As you are still featuring space excavators etc. in the blog, wondered if these were of interest. They are from "By Space Ship to the Moon" by Jack Coggins and Lester Pratt. I think it was published in the 1950s. I understand it and the companion, "Rockets, Jets & Guided Missiles" were very influential reading matter for some boys who grew up to be rocket scientists at NASA. The art is very good in both volumes, and could copy more if anyone is interested.