NASA's Nancy Grace Roman Space Telescope, formerly known as WFIRST (Wide Field Infrared Survey Telescope), is a next-generation mission designed to address fundamental questions in astrophysics, including the nature of dark energy and dark matter, the search for exoplanets, and the study of galaxy formation and evolution. Its most distinctive feature is a field of view 100 times larger than that of the Hubble Space Telescope, which will allow it to map large areas of the sky much more efficiently.

Roman is equipped with a 2.4-meter primary mirror, the same size as Hubble's, but its instrumentation is optimized for near-infrared observations. This is crucial for observing distant, faint objects, as the expansion of the universe shifts the light from these objects to longer wavelengths. The mission includes two key instruments: the Wide Field Instrument (WFI), which will provide high-resolution imaging and wide-field spectroscopy, and the Coronagraph Instrument (CGI), a technology demonstration that will block starlight to enable direct observation of exoplanets.

Roman's primary scientific objectives focus on cosmology and exoplanet astrophysics. In cosmology, it will conduct weak gravitational lensing and Type Ia supernova surveys to measure the universe's expansion history and understand dark energy. In exoplanets, it will use the gravitational microlensing technique to discover thousands of exoplanets, including those in wide orbits and of low mass, and the CGI will attempt to directly characterize the atmospheres of nearby exoplanets.