Exploring new worlds, understanding our universe

For the first time in human history, technologies have matured sufficiently to enable an affordable space-based telescope mission capable of discovering and characterizing habitable planets like the Earth orbiting nearby bright sunlike stars. Such an observatory can be equipped with instruments that provide a wide range of capabilities, enabling unique science not possible from ground-based facilities. This science is broad and exciting, ranging from new investigations of our own solar system to understanding the life cycle of baryons and its impact on the formation and evolution of galaxies, to addressing fundamental puzzles in cosmology. The Habitable Exoplanet Observatory, or HabEx, has been designed to be the Great Observatory of the 2030s, a successor to the Hubble Space Telescope (HST) with enhanced capabilities and community involvement through a competed and funded Guest Observer (GO) program. This GO program-which shall represent 50% of HabEx's prime 5-year mission-will include competed novel observations, parallel and serendipitous observations, and archival research. After HabEx's 5-year prime mission, HabEx is capable of undertaking an extended mission of at least five additional years without servicing, during which the GO program would represent 100% of observing time. HabEx is a space-based 4 m diameter telescope with ultraviolet (UV), optical, and near-infrared (near-IR) imaging and spectroscopic capabilities, replacing and enhancing those lost at the end of HST's lifetime. During its 5-year prime mission, HabEx has three driving science goals described in Table ES-1 and Figure ES-1.