You might not think that geotechnical engineering would have anything to do with the Apollo 11 mission that put the first humans on the surface of the moon, but you would be wrong. The landing pads of the lunar excursion module (LEM) had to act as footings on the surface of the moon. If they settled too much, the jet nozzles would become too close to the surface and could potentially become choked with moon dust during launch. And differential settlement which would cause angular rotation had to be kept below some critical value which could prevent the LEM’s eventual rendezvous with the Command Module. So how do the principles of soil mechanics work on the moon, in a vacuum? And how do you know what the composition, grain size, and other material properties of lunar soil are before anyone has ever been there?
One of the geotechnical engineers who worked on these problems while at Grumman Aerospace during the leadup to the Apollo 11 mission was the late Dr. Edward Nowatzki, PhD, PE. Ed was my foundation engineering professor, and later a colleague and an amazing mentor at URS Corporation and NCS Consultants in Tucson, Arizona. In 2007, he wrote an article for GeoPrac titled The Ultimate Geotechnical Engineering Challenge that described his experiences working on this project and answers some of those questions above. As we are remembering the 50th Anniversary of the Apollo 11 mission, I invite my fellow geotechnical engineers to spend a few minutes reading about this amazing work, a unique connection between a historic event that seemingly would have nothing to do with our profession!