, that can never be entirely eliminated. It seems rational to us that you'd err on the side of the thing not going off. But then again we're not in an arms race right now. Someone might well reason that if you introduce something that's going to introduce a certain failure rate into your system, that's going to mean you have to invest in more weapons to reach the degree of force you want. Especially if they're reasoning in a very constrained space - i.e. they primarily think about the threats they're used to - and just don't think of things like bombers going down, (which in any case they're going to find themselves encouraged not to do since it implies fault on their part) that's going to be a very easy rationalisation for them to make to themselves.