Ronald Evans (astronaut) 19 astronauts selected by NASA in April 1966. He served as a member of the astronaut support crews for the Apollo 7 and Apollo 11 flights, and as backup Command Module Pilot for Apollo 14. Evans' only space flight was as Command Module Pilot of Apollo 17, the last scheduled U.S. manned mission to the Moon. He was accompanied by Eugene Cernan and Harrison Schmitt. While Cernan and Schmitt landed and worked on the Moon in the Taurus–Littrow valley, Evans remained in lunar orbit on board the Command Module "America", completing assigned work tasks which required visual geological observations, hand-held
Apollo 17 out to the Moon, back to Earth, and in lunar orbit. The Apollo 17 crew conducted an experiment, also conducted on Apollo 16, with the objective of linking these light flashes with cosmic rays. As part of an experiment conducted by NASA and the University of Houston, one astronaut wore a device that recorded the time, strength, and path of high-energy atomic particles that penetrated the device. Analysis of the results concluded that the evidence supported the hypothesis that the flashes occurred when charged particles travelled through the retina in the eye. Apollo 17 was the only lunar surface expedition