- The last two spacecraft of NASA’s Mariner series Mariner Jupiter/Saturn A and B, renamed Voyager 1 and 2 were the first in that series to be sent to explore the outer solar system. Preceeded by the Pioneer 10 and 11 missions, Voyager 1 and 2 were to make studies of Jupiter and Saturn, their satellites, and their magnetospheres as well as studies of the interplanetary medium. An option designed into the Voyager 2 trajectory, and ultimately exercised, would direct it toward Uranus and Neptune to perform similar studies.