In April of 1972 the penultimate Apollo mission sent NASA astronauts John Young and Charles Duke to the surface of the Moon, with Ken Mattingly piloting the command module Casper in lunar orbit. After launch on April 16, the Apollo 16 craft and crew completed two orbits of Earth before burning the J-2 engine of the Saturn V’s third stage, the S-IVB (“S four B”), sending the crew off to the Moon.
Following the CSM and LM separation and TLI the spent S-IVB third stage continued along its course for a planned impact of the lunar surface. This was done as part of seismic experiments which collected data on lunar geology via surface instruments set up during previous missions. The 12-ton Apollo 16 rocket stage struck the Moon on April 19, a day and a half before the LM Orion touched down in the Descartes Highlands. But because the tracking signal was lost before impact it’s never been known exactly where the Apollo 16 S-IVB impact site was located.
That is, until now. After 43 years, one researcher at the Johns Hopkins University Applied Physics Laboratory has identified the crater left by the Apollo 16 third stage in image data gathered by NASA’s Lunar Reconnaissance Orbiter.