Plasma Thruster Eclipse Management

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Solution Overview

Problem

Space vehicles equipped with plasma thrusters face prolonged re-ignition times during solar eclipses due to the need for initial heating of the electron emitting member, leading to reduced thrust duration and increased fatigue on critical components.

Innovation Solution

A method for managing the plasma thruster system during solar eclipses involves reducing the fluid flow and increasing the electric current to the temperature maintaining plasma, allowing the electron emitting member to remain operational without thrust, and resuming thrust quickly upon eclipse exit, thereby minimizing re-ignition times and reducing component fatigue.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the plasma thruster is completely shut down during solar eclipses to save power, then electrical energy consumption is reduced, but the re-ignition time increases significantly due to the need for initial heating of the electron emitting member

Engineering Contradiction:
Improveelectrical energy consumptionVSAvoidre-ignition time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The patent applies preliminary action by maintaining the temperature maintenance plasma and electron emitting member in a ready state during solar eclipses rather than completely shutting them down. This preliminary preparation ensures that when sunlight returns, the thruster can resume operation immediately without requiring full re-ignition heating, thus resolving the contradiction between energy saving and quick re-ignition

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous useful action by keeping the temperature maintenance plasma active throughout the solar eclipse period. This continuous maintenance of thermal conditions in the electron emitting member allows the system to transition smoothly from eclipse to operational mode, eliminating the need for time-consuming re-heating while consuming minimal energy compared to full operation

Inventive Principle:
Principle #20Continuity of useful action

2Duration of action of moving object

If the plasma thruster maintains full operational status during solar eclipses, then re-ignition time is minimized, but electrical energy consumption increases significantly

Engineering Contradiction:
Improvethrust durationVSAvoidelectrical energy consumption
Core Design Contradiction:
Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by maintaining only the temperature maintenance plasma and electron emitting member in a ready state during solar eclipses, rather than maintaining full thrust operation. This partial maintenance keeps the system ready for quick resumption while consuming significantly less energy than full operation, thus resolving the contradiction between thrust duration and energy consumption

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes operational parameters by switching from full power mode to a low-power standby mode during solar eclipses. The temperature maintenance plasma is sustained at reduced power levels, and the electron emitting member is kept warm rather than at full operating temperature, allowing the system to maintain readiness while dramatically reducing electrical energy consumption

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the plasma thruster is repeatedly re-ignited during solar eclipses, then thrust duration is maintained, but fatigue on critical components like cathodes or neutralizers increases

Engineering Contradiction:
Improvethrust durationVSAvoidcomponent lifespan
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by maintaining the electron emitting member in a ready state throughout the solar eclipse, preventing the need for repeated re-ignition cycles. This continuous maintenance of operational readiness preserves component lifespan by avoiding thermal cycling fatigue, while ensuring thrust can resume immediately when sunlight returns, thus resolving the contradiction between productivity and reliability

Inventive Principle:
Principle #10Preliminary action

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

This approach significantly reduces the restart time of the plasma thruster, increases available thrust time, and minimizes the impact on propulsion fluid and electrical energy consumption, while extending the lifespan of critical components like cathodes or neutralizers.

Implementation Method 1

increasing the electric current in the temperature maintenance plasma, at least in the electron emitting member to neutralize the ion beam, up to a predefined value for maintaining the temperature

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

A fluid, usually xenon, is injected and ionized in a chamber, called a discharge chamber, to form a propulsion plasma

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 3

The electrons follow the magnetic field lines created by a magnet or a coil before each striking an atom of the fluid material and generating a positive ion

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP4363323B1Method for controlling a plasma thruster
Publication Date: 2024.11.20 AIRBUS DEFENCE & SPACE SAS
  • EP4363323B1 patent drawingFigure 1
  • EP4363323B1 patent drawingFigure 2
  • EP4363323B1 patent drawingFigure 3

AI summary

The invention relates to improving the propulsion of a HET, RIT or GIT engine during solar eclipses and comprises, before the solar eclipse: deactivating the thrust and then disconnecting the bus supplied with power by the solar panel (TDoff); decreasing the flow rate of the fluid (Db) feeding the temperature-maintaining plasma in the electron-emitting member for neutralising the ion beam; increasing the current (Ch) through the temperature-maintaining plasma supplied by the battery; at the end of the solar eclipse: increasing the flow rate of the fluid feeding the temperature-maintaining plasma; decreasing the current through the temperature-maintaining plasma; when the eclipse finishes: reconnecting the bus supplied with power by the solar panel and then reactivating the thrust.