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…
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.
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.
Apollo Saturn 201 employed the Saturn IB launch vehicle, which was the up-rated version of the Saturn I rocket flown in ten earlier Saturn-Apollo missions. It featured an upgrade of the first stage engines to increase thrust from 1,500,000 lb-ft of thrust to 1,600,000 lb-ft. The second stage was the S-IVB. This stage used a new liquid hydrogen-burning J-2 engine which would also be used on the S-II second stage of the Saturn V lunar launch vehicle…
The Pegasus satellite was named for the winged horse of Greek mythology. Like its namesake, the Pegasus was notable for its “wings”, a pair of 29 meter long, 4.3 meter wide arrays of 104 panels fitted with sensors to detect punctures by micrometeoroids at high altitudes. In its stored position with panels folded inside the Apollo service module, the Pegasus was 5.3-meters high, 2.1 meters wide, and 28-cm deep.