Calculating based on the Mk1 missile frigate being S16 and having 12.5k health (UL cap), S4M should be 3.14B health, which would take about 125 Mk3 lightning warheads to kill.
That's 10m28s of unboosted building even if you can somehow negate the build delay, and 11.3M metal, which I don't have and would take on the order of 20-30 minutes to gather (There are a few distribution nodes floating around, but not that many) My Champion is a battleship with everything unlocked, but my ModForts are at the choke.
I have grav turret 3 and engineer 3 unlocked, so I think it is maybe a quarter of the way to conceivable to pull this off if the warhead cooldown can be overcome. Especially if you back up to the autosave from 5 RL minutes before.
... oh, and cheats are enabled, albeit not used, so obviously one could use "Armor Em" a dozen times to get the needed missiles, but that's no fun. (Wait, does that give mk1 missiles or mk3? If the former, you would need to do it about 60 times)