The thermal control system of the Faint Object Camera /FOC/

The thermal control system of the Faint Object Camera (FOC) is described. The very demanding image stability requirements in the order of 3 microns requires an active thermal control system of the Optical Bench Enclosure (OBE) where the optical relays and the detectors are housed. The analytically derived requirements of the thermal control system are as follows: (1) long term stability 17 C plus or minus 2 C; and (2) short term stability requirement within an exposure (duration up to 24 hours) is: (a) longitudinal gradient variation of the optical bench, 1 C; (b) transversal gradient variation of the optical bench, 0.5 C; and (c) average temperature change of the optical bench, 0.5 C. The presentation deals with the design of the thermal control system and the verification program.