Lee Thomson has a copy of Gene Roddenberry's March 1964 pitch for Star Trek. There were many changes made before the first and second pilot episodes were filmed. The ship's doctor, for example, went by a different name, but was still known as "Bones". Sex kitten Yeoman Rand was called "Colt", and Roddenberry clearly had a larger role in mind for that character.
Link via Geekosystem
In "The Making of Star Trek" Roddenberry explains that he was aware of the Drake equation while he was writing the pitch but didn't actually have it on hand to include, so he made up a complicated-looking equation to give credence to his premise!
At one point, the Talosians, when Pike isn't being quick enough in his romancing of whats-her-name, teleport in Colt and Number One to give Pike more variety...