The mode that Apollo would use to land on the moon was the most studied, analyzed, and debated decision made for the lunar landing program. There were four main choices Direct-ascent, Earth-Orbit Rendezvous, Lunar-Orbit Rendezvous, and Lunar Surface Rendezvous.
Max Faget thought the first stage of the moon rocket should use four solid-fueled engines, 6.6 meters in diameter. He reasoned these could certainly accomplish whatever mission was required of either the Saturn or Nova, and it would be more cost effective. Faget said it made good sense to use cheap solid fuels for expendable rockets and more expensive liquid fuels for reusable engines. Faget called the individual solid rocket ‘the Tiger.’