Saturday Night Science: Apollo 8 Fifty Years Ago

Apollo 8 EarthriseAs the tumultuous year 1968 drew to a close, NASA faced a serious problem with the Apollo project. The Apollo missions had been carefully planned to test the Saturn V booster rocket and spacecraft (Command/Service Module [CSM] and Lunar Module [LM]) in a series of increasingly ambitious missions, first in low Earth orbit (where an immediate return to Earth was possible in case of problems), then in an elliptical Earth orbit which would exercise the on-board guidance and navigation systems, followed by lunar orbit, and finally proceeding to the first manned lunar landing. The Saturn V had been tested in two unmanned “A” missions: Apollo 4 in November 1967 and Apollo 6 in April 1968. Apollo 5 was a “B” mission, launched on a smaller Saturn 1B booster in January 1968, to test an unmanned early model of the Lunar Module in low Earth orbit, primarily to verify the operation of its engines and separation of the descent and ascent stages. Apollo 7, launched in October 1968 on a Saturn 1B, was the first manned flight of the Command and Service modules and tested them in low Earth orbit for almost 11 days in a “C” mission.

Apollo 8 was planned to be the “D” mission, in which the Saturn V, in its first manned flight, would launch the Command/Service and Lunar modules into low Earth orbit, where the crew, commanded by Gemini veteran James McDivitt, would simulate the maneuvers of a lunar landing mission closer to home. McDivitt’s crew was trained and ready to go in December 1968. Unfortunately, the lunar module wasn’t. The lunar module scheduled for Apollo 8, LM-3, had been delivered to the Kennedy Space Center in June of 1968, but was, to put things mildly, a mess. Testing at the Cape discovered more than a hundred serious defects, and by August it was clear that there was no way LM-3 would be ready for a flight in 1968. In fact, it would probably slip to February or March 1969. This, in turn, would push the planned “E” mission, for which the crew of commander Frank Borman, command module pilot James Lovell, and lunar module pilot William Anders were training, aimed at testing the Command/Service and Lunar modules in an elliptical Earth orbit venturing as far as 7400 km from the planet and originally planned for March 1969, three months later, to June, delaying all subsequent planned missions and placing the goal of landing before the end of 1969 at risk.... [Read More]