The invention discloses a
solid carrier
rocket sub-stage capable of being recycled and reused. The
solid carrier
rocket sub-stage comprises a sub-stage body, an
inflatable heat protection structure and a
solid rocket engine; the
inflatable heat protection structure comprises a front-end
airbag which covers the windward side of a front cabin section under an expanding state and is in a shape of a rotating body, and the front-end
airbag comprises a flexible heat-insulating layer and a heat-proof
coating which are sequentially arranged from inside to outside; and the solid
rocket engine comprisesa
combustion chamber shell with a cavity allowing a grain to be placed, and a
combustion chamber heat protection structure is arranged on the inner wall of the
combustion chamber shell. By adopting the
inflatable heat protection structure with heat protection, deceleration and buffering combined, the front-end
airbag can maintain the good aerodynamic shape, the sub-stage is not damaged due to pneumatic heating and large landing
impact force in the reentry process, and can be recycled, through re-charging, replacing of disposable parts and the like of the
rocket engine, the sub-stage and the engine thereof can be reused, and thus the launching cost of a solid carrier rocket is lowered.