Mars beckons, and planet Earth is set to respond. On June 2, the European Space Agency is set to launch Mars Express/Beagle 2 to the red planet, followed by a NASA mission that involves sending two rovers on June 5 and 25. These robotic geologists are designed to scrutinize soil and rocks for clues to the history of the planet’s climate. Together, the missions represent a vital step in the quest to answer the question: Did Mars ever offer an environment capable of nurturing life?