Technological maturation of a Gigapixels Astrometry instrument for the Habitable World Observatory.
This paper presents the development strategy for HWO-AGATE (Accurate Guiding and Astrometry Targeting Exoearths), a high-precision relative astrometry instrument concept designed for the future Habitable Worlds Observatory (HWO). The instrument is based on a gigapixel-class focal plane that incorporates the new generation of large-format GigaPyx CMOS sensors developed by Pyxalis. The proposed architecture relies on four 220-megapixel sensors assembled into a focal plane array and coupled with a dedicated calibration system to achieve the astrometric precision required for exoplanet detection and characterization. Preliminary study identified three major technological challenges. First, the performance of the 220-MP detectors must be validated against HWO's astrometric requirements. Second, the development of space-qualified packaging and integration solutions is required for a multi-sensor focal plane, while addressing the electrical and thermal constraints associated with the fast readout of large-format CMOS detectors. Third, an onboard calibration data-processing architecture must be implemented to reduce the raw data volume by approximately two orders of magnitude, enabling efficient operation within spacecraft resource limits. To address these challenges, we propose a comprehensive technology maturation program based on the construction of a representative end-to-end detection chain. The demonstration setup will include a partial focal plane equipped with 220-MP sensors, front-end electronics, a dedicated processing unit, and the calibration subsystem. The objective is to demonstrate compliance with HWO-AGATE requirements and to raise the maturity of large-format CMOS detector technology to Technology Readiness Level 5 (TRL 5). Detector validation and space-qualified packaging activities are already supported through institutional funding and the French national PEPR ORIGINS program in the RETINA (Researching Exoplanets Through Imaging for Narrow-angle Astrometry) project.