Even before President Kennedy committed the United States to a Moon landing, engineers (like Wernher von Braun) envisioned that the vehicle needed to complete such a mission would have to be assembled in Earth orbit. The Earth-orbit rendezvous concept would require at least two launches of the Saturn V launch vehicle and development of an even larger booster, the Nova. Possibly, it would even mean establishing a space station in Earth orbit first so a crew could assemble the spacecraft before it's lunar voyage.