Hal Walker Jr.
Called the lunar laser ranging experiment, it studies the Earth-Moon system and returns data to scientific centers around the world, including NASA's Jet Propulsion Laboratory. The experiment consists of an instrument called the lunar laser ranging reflector, designed to reflect pulses of laser light fired from the Earth. The idea was to determine the round-trip travel time of a laser pulse from the Earth to the Moon and back again, thereby calculating the distance between the two bodies to unprecedented accuracy. Unlike the other scientific experiments left on the Moon, this reflector requires no power and is still functioning perfectly after 35 years.
This milestone is honored by a special exhibit on lunar laser ranging at the National Museum of American History, Smithsonian in Washington, D.C. in the Permanent exhibit “Science in American Life, The New Moon.” Hal Walker’s picture and remarks are included along with actual components from the Korad K-1500 Ruby Laser System.