This paper deals with attitude control of planar space robots, whose conservation of the angular momentum leads to a non-integrable constraint (: nonholonomic constraint) . Although most of previous works on feedback control for nonholonomic systems are developed for Chained (or Power) form, the space robot has singular configuration in transformation to the chained system. This paper seeks possibility of feedback control using manifolds, instead of an invariant manifold usually constructed through numerical integration for non-chained systems. The relation between the type of the manifold and behavior of the state variables are investigated in detail, and some conditions of the manifold are specified. Also, behavior of the state variables of space robots is verified numerically.