At the Alphonsus, three scientific objectives were determined to be of primary interest and paramount importance: the possibility of old, pre-Imbrium impact material from within the crater's wall, the composition of the crater's interior and the possibility of past volcanic activity on the floor of the crater at several smaller "dark halo" craters. Geologists feared, however, that samples obtained from the crater might have been contaminated by the Imbrium impact, thus preventing Apollo 16 from obtaining samples of pre-Imbrium material. There also remained the distinct possibility that this objective had already been satisfied by the Apollo 14 and Apollo 15 missions, as the Apollo 14 samples had not yet been completely analyzed and samples from Apollo 15 had not yet been obtained.