 Polaris had enough range that the submarines could roam open areas of the ocean, and would be essentially invulnerable to attack no matter how many missiles the Soviets had, or how accurate they were.Based on the same 400 equivalent megatons calculation, they set about building a fleet of 41 submarines carrying 16 missiles each, giving the Navy a finite deterrent that was unassailable.A February 1960 memo by RAND, entitled "The Puzzle of Polaris", was passed around among high-ranking Air Force officials.