Abstract: A system for mounting a movable thrust nozzle to a rocket case, wherein a plurality of cups surrounding the nozzle is fixed in a common plane to one of the members (the nozzle or case) and a plurality of plugs, each loosely fitting into a corresponding one of the cups, is fixed to the other member. The plugs and cups are arranged so that they tend to be forced together by pressure of propulsive gases of the rocket. A bladder, partially filled with fluid, is confined in each cup by its plug. Tubes connect either adjacent or diametrically opposite bladders; so that fluid may be displaced and exchanged between bladders as the nozzle is moved for steering the rocket. Hydraulic actuators may be interposed in tubes connecting diametrically opposite bladders for forcibly moving fluid from one to the other, and thereby move the nozzle. Alternatively, each bladder may be connected directly to a source of hydraulic fluid and be selectively inflated or deflated thereby for moving the nozzle.