Randall Clague wrote:
You put blowout panels in your tanks. You need a mechanism to blow
them out in an emergency. But you need to be damn sure they don't
blow out at any other time, or it will BE an emergency. The
damn-sure-they-don't has to have many times the reliability of the
damn-sure-they-do, since hopefully you have few emergencies where you
have to use the blowout panels.
There is a probability argument; about whether the panels can blow out
when you don't want them to. I think that that probability can be
negligible- after all, the Shuttle has range safety devices on it. So an
existence proof exists that the range safety can be sufficiently
reliable to be designed into a manned flight vehicle, that, when it was
designed, was aiming for a lot of 9s. (I know they didn't hit the 9's
but we have no reason to think the range safety is unreliable in a false
triggering sense.)
So you have to put a lot of
reliability in the vehicle somewhere - why not in the engines? Which
you will use every time you fly, in contrast to the blowout panels
which hopefully you will never use.
Probably because making range safety devices reliable is comparatively
cheap and easy, whereas making engines reliable isn't as cheap and easy.
-R
--
-Ian
Motto: "You're Not Authorized to Know Our Motto."
So, like, how many lives DOES Shroedinger's cat have anyway?
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