Embedded Cryogen Radiation Shield for Superconducting Coil Cooling
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Solution Overview
Problem
Existing radiation shield devices for spacecraft and similar environments face challenges in efficiently deflecting proton and heavy ion radiation without excessive weight and power consumption, particularly when using superconductive coils that require cryogenic cooling, which often necessitate large quantities of liquid helium and limited mission availability.
Innovation Solution
A cryogenically cooled radiation shield device with embedded cryogen storage and thermal insulation, where coils are maintained in a state of readiness throughout the mission by using a combination of cryogenic liquids with different boiling points to efficiently cool superconductive coils, reducing the need for continuous liquid helium boil-off and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If electrical refrigeration units are used to cool superconductive coils, then the coils can be maintained at superconducting temperatures, but the system weight and power consumption increase substantially
Solution Approach 1:
The patent replaces electrical refrigeration units with a passive thermal conduction cooling system using cryogenic fluid reservoirs and heat transfer conduits. This substitution eliminates the need for heavy electrical motors, compressors, and power distribution systems while achieving the same cooling function through thermodynamic principles.
Solution Approach 2:
The system uses the inherent thermal properties of cryogenic fluids (liquid hydrogen and liquid helium) to automatically cool the superconductive coils through thermal conduction. The cryogenic fluids naturally flow and transfer heat without requiring external power input, making the cooling system self-regulating and eliminating continuous power consumption.
2Temperature
If liquid helium is used to cool superconductive coils, then the coils reach superconducting temperatures, but excessive quantities of liquid helium are required, increasing spacecraft weight
Solution Approach 1:
The cooling system is divided into two separate cryogenic fluid subsystems: an inner reservoir containing liquid hydrogen and an outer reservoir containing liquid helium. This segmentation allows each fluid to serve a specific thermal function, with the hydrogen providing primary cooling and the helium providing secondary cooling and thermal mass, thereby reducing the total quantity of helium needed.
Solution Approach 2:
The system employs a composite cryogenic approach by combining two different cryogenic fluids (liquid hydrogen and liquid helium) with complementary thermal properties. This composite approach leverages the high specific heat capacity of hydrogen for primary cooling and the low temperature capability of helium for maintaining superconducting conditions, achieving efficient cooling with reduced overall cryogen quantity.
3Use of energy by moving object
If superconductive coils are not maintained at superconducting temperatures continuously, then power consumption is reduced, but mission availability and reliability are limited
Solution Approach 1:
The system pre-cools the superconductive coils by immersing them in cryogenic fluids before radiation events occur. The thermal mass of the cryogenic reservoirs maintains the coils at or near superconducting temperatures continuously, ensuring immediate readiness to generate protective magnetic fields without requiring continuous power input to refrigeration systems.
Solution Approach 2:
The system changes the thermal parameters of the cooling system by using phase-change materials and thermal conduction pathways that maintain stable low temperatures. The cryogenic fluids are maintained in liquid phase with sufficient thermal mass to sustain superconducting temperatures through radiation events, dynamically adjusting the thermal state to ensure reliability while minimizing power consumption.
4Temperature
If liquid helium is stored onboard the spacecraft, then the coils can be cooled to superconducting temperatures, but the interior volume available for other purposes is reduced
Solution Approach 1:
The cooling system is nested within the radiation shield structure itself. The superconductive coils are positioned within the radiation shield, and the cryogenic fluid reservoirs are integrated into the shield's internal volume. This nesting allows the cooling system to occupy space that would otherwise be structural or dead weight, maximizing the use of available volume while minimizing impact on habitable or equipment space.
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 continuous mission readiness and reduced weight and power consumption by efficiently cooling superconductive coils using a multi-stage cryogenic cooling system, maintaining the coils at a temperature suitable for superconducting operations while minimizing the quantity of coolant required.
Implementation Method 1
By passing current through the coil(s) of the radiation shield device, a magnetic field may be generated that deflects particles of radiation that may otherwise impinge upon the spacecraft
Implementation Method 2
In order to facilitate the generation of the protective magnetic field, a radiation shield device may include coils formed of a superconductive material. During operation, the coils formed of the superconductive material must therefore be maintained at a temperature below its critical superconducting temperature onset level
Implementation Method 3
the coils formed of a superconductive material may alternatively immerse the coils in liquid helium, which lowers the temperature of the coils from an ambient temperature, such as about 23° C., to a temperature required for superconducting operations, such as −269° C., as a result of the boil-off vaporization of the liquid helium
Implementation Method 4
Since the latent heat of the liquid helium is relatively low, however, an excessive amount of liquid helium, as measured in terms of the weight and volume of the liquid helium, may need to be boiled off in order to cool the coils
Implementation Method 5
The radiation shield device also includes thermal insulation surrounding the first conduits and positioned between the first conduits and the at least one second conduit
Data Source
AI summary
A cryogenically cooled radiation shield device as well as an associated method are provided in order to shield an area, such as a space vehicle capsule, from radiation. The radiation shield device may have embedded cryogen storage. The radiation shield device may include inner and outer coil shells that extend about the area to be shielded. Each coil shell includes coils formed of a superconductive material and disposed within respective first conduits. The radiation shield device may also include a first storage tank configured to store a first cryogen liquid and disposed in fluid communication with the first conduits. The first storage tank is disposed between the inner and outer coil shells. The radiation shield device may further include a second conduit at least partially surrounding the inner and outer coil shells that is at least partially filled with a second cryogen liquid, different than the first cryogen liquid.