Satellite Propulsion System with Reorientable Thruster

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Solution Overview

Problem

Current orbit control systems for geostationary satellites are complex, expensive, and have a high mass, limiting the payload capacity due to the need for multiple thrusters of different types at various locations on the satellite, which complicates fuel management and increases costs.

Innovation Solution

A propulsion system with a thruster and motorized mechanism that can be stored and reoriented, allowing for controlled thrust and torque generation to manage satellite attitude and angular momentum, enabling efficient control of all six orbital parameters using a single system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple thrusters of different types are positioned at various locations on the satellite, then all mission requirements from transport to orbital maintenance are met, but the system mass and cost increase significantly

Engineering Contradiction:
Improvemission capabilityVSAvoidpropulsion system mass
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

A single secondary thruster is designed to perform multiple functions: orbit maintenance (controlling inclination, eccentricity, and drift) and attitude control (managing angular momentum and orientation). The thruster achieves this by selectively applying thrust at different locations on the satellite structure and in different directions, replacing the need for separate orbit control and attitude control thrusters.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the functions of orbit control thrusters and attitude control thrusters into a single secondary thruster system. By positioning one thruster at a location offset from the satellite's center of mass and controlling its thrust vector, the system combines orbital parameter control with angular momentum management, thereby reducing the total number of thrusters and associated mass.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If multiple thrusters of different types are positioned at various locations on the satellite, then all mission requirements are met, but the system complexity increases

Engineering Contradiction:
Improvemission capabilityVSAvoidpropulsion system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The secondary thruster is designed as a multi-functional device that can control all six orbital parameters (three for orbit position and three for orbit shape/orientation) as well as manage satellite attitude. This universal thruster replaces multiple specialized thrusters, simplifying the propulsion system architecture while maintaining full mission capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The thruster system employs dynamic control of thrust magnitude and direction to achieve multiple functions. By adjusting the thrust vector and application point, the same thruster can control different orbital parameters at different times, replacing the need for fixed, dedicated thrusters for each function.

Inventive Principle:
Principle #15Dynamics

3Weight of moving object

If a single secondary thruster is used for both orbit maintenance and attitude control, then mass and cost are reduced, but the ability to independently control all six orbital parameters and angular momentum is compromised

Engineering Contradiction:
Improvepropulsion system massVSAvoidcontrol capability
Core Design Contradiction:
Weight of moving objectVSAdaptability or versatility

Solution Approach 1:

The system uses dynamic thrust vectoring and selective application of thrust at different satellite locations to achieve independent control of all six orbital parameters and angular momentum. The control system calculates the optimal thrust application strategy to simultaneously or sequentially control inclination, eccentricity, drift, and attitude without requiring multiple physical thrusters.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameters of thrust application (magnitude, direction, duration, and application location) to achieve different control objectives. By varying these parameters, a single thruster can control multiple orbital parameters independently, maintaining full control capability while reducing system mass.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If chemical and electric thrusters are used for orbit control, then mission requirements are met, but the cost and initial mass are high

Engineering Contradiction:
Improvemission capabilityVSAvoidpropellant mass
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The secondary thruster is designed to replace both chemical orbit control thrusters and electric attitude control thrusters with a single system. This universal thruster uses electric propulsion technology to provide the necessary thrust for orbit maintenance while also managing satellite attitude, thereby reducing the total propellant mass and eliminating the need for separate chemical thruster systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution simplifies the propulsion system architecture, reduces mass and cost, and allows for comprehensive orbit control, including inclination, eccentricity, and drift corrections without de-optimizing other parameters, enhancing the satellite's payload capacity and operational efficiency.

Implementation Method 1

the ability to generate force through mass ejection (also called specific impulse)

Methodology Applied
Scientific EffectThrust generation through mass ejection: Rocket

Implementation Method 2

positioned at a location on the satellite structure offset from the center of mass of the satellite, to enable the thruster to generate a force along an axis F and to generate a torque when the thruster delivers the force

Methodology Applied
Scientific EffectTorque generation through off-center thrust: Torque

Implementation Method 3

a motorized mechanism connected on one side to the thruster and on the other to a structure of the satellite, the motorized mechanism being capable of moving the thruster

Methodology Applied
Scientific EffectMechanical actuation for position control: Linear Motor

Implementation Method 4

Once in this initial orbit, the satellite's propulsion system takes over to propel the satellite to its final orbit. This transfer is generally achieved using a primary satellite thruster (PSP) that consumes a chemical propellant, delivering a high-powered thrust to quickly reach the final orbit.

Methodology Applied
Scientific EffectOrbital transfer through propulsion: Rocket

Implementation Method 5

Once in orbit, several lower-power secondary thrusters maintain the satellite's position. These station-keeping operations require a sufficient fuel reserve throughout the satellite's lifetime.

Methodology Applied
Scientific EffectOrbital maintenance through periodic thrust: Rocket

Data Source

PatentEP2666723B1Propulsion system for satellite attitude control and orbit control
Publication Date: 2019.06.26 THALES SA
  • EP2666723B1 patent drawingFigure 1
  • EP2666723B1 patent drawingFigure 2
  • EP2666723B1 patent drawingFigure 3a~3c

AI summary

The system (50a) has a motor-driven mechanism (52a) for displacing a thruster (51) on sides of an orbit plane and orienting the thruster so as to control a component perpendicular to the orbit of force to control inclination of the satellite. The mechanism displaces the thruster along an axis parallel to velocity of the satellite and orients the thruster so as to control a component of force on the axis to control orbit, an amplitude and a direction of torque in a plane perpendicular to another axis (F), to control kinetic moment, where the system controls orbital parameters of the satellite. An independent claim is also included for a satellite in earth orbit provided with a propulsion system.