Propellant Injector System for Plasma Thrusters
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Solution Overview
Problem
The widespread use of xenon as a propellant in plasma thrusters is hindered by its rarity, high cost, and difficulty in availability, necessitating the development of more accessible and cost-effective alternatives, such as water vapor, which poses technical challenges and requires a versatile thruster architecture adaptable to various condensable propellants.
Innovation Solution
A plasma production device featuring a radio frequency (RF) antenna, a propellant tank, and a plenum that maintains higher propellant pressure than the plasma production chamber pressure, facilitating ionization and thrust generation, and a propellant injector with multiple apertures to optimize propellant flow and ionization, allowing for the use of condensable propellants like water vapor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If xenon is used as propellant, then plasma production efficiency is improved, but cost and availability deteriorate
Solution Approach 1:
The patent changes the propellant parameter from xenon to water vapor, fundamentally altering the substance used while maintaining plasma production capability. This parameter change addresses the availability issue by using a abundant, inexpensive alternative that can be stored and transported easily.
Solution Approach 2:
The patent adopts water vapor as a disposable, inexpensive propellant that can be easily replaced and stored, eliminating the need for expensive xenon. The propellant is consumed during operation and can be replenished from easily storable reservoirs.
2Quantity of substance
If water vapor is used as propellant, then cost and availability are improved, but technical design complexity increases
Solution Approach 1:
The patent designs a universal thruster architecture that can accommodate multiple propellant types including water vapor, xenon, and other condensable propellants. The common architecture includes a plenum chamber and injector system that adapts to different propellant properties, reducing overall design complexity despite the variety of possible propellants.
Solution Approach 2:
The patent introduces a plenum chamber as an intermediary component between the propellant storage and the plasma generation region. This plenum serves as a buffer that accommodates pressure differences and facilitates smooth propellant flow into the plasma chamber, simplifying the overall system design.
3Productivity
If plenum pressure is maintained higher than plasma chamber pressure, then propellant flow is improved, but system complexity increases
Solution Approach 1:
The patent segments the propellant delivery system into distinct pressure zones: a high-pressure plenum chamber for propellant storage and a low-pressure plasma generation chamber. This segmentation allows independent pressure control in each zone, simplifying the overall pressure management despite the complexity introduced by maintaining different pressure levels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient and cost-effective plasma production and thrust generation using various propellants, including water vapor, suitable for spacecraft propulsion and other applications, with a scalable and robust design suitable for small satellite constellations.
Implementation Method 1
Radio frequency (RF) thrusters are electric propulsion systems that use radio frequency electromagnetic signals to accelerate a plasma propellant, thereby generating thrust
Implementation Method 2
a radio frequency (RF) antenna external to the plasma production chamber, electrically coupled to an AC power source, and configured to deliver an RF energy to an interior region of the plasma production chamber
Implementation Method 3
it is desirable to develop other, more commonly-available propellants for plasma-based thrusters... condensable propellants like water vapor
Implementation Method 4
it is relatively easy to pump in vacuum facilities by means of condensation on cryopumps
Implementation Method 5
the plenum is adapted to accept propellant at an upstream end from the propellant tank and dispense propellant at a downstream end into the plasma production chamber... the propellant has a plenum pressure (Pp) that is greater than a plasma production chamber pressure (Pc)
Data Source
AI summary
An electrothermal plasma production device is presented. The plasma production device includes: a plasma production chamber; an RF antenna external to the plasma production chamber; a propellant tank and flow regulator external to the plasma production chamber and in communication with the plasma production chamber; and a plenum disposed between the propellant tank and the plasma production chamber. The RF antenna, in combination with an AC power source, is configured to provide an RF energy to an interior region of the plasma production chamber and to an interior region of the plenum with sufficient power to ionize at least some of the propellant in the plenum. The plasma production chamber is configured to include a propellant injector for receiving propellant at a first closed end of the plasma production chamber.