Cup-Cone Hold-Down Release System for Spacecraft
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Solution Overview
Problem
Existing restraint and release devices for space-based deployable bodies, such as satellites and solar panels, face challenges in providing secure restraint, reliable release, shock reduction, thermal isolation, and integration ease, while also being compact and lightweight, with current solutions often failing to meet multiple desired characteristics simultaneously.
Innovation Solution
An integrated Hold-down and Release System (HRS) with differentiated subassemblies featuring cup-cone surfaces, a tensioned element for compressive pre-load, embedded pre-load measurement, and a remotely activated release mechanism, combined with shock reduction techniques like spherical articulation and low thermal conductance materials, to ensure secure restraint, low shock release, and modular thermal control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple releasable restraint devices are used to restrain a body from different points, then stability of holding configuration is improved, but forces are present during release due to assembly-induced loading or thermoelastic loading
Solution Approach 1:
The restraint system is divided into multiple independent restraint devices, each applying force at different locations on the deployable body. This segmentation allows the system to achieve stable holding configuration while distributing the forces, preventing excessive force concentration at any single release point.
Solution Approach 2:
The restraint devices are designed with adjustable pre-load parameters that can be tuned to compensate for assembly-induced loading and thermoelastic loading. By changing the pre-load parameters, the system maintains stable restraint while minimizing residual forces during release.
2Ease of operation
If a remotely activated release device is used to release the preload, then free separation of cup and cone surfaces is achieved, but a high level of shock is generated
Solution Approach 1:
Shock-absorbing elements are incorporated into the restraint device design before release occurs. These elements are pre-positioned to cushion the impact when the preload is released, thereby reducing the shock level while maintaining the remote release capability. The cushioning elements are activated automatically upon release.
Solution Approach 2:
An intermediary mechanism is introduced between the remote release device and the cup-cone restraint system. This intermediary mechanism decouples the release action from the shock generation, allowing remote activation while minimizing shock transmission to the deployable body.
3Strength
If a massive metallic construction is used for the restraint device, then loading capability is improved, but thermal conductance is high
Solution Approach 1:
The restraint device employs composite material construction, combining metallic components for strength and loading capability with low thermal conductance materials for thermal isolation. This composite approach allows the device to maintain high loading capability while minimizing thermal conductance between the deployable body and support structure.
Solution Approach 2:
Different regions of the restraint device are constructed with different material properties optimized for their specific functions. Load-bearing elements use high-strength metals, while thermal isolation regions use low thermal conductance materials. This local quality differentiation achieves both high loading capability and low thermal conductance.
4Reliability
If cup-cone surfaces are used to prevent lateral movement, then restraint effectiveness is improved, but rotational stiffness is high
Solution Approach 1:
The restraint system is designed to be dynamically adaptable, allowing rotational movement within certain limits while maintaining effective lateral restraint. The cup-cone surfaces provide constraint when needed but permit rotation when deployment is initiated, transitioning from a static high-stiffness system to a dynamic system that adapts to deployment requirements.
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 system provides robust strength and stiffness, minimizes rotational stiffness, adjusts for dimensional imperfections, and reduces thermal conductance, ensuring reliable deployment with low shock and ease of integration, while allowing for pre-load monitoring and adjustment without disassembly.
Implementation Method 1
a tensioned element, mechanically connected to both of the separable subassemblies, exerting a compressive action on the subassemblies that applies, at installation, a compressive pre-load to the cup-cone or similar arrangement
Implementation Method 2
shock reduction techniques like spherical articulation
Implementation Method 3
low thermal conductance materials, to ensure secure restraint, low shock release, and modular thermal control
Data Source
AI summary
A device for the restraint and release of a deployable body mounted on a support structure, the device being operable between a stowed condition and a released condition, and having:a pair of subassemblies, each for being attached to either the deployable body or the support structure, these subassemblies having mating surfaces which interlock with one another in the stowed condition to substantially prevent lateral movement of the deployable body relative to the support structure;a releasable tensioned element which is connected to both of the subassemblies, exerting a compressive pre-load action on the said subassemblies that keep them together;a force measurement system that allows monitoring the cited compressive pre-load action applied;a releasing device for releasing the cited pre-load, allowing the free separation of the subassemblies;further being provided with a tensioning mechanism embedded in the device such that it applies a substantially pure-tension pre-load to the releasable tensioned element.