7.5 Why do a rendezvous in lunar orbit, which makes no sense?

IN A NUTSHELL: Actually, it does. Lunar rendezvous was chosen despite its dangers because it reduced drastically the fuel and payload requirements. It’s riskier than doing it in Earth orbit, or avoiding it completely by landing directly on the Moon with a single spacecraft instead of using a two-part vehicle, but these alternatives would have required a truly gigantic rocket, far bigger than the already massive Saturn V.

THE DETAILS: Some Moon hoax believers find it preposterous that NASA chose to perform intricate undockings, redockings and rendezvous between the command module and the lunar module, and to perform them near the Moon instead of in Earth orbit, which offered better chances of rescue. Better still, why not follow the classic method featured in so many science fiction movies and land directly on the Moon with the main spacecraft, without using a separate lunar module?

Actually, NASA’s initial plan was indeed to land on the Moon with a single, large, tall spacecraft: a concept known as tailsitter. However, a direct flight to the Moon would have required a colossal rocket, the Nova (Figure 7-5), which didn’t exist yet and could not be completed in time for President Kennedy’s deadline. The only booster that could be developed in time was the Saturn V, which was relatively smaller.

Figure 7-5. The giant Nova booster (right) compared with the C-5, precursor of the Saturn V (center). Document M-MS-G-36-62, April 1962.

Mission planners also considered using a first Saturn V to launch an uncrewed tailsitter spacecraft into Earth orbit, followed by a second Saturn with the fuel. This was known as Earth Orbit Rendezvous and was NASA’s favored plan for some time. However, it entailed two closely coordinated launches and a dangerous transfer of fuel in space.

An alternative option was to split the tailsitter into two separate vehicles: the main one would remain in orbit around the Moon and the secondary one would be a stripped-down, specialized Moon lander. This approach reduced weight and fuel requirements so much that it allowed to launch the entire mission with a single Saturn V rocket. However, the savings came at the cost of a risky rendezvous in lunar orbit (hence the name Lunar Orbit Rendezvous or LOR), which entailed certain death for the moonwalkers if it failed. A high-stakes gamble, in other words, but a perfectly logical one.

The lunar orbit rendezvous plan wasn’t new: it had been conceived in 1916 by Russian spaceflight theoretician Yuri Vasilievich Kondratyuk. Nevertheless, NASA was very reluctant to take this perilous and untested path. John Houbolt, a relatively low-ranking aerospace engineer in the agency, is often credited with turning Wernher von Braun and NASA management around on this matter in 1962.