Abstract: A control valve for a pulsating rocket engine comprises a valve seat and a movable valve part, one of which has a facing surface, of a non-deformable material, having a plurality of concentrically arranged saw-tooth shaped sealing ridges with flat sealing faces at their apices which extend perpendicular to the movement direction or force application direction. The other valve part has a facing surface of polytetrafluorethylene or polyamide which is initially smooth and plain but which, upon the first closing operation of the valve, responsive to a pressure load thereon exceeding a predetermined pressure load, is irreversibly deformed by the saw-tooth shaped sealing ridges, with flat sealing faces, of the other valve part to form therein grooves complementary to the sealing ridges.