On Sunday, August 5, the Mars Science Laboratory (MSL) rover, known as Curiosity, will make its dramatic descent onto Mars's surface. Once it lands, the rover will check its instruments to make sure everything's functioning properly—and then it will get right to work. Caltech's Ken Farley and Bethany Ehlmann will be among the 300 scientists working here on Earth, taking the information Curiosity sends home and trying to figure out what it all means.