Artists and engineers share this bond: their visions are often first embodied in rough, rudimentary form. Whether it's a sculptor working in clay or an industrial designer using three-dimensional software, modeling is not just part of the creative process: to a large degree, it is the creative process.
For NASA's engineers, finding ways to model the remarkable craft that would not only land astronauts on the moon, but would allow them to lift off from the lunar surface, rendezvous and link up with an orbiting vessel and return safely to Earth and their families — well, tackling that sort of challenge is the reason so many of the best and brightest join NASA in the first place.
Here, LIFE.com offers a series of images celebrating the various Lunar Excursion Modules -- scale-model and life-size -- that NASA built through the years; the men who flew them; and the brilliant, daring minds that envisioned the extraordinary spacecraft in the first place.
First deployed during Apollo 9's 10-day mission in March 1969, roughly 100 miles above the earth, and tested again a few months later less than 10 miles above the lunar surface during Apollo 10's "dry run" for the July 1969 moon landing, the various versions of the lunar module that NASA designed and produced represent, in microcosm, pretty much everything technological that got people excited about the American space program in the 1960s.
After all, behind the craft's mind-bendingly complex and rigorous development is an audaciously straightforward idea — enter moon's orbit; separate from command module; land on moon; lift off from moon; reconnect with command module; come home — that would take years of effort (and not a few mistakes) to finally put into triumphant, era-defining practice.
In July 1969, when Apollo 11's rendition of the LEM, Eagle, touched down on a vast lunar plain — named Mare Tranquillitatis, or the Sea of Tranquility, centuries before by two Italian astronomers — Neil Armstrong radioed a simple, momentous phrase to Mission Control a quarter-million miles away in Houston.
"The Eagle has landed," he said, cementing the lunar module's central role in one of humanity's greatest dramas.