Building the LEM’s Legs
If you built a car in, say, Germany, for use in Canada, you could assume that the roads will be more or less the same. Gravity will work the same. While the weather might not be exactly the same, it won’t be totally different. But imagine designing the Lunar Excursion Module that would land two astronauts on the moon for the first time. No one had any experience landing a craft on any alien body before.
The LEM was amazing for many reasons, but as [Apollo11Space] points out, the legs were a particularly thorny engineering problem. They had to land on mostly unknown terrain, stay upright, allow for the ascent module to take off again, and, of course, not weigh down the tiny spaceship. They also had to survive the blast of the LEM’s engine.
Sure, there were some automated probes that landed in 1966 (the Soviets got there first, but NASA was just a few months behind). But by 1966, the first LEM was already three years old.
The video shows how many options were on the table, but the four-legged splayed footprint design was the winner. A Canadian company was instrumental in the successful production of the legs. One interesting thing is that the legs had a one-shot aluminum honeycomb shock absorber that destroyed itself as it absorbed the impact of landing.
It offers a fascinating glimpse into how it must have been to design something for the unknown, which couldn’t be properly tested until it was actually used. It was also fun to see the giant gantry they used to simulate lunar gravity for the test articles (that didn’t look much like the real thing, by the way).
The LEM famously served as a lifeboat for Apollo 13, but the legs probably didn’t matter for that. Of course, what we usually talk about is the amazing software onboard, but that’s only part of the story.
youtube.com/embed/lsiUJnaU1Ek?…