Pierced waveguide thruster

1. A propulsion system for a space vehicle, the propulsion system comprising:

a source of microwave energy;

a waveguide coupled to the source of microwave energy, the waveguide configured to have a propagation direction;

a primary propellant chamber at least partially disposed within the waveguide, the primary propellant chamber having a chamber wall, an ingress port, and an egress port, and the chamber wall comprising a dielectric material;

a propellant injection mechanism configured to inject propellant into the primary propellant chamber via the ingress port; and

a controller configured to:

cause the propellant injection mechanism to inject the propellant into the primary propellant chamber; and

cause the source of microwave energy to supply energy to the propellant in the primary propellant chamber through the dielectric material of the chamber wall and via the waveguide to thereby heat the propellant and cause the heated propellant to exit the primary propellant chamber via the egress port.

2. The propulsion system of claim 1 , further comprising:

a secondary ionization device configured to ionize a portion of the propellant.

3. The system of claim 1 , wherein:

the waveguide includes a resonant cavity to enhance microwave energy density in the primary propellant chamber.

4. The propulsion system of claim 1 , wherein the primary propellant chamber pierces the waveguide orthogonally to the direction of propagation of the waveguide.

5. The propulsion system of claim 1 , further comprising:

a sensor configured to generate a signal indicative of an amount of energy absorbed by the propellant; and

wherein the controller is configured to either i) cause the propellant injection mechanism to inject the propellant into the primary propellant chamber, or ii) cause the source of microwave energy to supply energy to the propellant in the primary propellant chamber at least in response to the signal indicative of the amount of energy absorbed by the propellant.

6. The propulsion system of claim 5 , wherein the sensor configured to generate the signal indicative of the energy absorbed by the propellant is configured to measure either i) a degree of ionization, or ii) a temperature of the propellant in the primary propellant chamber.

7. The propulsion system of claim 1 , wherein:

the egress port is a nozzle; and

the heated propellant exiting the primary propellant chamber via the nozzle generates thrust.

8. The propulsion system of claim 7 , further comprising:

a cooling sleeve surrounding the nozzle.

9. The propulsion system of claim 7 , further comprising:

a magnet disposed at the nozzle so as to guide ionized propellant along magnetic field lines established by the magnet.

10. The propulsion system of claim 1 , further comprising:

a secondary propellant chamber in fluidic connection with the primary propellant chamber, where in operation the primary propellant chamber is configured to hold propellant at a first pressure, and the secondary propellant chamber is configured to hold propellant at a second pressure different from the first pressure; and

a secondary energy source configured to add heat to the propellant in in the secondary propellant chamber.

11. The propulsion system of claim 10 , wherein:

the egress port of the primary propellant chamber is configured to guide the heated propellant exiting the primary propellant chamber to the secondary propellant chamber; and

the secondary propellant chamber includes a nozzle configured to guide the heated propellant out of the secondary propellant chamber to produce thrust.

12. The propulsion system of claim 10 , wherein:

the propellant injection mechanism is further configured to inject the propellant into the ingress port of the primary propellant chamber via the secondary propellant chamber; and

the egress port of the primary propellant chamber is a nozzle configured to guide the heated propellant out of the primary propellant chamber to produce thrust.

13. The propulsion system of claim 12 , wherein:

the second pressure is at least twice as high as the first pressure; and

the propulsion system includes a magnet configured to guide ionized propellant through the primary propellant chamber along magnetic field lines established by the magnet.

14. A method of operating a propulsion system in a space vehicle, the method comprising:

generating microwave energy using a source of microwave energy;

coupling the generated microwave energy to a waveguide, the waveguide configured to have a propagation direction;

injecting, via an ingress port using a propellant injection mechanism controlled by a controller, propellant into a primary propellant chamber at least partially disposed within the waveguide, the chamber wall comprising a dielectric material; and

supplying, via the waveguide and through the dielectric material of the chamber wall, energy to the propellant in the primary propellant chamber to thereby heat the propellant and cause the heated propellant to exit the primary propellant chamber via an egress port.

15. The method of claim 14 , further comprising:

ionizing a portion of the propellant using a secondary ionization device.

16. The method of claim 14 , wherein:

the waveguide includes a resonant cavity to enhance microwave energy density in the primary propellant chamber.

17. The method of claim 14 , further comprising:

generating, using a sensor, a signal indicative of an amount of energy absorbed by the propellant; and

either i) causing, by the controller, the propellant injection mechanism to inject the propellant into the primary propellant chamber, or ii) causing, by the controller, the source of microwave energy to supply energy to the propellant in the primary propellant chamber at least in response to the signal indicative of the amount of energy absorbed by the propellant.

18. The method of claim 17 , wherein the sensor generating the signal indicative of the energy absorbed by the propellant measures either i) a degree of ionization, or ii) a temperature of the propellant in the primary propellant chamber.

19. The method of claim 14 , wherein:

the egress port is a nozzle; and

the heated propellant exiting the primary propellant chamber via the nozzle generates thrust.

20. The method of claim 19 , further comprising cooling the nozzle using a cooling sleeve surrounding the nozzle.

21. The method of claim 19 , further comprising:

guiding ionized propellant along magnetic field lines established by a magnet disposed at the nozzle.

22. The method of claim 14 , further comprising:

holding, in a secondary propellant chamber in fluidic connection with the primary propellant chamber, propellant at a pressure different from propellant pressure in the primary propellant chamber; and

adding, using a secondary energy source, heat to the propellant in in the secondary propellant chamber.

23. The method of claim 22 , wherein:

the egress port of the primary propellant chamber is configured to guide the heated propellant exiting the primary propellant chamber to the secondary propellant chamber; and

the secondary propellant chamber includes a nozzle configured to guide the heated propellant out of the secondary propellant chamber to produce thrust.

24. The method of claim 22 , wherein:

the propellant injection mechanism is further configured to inject the propellant into the ingress port of the primary propellant chamber via the secondary propellant chamber; and

the egress port of the primary propellant chamber is a nozzle configured to guide the heated propellant out of the primary propellant chamber to produce thrust.

25. The method of claim 24 , wherein:

the second pressure is at least twice as high as the first pressure; and

the propulsion system includes a magnet configured to guide ionized propellant through the primary propellant chamber along magnetic field lines established by the magnet.