Satellite Hold-Down Release Mechanism With Shock-Free Nut Segment Actuation

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Solution Overview

Problem

Existing hold-down release mechanisms for space satellites suffer from mechanical shocks, material release that can harm optical apparatus, storage and use challenges, need for part replacement and reset, limited actuations, and uncertainty in pre-flight verification.

Innovation Solution

A device with an articulated mechanism using a rotatable elastic ring and piezoelectric or shape memory material actuators for controlled radial displacement of nut segments, enabling simultaneous and coordinated motion between retaining and release positions without mechanical shocks or material release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pyrotechnic charges, cutting wires, or explosive actuators are used for release, then the release function is achieved, but mechanical shocks are generated that may affect satellite instruments

Engineering Contradiction:

Improverelease functionVSAvoidmechanical shock

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces traditional mechanical/pyrotechnic release mechanisms with a shape memory alloy-based actuation system. The SMA wire, when electrically heated, undergoes phase transformation to change from martensite to austenite structure, generating sufficient force to release the nut segments and disconnect the screw, thereby eliminating mechanical shocks from explosive or pyrotechnic actuators

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention utilizes the phase transition properties of shape memory alloy material. The SMA wire transforms from martensite phase (low temperature, flexible) to austenite phase (high temperature, rigid) through electrical heating, producing controlled mechanical force for release without generating harmful mechanical shocks

Inventive Principle:

Principle #36Phase transitions

2Reliability

If traditional release mechanisms are used, then release is achieved, but material (solid, liquid or gaseous) is released that is pollutant and potentially harmful for optical apparatus

Engineering Contradiction:

Improverelease functionVSAvoidpollutant material

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent eliminates pyrotechnic charges and explosive materials by using an electrical heating system with shape memory alloy wire. The release is achieved through controlled phase transformation of the SMA material, producing no solid, liquid, or gaseous pollutants that could harm optical apparatus on the satellite

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional hold-down mechanisms are used, then retention during launch is achieved, but the system requires reset or part replacement after every actuation, affecting costs and reliability

Engineering Contradiction:

Improvehold-down functionVSAvoidreset and replacement requirement

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The shape memory alloy wire can be electrically re-actuated multiple times without requiring physical replacement or manual reset. The SMA material retains its shape memory properties after each phase transformation cycle, allowing the same component to perform multiple hold-down and release operations, thereby eliminating the need for part replacement or complex reset procedures

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system utilizes reversible parameter changes in the shape memory alloy material. By controlling temperature through electrical heating, the SMA wire can be cycled between martensite and austenite phases multiple times, enabling repeated actuation of the release mechanism without degrading the component's functionality

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

The solution allows for high pre-load application, unlimited actuations, no part replacement or reset, and easy pre-load verification, ensuring reliable and precise release without mechanical shocks or material release, using patented actuation technology.

Implementation Method 1

piezoelectric actuator for radially displacing the nut segments from the retaining position to the release position

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

shape memory material actuators

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

shape memory material actuators for controlled radial displacement of nut segments

Methodology Applied

Scientific EffectShape memory effect: Shape Memory Alloy

Data Source

PatentUS11608199B2Device for the hold-down and controlled release of space satellites installed on launchers and loads installed on space satellites

Publication Date: 2023.03.21 AEREA

AI summary

A device for the hold-down and controlled release of space satellites installed on launchers and loads installed on space satellites, includes a blocking member made up of segments radially displaceable from a mutually approached retaining position to a mutually spaced-apart release position of a connecting screw. In order to control the radial displacement of the segments between the retaining position and the release position there are provided a rotatable element coaxial with the blocking member, an articulated mechanism which operatively connects the rotatable element with the segments of the blocking member, and linear motors for driving the controlled rotation of the rotatable element and, through the articulated mechanism, the simultaneous displacement of the segments of the blocking member.