This study deals with the in-plane motion of a free-floating planar satellite equipped with two thrusters having constant force magnitude and fixed direction with respect to the satellite. This paper discusses the motion of such a satellite, and proposes a simple trajectory design procedure for controlling both the satellite's position and attitude angle. First, this paper investigates the motion for constant force magnitude. A drift-less rotational maneuver forms an "invariant manifold", which can be used to design a trajectory for the target state. Then, the condition of the input profile for the drift-less motion is discussed. Furthermore, this paper explains an advantage of a rotational maneuver which intentionally generates drift velocity.