Hall-Effect Thruster Magnetic Nulling for Spacecraft Torque Reduction
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Solution Overview
Problem
Existing Hall-effect thrusters generate a significant magnetic dipole moment that interacts with external magnetic fields, applying torque to spacecraft, which can be destabilizing.
Innovation Solution
Incorporation of nulling magnets, shielding, or a combination of both within the thruster to reduce the net magnetic dipole moment to near-zero, minimizing interaction with external magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional Hall-effect thruster design is used, then thrust generation is achieved, but significant magnetic dipole moment is generated causing torque on spacecraft
Solution Approach 1:
The patent applies the principle of converting harm into benefit by using shielding materials and nulling magnets to transform the harmful magnetic dipole moment into a beneficial near-zero net magnetic moment. The shielding materials (mu-metal, permeable materials) and nulling magnets are strategically positioned to cancel out the magnetic field interactions that cause torque, while preserving the thrust-generating magnetic field configuration. This resolves the contradiction by eliminating the harmful magnetic interaction without sacrificing thrust generation capability.
Solution Approach 2:
The patent introduces shielding materials and nulling magnets as intermediary elements between the thruster's magnetic field and the spacecraft body. These intermediaries act as mediators that block or cancel the magnetic dipole moment's interaction with external magnetic fields, preventing torque transmission to the spacecraft while allowing the primary magnetic field to continue accelerating ions for thrust generation.
2Object-affected harmful factors
If nulling magnets and shielding are added to reduce magnetic dipole moment, then torque is reduced, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by designing magnetic components that serve dual purposes: the magnetic field generating structure simultaneously provides thrust generation and, when properly configured with shielding and nulling elements, reduces magnetic dipole moment. The shielding materials and nulling magnets are integrated into existing thruster components rather than adding entirely separate systems, allowing one structure to perform multiple functions and reducing overall complexity.
Solution Approach 2:
The patent merges the nulling function with the existing magnetic field generating structure. Rather than adding completely separate nulling systems, the design integrates nulling magnets and shielding materials into the magnetic circuit components already present in the thruster. This consolidation combines multiple functions (thrust generation and magnetic moment reduction) into unified structures, minimizing the increase in device complexity.
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
Reduces the torque applied to the spacecraft by external magnetic fields, stabilizing the thruster and spacecraft operation.
Implementation Method 1
A magnetic circuit including a plurality of magnetic field sources and magnetic field flux guide material is configured to create a radially-oriented magnetic field
Implementation Method 2
the magnetic circuit generates a magnetic dipole moment
Implementation Method 3
Hall-effect thruster assembly
Implementation Method 4
Voltage applied between a cathode positioned at or near a first, discharge end and an anode positioned at or near a second end forms an electric field extending axially
Implementation Method 5
A radially-oriented magnetic field is created in a discharge area of the discharge chamber. The radially-oriented magnetic field impedes a flow of electrons toward the anode, enabling ionization of a propellant gas moving through the discharge area
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A Hall-effect thruster assembly includes a plurality of magnetic sources for creating a magnetic circuit. The plurality of magnetic sources are positioned between a first end and a second, opposite end of the Hall-effect thruster. The plurality of magnetic sources define a longitudinal axis extending through the first end and the second end. The first end is configured as a discharge end. A mount assembly is coupled to the second end. The mount assembly is configured to secure the plurality of magnetic sources to a spacecraft. A magnetic element is supported by the mount assembly. The magnetic element is positioned relative to the plurality of magnetic sources by the mount assembly.