That's basically what the Minotaur rockets are.
> The Minotaur I and II are derived from the Minuteman missile, while the Minotaur III, IV and V are derived from the Peacekeeper. [1]
It's not quite the same thing as repurposing the actual ICBMs in the silos, but the parts commonality is quite high. In a true emergency, they may even be able to convert ICBMs, although it seems unlikely that there would be an emergency so urgent that ICMBs would need to be converted into satellite launch vehicles, but not so urgent that the ICMBs wouldn't be used for the intended purpose.
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