Mission Impossible 4, “Ghost Protocol.” Just saw it today on disk. Nifty! Enjoyed it!
Tech questions:
Do sub-launched nuclear-tipped missiles have two stages? The movie depicted a sub-launched missile dropping its booster and firing a second stage. Nuh uh?
And…self-destruct/abort capability on nuclear missiles? I’ve always been told that there is no way to “cancel” a missile once it’s launched. (Otherwise, too big a risk the enemy might get hold of your cancel codes.) So… Nuh uh twice?
(Didn’t mind it a bit! This series of movies has a LOT of things that are not plausible. Still a hell of a romp!)
An otherwise fun movie, that certainly bollocksed that bit up.
It’s not impossible for a two stage ICBM just unlikely. All modern versions are single stage. The worse gaff though, IIRC the missile in the movie powered the entire way to the target which is completely wrong as well.
Definitely no abort code. I believe American ICBM’s use an accelerometer to arm the warhead, and once activated is adios muchachacos. I’m not sure if that’s how the Russians and Chinese do it.
It just occurred to me that there is another (very minor) error in the depiction: the warhead would have detonated at an altitude of several thousand feet (because air bursts are worse than ground bursts,) so, by the time we see it becoming inert, it would already have detonated.
I’m mostly cool with liberties like this; it just momentarily paralyzed my ability to suspend disbelief, because once I saw the submarine launch the missile, my soul knew within me, “millions are about to die,” and cringed.
ETA: Oh, well… It’s not as if I could conceivably make a movie one one-hundredth as good as that one!
ryan: Interesting! I hadn’t known they’d ever gone that far beyond the old Polaris archetype.
Why? Why bother with multi-staging in a sub-launched missile? It adds complexity and additional failure points. What’s the benefit? The missile arrives more quickly? This is the “stealth” leg of the triad: it isn’t about getting there fast, it’s just about getting there. What’s the benefit?
My WAG: the usual reason for multiple stages is so that you can drop a bunch of weight and get “more bang of the buck” from the second stage. So maybe having multiple stages allows the missile to go farther with less fuel.
Weight and size. Multistage rockets can accomplish the same delta V in a smaller package. So you might be able to fit 24 missiles on your boomer instead of 18 or 20. Or other design contraints could be met.
SenorBeef: Gotcha! Cramming more missiles into the sub makes (horrible) sense.
Watching all four movies in one weekend is so much fun! You can watch technology in progress. In M.I. 1, you actually have 2 1/2 inch floppy disks; in the last movie, they’ve gone on to USB data sticks…including one that is read remotely, without actually being plugged in to a USB socket! I love this kind of stuff!
