trips to sites specifically selected to prepare for Apollo 17's landing site. Both Cernan and Schmitt had served on backup crews for Apollo landing missions, and were familiar with many of the procedures. Their trainers, such as Gordon Swann, feared that Cernan would defer to Schmitt as a professional geologist on matters within his field. Cernan also had to adjust for the loss of Engle, with whom he had trained for Apollo 14. In spite of these issues, Cernan and Schmitt worked well together as a team, and Cernan became adept at describing what he was seeing on geology field trips, and working independently of Schmitt when necessary. The landing crew aimed for a division of labor so that, when they arrived in a new area, Cernan would perform tasks such as adjusting the antenna on the Lunar Roving Vehicle so as to transmit to Earth while Schmitt gave a report on the geological aspects of the site. The scientists in the geology "backroom" relied on Schmitt's reports to adjust the tasks planned for that site, which would be transmitted to the CapCom and then to Cernan and Schmitt. According to William R. Muehlberger, one of the scientists who trained the astronauts, "In effect [Schmitt] was running the mission from the Moon. But we set it up this way. All of those within the geological world certainly knew it, and I had a sneaking hunch that the top brass knew it too, but this is a practical way out, and they didn't object." Also participating in some of the geology field trips were the commander and lunar module pilot of the backup crew. The initial field trips took place before the Apollo 15 astronauts were assigned as the backup crew for Apollo 17 in February 1972. Either one or both of Scott and Irwin of Apollo 15 took part in four field trips, though both were present together for only two of them. After they were removed from the backup crew, the new backup commander and LMP, Young and Duke, took part in the final four field trips. On field trips, the backup crew would follow half an hour after the prime crew, performing identical tasks, and have their own simulated CapCom and Mission Control guiding them. The Apollo 17 astronauts had fourteen field trips—the Apollo 11 crew had only one. Evans did not go on the geology field trips,