Back in the early '60s, I was avidly following the U.S. space program. My discovery of libraries (first in the school system, later the County library) gave me access to the closest thing in those days to the Internet. I realize this concept will be foreign to many of my readers, but back then if you wanted up-to-date information on science and technology, you simply couldn't get it from your home. It wasn't possible. You had to go to a library that subscribed to the (very expensive) science and technology journals. Fortunately for me, even the elementary school I went to had some subscriptions to such journals, including some that were written in a way that was accessible to someone quite young.
In those journals I learned about the story of the Lunar Orbit Rendezvous (LOR) mode that was eventually selected for the Apollo moon landings, and of John Houbolt's passionate advocacy for it. When NASA was deciding which mode to use, the direct ascent mode was the obvious one that most people assumed is what NASA would do. In that mode, a gigantic rocket (called Nova) would launch directly toward the moon, land on it, take off from the moon, and head directly back to Earth. This seemed the simplest and safest route to just about everybody – except John Houbolt. He did the math, and realized that it would be possible for a rocket less than half the size of Nova to take astronauts to the moon and back – but only if they did this crazy thing called LOR.
LOR, which is the mode used on all the Apollo lunar missions, required many more steps and complex-sounding maneuvers. First, a Saturn V rocket would launch the Apollo spacecraft into Earth orbit. It included a Command Module (which had the re-entry shield), a Service Module (with a rocket engine, fuel, and other supplies), and the Lunar Module (encased in an aerodynamic shroud). Once in orbit, the shrouds around the Lunar Module were blown away with explosives, and then the combined Command Module/Service Module would pull away, turn around, and dock with the Lunar Module. This combined spacecraft would then blast away (using the Service Module's rocket) toward the moon. Once at the moon, they'd use the Service Module rocket again to slow the spacecraft down for injection into lunar orbit. At that point, two of the three astronauts would crawl into the Lunar Module, undock from the Command Module, and use the Lunar Module's rockets to land on the moon. Meanwhile, the remaining astronaut stayed in the Command Module, orbiting the moon while his two companions explored the lunar surface. When the lunar mission was finished, the two lunar astronauts would climb back into the Lunar Module, and the top half of it would blast off back into lunar orbit, where they would rendezvous with their ride home (the Command Module). This was always the most frightening part of those missions for me, following closely here on Earth. If those lunar astronauts couldn't rendezvous with the Command Module, they were doomed to an awful fate, orbiting the moon forever. That rendezvous worked every time, though. Once the Lunar Module had redocked with the Command Module, the lunar astronauts would crawl back into the Command Module. Then they'd undock from the Lunar Module, and light off the Service Module's rocket to blast them back toward Earth. Once they neared Earth, the Command Module would disconnect from the Service Module, and just the Command Module would safely re-enter Earth's atmosphere and parachute down to an ocean landing.
If you manage to make it through my description of LOR above, I'm sure you'll recognize just how complex and Rube Goldberg-like LOR sounded to all the NASA engineers other than John Houbolt. On more than one occasion, people called him crazy and much worse. But with sheer persistence and a stubborn refusal to be silenced, John Houbolt eventually persuaded the rest of NASA that LOR was actually the only mode that had a chance of meeting JFK's goal for a man on the moon by the end of the '60s decade. Why? There were two main reasons. First, NASA's engineers realized that they couldn't possibly build the gigantic Nova rocket in time. Second, they realized that all of the maneuvers required for LOR were actually practicable in the time provided. The challenges there were actually easier, engineering-wise, than building Nova.
John C. Houbolt's story was inspiring to me as a young man, and most especially, as a wannabe engineer. His careful marshaling of facts and evidence to support his proposal fascinated me. After LOR was selected, he led the engineering team that actually developed it – and that was another fascinating story to follow. For nearly ten years, I devoured stories about he and his team as they developed the LOR systems. On Apollo 10, the Lunar Module first flew separately in lunar orbit, and the crew successfully did the first lunar orbit rendezvous – and I remember reading about the relief and celebration in John Houbolt's team. LOR worked!
That moment when something you imagined, designed, and built actually functions as intended – for me, that's the essence of what it means to be an engineer. It's the kind of achievement that I find most satisfying and fun. John C. Houbolt was the embodiment of that for me, in my youth. His story inspired me, and I often thought of him when people told me I couldn't do something or other (which happened rather a lot :). Though I've never met anyone else who said the same, I'd bet there are a lot of other engineers roughly my age who would.
RIP, John C. Houbolt. That's a helluva a story you've left behind!
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