Use of new types of propellants for electric propulsion
Patent Information
- Application Number
- JP2024536308
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2021-12-17
- Filing Date
- 2022-12-16
- Publication Date
- 2024-12-26
AI Technical Summary
【0011】 電気推進における推進剤としての劣化六フッ化ウランは、以下の利点を有する。 蒸気圧が準大気温度及び圧力での昇華リミットを持つ。 UF6ガスがキセノン(131g/モル)に対して著しく重い(352g/モル)という事実により、一定出力でのスラストがはるかに良好である。 非常に安定した六フッ化ウランが共通の温度で昇華することで結晶化形態での輸送を可能にし、それゆえに液化又は極低温ガスの管理をもはや必要としないという事実により、推進される六フッ化ウランの密度が温度のみにより管理される。 ポンプ作用ではなく極低温により試験室の真空が得られて地上試験が簡易化され、六フッ化ウランの管理は、核燃料サイクルに携わる者にはよく知られている。 キセノンよりもはるかに低コストで入手可能性がはるかに高く、劣化六フッ化ウランは特に、フッ素化天然ウラン(例えば、ジョルジュ·ベス(George Besse)2(GBII)の劣化ウラン)の同位体分離プラントの廃棄物を介して特に入手可能である。 イオン化プロセス中に六フッ化ウランは陽イオン(このケースではUF5+)と陰イオン(このケースではF-)の両方を生成しやすいという事実により、全てのタイプの電気スラスタ、特に電気的負性電気スラスタでの使用が可能である。 引力の強いものを除いて全てのタイプの宇宙飛行、特に軌道の変化が予定される宇宙飛行、衛星の再配向、惑星間旅行、物体の回避での使用が可能である。
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Abstract
Description
[Technical field]
[0001] The present invention relates to the use of a novel type of propellant for electric propulsion, and in particular for space electric propulsion. [Background technology]
[0002] In general, propulsion relies on the exchange of momentum between the propellant material and a propelling machine, the propellant material possibly hot gases resulting from an exothermic combustion reaction of a propellant containing a fuel and an oxidizer, which are ejected by hot expansion through a nozzle, this case corresponding to chemical propulsion; Charged particles from the plasma generated by the propellant, and the energy that creates the plasma and accelerates the ions of this plasma for ejection is energy of electrical origin, in this case corresponding to electric propulsion, It is composed of:
[0003] Electric propulsion, also called plasma or ion propulsion, allows high ejection velocities to be reached due to the separation of the energy source and the ejected material, and therefore has a very low propellant consumption, unlike chemical propulsion. When electric propulsion is used in the space sector, and more specifically in satellite propulsion, it is possible to reduce the mass of the satellite to be propelled, and therefore its launch costs, and to extend the duration of the mission and increase its effectiveness. Thus, despite its low thrust level and lower than that of chemical propulsion, electric propulsion allows gains in capacity and costs, making it possible to carry out strategies and missions that would otherwise be difficult to achieve.
[0004] Currently, electric propulsion is primarily ensured operationally by two relatively similar technologies: gridded ion thrusters and Hall effect thrusters, which differ in the way they generate the electric field at the start of the ion jet, which is generated due to two bias grids for gridded ion thrusters, and by a combination of a magnetic field and an electrostatic potential difference between the anode and cathode of a Hall effect electric thruster.
[0005] These electric thrusters use various types of propellants, in particular: The most commonly used rare gases are xenon, krypton, and argon. a solid propellant, such as diode, magnesium, or zinc; may be used.
[0006] Electric propulsion can still be achieved today, still at the prototype stage, by so-called "electronegative thrusters", which consist in using both positive and negative ions for thrust, but this traditionally requires the management of two propellants, one capable of generating positive ions (e.g. argon) and one capable of generating negative ions (e.g. sulfur hexafluoride) under similar pressures, but the use of two types of propellants generates extra weight that is detrimental to propulsive performance. Summary of the Invention [Problem to be solved by the invention]
[0007] Taking into account what is already existing, the inventors of the present invention set themselves the objective of proposing a new propellant that can be effectively used in the field of electric propulsion, more particularly electric space propulsion, and more specifically can be used in all types of electric thrusters, in particular electro-negative electric thrusters, without requiring the use of two separate propellants. [Means for solving the problem]
[0008] The present invention therefore relates to the use of depleted uranium hexafluoride (UF6) as a propellant in electric thrusters, and more particularly in space electric thrusters.
[0009] The concept of propellant may also be referred to as a propellant gas.
[0010] Traditionally, depleted uranium hexafluoride contains small amounts of lighter isotopes, more specifically, 0.2-0.4% 235It corresponds to uranium hexafluoride, which contains uranium with an isotopic composition containing U, and depleted uranium hexafluoride is derived specifically from spent fuel reprocessing areas.
[0011] Depleted uranium hexafluoride as a propellant in electric propulsion has the following advantages: The vapor pressure has a sublimation limit at subambient temperatures and pressures. Due to the fact that UF6 gas is significantly heavier (352 g / mole) versus xenon (131 g / mole), thrust at a constant power is much better. Due to the fact that the highly stable uranium hexafluoride sublimes at common temperatures, allowing it to be transported in a crystalline form and therefore no longer requiring liquefaction or cryogenic gas management, the density of the propelled uranium hexafluoride is controlled by temperature alone. Ground-based testing is simplified as the chamber vacuum is achieved by cryogenics rather than pumping, and the management of uranium hexafluoride is well known to those involved in the nuclear fuel cycle. Much less expensive and much more available than xenon, depleted uranium hexafluoride is particularly available via the waste products of isotope separation plants that produce fluorinated natural uranium (e.g., George Besse II (GBII) depleted uranium). During the ionization process, uranium hexafluoride is converted into a positive ion (in this case UF5 + ) and an anion (in this case F - ), allowing its use in all types of electric thrusters, particularly in electro-negative electric thrusters. It can be used in all types of space flight except those with strong gravitational forces, especially those where orbital changes are planned, reorienting satellites, interplanetary travel, and object avoidance.
[0012] The invention will now be described with reference to the following examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] example Successful tests have been carried out using uranium hexafluoride in Hall effect electric thrusters with power outputs in the kilowatt range, and its extremely high ionization cross section allows it to be accommodated over the wide range of power outputs available from commercially available Hall effect thrusters.
Claims
1. Depleted uranium hexafluoride (UF) as a propellant in electric thrusters ６ Use of.
2. The use according to claim 1 , wherein the electric thruster is a space electric thruster.