Harrison Schmitt credits the image to the entire Apollo 17 crew. While on the Moon's surface, Schmitt — the only geologist in the astronaut corps — collected the rock sample designated Troctolite 76535, which has been called "without doubt the most interesting sample returned from the Moon". Among other distinctions, it is the central piece of evidence suggesting that the Moon once possessed an active magnetic field. As he returned to the Lunar Module before Cernan, Schmitt is the next-to-last person to have walked on the Moon's surface. After the completion of Apollo 17, Schmitt played an active role in documenting the
NASA Astronaut Group 6 1972 but ultimately rejoined the Astronaut Corps for a second nine-year stint in 1979. The requirement for scientists to be trained as jet pilots was eventually lifted with the creation of the Mission Specialist position in the Shuttle Program. The seven members of Group 6 who stayed with the program after Apollo went on to form the core of early Shuttle Mission Specialists, accomplishing a total of 15 flights. NASA Astronaut Group 6 Astronaut Group 6 (the 'XS-11') was a group of eleven astronauts announced by NASA on August 11, 1967, the second group of scientist-astronauts. Although Director of Flight