Micro and Nano-satellites with their low thermal capacitance are vulnerable to rapid temperature fluctuations. Therefore, thermal control becomes more important, but the limitations on mass and electrical power require new approaches. Possible solutions to actively vary the heat rejection of the satellite in response to variations in the thermal load and environmental condition are the use of variable emissivity devices, such as micro louvers, micro thermal switches, etc. Micro louvers with small volume, low weight, less power consumption and large emissivity variation, will be the more suitable solution for micro and Nano-satellites thermal control. In this paper, a polyimide based micro louver is developed. The device structure was designed, the actuation voltage was analyzed theoretically and fabrication process was described. The main parameters were tested and results were presented.