Shape Memory Alloy Thermal Interface for Spacecraft Heat Rejection

Solution Overview

Problem

Thermal interfaces in spacecrafts face inefficiencies in heat rejection due to temperature differences, leading to ineffective heat transfer and potential damage to electronic devices, particularly when surfaces exposed to high solar radiation cannot be used for heat rejection without adding complexity, weight, and cost through thermal shields or heat pumps.

Innovation Solution

A thermally conductive interface assembly using a shape memory alloy component that moves between states based on temperature, allowing for selective heat transfer by altering the contact between interface surfaces, enabling any surface to be used for heat rejection without additional barriers or control systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermal shields or heat pumps are added to enable heat rejection from surfaces exposed to solar radiation, then heat rejection capability is improved, but device complexity, weight, and cost increase

Engineering Contradiction:

Improveheat rejection capabilityVSAvoidsystem complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The shape memory alloy fasteners automatically adjust the thermal interface assembly's state based on temperature changes caused by solar radiation, eliminating the need for external control systems, motors, or sensors. The system self-regulates heat rejection by transitioning between thermal contact and gap states in response to environmental temperature variations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention changes the physical state of the thermal interface assembly by utilizing the shape memory alloy's temperature-dependent phase transformation. At different temperatures, the fasteners transition between martensitic and austenitic phases, automatically adjusting the thermal contact between surfaces to optimize heat rejection without additional control mechanisms.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If thermal shields or heat pumps are added to enable heat rejection from surfaces exposed to solar radiation, then heat rejection capability is improved, but weight increases

Engineering Contradiction:

Improveheat rejection capabilityVSAvoidsystem weight

Core Design Contradiction:

TemperatureVSWeight of moving object

Solution Approach 1:

The shape memory alloy fasteners automatically adjust the thermal interface assembly's state based on temperature changes caused by solar radiation, eliminating the need for external control systems, motors, or sensors. The system self-regulates heat rejection by transitioning between thermal contact and gap states in response to environmental temperature variations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention changes the physical state of the thermal interface assembly by utilizing the shape memory alloy's temperature-dependent phase transformation. At different temperatures, the fasteners transition between martensitic and austenitic phases, automatically adjusting the thermal contact between surfaces to optimize heat rejection without additional control mechanisms.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If thermal shields or heat pumps are added to enable heat rejection from surfaces exposed to solar radiation, then heat rejection capability is improved, but cost increases

Engineering Contradiction:

Improveheat rejection capabilityVSAvoidsystem complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The shape memory alloy fasteners automatically adjust the thermal interface assembly's state based on temperature changes caused by solar radiation, eliminating the need for external control systems, motors, or sensors. The system self-regulates heat rejection by transitioning between thermal contact and gap states in response to environmental temperature variations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention changes the physical state of the thermal interface assembly by utilizing the shape memory alloy's temperature-dependent phase transformation. At different temperatures, the fasteners transition between martensitic and austenitic phases, automatically adjusting the thermal contact between surfaces to optimize heat rejection without additional control mechanisms.

Inventive Principle:

Principle #35Parameter changes

4Productivity

If the thermal interface maintains direct physical contact between surfaces, then heat transfer efficiency is improved, but heat rejection from sun-facing surfaces becomes ineffective

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidheat rejection effectiveness

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The thermal interface assembly transitions dynamically between two states: a first state with direct physical contact for efficient heat transfer, and a second state with a gap for heat rejection. The shape memory alloy fasteners enable this dynamic reconfiguration in response to solar radiation conditions, allowing the same surface to serve different thermal functions at different times.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the physical state of the thermal interface assembly by utilizing the shape memory alloy's temperature-dependent phase transformation. At different temperatures, the fasteners transition between martensitic and austenitic phases, automatically adjusting the thermal contact between surfaces to optimize heat rejection without additional control mechanisms.

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 solution allows for efficient heat transfer management, reducing the complexity and weight of spacecraft systems, enabling any surface to be used for heat rejection while maintaining cost-effectiveness and increased heat transfer efficiency.

Implementation Method 1

a shape memory alloy component coupled to the thermally conductive interface assembly and configured to move one or more components of the thermally conductive interface assembly between a first state and a second state based on a temperature of the shape memory alloy component

Methodology Applied

Scientific EffectShape memory alloy: Shape Memory Alloy

Implementation Method 2

a thermally conductive interface assembly including a first component associated with a first interface surface and a second component associated with a second interface surface

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11225339B2System and method for shape memory alloy thermal interface

Publication Date: 2022.01.18 THE BOEING CO

AI summary

An apparatus includes a thermally conductive interface assembly including a first component associated with a first interface surface and a second component associated with a second interface surface. The apparatus also includes a shape memory alloy component coupled to the thermally conductive interface assembly and configured to move one or more components of the thermally conductive interface assembly between a first state and a second state based on a temperature of the shape memory alloy component. In the first state, the first interface surface is in physical contact with the second interface surface, and in the second state, a gap is defined between the first interface surface and the second interface surface.