Microsatellite BIRD (Bispectral InfraRed Detection) with mass 92 kg and overall sizes 0.55 × 0.61 × 0.62 m operates in a sun-synchronous orbit more than 5 years. The temperature range −10 . . .+30 • C for payload with average power about 35 W and peak power of 200 W in observation mode, continuing 10-20 min, is provided by passive thermal control system (TCS). Operation of TCS foresees a thermal stability of payload structure by use of heat transfer elements -conductors and grooved heat pipes, thermally jointing the satellites segments. Two radiators, multilayer insulation (MLI) and low-conductive stand-offs provide the required temperature level. Review of TCS performance is based on an analysis of daily telemetric data, collected by 33 temperature sensors and power consumption. The analysis includes the definition of minimal, maximal and averaged temperatures of satellite main units and comparison with designed parameters. TCS successfully supports the required temperature level of satellite components during the whole period of exploitation.