Nuclear thermal propulsion system with reactor direct drive of cryocooler turbine
Systems and methods for nuclear reactor direct drive of a cryocooler turbine. A nuclear thermal propulsion (NTP) system may have a nuclear reactor that heats a thermal working fluid for directly driving the turbine to power a cryogenic fluid management (CFM) system for keeping propellant at cryogenic temperatures. The features may be used on NTP rockets. The propellant may be liquid hydrogen.
1. A method of operating a spacecraft having a cryogenic fluid management (CFM) system, the method comprising:
driving a cryocooler turbine of the CFM system using a heated first thermal working fluid;
maintaining a cryogenic temperature of propellant using the cryocooler turbine;
pumping the propellant along a nuclear reactor core of the spacecraft, thereby heating the propellant; and
expelling the propellant to provide thrust to the spacecraft.
2. The method of claim 1 , wherein the heated first thermal working fluid is heated by the nuclear reactor core of the spacecraft.
3. The method of claim 1 , further comprising driving a first compressor via a shaft rotated by the cryocooler turbine and circulating the first thermal working fluid through the first compressor.
4. The method of claim 1 , further comprising circulating the first thermal working fluid back to thermal communication with the nuclear reactor core of the spacecraft.
5. The method of claim 1 , wherein maintaining the cryogenic temperature of the propellant comprises circulating a second thermal working fluid in thermal communication with the propellant.
6. The method of claim 5 , wherein the cryocooler turbine drives a second compressor through which the second thermal working fluid circulates.
7. The method of claim 5 , wherein the first thermal working fluid is He—Xe and the second thermal working fluid is liquid He.
8. The method of claim 1 , wherein the propellant is liquid hydrogen.
9. The method of claim 1 , wherein the spacecraft comprises a nuclear thermal propulsion rocket.
10. A spacecraft comprising:
a cryocooler turbine configured to be directly driven by a first thermal working fluid heated by a nuclear reactor core of the spacecraft;
a cryogenic fluid management (CFM) system powered by the cryocooler turbine to thereby maintain a liquid state of propellant while stored in a cryogenic tank;
a fluid circuit configured to pump the propellant from the cryogenic tank along the nuclear reactor core, thereby heating the propellant; and
a nozzle configured to expel therefrom the heated propellant to produce a specific impulse.
11. The spacecraft of claim 10 , wherein the CFM system comprises one or more compressors configured to be mechanically driven by the cryocooler turbine.
12. The spacecraft of claim 10 , wherein the CFM system further comprises a second thermal working fluid that cools the propellant stored in the cryogenic tank.
13. The spacecraft of claim 10 , wherein the CFM system further comprises a heat exchanger.
14. The spacecraft of claim 10 , wherein the propellant is liquid hydrogen.
15. The spacecraft of claim 10 , further comprising a radiation shield.
16. The spacecraft of claim 10 , wherein the CFM system comprises a reverse turbo-Brayton cryocooler.
17. A spacecraft comprising:
a first fluid circuit configured to convey a first thermal working fluid in thermal communication with a reactor;
a turbine configured to be directly driven by the first thermal working fluid;
a cryogenic tank configured to store a propellant;
a second fluid circuit configured to convey the propellant along the reactor, and wherein the turbine is configured to affect a temperature of the propellant; and
a nozzle configured to expel the propellant conveyed along the reactor.
18. The spacecraft of claim 17 , further comprising a compressor configured to be mechanically driven by the turbine and through which the first thermal working fluid is configured to circulate via the first fluid circuit.
19. The spacecraft of claim 17 , further comprising a compressor configured to be mechanically driven by the turbine and through which the propellant is configured to circulate via the second fluid circuit.
20. The spacecraft of claim 17 , wherein the nozzle is a rocket nozzle.