  The Coronagraph Instrument (CGI) on the Nancy Grace Roman Space Telescope
will demonstrate the high-contrast technology necessary for visible-light
exoplanet imaging and spectroscopy from space via direct imaging of
Jupiter-size planets and debris disks. This in-space experience is a critical
step toward future, larger missions targeted at direct imaging of Earth-like
planets in the habitable zones of nearby stars. This paper presents an overview
of the current instrument design and requirements, highlighting the critical
hardware, algorithms, and operations being demonstrated. We also describe
several exoplanet and circumstellar disk science cases enabled by these
capabilities. A competitively selected Community Participation Program team
will be an integral part of the technology demonstration and could perform
additional CGI observations beyond the initial tech demo if the instrument
performance warrants it.
