Design of subpixel response characterization measurements for the Earth 2.0 mission

The Earth 2.0 (ET) mission is a Chinese space mission designed to detect thousands of terrestrial-like planets, including habitable Earth-like planets orbiting solar type stars (i.e., Earth 2.0s), cold low-mass planets, and free-floating planets. Six 30cm telescopes are used for very high precision photometry measurements to detect transiting planets. In order to reach very high precision photometry, an intra-pixel response function (IPRF) of detectors needs to be measured for the ET design to keep image motions caused by spacecraft operation within an acceptable level. To characterize detectors, two setups have been developed in the lab to measure spot size of the characterization beam and subpixel sensitivity. Early characterization results are reported.