In this paper the feedback control problem of planar space robot is addressed. Main idea of the proposed control law is to use the properties of the Caplygin system where attitude of the base satellite is determined via contour integral on the plane of the manipulator coordinates. This controller is differentiable and can make the states of the space robot converge to the equilibrium from almost any initial state. The usefulness and validity of this controller can be demonstrated by hardware experiments. In these experiments free flying planar space robot is floated by air on the horizontal plane and controlled by angular velocity inputs. Experimental results show that the proposed smooth control stabilizes the planar space robot and does not excite unmodeled dynamics associated with link flexibility, leading to vibrations.