Spacecraft Release Bolt Locking for Low-Shock Resettable Separation

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Solution Overview

Problem

Existing hold-down and release devices for spacecraft require complex refurbishment after activation and lack a simple, low-shock, non-explosive release mechanism that allows easy reset.

Innovation Solution

A hold-down and release device featuring a release bolt locked by a segmented ring and actuated by a rod with a locking pin, operated by a compression spring and actuator, enabling non-explosive, low-voltage activation and user-resettable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing hold-down and release devices are used, then the release function is performed satisfactorily, but complex refurbishment is required after activation

Engineering Contradiction:
Improverelease functionVSAvoidrefurbishment complexity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The locking mechanism is divided into separate functional components: a segmented ring for locking, a separate rod with locking pin for actuation, and an independent compression spring system. This segmentation allows individual components to be replaced or reset without refurbishing the entire device, directly addressing the refurbishment complexity issue while maintaining reliable release function

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device transitions from a permanent explosive charge state to a reversible mechanical spring state. The compression spring can be compressed and released multiple times, changing the operational parameter from single-use to multi-use, thereby eliminating complex refurbishment requirements while ensuring reliable release

Inventive Principle:
Principle #35Parameter changes

2Reliability

If explosive release mechanisms are used, then release function is achieved, but high shock is generated

Engineering Contradiction:
Improverelease functionVSAvoidshock
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The explosive chemical energy system is replaced with a mechanical spring energy system. The compression spring stores mechanical energy that is gradually released through controlled mechanical motion of the rod and locking pin, eliminating the high shock associated with explosive decomposition while maintaining effective release function

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

Solution Approach 2:

The energy release parameter changes from instantaneous explosive energy to controlled mechanical energy release. The compression spring provides a gradual, controlled force application that reduces shock impact while achieving the same release objective, directly addressing the harmful shock factor

Inventive Principle:
Principle #35Parameter changes

3Extent of automation

If high-voltage pyrotechnic systems are used, then release activation is achieved, but high voltage is required

Engineering Contradiction:
ImproveactivationVSAvoidvoltage
Core Design Contradiction:
Extent of automationVSUse of energy by moving object

Solution Approach 1:

The high-voltage pyrotechnic electrical system is replaced with a low-voltage electromagnetic actuator system. The actuator uses low-voltage electrical signals to control the mechanical movement of the rod and locking pin, significantly reducing the voltage requirement while maintaining automated activation capability

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

Solution Approach 2:

The actuator serves as an intermediary between the low-voltage electrical control signal and the mechanical release mechanism. It converts low-voltage electrical energy into the mechanical motion needed to operate the locking pin and rod, enabling automated activation at low voltage without requiring high-voltage pyrotechnics

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If complex locking mechanisms are used, then secure hold-down is achieved, but device complexity increases

Engineering Contradiction:
Improvehold-down strengthVSAvoidmechanism complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The locking function is segmented into simple, discrete components: the segmented ring provides the locking interface, the rod with locking pin provides the actuation interface, and the compression spring provides the holding force. This segmentation achieves secure hold-down through simple, well-defined mechanical interfaces rather than complex integrated mechanisms

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The essential hold-down function is extracted and performed by the compression spring, while the locking and actuation functions are extracted and performed by the simple ring and rod mechanisms. This separation of functions reduces overall device complexity while maintaining strong hold-down capability through the dedicated spring element

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables non-explosive release with low shock, allows user-resetting without refurbishment, and facilitates synchronized multiple releases.

Implementation Method 1

a compression spring, intended to abut the housing of the locking device and also arranged around the rod with the locking pin cooperating with the groove of the housing to make the rod turn around its longitudinal axis

Methodology Applied
Scientific EffectElastic potential energy storage and release: Spring

Implementation Method 2

an extraction system for the release bolt, comprising a spring, an upper support, a lower support and a nut between the upper support and the lower support, the spring being guided by the upper support and the lower support, the release bolt being preloaded by the action of the nut

Methodology Applied
Scientific EffectCompressive force: Compression

Data Source

PatentEP4299451B1Retaining and releasing device and assembly for spaceships
Publication Date: 2026.01.07 AIRBUS DEFENCE & SPACE SAU
  • EP4299451B1 patent drawingFigure 1
  • EP4299451B1 patent drawingFigure 2
  • EP4299451B1 patent drawingFigure 3

AI summary

Hold down and release device for spacecraft, configured for the hold-down and release of a releasable body (M) with respect to a support structure (F), that comprises: - a release bolt (1) configured to keep the releasable body (M) and the support structure (F) together in a locked position of the hold-down and release device, - a locking device for locking the release bolt (1) in the support structure (F), the locking device comprising a housing (3) and a segmented ring (2), the housing (3) being movable in the direction of the axis of the release bolt (1) and comprising an end with a passing groove (15) on its surface, - a release system for acting on the locking device, comprising an actuator (9), a rod (5) with a locking pin (6), the rod (5) having the same orientation as the release bolt (1), and the locking pin (6) configured to cooperate with the groove (15) of the housing (3), and a compression spring (10), such that the actuator (9) is configured to lock the rod (5) in a locked position of the hold-down and release device, and the compression spring (10) is arranged to abut the housing (3) of the locking device and is also arranged around the rod (5) to make the rod (5) turn, and - an extraction system for the release bolt (1).