Rocket stage for a multistage space launch vehicle, wherein the rocket stage comprises a main engine for providing thrust for liftoff of the space launch vehicle from the surface of the earth and wherein the rocket stage is configured for stage separation from the remaining parts of the space launch vehicle during the ascent after liftoff such that the space launch vehicle continues towards space and the rocket stage returns to the surface of the earth, wherein the rocket stage comprises: - a pressure tank attached to the rocket stage, - an inflatable hull for receiving and retaining lifting gas from the pressure tank, - an inflation unit to perform the inflation of the hull with lifting gas, - a propulsion- and steering unit to provide thrust and attitude control for the rocket stage while the hull is at least partially inflated, and - a control unit to control the inflation unit and the propulsion- and steering unit, wherein the control unit is configured to initiate the inflation of the hull by controlling the inflation unit when a predefined condition after stage separation is fulfilled, for increasing the volume of the hull by filling the hull with lifting gas to generate aerostatic lift, and to control the propulsion- and steering unit to maneuver the rocket stage in a descent to a specified landing site on the surface of the earth while the hull is at least partially filled with lifting gas during the descent, wherein the fully inflated hull has the shape of a blimp-airship comprising aerodynamically stabilizing tail fins, characterized in that a body of the rocket stage is in a horizontal attitude while suspended below the inflated hull during a phase of the descent, and the rocket stage comprises a deceleration system to decrease the velocity of the rocket stage with respect to earth, and in that the control unit is configured to start the activation of the deceleration system during or after stage separation and before the inflation of the hull. wherein the rocket stage comprises a main engine for providing thrust for liftoff of the space launch vehicle from the surface of the earth and wherein the rocket stage is configured for stage separation from the remaining parts of the space launch vehicle during the ascent after liftoff such that the space launch vehicle continues towards space and the rocket stage returns to the surface of the earth, wherein the rocket stage comprises: - a pressure tank attached to the rocket stage, - an inflatable hull for receiving and retaining lifting gas from the pressure tank, - an inflation unit to perform the inflation of the hull with lifting gas, - a propulsion- and steering unit to provide thrust and attitude control for the rocket stage while the hull is at least partially inflated, and - a control unit to control the inflation unit and the propulsion- and steering unit, - a pressure tank attached to the rocket stage, - an inflatable hull for receiving and retaining lifting gas from the pressure tank, - an inflation unit to perform the inflation of the hull with lifting gas, - a propulsion- and steering unit to provide thrust and attitude control for the rocket stage while the hull is at least partially inflated, and - a control unit to control the inflation unit and the propulsion- and steering unit, wherein the control unit is configured to initiate the inflation of the hull by controlling the inflation unit when a predefined condition after stage separation is fulfilled, for increasing the volume of the hull by filling the hull with lifting gas to generate aerostatic lift, and to control the propulsion- and steering unit to maneuver the rocket stage in a descent to a specified landing site on the surface of the earth while the hull is at least partially filled with lifting gas during the descent, wherein the fully inflated hull has the shape of a blimp-airship comprising aerodynamically stabilizing tail fins, characterized in that a body of the rocket stage is in a horizontal attitude while suspended below the inflated hull during a phase of the descent, and the rocket stage comprises a deceleration system to decrease the velocity of the rocket stage with respect to earth, and in that the control unit is configured to start the activation of the deceleration system during or after stage separation and before the inflation of the hull.