Radiation-induced Degradation and On-orbit Performance Assessment of an sCMOS Detector

Abstract Optical astronomical projects have traditionally relied on charge-coupled device (CCD) detectors. However, next-generation complementary metal-oxide-semiconductor (CMOS) technology, with advantages including high-speed readout, low dark current, and electronic shutter capability, is reshaping observational strategies and substantially improving observing efficiency. Many ground-based facilities are now transitioning from CCDs to scientific CMOS (sCMOS) detectors, yet the long-term radiation-induced performance degradation of sCMOS devices in space environments has not been systematically characterized. In this work, we irradiate a GSENSE1081BSI sCMOS detector under representative on-orbit operating conditions, including vacuum and low temperature, and continuously monitor its performance during both the irradiation and subsequent annealing phases. Based on the measured evolution of key detector parameters, we predict the corresponding on-orbit degradation of photometric signal-to-noise ratio. The predicted performance meets the requirements of the microlensing telescope of the forthcoming Earth 2.0 mission, demonstrating the suitability of this detector for space-based time-domain observations and for potential application in future space missions. Our results further provide quantitative benchmarks and practical guidance for ground-based radiation testing of sCMOS detectors and for assessing their long-term performance evolution in space.