<P> Apollo 17 was the only Apollo lunar landing mission to carry the Traverse Gravimeter Experiment . As gravimeters had proven to be useful in the geologic investigation of the Earth, the objective of this experiment was to determine the feasibility of using the same techniques on the Moon to learn about its internal structure . The gravimeter was used to obtain readings at the landing site in the immediate vicinity of the Lunar Module (LM), as well as various locations on the mission's traverse routes . The TGE was carried on the Lunar Roving Vehicle; measurements were taken by the astronauts while the LRV was not in motion or after the gravimeter was placed on the surface . </P> <P> A total of twenty - six measurements were taken with the TGE during the mission's three moonwalks, with productive results . As part of the Apollo Lunar Surface Experiments Package (ALSEP), the astronauts also deployed the Lunar Surface Gravimeter, a similar experiment, which ultimately failed to function properly . </P> <P> Sector one of the Apollo 17 Service Module (SM) contained the Scientific Instrument Module (SIM) bay . The SIM bay housed three experiments for use in lunar orbit: a lunar sounder, an infrared scanning radiometer, and a far - ultraviolet spectrometer . A mapping camera, panoramic camera, and a laser altimeter were also included in the SIM bay . </P> <P> The lunar sounder beamed electromagnetic impulses toward the lunar surface, which were designed with the objective of obtaining data to assist in developing a geological model of the interior of the Moon to an approximate depth of 1.3 km (0.81 mi). </P>

When was the last time anyone walked on the moon