Third-party evidence for Apollo Moon landings their orbits. According to the group, in December 1972 a member "picks up Apollo 17 on its way to the Moon". Paul Maley reports several sightings of the Apollo 12 Command Module. Chabot Observatory calendar records an application of optical tracking during the final phases of Apollo 13, on April 17, 1970: Corralitos Observatory photographed Apollo 14. Paul Wilson and Richard T. Knadle, Jr. received voice transmissions from the Command/Service Module in lunar orbit on the morning of August 1, 1971. In an article for "QST" magazine they provide a detailed description of their work, with photographs. Jewett Observatory at
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,