Satellite Thruster Reorientation for Torque Cancellation

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Solution Overview

Problem

The low thrust of electric propulsion systems in satellites increases transfer time, and existing solutions for thruster failures either prolong the transfer or increase Xenon consumption, failing to maintain maximum thrust efficiently.

Innovation Solution

An electric propulsion device for satellites with four active thrusters that includes means to detect failures and reorient thrusters to maintain parallel thrust directions, calculating an angle to redirect active thrusters and cancel torque around the center of mass, thereby maximizing thrust and optimizing transfer duration and Xenon consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If electric propulsion is used to reduce launch mass, then efficiency improves, but thrust is too low and transfer time increases

Engineering Contradiction:
Improvepropulsion efficiencyVSAvoidtransfer time
Core Design Contradiction:
Use of energy by moving objectVSDuration of action of moving object

Solution Approach 1:

The patent combines multiple thrusters (3 or 4) to operate in parallel, merging their thrust contributions to achieve maximum total thrust while maintaining the efficiency benefits of electric propulsion. This allows the system to overcome the low thrust of individual thrusters.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic reorientation of thrusters using pointing mechanisms to adjust thrust direction and maintain optimal alignment with the velocity vector throughout the transfer maneuver, maximizing propulsion efficiency at all times.

Inventive Principle:
Principle #15Dynamics

2Productivity

If 4 thrusters are used in parallel for maximum thrust, then transfer time is reduced, but failure of one thruster forces reduction to 2 or 3 thrusters, doubling transfer time or increasing Xenon consumption

Engineering Contradiction:
Improvetransfer rateVSAvoidthruster failure tolerance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent pre-configures the satellite with 4 thrusters and pointing mechanisms, preparing the system in advance to handle thruster failures. The detection and reorientation capabilities are built in beforehand, allowing immediate response to failures without sacrificing performance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the operational parameters by reorienting the remaining active thrusters using pointing mechanisms to compensate for the failed thruster. This allows the system to maintain maximum effective thrust with 3 thrusters by adjusting their angular positions, rather than simply reducing to 2 thrusters.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If thrusters are repointed towards center of gravity after failure, then balance is maintained, but Xenon consumption increases and transfer duration is not optimized

Engineering Contradiction:
Improvesatellite balanceVSAvoidXenon consumption
Core Design Contradiction:
Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The patent implements a feedback control system that detects thruster failures and calculates optimal reorientation angles to maintain both satellite balance and maximum thrust efficiency. This ensures Xenon is consumed at the optimal rate while maintaining stable operation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3038923B1Method and device for electric satellite propulsion
Publication Date: 2018.04.11 THALES SA
  • EP3038923B1 patent drawingFigure 1
  • EP3038923B1 patent drawingFigure 2
  • EP3038923B1 patent drawingFigure 3

AI summary

The present invention relates to an electric propulsion device for a satellite (100) equipped with at least four active propellers exerting parallel thrust during a transfer, the device comprising means for detecting a propeller breakdown and means for reorienting the propellers, and being characterized in that it comprises means for calculating a reorientation angle of the propellers remaining active during a breakdown of a propeller, the value of the angle being calculated to reorient at least two of the remaining propellers in order to cancel out the total torque around the mass centre of the satellite.