primary objectives for Apollo 17: obtaining old highlands material a substantial distance from Mare Imbrium, sampling material from young volcanic activity (i.e., less than three billion years), and having minimal ground overlap with the orbital ground tracks of Apollo 15 and Apollo 16 to maximize the amount of new data obtained. A significant reason for the selection of Taurus–Littrow was that Apollo 15's CMP, Al Worden, had overflown the site and observed features he described as likely volcanic in nature. Gassendi was eliminated because NASA felt that its central peak would be difficult to reach due to the roughness of the local terrain, and, though Alphonsus might be easier operationally than Taurus–Littrow, it was of lesser scientific interest. At Taurus–Littrow, it was believed that the crew would be able to obtain samples of old highland material from the remnants of a landslide event that occurred on the south wall of the valley and the possibility of relatively young, explosive volcanic activity in the area. Although the valley is similar to the landing site of Apollo 15 in that it is on the border of a lunar mare, the advantages of Taurus–Littrow were believed to outweigh the drawbacks. The Apollo Site Selection Board, a committee of NASA personnel and scientists charged with setting out scientific objectives of the Apollo landing missions and selecting landing sites for them, unanimously recommended Taurus–Littrow at its final meeting in February 1972. Upon that recommendation, NASA selected Taurus–Littrow as the landing site for Apollo 17. Training As with previous lunar landings, the Apollo 17 astronauts underwent an extensive training program that included learning to collect samples on the surface, usage of the spacesuits, navigation in the Lunar Roving Vehicle, field geology training, survival training, splashdown and recovery training, and equipment training. The geology field trips were conducted as much as possible as if the astronauts were on the Moon: they would be provided with aerial images and maps, and briefed on features of the site and a suggested routing. The following day, they would follow the route, and have tasks and observations to be done at each of the stops. The geology field trips began with one to Big Bend National Park in Texas in October 1971. The early ones were not specifically tailored to prepare the astronauts for Taurus–Littrow, which was not selected until February 1972, but by June, the astronauts were going on field