Waterless Electrically Operated Propellant for Space Temperature Stability

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Solution Overview

Problem

Existing electrically operated propellants face challenges due to water content, which can boil or freeze in space environments, leading to inoperability and compatibility issues with materials, especially in space propulsion applications, and volatility in other applications like airbag inflators.

Innovation Solution

Development of electrically operated propellants that are substantially waterless, using ionic liquids, polyelectrolytes, or a combination thereof, as electrolyte sources, along with polymeric binders and optional perchlorate oxidizers, eliminating aqueous solvents to maintain stability and functionality across varying temperatures and pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If aqueous solvents are used in electrically operated propellants, then the propellants can be easily formulated and processed, but they become inoperable in space environments due to water boiling or freezing

Engineering Contradiction:
Improveformulability and processingVSAvoidoperational reliability in space environment
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the fundamental parameter of the solvent system from aqueous to non-aqueous (ionic liquid-based). This parameter change eliminates water-related issues (boiling/freezing in space) while maintaining the liquid state and ionic conductivity necessary for electrical operation. The ionic liquid serves as both solvent and electrolyte, providing a stable medium that operates reliably across the temperature and pressure ranges encountered in space applications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite propellant system combining ionic liquids with polymeric binders and metal fuels. This composite approach integrates multiple functions: the ionic liquid provides ionic conductivity and acts as electrolyte, the polymeric binder provides structural integrity and binding, and the metal fuel provides combustion energy. This composite material system achieves both ease of formulation and operational reliability in space environments.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If water is present in propellants, then the propellants can maintain fluidity and ionic conductivity, but they experience volatility and compatibility issues with materials

Engineering Contradiction:
Improvefluidity and ionic conductivityVSAvoidvolatility and material compatibility issues
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The ionic liquid acts as an intermediary substance that provides ionic conductivity without the harmful properties of water. It mediates between the need for electrical conductivity (for ignition and control) and the need for stability (no volatility or material compatibility issues). The ionic liquid's unique properties allow it to conduct ions while being non-volatile and chemically stable, thus resolving the contradiction between ease of operation and harmful factors.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical composition parameter from water-based to ionic liquid-based. This parameter change fundamentally alters the properties: ionic liquids maintain ionic conductivity and fluidity while eliminating volatility and material compatibility problems associated with water. The ionic liquid's molecular structure allows it to provide necessary electrical properties without the harmful effects of aqueous systems.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If traditional solid rocket propellants are used, then they provide continuous thrust, but they cannot be selectively ignited or extinguished during flight

Engineering Contradiction:
Improvecontinuous thrust generationVSAvoidselective ignition and extinguishment capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic control capability to the propellant system through electrical electrodes embedded in the ionic liquid-based composition. The ionic liquid's ionic conductivity allows it to respond dynamically to electrical signals, enabling selective ignition and extinguishment. This dynamic control transforms the propellant from a static, continuously burning solid into an actively controllable system that can be turned on/off or throttled during flight, providing adaptability while maintaining continuous thrust capability when needed.

Inventive Principle:
Principle #15Dynamics

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

The waterless propellants ensure operational reliability in space and other environments by preventing inoperability and volatile water issues, allowing controlled ignition and extinguishment for variable thrust applications.

Implementation Method 1

The electrolyte source is an ionic liquid, a polyelectrolyte, or a combination thereof

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

Missiles and rockets burn propellants within combustion chambers to generate pressurized gases

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

The pressurized gases are directed through a nozzle to provide thrust and accordingly propel the body of the missile or rocket

Methodology Applied
Scientific EffectPressure-driven expansion: Pressure Gradient

Data Source

PatentEP4192800B1Waterless electrically operated propellant
Publication Date: 2025.08.27 RAYTHEON CO
  • EP4192800B1 patent drawingFigure 1
  • EP4192800B1 patent drawingFigure 2

AI summary

An electrically operated propellant includes an electrolyte source. The electrolyte source is an ionic liquid, a polyelectrolyte, or a combination thereof. The electrically operated propellant also includes a polymeric binder. The electrically operated propellant is substantially waterless with a water content of less than 10 wt.% water based on total weight of the electrically operated propellant.