In the fall of 1962, NASA engineers debated fiercely over how to reach the Moon: direct ascent, Earth orbit rendezvous, or the riskier-seeming Lunar Orbit Rendezvous, which required a separate lunar module to detach, land, and redock. Advocates like John Houbolt pushed hard for LOR's efficiency. The decision, solidified around this period, made the lunar module concept the backbone of the Apollo missions that landed twelve astronauts on the Moon.
When NASA set its sights on landing a man on the Moon before 1970, the agency faced a fundamental engineering puzzle: what was the safest and most efficient way to get there and back? Three competing plans emerged. Direct ascent envisioned a single giant rocket flying straight to the Moon and back. Earth orbit rendezvous would assemble a moonship in Earth orbit from multiple launches. Lunar orbit rendezvous, the most radical idea, proposed sending a mothership to lunar orbit, then detaching a small lander for the descent while the command module waited above.
John Houbolt, a NASA engineer at Langley, championed LOR against considerable institutional skepticism, even writing directly to NASA's associate administrator to make his case when his superiors dismissed the idea. His persistence paid off. By the fall of 1962, NASA leadership, including Wernher von Braun's team, had come around to LOR as the most weight-efficient and practical approach.
The decision meant designing an entirely new class of spacecraft, the lunar module, a spidery, ungainly vehicle built solely to operate in the vacuum of space and touch down on the lunar surface. That choice, refined through the early 1960s, became the technical foundation for Apollo 11's landing in 1969 and the five missions that followed it.