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The reason for wanting an accuracy better than 100 metres with a
thermonuclear warhead is for when you aim to crack the hardened silo in
which the other guy's ICBM is (if you are lucky) still waiting to be
fired at your now-empty silo. Outside of the circle of those who really
know (but won't talk), it is widely supposed that that needs extreme
accuracy.

It is also said (but again not in public by those who really know) that
an ICBM's warhead spends the great majority of its flight in free-fall.
All navigation towards the target has to be provided during the brief
period between launch and separation from the rocket when the latter
runs out of fuel. Supposedly, the extreme accuracy of GPS was designed
to provide U.S. ICBMs with sufficiently-precise positional information
early in their flights, so that even after any errors had been magnified
by the long extrapolation in free-fall, they would still arrive close
enough to their hardened targets to do their jobs.

Did the Soviets not develop their own GPS-like system? If so, does
anyone know whether it is still operational?


Trevor Kenchington


> Fascinating.  I was once told that Soviet ICBMs used a form of cel nav for
> targeting, as they could not trust a potential enemy's GPS system ;-)  I
> quipped, "Big deal. So SA is on and you miss by 100 meters.  What does that
> matter with multiple warheads?
>
> I was surprised to learn that the destination was locked in while the
> missile was high above the Earth, so a few seconds of an arc off could make
> a potentially significant difference on final destination.
>
> Bill


--
Trevor J. Kenchington PhD                         Gadus@iStar.ca
Gadus Associates,                                 Office(902) 889-9250
R.R.#1, Musquodoboit Harbour,                     Fax   (902) 889-9251
Nova Scotia  B0J 2L0, CANADA                      Home  (902) 889-3555

                     Science Serving the Fisheries
                      http://home.istar.ca/~gadus

   

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