"John Grunsfeld will retire from NASA April 30, capping nearly four decades of science and exploration with the agency. His tenure includes serving as astronaut, chief scientist, and head of NASA's Earth and space science activities. Grunsfeld has directed NASA's Science Mission Directorate as associate administrator since 2012, managing more than 100 science missions -- many of which have produced groundbreaking science, findings and discoveries."
Keith's note: Click here you will see a larger version of this image. In it John was "vulcanized" by Star Trek's Mike Okuda when John left his NASA Chief Scientist position. This photo somehow made its way to the National Air and Space Museum where a less-than-observant curator made it part of an exhibit of Hubble hardware returned after a servicing mission. Eventually NASM figured out that John was a Vulcan in this picture (but not in real life) and replaced it. But it took a while.