USE OF A NOVEL TYPE OF PROPELLANT FOR ELECTRIC PROPULSION

Abstract

Depleted uranium hexafluoride (UF.sub.6) may be used as a propellant in an electric thruster. An electric thrusters may be propelled with a propellant including such depleted uranium hexafluoride, e.g., in a range of from 0.2 and 0.4% of .sup.235U. The propelling with such a propellant may be conducted in outer space. The propelling may include producing cations and anions without two distinct propellants. The propelling may include, for example, a changing orbit, reorienting a satellite, interplanetary journeying, and/or avoiding an object in space.

Claims

1. A propellant suitable for an electric thruster, the propellant comprising: depleted uranium hexafluoride.

2. The propellant of claim 1, wherein the electric thruster is a space electric thruster.

3. The propellant of claim 1, wherein the depleted uranium hexafluoride comprises .sup.235U in a range of from 0.2 to 0.4 wt. %.

4. The propellant of claim 1, having more thrust at fixed power than xenon propellant.

5. The propellant of claim 1, which does not comprise two distinct propellants.

6. The propellant of claim 1, which does not comprise krypton.

7. The propellant of claim 1, which does not comprise xenon.

8. The propellant of claim 1, which does not comprise xenon or krypton.

9. The propellant of claim 1, which does not comprise diode, magnesium, or zinc.

10. A method of operating an electric thruster, the method comprising: propelling the electric thruster with a propellant comprising depleted uranium hexafluoride.

11. The method of claim 10, wherein the electric thruster is a space electric thruster.

12. The method of claim 10, wherein the propelling is conducted in outer space.

13. The method of claim 10, wherein the propelling comprises producing cations and anions without two distinct propellants.

14. The method of claim 10, wherein the propelling comprises a changing orbit, reorienting a satellite, interplanetary journeying, and/or avoiding an object in space.

Description

DISCLOSURE OF THE INVENTION

[0012] Thus, the invention relates to the use of depleted uranium hexafluoride UF.sub.6, as propellant in an electric thruster and, more particularly, in a space electric thruster.

[0013] The concept of propellant can also be referred to as propellant gas.

[0014] Conventionally, depleted uranium hexafluoride corresponds to uranium hexafluoride whose uranium has an isotopic composition including a low abundance of light isotopes, and, more specifically comprised between 0.2 and 0.4% of .sup.235U, depleted uranium hexafluoride originating, in particular, from spent fuel reprocessing sectors.

[0015] Depleted uranium hexafluoride as propellant in electric propulsion has the following advantages: [0016] a vapour pressure with a sublimation limit at near-ambient temperature and pressure; [0017] a much better thrust at fixed power, due to the fact that the gas UF.sub.6 is significantly heavier (352 g/mol) relative to xenon (131 g/mol) [0018] a management by the temperature only of the density of propelled uranium hexafluoride, due to the fact that very stable uranium hexafluoride sublimates at common temperatures, thus allowing its transport in crystallised form and thus no longer involving a management of liquefied or cryogenic gases; [0019] simplified ground tests with a vacuum in the test chamber obtained by cryogenics and not pumping, the management of uranium hexafluoride being well known to those involved in the nuclear fuel cycle; [0020] a much lower cost and a much greater availability than those of xenon, depleted uranium hexafluoride being in particular available via the rejection of isotopic separation plants of fluorinated natural uranium (for example, depleted uranium from George Besse 2 (GBII)); [0021] a possibility of use in all types of electric thrusters and in particular in electronegative electric thrusters, due to the fact that uranium hexafluoride is likely to produce both positive ions (in this case, UF.sub.5.sup.+) and negative ions (in this case, F.sup.) during the ionisation process; [0022] the possibility of being used for all types of space flights, except those with strong gravitation and, in particular, for the space flights intended for a change of orbit, a reorientation of a satellite, an interplanetary journey, an avoidance of objects.

[0023] The invention will now be described with regard to the following example.

DESCRIPTION OF A PARTICULAR EMBODIMENT

Example

[0024] A test was successfully carried out, using uranium hexafluoride in a Hall-effect electric thruster with a power in the kilowatt range. Moreover, the particularly high ionisation cross section can accommodate the wide range of powers available from the Hall-effect thrusters on the market.