Residual bulk image (RBI) is significant in the KAF09000 CCD. Residual images are observed 2 h after illumination at −20C. Trap leakage and capacity are studied as a function of temperature. A flood-flush protocol is evaluated for eliminating RBI artifacts. A substrate trap fixed pattern noise is observed and is removed by dark-subtraction. An increase of dark current shot noise due to trap leakage will occur but can be minimized by deep cooling. Operating temperature targets are set as a function of target noise levels. An operating temperature of -87C for a 30 min exposure is projected to support a read noise constraint of 5 e-.