If the reference is to: Lloyd S. Swenson, James M. Grimwood, Charles C. Alexander; "This New Ocean: A History of Project Mercury"; SP-4201; NASA; Washington; 1966 "WD-40" does not appear in the index. There's another less likely book ("Project Mercury: A Chronology", or something like that), but I can't be bothered to drag it out and look, because I'm pretty sure that's incorrect. My understanding is that WD-40 was invented to protect the stainless steel skin of the Atlas ICBM (which was often left un-painted), built by Convair. I do recall seeing this in one of my Atlas books, which is alas currently not shelved, and I don't have time to find it. FWIW, Wikipedia agrees. The rest of that post (about how it's a waxy material in a solvent) is I think correct; it certainly agrees with its original intended usage (above). Noel