Apollo Command/Service Module
The Apollo Command/Service Module (CSM) was originally designed to take three men directly to the surface of the Moon, atop a large landing stage with legs. The Command Module sized out at in diameter, by long. The Service Module was long, with a total vehicle length of including the engine bell. The hypergolic propellant service propulsion engine was sized at to lift the CSM off the lunar surface and send it back to Earth. This required a single-launch vehicle much larger than the Saturn V, or else multiple Saturn V launches to assemble it in Earth orbit before sending it to the Moon.