Study of a four-band far-UV to near-IR high-resolution imager for the Habitable Worlds Observatory

Abstract

The Habitable Worlds Observatory (HWO) is NASA’s planned flagship mission aimed at the direct detection and characterisation of Earth-like exoplanets around nearby Sun-like stars. As part of a UK Space Agency–funded feasibility effort, a high-resolution imager (HRI) has been studied as a potential UK-led contribution to the mission’s instrument suite. Science drivers derived from the HWO Science Case Definition Documents informed the required imaging performance across the UV–optical–near-IR, with additional consideration of sub-microarcsecond astrometric capability for measuring exo-Earth masses and supporting observatory-level guiding and wavefront sensing. The study assessed candidate instrument architectures, optical designs, detector technologies, mass and volume constraints, and data-handling requirements. Supported by the science requirements, this led to an imager design covering the wavelength range of 90 to 2500 nm, covered by 4 channels roughly aligned with the four main parts of the spectrum – Far-UV (FUV), Near-UV (NUV), Visible (Vis) and Near-IR (NIR), with the possibility of simultaneous imaging in the NUV, VIS and NIR bands. We discuss instrument performance, mass, power, and thermal design, identify key technology challenges, and outline plans for future development. The study demonstrates strong alignment with UK industrial and academic expertise and confirms the scientific and technical feasibility of a UK-led HRI for HWO.