A very simple feed-forward technique taken from control theory, which we refer to as a drop-floor algorithm, was chosen to reduce the time for the receiver to return to equilibrium after a shutter motion. Since the radiant power received from the Earth is a slowly varying signal, the values measured during the last shutter cycle are a good starting point, or guess, for the servo to start from. The prior integrator value is stored for the two cases of shutter open and closed, then as the shutter begins its motion the current integrator value is frozen then transitioned to the prior value in a manner that is proportional to the instantaneous aperture area that is exposed. This forces the heater power to increase or decrease in proportion to the shutter motion, thereby minimizing any temperature disturbance in the receiver. Hence, the loop is always controlling at its optimum noise performance.