Published in the University of Maryland School of Medicine Bulletin, Fall of 1983
“Walter Wiechetek, who is medical director at the Johnson Space Center (see note below), is credited with designing the patch worn on space suits of NASA astronauts. The patch was adapted from a Leonardo da Vinci sketch entitled, “The Dimensions of Man.” Wiechetek spent a week in Houston where he was one of the few civilians ever to put on and be pressurized in a space suit, explaining that, ‘this was an achievement in itself, as there are some astronauts who have not donned the garment as yet.’”
Note: this appears to be an error on the part of the Bulletin publication. He was medical director for United Technologies – Hamilton Standard which was contracted by NASA.