In 1964, Mariner 4 had flown by Mars and returned the first photographs of the planet ever taken by a mission to the Red Planet. With two additional Mariners flying to Mars, scientists wanted to make sure the photographs were clearer and even better.
In 1969 NASA geared up for a closer look and sent two more spacecraft--Mariners 6 and 7. Mariners 6 and 7 were designed to fly over the equator and the southern hemisphere of Mars. Mariner 6 was launched in February 1969 and reached Mars five months later. Mariner 7 left Earth a month later and began to orbit Mars in August of that year. This time NASA aimed closer to the surface of the planet--an altitude of only 2,200 miles. These more sophisticated spacecraft transmitted more than 200 pictures, giving NASA scientists wonderful images of the Martian surface.
Scientists could piece together a topographical map of the Martian surface. This map, however, was nowhere near complete--nor did it cover the entire globe. The two spacecraft also used television cameras to spot the larger of Mars's two moons, Phobos.
Photo. The Mariner 6 spacecraft. Courtesy of NASA, JPL.
Mission to Mars. An educational site created for the ThinkQuest contest.