Spacecraft Three-Axis Stabilization Propellant Reduction

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Solution Overview

Problem

Spacecraft propellant consumption is high during orbit transfer operations due to the need for spin stabilization, momentum dumping, and reorientation, which are energy-intensive and inefficient.

Innovation Solution

Maintaining a continuous three-axis stabilized mode during orbit raising maneuvers, using reaction wheels for momentum management and attitude control, and avoiding propellant use for reorientation by slow slewing, thus eliminating the need for propellant-based spinning or despinning and momentum dumping during coast periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If spin stabilization is used during orbit transfer operations, then attitude control is simplified, but propellant consumption increases due to momentum dumping requirements

Engineering Contradiction:

Improveattitude controlVSAvoidpropellant consumption

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The patent replaces spin stabilization (mechanical rotation) with three-axis stabilized attitude control using reaction wheels and control moment gyroscopes. This substitution eliminates the need for momentum dumping operations that consume propellant, while maintaining attitude control capability through electromagnetic actuation systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters from spin-stabilized mode to three-axis stabilized mode, fundamentally altering how attitude control is achieved. This parameter change enables continuous attitude control without the periodic momentum dumping cycles that characterize spin stabilization, thereby reducing propellant consumption.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If momentum dumping is performed during coast periods, then reaction wheel momentum is offloaded, but propellant is consumed

Engineering Contradiction:

Improvemomentum managementVSAvoidpropellant consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces propellant-based momentum dumping with reaction wheel desaturation techniques that use control moment gyroscopes or magnetorquers. This substitution allows momentum to be transferred to the Earth's magnetic field or stored in CMGs, eliminating the need to consume propellant for momentum offloading during coast periods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If propellant is used for reorientation between sun-safe orientation and maneuver orientation, then attitude control is achieved, but propellant consumption increases

Engineering Contradiction:

Improvereorientation capabilityVSAvoidpropellant consumption

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The patent replaces propellant-based reorientation with reaction wheel actuation. The reaction wheels provide the necessary torque to reorient the spacecraft between sun-safe orientation and maneuver orientation without consuming propellant, utilizing electromagnetic actuation instead of chemical propulsion for attitude adjustments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Substantially reduces propellant consumption by maintaining zero or very small rotation rates and eliminating the need for propellant-based reorientation and momentum dumping, enhancing energy efficiency and operational stability during orbit transfer.

Implementation Method 1

control authority for maintaining satellite orientation may be provided by on board reaction wheels

Methodology Applied

Scientific EffectReaction wheel: Reaction Wheel

Implementation Method 2

attitude knowledge may be provided by one or more star trackers

Methodology Applied

Scientific EffectStar tracking:

Implementation Method 3

Each orbit raising maneuver may include either or both of a chemical thruster firing and an electric thruster firing

Methodology Applied

Scientific EffectChemical thruster: Rocket

Implementation Method 4

Each orbit raising maneuver may include either or both of a chemical thruster firing and an electric thruster firing

Methodology Applied

Scientific EffectElectric thruster: Electromagnetic Propulsion

Data Source

PatentUS8763957B1Spacecraft transfer orbit techniques

Publication Date: 2014.07.01 LANTERIS SPACE LLC

AI summary

Spacecraft transfer orbit operations include separating a spacecraft from a launch vehicle, while in a launch vehicle transfer orbit. The spacecraft includes a propulsion subsystem and a spacecraft controller that controls the spacecraft in a three-axis stabilized mode. With the spacecraft continuously in the three-axis stabilized mode, one or more orbit raising maneuvers are performed by firing either or both of a chemical thruster and an electric thruster firing. Any two consecutive orbit raising maneuvers are separated by a respective intervening coast period. While in the three-axis stabilized mode, the spacecraft does not rotate about any axis at a rate greater than 0.1 degree/sec and dumping of momentum stored in a reaction wheel system is avoided.