Mars has attracted human interest throughout history. The War of the Worlds(1898) by H. G. Wells, about an advanced Martian civilization that came to attack Earth, was inspired by the work of the Italian astronomer Giovanni Schiaparelli, who observed canali (channels) on Mars. (The Italian word canali was mistranslated as "canals.") This led to interest in the possibility of intelligent life on Mars.

Although it is now known that there is no intelligent life on Mars, planning for exploration of the Red Planet is at an all-time high. The question of whether simple life ever arose on Mars is a strong motivation for exploration. Other questions include how the Martian climate evolved and how it differs from that on Earth and how the surface and interior of Mars evolved.

Proposed Missions

With the long-term goal of human exploration, many preliminary missions are needed to address these...