Dorado is an astrophysics Mission of Opportunity that addresses two “frontier” discovery areas highlighted by the 2010 Astronomy and Astrophysics Decadal Survey: gravitational waves (GWs) and time-domain astronomy. Dorado provides the highest priority observational capability identified by the community in order to fully capitalize on the highly anticipated multi-messenger era in the mid-2020’s—sensitive, wide-field ultraviolet (UV) imaging. By promptly (<2 hours) imaging the large localizations provided by ground-based GW detectors at UV wavelengths, Dorado can uniquely address such fundamental questions as where heavy (r-process) elements are formed, and how relativistic jets are launched and propagate. While awaiting GW triggers, Dorado conducts a transformative UV time-domain survey, imaging an area of 1000 square degrees every 3 hours to a depth of 19.9 mag (AB). In addition to the hundreds of transient discoveries (e.g., supernovae, tidal disruption events, flaring stars) resulting from this survey, Dorado will complement contemporaneous flagship facilities across the electromagnetic spectrum, including the Vera C. Rubin Observatory (optical), the Nancy Grace Roman Space Telescope (near-infrared), and the Square Kilometer Array (radio).
The Wide-field Imager (WI) instrument on Dorado is a refractive telescope with a 50.6 square degree field-of-view, more than 600× larger than the Swift UVOT. Despite a modest 13 cm aperture, the instrument employs two key enabling technologies—high-throughput anti-reflection coatings, and a high-efficiency delta-doped CCD detector—to achieve comparable effective area to the 50 cm GALEX mission. The WI is housed in a high-heritage SmallSat spacecraft built by the Space Dynamics Laboratory (SDL) and deployed as a secondary payload from an ESPA port. The project couples an efficient, experienced leadership team with the organizational expertise of the three major partners: GSFC, JPL, and SDL. The mission is readily executable within the $35M cost cap, providing exceptional value for the first NASA Astrophysics SmallSat.