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Front cover illustrations: (Upper) Artist's rendition of the Dawn spacecraft operating its ion propulsion system upon arrival at the main-belt asteroid Vesta in 2011. Image courtesy McRel, Mid-continent Research for Education and Learning. (Next lower) Artist's concept of the Phoenix lander operating in the Martian Arctic, as it did from May to November 2008. Image courtesy University of Arizona. (Lower left) Artist's concept of the Cassini spacecraft as it operates in Saturn orbit July 2004 through the present day. Back cover illustrations: (Left) A near-duplicate of the Mars Phoenix lander used in developing command sequences before being sent to the spacecraft. Here, members of the Robotic Arm Engineering Team test the arm's motorized raft in the Payload Interoperability Testbed at the University of Arizona, Tucson in July 2008. Image courtesy University of Arizona. (Right) Rob Manning, Chief Engineer of NASA's Mars Exploration Program, cheers along with other team members as the ®rst images from rover Spirit come back from Mars. Courtesy NASA/Bill Ingalls.