Apollo 15 to Apollo 12, and since Apollo 11's backup crew had been designated for Apollo 13 (which did not land on the Moon), they were the first Apollo crew for a successful lunar landing mission to have backed up another such mission. Having had the opportunity to familiarize themselves with the Apollo spacecraft, they could devote more of their training time as prime crew for Apollo 15 to geology and sampling techniques. The astronauts at NASA who were scientists, such as geologist Harrison Schmitt, pushed though the early Apollo missions for a greater place for science as part of the mission,
Apollo 15 voyage, and Apollo 15 was the first lunar landing mission on which there was a heavy emphasis on science. If Apollo 15 had flown as an H mission, it would have been with CSM-111 and LM-9. That CSM was used by the Apollo–Soyuz Test Project in 1975, but the lunar module went unused and is now on display at the Kennedy Space Center Visitor Complex. Technicians at the Kennedy Space Center had some problems with the instruments in the service's module's SIM bay. Some instruments were late in arriving, and principal investigators or representatives of NASA contractors sought additional testing