Plug nozzle with a foldable inner cone

The engine (1) for the propulsion of the upper stage of a space launcher has a longitudinal axis (L-L) and comprises a central core (7) and a functional lateral cone shaped surface (9) whose base (10) is located on the side of the engine. Pressurized gas flow generators (12) located at the periphery of the lateral surface base generate gas flows striking the lateral surface. The end point (11) of the central core is constituted from a deformable structure (13) able to take either a folded position or a deployed position.