Like Apollo 15 and Apollo 16, Apollo 17 was slated to be a "J-mission", an Apollo mission type that featured lunar surface stays of three days, higher scientific capability, and the usage of the Lunar Roving Vehicle. Since Apollo 17 was to be the final lunar landing of the Apollo program, high-priority landing sites that had not been visited previously were given consideration for potential exploration. A landing in the crater Copernicus was considered, but was ultimately rejected because Apollo 12 had already obtained samples from that impact, and three other Apollo expeditions had already visited the vicinity of Mare Imbrium. A landing in the lunar highlands near the crater Tycho was also considered, but was rejected because of the rough terrain found there and a landing on the lunar far side in the crater Tsiolkovskiy was rejected due to technical considerations and the operational costs of maintaining communication during surface operations. A landing in a region southwest of Mare Crisium was also considered, but rejected on the grounds that a Soviet spacecraft could easily access the site; Luna 21 eventually did so shortly after the Apollo 17 site selection was made.