Methods and structures are provided that enhance the accuracy of the service attitude of an inclined-orbit spacecraft and, thereby, facilitate reduction of service error between a communication service area and the spacecraft’s payload beam. A reactor tube having open ends is supported by the partition over the hole, and a grate spaced below the hole. The filter is used for generating a prediction of the signal and an error variance matrix. The control valve is connected to the operation levers and the pedals to perform drive control of a hydraulic actuator, and is placed at an incline so as to be high at the front and low at the rear. Next to the intermediate frequency amplifying circuit, there is a second trap circuit which, for reception of a TV signal, brings about attenuation between the video intermediate frequency in the intermediate frequency band and the sound intermediate frequency of the adjacent channel and, for reception of an FM broadcasting signal, brings about attenuation around the video intermediate frequency.