Perhaps the most significant point about the lunar-orbit flight proposed for Apollo 8 was that the command and service modules would fly the same route to the moon as would be used for the actual lunar landing.
An ‘A’ type mission would be flown with a Saturn V and be used to test the Launch vehicle, spacecraft, and a high velocity lunar return. Nasa cover the ‘A’ mission with Apollo 4 & 6.
A ‘B’ type mission would be flow with a Saturn IB and test the lunar module development, and propulsion, and launch vehicle staging. This was accomplished with Apollo 5.
A ‘C’ type mission would be flown with a Saturn IB and test the command and service module and evaluate the crew performance in low earth orbit. This was accomplished with Apollo 7…
Command Service Module-101 started through the manufacturing cycle early in 1966. By July, it had been formed, wired, fitted with subsystems, and made ready for testing. After the Apollo 1 fire in January 1967, changes had to be made, mainly in the wiring, hatch areas, and the forward egress tunnel. It was December before the spacecraft came back into testing. CSM-101 passed through a three-phase customer acceptance review; during the third session, held in Downey on May 7th 1968, no items showed up that might be a “constraint to launch.” North American cleared up what few deficiencies there were (13) and shipped the craft to Kennedy on May 30th 1967…
Had it not been for the fact that Eisele damaged his shoulder during a zero-G training flight aboard a KC-135 aircraft just before Christmas 1965, he might have been in the senior pilot’s seat aboard Apollo 1, instead of Ed White.
When we left the Soviet Union they had somewhat successfully landed a probe on Venus and they had completed the automatic docking of two Soyuz 7K-OK spacecrafts. However they did not reach their goal of a circumlunar flight in time for the 50th anniversary of the glorious revolution.
The success of Apollo 4 gave good reason to believe that the Saturn V could be trusted to propel men into space. But NASA pushed on with its plans for a second unmanned booster flight, primarily to give the Pad 39 launch team another rehearsal before sending men into deep space on the Saturn V. The mission was called Apollo 6…
“The fire-in-the-hole abort was the most critical test of the mission and one we had to accomplish successfully prior to a manned mission.” Gene Kranz – Flight Director Apollo 5
“…our building’s shaking here. Our building’s shaking! Oh it’s terrific, the building’s shaking! This big blast window is shaking! We’re holding it with our hands! Look at that rocket go into the clouds at 3000 feet!…you can see it…you can see it…oh the roar is terrific!…” Walter Cronkite – Apollo 4 launch.