Spacecraft Shape Memory Polymer Deployment Mechanism

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Solution Overview

Problem

Existing mechanisms for deploying satellite parts in space are complex, costly, and add significant volume and mass, making them undesirable for small satellite platforms with limited constraints.

Innovation Solution

The use of a shape memory polymer actuator, integrated with a shape memory alloy material, that deploys satellite parts by changing shape when heated, providing the necessary force for deployment, and can be additively manufactured for reduced complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional deployment mechanisms are used, then reliable deployment is achieved, but device complexity and mass increase significantly

Engineering Contradiction:
Improvedeployment reliabilityVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical deployment mechanisms with a shape memory polymer (SMP) actuator system that uses thermal stimulation to trigger deployment. The SMP material undergoes a phase transition when heated, causing it to change shape and deploy the satellite part automatically, eliminating the need for complex mechanical actuators, motors, and control systems while maintaining reliable deployment functionality

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention utilizes the temperature-dependent shape memory effect of SMP materials. By changing the temperature parameter (heating the SMP above its glass transition temperature), the material transitions from a rigid state to a flexible state, enabling it to change shape and deploy the attached component. This parameter-based control simplifies the deployment mechanism while ensuring reliable actuation

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional deployment mechanisms are used, then deployment function is achieved, but mass and volume constraints are violated

Engineering Contradiction:
Improvedeployment functionVSAvoidspacecraft mass
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces heavy mechanical deployment mechanisms with a lightweight shape memory polymer actuator. The SMP material, being a polymer-based smart material, has significantly lower density and mass compared to traditional metallic mechanical systems. This substitution maintains the deployment function while dramatically reducing the mass penalty, making it suitable for small satellite platforms with strict mass constraints

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention employs shape memory polymer composites that combine the shape memory effect with structural functionality. The SMP actuator is integrated with the deployable structure itself, creating a composite system where the actuator and structure are unified. This integration eliminates separate mechanical components and reduces overall mass while maintaining deployment reliability

Inventive Principle:
Principle #40Composite materials

3Device complexity

If shape memory polymer actuator is used, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvemechanism complexityVSAvoidactuator fabrication precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention exploits the glass transition temperature parameter of shape memory polymers to enable simple processing and forming operations. The SMP material can be heated above its Tg to become flexible and easily shaped, then cooled to lock in the desired geometry. This temperature-based processing approach allows for straightforward manufacturing of complex actuator geometries without requiring high-precision machining or assembly operations

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 enables efficient, lightweight, and cost-effective deployment of satellite parts such as antennas, solar panels, and sunshades, reducing the overall mass and volume of the spacecraft while maintaining structural integrity and allowing for rapid prototyping.

Implementation Method 1

the actuator includes a shape memory polymer material that changes shape when heated in order to deploy the deployable part

Methodology Applied
Scientific EffectShape memory polymer effect: Shape Memory Polymer

Implementation Method 2

the actuator includes a shape memory alloy material in contact with the shape memory polymer material, and wherein the shape memory alloy material also changes shape when heated, to provide a force that aids in deploying the deployable part

Methodology Applied
Scientific EffectShape memory alloy effect: Shape Memory Alloy

Implementation Method 3

the actuator includes an electrical power source for electrical heating the shape memory polymer material

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3365233B1Spacecraft with shape memory polymer deployment mechanism
Publication Date: 2020.07.15 RAYTHEON CO
  • EP3365233B1 patent drawingFigure 1~4
  • EP3365233B1 patent drawingFigure 5~11
  • EP3365233B1 patent drawingFigure 12~13

AI summary

A spacecraft (10), such as a satellite, uses a shape memory polymer actuator (18) to deploy one or more deployable parts (14). The shape memory polymer actuator may be formed integrally with a deployable part and/or with a fuselage (12) or other structure of the spacecraft, with the shape memory polymer actuator being for example a relatively thin portion of the shape memory polymer material of the integral structure. The shape memory actuator allows deployment of the deployable part(s) upon heating of the shape memory polymer material of the actuator, such as after the satellite has been launched into space. The heating may be caused by a heat source that is part of the spacecraft itself, or may be merely the result of exposing the spacecraft to solar heating after launch. The deployable part of the spacecraft may include any of a wide variety of parts that are used after launch.