Abstract: The Habitable-Exoplanet Observatory (HabEx) is a candidate flagship mission being studied by NASA and the astrophysics community in preparation of the 2020 Decadal Survey. The HabEx mission concept is a large (~4m) diffraction-limited space telescope, providing unprecedented resolution and contrast in the optical, with likely extensions into the near UV and near infrared domains.

The primary goal of HabEx is to answer fundamental questions in exoplanet science, such as searching for and characterizing potentially habitable worlds, providing the first complete “family portraits” of planets around our nearest Sun-like neighbors, and placing the solar system in the context of a diverse set of exoplanets.  At the same time, HabEx will enable a broad range of Galactic, extragalactic, and solar system astrophysics, from resolved stellar population studies that inform the stellar formation history of nearby galaxies, to characterizing the life cycle of baryons as they flow in and out of galaxies, to detailed studies of bodies in our own solar system.

We report here on our team’s efforts in defining a scientifically compelling HabEx mission that is technologically executable, affordable within NASA’s expected budgetary envelope, and timely for the next decade. In particular, we motivate the architecture, quantify the technical requirements, and predict the science yield, for a small number of design reference missions, all with broad capabilities in exoplanet, cosmic origins, and planetary science.