In recent years, planetary science has seen a tremendous growth in new knowledge. Deposits of water ice exist at the Moon’s poles. Discoveries on the surface of Mars point to an early warm wet climate, and perhaps conditions under which life could have emerged. Liquid methane rain falls on Saturn’s moon Titan, creating rivers, lakes, and geologic landscapes with uncanny resemblances to Earth’s. Comets impact Jupiter, producing Earth-sized scars in the planet’s atmosphere. Saturn’s poles exhibit bizarre geometric cloud patterns and changes; its rings show processes that may help us understand the nature of planetary accretion. Venus may be volcanically active. Jupiter’s icy moons harbor oceans below their ice shells: conceivably Europa’s ocean could support life. Saturn’s tiny moon Enceladus has enough geothermal energy to drive plumes of ice and vapor from its south pole. Dust from comets shows the nature of the primitive materials from which the planets and life arose. And hundreds of new planets discovered around nearby stars have begun to reveal how our solar system fits into a vast collection of others.
This report was requested by NASA and the National Science Foundation (NSF) to review the status of planetary science in the United States and to develop a comprehensive strategy that will continue these advances in the coming decade. Drawing on extensive interactions with the broad planetary science community, the report presents a decadal program of science and exploration with the potential to yield revolutionary new discoveries. The program will achieve long-standing scientific goals with a suite of new missions across the solar system. It will provide fundamental new scientific knowledge, engage a broad segment of the planetary science community, and have wide appeal for the general public whose support enables the program.