MAVEN Will Uncover the Secrets of Mars' Ancient PastIn the distant past, both Earth and Mars were covered in thick atmospheres and held large bodies of water. While Earth has become a cradle of life in our solar system, Mars lost its atmosphere and became a barren, desert world. No one knows why. NASA's 2013 MAVEN mission will offer scientists many clues as they try to solve this Martian mystery.A few years ago, NASA put out a call for mission proposals to explore the Martian atmosphere. They wanted to do it as inexpensively as possible, with a robust mission plan that had a "low implementation risk." In other words, it'll be tough to screw up. They chose MAVEN over more complicated proposals like the Aerial Regional-scale Environmental Survey of Mars (ARES, pictured) because it's basically a satellite that will orbit Mars for a year and report back what it finds. As it orbits the Red Planet, MAVEN, which is the somewhat tortured acronym for "Mars Atmosphere and Volatile EvolutioN," will use a suite of eight instruments to sample the atmosphere. It will track the composition of the Martian air and create a precise record of current atmospheric loss on Mars. That will give scientists a window to Mars' mysterious past. One theory suggests that the loss of the planet's magnetic field led the atmosphere to be stripped away. Image by: NASA. NASA Selects 'MAVEN' Mission to Study Mars Atmosphere. [NASA]