Rocket propellant tank arrangement, rocket propulsion unit, and rocket

A method of carrying propellant in a rocket and of supplying propellant to an engine of the rocket, comprising:

• carrying liquid oxygen in an oxygen tank;
• carrying liquid fuel in a fuel tank, with the fuel tank having a fuel tank wall, with the fuel tank being at least partially arranged within the oxygen tank and with the liquid fuel being one of liquid propane, liquid propene, and liquid propylene, wherein an inner surface of the fuel tank wall is in fluid communication with the fuel in the fuel tank and an outer surface of the fuel tank wall is in fluid communication with the oxygen in the oxygen tank;
• wherein the fuel tank has a generally cylindrical shape, with the fuel tank wall being generally cylindrical, and wherein the oxygen tank has a generally hollow cylindrical shape, formed between the generally cylindrical fuel tank wall and a generally cylindrical oxygen tank wall, and wherein the fuel tank comprises generally disk-shaped fuel tank caps at its top and bottom ends and wherein the oxygen tank comprises annular oxygen tank caps at its top and bottom ends;
• jointly controlling a liquid oxygen temperature of the liquid oxygen and a liquid fuel temperature of the liquid fuel, with the fuel tank wall allowing for mutual cooling of the liquid oxygen and the liquid fuel;
• and
• supplying the liquid oxygen and the liquid fuel via short range supply lines from a lower portion of the oxygen tank and a lower portion of the fuel tank to the engine, which is arranged below the oxygen tank and the fuel tank.