A method for operating a rocket propulsion system comprises the steps of supplying oxygen to a combustion chamber, supplying hydrogen to the combustion chamber and combusting the oxygen-hydrogen mixture in the combustion chamber. The rocket propulsion system is operated alternately in a first operating mode, in which oxygen and hydrogen are supplied to the combustion chamber in a first mass mixing ratio of oxygen to hydrogen, and in a second operating mode, in which oxygen and hydrogen are supplied to the combustion chamber in a second mass mixing ratio of oxygen to hydrogen that is greater than the first mass mixing ratio.