Rocket engine and method for controlling supply of fuel or comburent to the rocket engine

Supply of a liquid fuel or comburent to a combustion chamber (2) of a rocket engine (1) is controlled by a feed valve (14) provided with an obturator (22) mobile between an open position and a closed position of at least one supply pipe (18), which has an inlet (21) that communicates with a tank (13) for containing the liquid component and an outlet (17) that communicates with the combustion chamber (2); the displacement of the obturator (22) from its closed position to its open position being triggered by a pressurized fluid supplied to the outlet (17) of the supply pipe (18).