Life on Mars If the surface life has been reanimated as recently as 450,000 years ago, then rovers on Mars could find dormant but still viable life at a depth of one meter below the surface, according to an estimate. In 1965, the Mariner 4 probe discovered that Mars had no global magnetic field that would protect the planet from potentially life-threatening cosmic radiation and solar radiation; observations made in the late 1990s by the Mars Global Surveyor confirmed this discovery. Scientists speculate that the lack of magnetic shielding helped the solar wind blow away much of Mars's atmosphere over the course of
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