CuRIOS-ED: optical AIT workflow and on-ground performance characterization of a 12U CubeSat imaging payload

CuRIOS-ED (CubeSats for Rapid Infrared and Optical Surveys – Exploration Demo) is a 12U CubeSat payload and pathfinder for the CuRIOS constellation, a fleet of CubeSats for optical monitoring of the transient sky. The payload combines a commercial Simera f/6 telescope with a Sony IMX455 CMOS detector in a custom camera housing. The system delivers a 3° field of view. We present the optical AIT workflow and on-ground performance of the telescope–detector assembly. A metrology-based alignment scheme positions the focal plane within the ±50 µm depth of focus, with a mean focus error <5 µm across the 36×24 mm sensor. End-to-end tests on a clean-room bench, using a custom OAP collimator, yield PSFs with core FWHM ≲1 pixel (<1.5″), consistent with the vendor wavefront map. PSF mapping after qualification-level vibration shows no measurable degradation, indicating that the CuRIOS-ED optical payload meets its image-quality budget and is robust against launch loads.