Modular Solid Rocket Motor Cartridges for Reusable Composite Cases
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Solution Overview
Problem
Conventional solid rocket motors (SRMs) face challenges in flexibility, adaptability, and efficiency due to their fixed design, making real-time adjustments to the burn rate difficult, and they are less efficient compared to liquid-fueled rockets. Additionally, the complexity of propellant casting and tooling, as well as the inability to reuse engine components across different missions, increases development time and costs.
Innovation Solution
A modular SRM design featuring a composite case with floating, swappable propellant cartridges that allow for axial and radial expansion during ignition, utilizing a radial retention interface and gas gaps to manage thermal and mechanical stresses, enabling easy assembly and disassembly, and allowing for interchangeable parts tailored to specific mission requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional net cast SRM design is used, then structural strength and thermal resistance are improved, but flexibility and adaptability deteriorate
Solution Approach 1:
The SRM is divided into modular cartridges that can be independently manufactured, tested, and replaced. Each cartridge contains a propellant grain segmented into multiple stacks, allowing individual cartridge replacement without affecting the entire motor structure. This segmentation enables flexibility and adaptability while maintaining the structural strength of the composite case.
Solution Approach 2:
The cartridge retention system uses dynamic retention interfaces that allow cartridges to be securely held during storage and transport, then easily released and replaced when needed. The retention mechanism transitions from a locked state to an accessible state, enabling rapid cartridge swaps while maintaining structural integrity throughout the motor lifecycle.
2Ease of manufacture
If fixed design SRM is used, then manufacturing simplicity is improved, but real-time adjustment capability deteriorates
Solution Approach 1:
The propellant system is segmented into replaceable cartridges with standardized interfaces. Each cartridge can be manufactured using simplified processes, then assembled into the motor in different configurations. This allows the basic manufacturing to remain simple while enabling flexible mission-specific configurations through cartridge selection and arrangement.
Solution Approach 2:
The standardized cartridge design with universal retention interfaces allows the same cartridge type to be used across multiple motor configurations and missions. The modular system provides multi-functionality, where a single cartridge design can serve various propulsion needs by changing the number of cartridges, their arrangement, or the motor case configuration.
3Stability of the object's composition
If propellant is cast directly into motor casing, then structural integration is improved, but development time and cost deteriorate
Solution Approach 1:
The propellant is manufactured as separate cartridge modules rather than being cast directly into the motor casing. This segmentation allows parallel manufacturing of cartridges and motor cases, independent testing of cartridge performance, and easier replacement during development iterations. The cartridges are then integrated into the completed motor case, maintaining structural stability while reducing overall development time.
Solution Approach 2:
Cartridges are manufactured, tested, and qualified independently before being integrated into the motor assembly. This preliminary action allows the propellant components to be fully developed and validated separately, reducing the time required for integrated motor testing and development. The pre-qualified cartridges can be quickly assembled into different motor configurations for various test campaigns.
4Device complexity
If engine components are not reusable, then design simplicity is improved, but waste and environmental impact deteriorate
Solution Approach 1:
The motor is segmented into reusable components, primarily the composite case and the propellant cartridges. The composite case is designed to be reused across multiple missions after the propellant cartridges are consumed. This segmentation enables the expensive and complex case structure to be preserved and reused, reducing waste and environmental impact while maintaining design simplicity through standardized interfaces and retention mechanisms.
Solution Approach 2:
The system is designed to discard only the consumable propellant cartridges while recovering and reusing the expensive composite motor case. After mission completion, the spent cartridges are removed and disposed of, while the case is inspected, refurbished if necessary, and prepared for the next mission. This selective discarding and recovery approach minimizes waste while maintaining design simplicity.
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 design reduces complexity and cost, enhances flexibility and efficiency, facilitates rapid assembly and deployment, and supports real-time ground testing, while reducing waste and environmental impact through reusable components and adaptive control systems.
Implementation Method 1
the gas gap permits the composite case to swell both radially and axially during ignition and burn
Implementation Method 2
the propellant is typically cast directly into the rocket motor casing... producing a controlled thrust output... As the fuel burns, it produces a high-temperature gas
Data Source
AI summary
The present invention is a system and method for manufacturing a modular motor architecture, comprising a rocket motor comprising an extended case with a forward end and an aft end. The forward end features a radial retention interface with a multi-stack polar boss, a multi-stack forward polar boss enclosure, and radial tabs. The multi-stack polar boss is molded using boss molding material into three to twenty radial tabs and is wound into the composite case. The motor includes multiple multi-stack cartridges that house propellant and a central combustion chamber. These cartridges, including a forward cartridge, a primary cartridge, and an aft cartridge, are suspended inside the case and secured co-axially with the composite case by various joints, including polar and aft joints. The aft cartridge is located at the aft end, which features a closure and a nozzle.