Cryogenic Xenon Tank Layout for Low-Pressure Spacecraft Storage
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Solution Overview
Problem
Current cryogenic liquid storage systems for spacecraft, particularly those using supercritical xenon, are heavy, complex, and pose safety risks due to high pressure, leading to increased dry weight and reduced reliability, making them unsuitable for interplanetary missions where weight reduction and safety are critical.
Innovation Solution
A cryogenic liquid storage system featuring a tank with an evacuated space between the tank and outer casing, a heat-conductive propellant management device cooled by a cryorefrigerator, and a low thermal conductivity holder system, allowing for efficient storage and delivery of liquefied inert gases like xenon at low pressure, eliminating the need for high-pressure expanders and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-pressure tanks are used to store supercritical xenon, then the storage density is increased, but the tank weight and overall system weight increase significantly
Solution Approach 1:
The patent changes the storage parameters by storing xenon in liquid state at low pressure (1-2 bar) instead of supercritical state at high pressure (15-19 MPa). This parameter change allows achieving comparable storage density with dramatically reduced tank weight and eliminated need for heavy high-pressure containment structures
Solution Approach 2:
The patent utilizes phase transition of xenon from supercritical state to liquid state by controlling temperature and pressure. The xenon is stored as liquid at low pressure and temperature, and transitions to gas phase when needed for thruster operation, eliminating the need for high-pressure supercritical storage
2Ease of operation
If high-pressure valves and expanders are interposed between the tank and thrusters, then the feed pressure is regulated, but the system complexity and number of components increase
Solution Approach 1:
The patent extracts and eliminates the expander component from the system by storing xenon in liquid state at low pressure. Since the storage pressure is already close to the required feed pressure for thrusters, no pressure reduction device is needed, simplifying the system architecture
Solution Approach 2:
The patent makes the storage tank directly compatible with thruster feed requirements by designing it to operate at low pressure (1-2 bar) which is suitable for both storage and feed operations, eliminating the need for separate pressure regulation stages
3Quantity of substance
If high-pressure tanks are used for xenon storage, then the storage capacity is sufficient, but the safety factor is too low for unrestricted personnel access after filling
Solution Approach 1:
The patent changes the operating pressure parameter from high pressure (15-19 MPa) to low pressure (1-2 bar), which maintains storage capacity while dramatically improving safety. The low pressure operation eliminates the severe safety hazards associated with high-pressure containment and allows unrestricted personnel access
4Quantity of substance
If the tank diameter is increased to store sufficient xenon, then the storage capacity is sufficient, but the tank volume and dry weight increase
Solution Approach 1:
The patent changes the storage density parameter by utilizing liquid phase xenon at low pressure, which provides sufficient storage capacity in a compact volume, avoiding the need for large-diameter tanks
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 achieves a significant reduction in tank weight and volume, improves safety by eliminating high-pressure components, and allows for easier tank modification and operation, enabling efficient xenon storage and delivery for electric thrusters, thus enhancing the performance and reliability of spacecraft systems.
Implementation Method 1
an evacuated space provided between the tank and the outer casing
Implementation Method 2
a propellant management device made of material that is a good conductor of heat and that is cooled by a cryorefrigerator
Implementation Method 3
a decoupling bellows
Data Source
AI summary
A cryogenic liquid storage system for a spacecraft comprising at least one liquid tank with an outer casing and an evacuated space arranged between the tank and the outer casing. The system further comprises a propellant management device made of material that is a good conductor of heat and that is cooled by a cryorefrigerator to localize the liquid inside the tank when in microgravity, a filler pipe situated in the portion of the tank that is at the bottom when the tank is on the ground, and that is surrounded by an evacuated insulating double wall and a purge pipe connecting the tank to the outer casing and presenting an internal length that is not less than half the diameter of the tank.