From Kerbal Space Program Wiki
|| Originally the result of a unit of measure conversion bug, the S4 series of fuel tanks transcend the preposterous into the truly absurd. When 'More boosters' fails and is replaced with 'More engines!', the S4 series tanks will be there to loft your dreams, no matter how ridiculous and over-engineered, into the sky on massive trails of fire.
- The Kerbodyne S4-256 Fuel Tank was inspired by the Saturn 5's second stage fuel tank