From September 1962 NASA planned to fly four early manned Apollo spacecraft on Saturn I boosters. A key prerequisite for these flights was complete wringing out of the launch escape system.
The tentative Apollo flight plan laid out the following unmanned tests before a manned flight would be undertaken:
By January 10, 1963, MSC and OMSF agreed that an unmanned Apollo spacecraft must be flown on the Saturn C-1 before a manned flight. SA-10 was scheduled to be the unmanned flight and SA-11, the first manned mission.
By the later summer of 1963 the value of the Saturn I missions seemed increasingly in doubt. The limited payload of the Saturn I meant that only partial systems could be installed. At a September 26, 1963 meeting in Washington, D.C., NASA's scheduling contractor, Bellcomm, was asked to develop an Apollo mission assignment program without a Saturn I.
Bellcomm quickly responded, recommending that the Apollo spacecraft flight test program should be transferred from the Saturn I to Saturn IB launch vehicles. The Saturn I program should end with flight SA-10. All Saturn IB flights, beginning with SA-201, should carry operational spacecraft, including equipment for extensive testing of the spacecraft systems in earth orbit. Associate Administrator for Manned Space Flight George E. Mueller recommended the changeover on October 26. NASA Administrator James E. Webb's concurrence came two days later. Development of the Saturn IB for manned flight would be accelerated and "all-up" testing would be started.
No crew assignments were ever made for these flights; the first two groups of astronauts were fully committed to the Gemini program. The third astronaut selection, in October 1963, was simultaneous with the decision to drop the Saturn I flights. Had these flights occurred, they would have run from fall 1965 to the end of 1966, concurrent with the flights of Gemini 5 to 12.