Mars in fiction the past; Mars is a setting rather than a goal. Mariner 4 in July 1965 found that Mars—contrary to expectations—is heavily cratered, with a very thin atmosphere. No canals were found; while scientists did not believe that Mars was a moist planet, the lack of surface water surprised them. Science fiction had so influenced real explorations of the planet, however—Carl Sagan was among the many fans who became scientists—that after Mariner 9 in 1971-1972, craters were named after Wells, Burroughs, and other authors. The Mariner and Viking space probes confirmed that the Martian environment is extremely hostile to life. By
Exploration of Mars and first European probe to achieve a soft landing on Mars. NASA's Mars Exploration Rover Mission (MER), started in 2003, is an ongoing robotic space mission involving two rovers, Spirit (MER-A) and Opportunity, (MER-B) exploring the Martian surface geology. The mission's scientific objective is to search for and characterize a wide range of rocks and soils that hold clues to past water activity on Mars. The mission is part of NASA's Mars Exploration Program, which includes three previous successful landers: the two Viking program landers in 1976; and Mars Pathfinder probe in 1997. The "Mars Reconnaissance Orbiter" (MRO) is a