A series of American interplanetary missions. In 1962, Mariner 2 staged the first successful encounter with another planet when it flew past Venus. Its instruments recorded Venus’ surface temperature and pressure, and the composition of its atmosphere and the clouds that envelope the planet. The next successful mission in the series, Mariner 4, snapped the first close-range pictures of Mars in 1965. The images revealed a Moon-like landscape. Mariner 9 became the first spacecraft to orbit Mars, and found that the planet has a much more varied and interesting surface than scientists had expected. Mariner 10 flew by Mercury three times in 1974 and 1975, and mapped about half of its battered, Moon-like surface, which is dominated by impact craters. Other successful missions in the series included Mariner 5 to Venus and Mariner 6 and 7 to Mars.
