Apollo 17 investigate the possibility of relatively new volcanic activity in the same area. Cernan, Evans, and Schmitt returned to Earth on December 19 after a 12-day mission. Apollo 17 is the most recent manned Moon landing and the most recent time humans travelled beyond low Earth orbit. It was also the first mission to have no one on board who had been a test pilot; X-15 test pilot Joe Engle lost the lunar module pilot assignment to Schmitt, a geologist. The mission broke several records: the longest moon landing, longest total extravehicular activities (moonwalks), largest lunar sample, and longest time in
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