Propulsion system for a spacecraft, comprising - at least one first drive device which can be operated with N 2 O as the oxidizer and with a hydrocarbon as the fuel, - a first tank device comprising at least one first storage chamber for storing the oxidizer and/or fuel and a first pressure chamber for receiving a pressurized fluid for maintaining a pressure level within the first storage chamber, and - a second storage chamber for storing the fuel and/or oxidizer, - a withdrawal arrangement comprising line means by means of which the first storage chamber and the second storage space are flow-connected to the first drive device for the supply of oxidizer and/or fuel, wherein - at least one heat input device for inputting heat into the pressurized fluid is arranged so as to be in thermal operative connection with the first pressure chamber, - the heat input device comprises at least one heat exchange device (30, 32) which is arranged in a heat exchanger circuit of the propulsion system and is or can be brought into thermal connection with the drive device as a heat source, wherein - the heat exchanger circuit is designed in such a way that fuel and/or oxidizer can flow through the heat exchange device (30, 32) as a heat transfer fluid, wherein the heat exchanger circuit comprises correspondingly arranged line means and at least one actuating means (44, 66), and a controllable and/or regulatable proportion of fuel and/or oxidizer can flow through the heat exchange device (30, 32) by means of the actuating means (44, 66), by means of a control device, characterized in that the heat exchange device (30, 32) of the heat input device is arranged in the first pressure chamber. - at least one first drive device which can be operated with N 2 O as the oxidizer and with a hydrocarbon as the fuel, - a first tank device comprising at least one first storage chamber for storing the oxidizer and/or fuel and a first pressure chamber for receiving a pressurized fluid for maintaining a pressure level within the first storage chamber, and - a second storage chamber for storing the fuel and/or oxidizer, - a withdrawal arrangement comprising line means by means of which the first storage chamber and the second storage space are flow-connected to the first drive device for the supply of oxidizer and/or fuel, - at least one heat input device for inputting heat into the pressurized fluid is arranged so as to be in thermal operative connection with the first pressure chamber, - the heat input device comprises at least one heat exchange device (30, 32) which is arranged in a heat exchanger circuit of the propulsion system and is or can be brought into thermal connection with the drive device as a heat source, wherein - the heat exchanger circuit is designed in such a way that fuel and/or oxidizer can flow through the heat exchange device (30, 32) as a heat transfer fluid, wherein the heat exchanger circuit comprises correspondingly arranged line means and at least one actuating means (44, 66), and a controllable and/or regulatable proportion of fuel and/or oxidizer can flow through the heat exchange device (30, 32) by means of the actuating means (44, 66), by means of a control device, characterized in that the heat exchange device (30, 32) of the heat input device is arranged in the first pressure chamber.