Abstract: The spacecraft control system with the solar thermal propulsion (STP) has some advantages, including the great specific impulse and a high efficiency. In this paper, the STP is applied to the orbit compensation control of a responsive vehicle, and is optimized for the mission with as less absorber mass and as smaller reflector area as possible. Firstly, the model of the orbit compensation control system is built. Then, the mass of the absorber and the area of the reflector are successively optimized according to the principle of the STP and the characteristics of the responsive orbit. Finally, a numerical simulation is performed to testify the feasibility of the STP-based orbit compensation control, and the results show that the scheme is applicable for the responsive orbit in the height of 210 km to 300 km, where the mass of the absorber and the area of the reflector are both practicable for applications.