Abstract: A missile or other moving body comprising a rotatable portion arranged for rotation relative to another portion of the missile or body and control means for rotating said rotatable portion to bring it to any one of a plurality of preselected positions in relation to a datum and for exerting a thrust thereon having a lateral component with respect to the axis of rotation of said rotatable portion to produce a steering effect on the missile or body, said control means including a variable-incidence control surface mounted on the rotatable portion for rotation about a rotary axis transverse to the rotary axis of the rotatable portion, and actuator means responsive to control signals applied thereto for turning said control surface about its rotary axis to a first disposition in which it produces a component thrust causing rotation of said rotatable portion, and a second disposition in which it produces a lateral steering force on the missile.