The path to Mars goes through the moon or the region of space near the moon, anyway. NASA aims to put boots on Mars in the 2030s after first gathering human-spaceflight experience and expertise in low Earth orbit and the "proving ground" of cis-lunar space near the moon. NASA has been working on this three-stage path to the Red Planet for some time, and the space agency lays out the basic plan in a 36-page report called "Journey to Mars: Pioneering Next Steps in Space Exploration," which was released Thursday (Oct.