Structural Propellant for Ion Rockets

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Solution Overview

Problem

Conventional Hall thruster designs for spacecraft require significant mass for propellant and propellant storage, increasing launch costs and reducing delta-v capability due to excess structure mass that is not utilized effectively in-space.

Innovation Solution

A structural propellant system for ion rockets (SPIR) that utilizes a removal device, such as mechanical cutters or laser cutters, to convert excess spacecraft structure, like magnesium, into a propellant ribbon fed into a Hall thruster system for thrust production, optimizing mass usage and increasing available fuel supply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional Hall thruster designs use separate propellant storage bottles, then the propellant can be stored and delivered to the thruster, but the spacecraft mass increases significantly due to the propellant bottle and propellant mass

Engineering Contradiction:
Improvepropellant massVSAvoidspacecraft mass
Core Design Contradiction:
Quantity of substanceVSWeight of moving object

Solution Approach 1:

The patent merges the propellant storage function with the spacecraft structure by designing the upper stage housing and structural components to be consumed as propellant. The magnesium alloy upper stage structure serves dual purposes: providing structural support during launch and serving as propellant mass for the Hall thruster after orbital insertion, eliminating the need for separate propellant storage bottles.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The upper stage structure is designed with multi-functionality, serving as both a structural component during launch and as propellant mass for in-space maneuvers. The magnesium alloy material provides both mechanical strength for launch vehicle integration and sufficient mass for Hall thruster propellant requirements, allowing the same structure to fulfill multiple functions across different mission phases.

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

2Duration of action of moving object

If significant propellant mass is carried in conventional designs, then the Hall thruster can produce thrust for extended maneuvers, but the launch costs increase due to the additional mass

Engineering Contradiction:
Improvethrust durationVSAvoidlaunch cost
Core Design Contradiction:
Duration of action of moving objectVSEase of manufacture

Solution Approach 1:

The patent combines the propellant mass requirement with the upper stage structure mass, eliminating the need to launch separate propellant tanks. The magnesium alloy structure provides both the mechanical integrity needed for launch and the propellant mass for extended Hall thruster operation, reducing launch mass and associated costs while maintaining sufficient thrust duration for orbital maneuvers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the material parameter by using magnesium alloy for the upper stage structure, which has favorable properties for both structural applications and propellant use in Hall thrusters. This material selection enables the structure to serve dual functions, optimizing the balance between thrust duration capability and launch mass constraints.

Inventive Principle:
Principle #35Parameter changes

3Strength

If excess spacecraft structure mass is present for launch, then the structure can support launch loads, but the delta-v capability is reduced due to the unused structure mass in-space

Engineering Contradiction:
Improvestructural strengthVSAvoiddelta-v capability
Core Design Contradiction:
StrengthVSSpeed

Solution Approach 1:

The patent merges the excess structure mass that would otherwise be dead weight in-space with the propellant mass requirement for delta-v capability. The magnesium alloy upper stage structure is designed to be consumed by the Hall thruster after launch, converting what would be unused structural mass into useful propellant mass, thereby enhancing delta-v capability while maintaining sufficient structural strength during launch.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the functional state of the structure from a static structural component to a consumable propellant resource. By selecting magnesium alloy with appropriate strength-to-mass ratios and consuming the structure through the Hall thruster, the system transforms excess structural mass into useful propulsion capability, directly improving delta-v while maintaining launch structural requirements.

Inventive Principle:
Principle #35Parameter changes

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 reduces spacecraft mass by repurposing unneeded structure as propellant, enhancing delta-v capability and payload capacity while minimizing launch costs by using existing structure as fuel post-orbit.

Implementation Method 1

at least one laser cutter

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

Hall thruster system

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 3

Hall thruster system

Methodology Applied
Scientific EffectElectromagnetic propulsion: Electromagnetic Propulsion

Data Source

PatentEP3196131B1Structural propellant for ion rockets (SPIR)
Publication Date: 2020.05.20 THE BOEING CO
  • EP3196131B1 patent drawingFigure 1~2
  • EP3196131B1 patent drawingFigure 3~4
  • EP3196131B1 patent drawingFigure 5~6

AI summary

Systems, methods, and apparatus for a structural propellant for ion rockets (SPIR) are disclosed. A method for in-space propulsion of a spacecraft involves removing, by a removal device, a portion of a structure of the spacecraft. The method further involves feeding, by the removal device, the portion into a Hall thruster system. Further, the method involves utilizing, by the Hall thruster system, the portion as propellant to produce thrust. The structure can be an upper stage of the spacecraft. The upper stage can comprise at least one structural support and/or at least one upper stage housing. The structure can be manufactured from magnesium, bismuth, zinc, and/or indium.