Radiation damage from cobalt-60 gamma rays is investigated for TSL235 Light to Frequency Converters. No dose rate effects were observed. the TSL235 is found suitable for use in Low Earth Orbit up to a total dose of 1.5 Krad(Si). Sudden failure of the device is observed at approximately 5 Krad(Si), exhibited by a rapid degradation in performance and a quick rise in device supply current leading to permanent damage (burnout). Annealing at room temperature for 24 hours showed no rebound.