Lunar Geology Investigation
The Apollo Program
| The Hadley/Apennine
site was selected for multiple objectives:
The Apennine Mountain front forms the arcuate southeastern rim of Mare Imbrium. It borders Palus Putredinis and, in the area of the site, it rises 12,000 feet (3658 m) above the surrounding mare. The Apennine Mountain front was believed to have been exposed at the time of the excavation of the giant Imbrium basin. The cratering event must have, therefore, exposed materials which are pre-Imbrian in age. Examination and collection of this ancient material as well as deep-seated Imbrium ejecta were the prime objectives of the mission. This was accomplished during the first and second EVAs when Scott and Irwin selected samples from the foot of the mountain scarp and from the ejecta blankets of craters which excavate mountain materials.
The second important objective of the mission was to study and sample the Hadley Rille, which runs parallel to the Apennine Mountain front and incises the Palus Putredinis mare material. The rille is a sinuous or meandering channel, much like a river gorge on Earth. It displays a V-shaped cross section, with an average slope of about 25 degrees. In the vicinity of the landing site, the rille is about one mile (1.6 km) wide and 1,300 feet (396 meters) deep.
The third objective of the mission was to study and sample the reasonably flat mare material of Palus Putredinis on which the LM landed. Analysis of the samples showed that this mare surface was younger than that visited on Apollo 11, and was closer to the age of the Apollo 12 mare site.
A complex of domical structures about 5 km north of the landing site constituted another objective of the mission. The hills may be made of volcanic domes superposed on the surrounding mare or buried domical structures thinly covered by the mare-like material
From Apollo 15 Press Kit