Pneumatic Insulation Mat Deployment for Cryogenic Tanks
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Solution Overview
Problem
Current cryogenic tank insulation systems for spacecraft face challenges such as increased heat input due to darkened external foam insulation, mechanical stress on panels, thermal bridges, complex deployment mechanisms, and limited adaptability to different rocket types, which affect the evaporation rate of cryogenic fuels and the service life of upper stages.
Innovation Solution
The use of shape-changing elements integrated into insulation mats that unfold through a controlled change in shape, eliminating the need for separate deployment mechanisms and allowing for a compact, versatile, and adaptable thermal insulation system that can be easily installed on various rocket types, with a focus on minimizing structural impacts and ensuring resistance to mechanical and thermal loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional foam insulation is used on cryogenic tanks, then thermal insulation is provided, but the foam darkens due to frictional heat during launch, increasing heat gain into the tank
Solution Approach 1:
The insulation system is segmented into multiple functional layers: a sacrificial outer layer that absorbs frictional heat and discoloration, and an inner insulation layer that remains protected and maintains its insulating properties. This segmentation allows the outer layer to deteriorate without affecting the thermal performance of the inner layer.
Solution Approach 2:
The outer sacrificial layer is designed to be replaceable and disposable, absorbing the mechanical and thermal stresses during launch. After launch, this layer can be jettisoned or replaced, allowing the primary insulation system to maintain optimal performance throughout the mission lifecycle.
2Strength
If panels are used to protect insulation material during launch, then insulation protection is improved, but the panels are subject to complex mechanical stresses and reduce accessibility to the rocket's upper stage
Solution Approach 1:
The protection system transitions from a static panel configuration to a dynamic deployable structure that can be configured during launch and then retracted or removed to provide access during operations. This dynamic behavior allows the system to fulfill protective functions when needed while eliminating obstacles when not needed.
3Strength
If connection structures are created for insulation panels, then insulation attachment is achieved, but thermal bridges are formed that limit improvement potential
Solution Approach 1:
The insulation system utilizes flexible insulation mats that can conform to the tank surface without requiring rigid connection structures. These flexible mats are attached using thermal isolation techniques such as low-conductivity fasteners or adhesive layers that maintain thermal breaks, eliminating the need for metal brackets and fasteners that would create thermal bridges.
4Ease of operation
If separate deployment mechanisms with stationary rollers and external drives are used for insulation mats, then insulation mat deployment is achieved, but space requirement and system complexity increase
Solution Approach 1:
The insulation mats are designed with self-deploying characteristics, utilizing the existing rocket structure and pneumatic pressure differentials to automatically unroll and position themselves. The mats may incorporate self-locking features or friction-based positioning that eliminates the need for complex mechanical deployment mechanisms, rollers, or external drives.
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 provides enhanced thermal insulation, reduces the evaporation rate of cryogenic fuels, allows for longer service life and multiple ignitions of the upper stage, and meets cleanliness and outgassing requirements, while being adaptable to different rocket types and resistant to environmental influences.
Implementation Method 1
The shape-changing element comprises at least one cavity that can be pressurized. The shape-changing element is thus pneumatically actuated, with the shape change occurring because the cavity is inflated to a predefined shape of the shape-changing element.
Implementation Method 2
Rockets are fueled with liquid, i.e., cryogenic, fuels such as hydrogen or oxygen due to their higher energy density. To minimize the evaporation rate of the liquid fuel, these tanks are insulated, usually with foam insulation on the inside and sprayed-on foam insulation on the outside.
Data Source
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AI summary
In a deployable device for the thermal insulation of cryogenic tanks (2) of spacecraft (1) comprising at least one insulation mat (8), preferably a plurality of insulation mats (8) arranged distributed in the circumferential direction of the tank, and the deployment means assigned to each of the insulation mat(s) (8) for unrolling the insulation mat(s) (8) from the rolled-up state to the extended state, the deployment means comprise at least one deformation element (7) extending in the unrolling direction, connected to or integrated into the insulation mat (8), which can be unrolled from the rolled-up state to the extended state by controlled deformation.