Astronaut Harrison "Jack" Schmitt is taking a scoop of lunar material from the lip of a small crater. Behind him, Apollo 17 Commander Gene Cernan is readying two sample bags to contain the soil for the quarter million-mile journey to Earth.

I phoned Jack one morning as I was working on this painting. He recalled trenching into a crater at one point during his lunar surface exploration. "Many craters are formed when meteoroids coming in from deep space strike the Moon's surface at very high speed, say 10,000 miles per hour or more. At the point of impact the soil and rocks are ejected up and out, resulting in the deepest and oldest material coming to rest at the surface. It's similar to the effect experienced when one turns back the bed covers, the sheet rests on top of the bedspread. By returning samples from a variety of depths, we begin to understand how long ago the crater was formed, and the subsequent cosmic ray and solar wind activity."

Jack continued, "I could see light and dark layering in the trench wall. This was a first, and a readily visible profile suggesting the different ages of the subsurface soil."

Jack is the only practicing professional geologist in all history to make first-hand observations any place other than our good old planet Earth. He was a superb scientist and a great astronaut. After the Apollo Program was completed, the people of New Mexico elected Jack to the United States Senate.

- Alan Bean