To find out, Scott and Jet Propulsion Laboratory engineer Floyd Roberson developed a soil sampler that resembled a small, square backhoe shovel.
The scoop would be mounted on an articulated, extensible trellis that could dig trenches, scrape up soil, lift large clods and drop them to break up the lumps.
“For the next two weeks,” Scott wrote, “Floyd and I happily and sleeplessly played with the lunar surface soil on the inside surface of a 650-foot-diameter crater.”[1] From those tests, he concluded that the lunar soil at the site was fine-grained with small cohesion and an internal friction angle of 35 degrees – similar to the properties of terrestrial sand[3] - with a bearing strength of about 10 pounds per square inch (0.7 kilograms per square centimeter, or 98 kilopascals).
I’ve left a print on the surface.”[1][2][3] In November 1969, Apollo 12's lunar module landed close enough to Surveyor 3 that astronauts Charles Conrad and Alan Bean walked over to it.
[3] He was a consultant in the investigation of the Baldwin Hills Dam failure in 1963 and again in the 1978 Bluebird Canyon landslide in Laguna Beach, California.
To reproduce the soil pressure at the bottom of a large earthen dam with a 1/100 scale model would require an effective gravity 100 times that of the earth.
Moreover, his centrifuge could incorporate seismic motion using a computer-controlled shaking table, enabling him to model the response of a dam to a large earthquake.