Mariner 8NASA and JPL launch Mariner 8, the first of two identical “Mars ’71” orbiters designed to visit Mars. Where previous missions have simply flown past the red planet, Mariners 8 and 9 are intended to put themselves in orbit and remain there to map the majority of the Martian surface. The second stage of the Atlas-Centaur booster used to launch Mariner 8 fails, however, and the robotic Mars explorer crashes into the Atlantic Ocean. Some of its mission objectives are transferred to the identical Mariner 9, due for launch at the end of the month.