Autogenous Pressurization for Pump-Free In-Space Propellant Feed
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Solution Overview
Problem
Existing in-space propulsion systems relying on gear pumps for green propellants are unreliable and unsuitable for long-duration missions, particularly in space logistics scenarios where high reliability and flexibility are needed, and they require multiple consumables, leading to inefficiencies in propellant management.
Innovation Solution
The Asynchronous Autogenously Pressurized In-Space Propulsion (A2P2) system uses onboard decomposition of green propellants to generate pressurant, eliminating the need for gear pumps and allowing for conformal fuel tanks, reducing the number of consumables to a single fluid, and enabling flexible and reliable refueling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gear pumps are used for green propellants, then propellant delivery is achieved, but system reliability deteriorates for long-duration missions
Solution Approach 1:
The patent removes the gear pump component from the propulsion system entirely, replacing it with an autonomous pressurization system that uses stored pressurant gas to deliver propellant directly to the thruster. This extraction of the unreliable mechanical component resolves the contradiction by eliminating the source of reliability issues while simplifying the overall system architecture.
Solution Approach 2:
The system employs an autonomous pressurization mechanism where stored pressurant gas automatically maintains propellant pressure and enables continuous delivery without mechanical pumps. The system serves itself by using the pressurant that would otherwise be consumed to actively manage propellant delivery, thereby achieving long-duration reliability without complex mechanical components.
2Productivity
If multiple consumables are used, then propulsion functions are achieved, but propellant management efficiency deteriorates
Solution Approach 1:
The patent merges the functions of multiple consumables (propellant and pressurant) into a single consumable system where the propellant serves dual purposes: as the reaction mass for thrust and as the pressurant to maintain system pressure. This consolidation eliminates the need for separate pressurant storage and management, thereby improving propellant management efficiency while reducing the total quantity of consumables required.
3Adaptability or versatility
If conventional tanks are used, then propellant storage is achieved, but system flexibility deteriorates
Solution Approach 1:
The patent employs flexible bladder-like structures instead of rigid conventional tanks. These flexible membranes can conform to various spacecraft geometries and can be easily refilled by simply replacing the bladder, providing significant system flexibility and adaptability while maintaining effective propellant storage and pressurization capabilities.
4Ease of operation
If refueling operations are simplified, then logistics are improved, but safety control deteriorates
Solution Approach 1:
The patent introduces an intermediary pressurant gas system that mediates between the external refueling source and the internal propellant storage. This pressurant acts as a buffer and control mechanism, allowing simple bladder replacement operations while maintaining precise pressure control and safety through the autonomous pressurization system that regulates propellant delivery throughout the refueling process.
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
A2P2 provides a reliable, efficient, and flexible propulsion system that minimizes waste and simplifies logistics by using a single consumable, enabling conformal tanks and reducing the complexity of refueling processes while maintaining high reliability for long-duration missions.
Implementation Method 1
a propellant management device (PMD) within the conformal fuel tank, the propellant management device to wick propellant to a liquid port of the conformal fuel tank
Implementation Method 2
a pressurant cat bed for decomposing propellant into pressurant
Data Source
AI summary
A system for managing propellant and pressurant for in-space propulsion of a spacecraft is provided. The system includes a conformal fuel tank having an ullage operatively connected for pressurization and a propellant management device (PMD) to wick propellant to a liquid port of the conformal fuel tank. The system further includes a pneumatic circuit including a tank pressurant vent valve for adjustment of operating pressure prior to refueling operations; a vent to release excess pressurant; a pressurant metering vent valve to provide control and safety relief for the pressurant; a check valve to prevent backflow; a pressurant cat bed for decomposing propellant into pressurant; a repressurizing valve to release pressurant once cooled; a burst disk to provide overpressure safety relief; a series of propellant extraction valves to intake a predetermined quantity of propellant for decomposition; and a pressure regulator that delivers proper pressure to a series of thrusters.