[PhantomGremlin]

My info was about the current Minutemen silos. I figured they were all the same.

The older missiles were liquid fueled, unlike Minuteman. Which means kerosene added when placed on alert, LOX added just before launch. Probably much simpler to have people do that on-site than try to automate. https://en.wikipedia.org/wiki/SM-65_Atlas#SM-65F_Atlas

And as to the (perhaps somewhat facetious) comment elsewhere in the thread that the Russkies might still have "2 nukes" pointed at this silo, there are currently 400 active Minuteman silos. I'm sure the Russians would rather target those than sites that were decommissioned in 1965.

[rsynnott]

Or, for Titan, much nastier things (while the current Titan space launch vehicles are fairly inoffensive solid-and-hydrogen, the Titan ICBMs and early launchers were hydrazine).

[rsynnott]

Er, or not. Just checked; while the Titan IV is no longer in use, it was hydrazine til the end, in 2005(!) I was thinking of the Delta family, which did go from UDMH to hydrogen.