Astrogeology

Astrogeology, also known as planetary geology, is the scientific study of the geology of celestial bodies such as planets, moons, asteroids, and comets, as well as the processes that shape their surfaces and interiors. It seeks to understand the formation, composition, structure, and evolution of these bodies, and to reconstruct the history of the solar system from geological evidence.

The field encompasses surface geology, subsurface structure, tectonics, volcanism, impact cratering, sedimentation, and erosion under extreme conditions such as high radiation, low gravity, and cryogenic temperatures. It relies on data from remote sensing, in situ exploration, and laboratory analyses of rocks and meteorites.

The field overlaps with planetary science and geophysics and is sometimes grouped under planetary geology. Key objectives include interpreting a body's history through its surface features, rock compositions, and interior structure, and comparing processes across the solar system.

Remote sensing, spacecraft missions, and sample analysis provide the primary data. Notable programs include Apollo and Luna for lunar samples, Mars rover missions, MESSENGER for Mercury, Cassini for Saturn, Rosetta for a comet, and OSIRIS-REx and Hayabusa2 for asteroid returns. Applications include resource assessment, mission planning, and planetary defense.