Rotary Switch Assembly for Ion Propulsion Power Distribution
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Solution Overview
Problem
Existing ion propulsion systems for spacecraft require large, heavy, and costly relay units to manage power distribution to ion thrusters, limiting their reliability and flexibility, especially when multiple failures occur, and do not allow for efficient isolation of thruster pairs.
Innovation Solution
A gridded ion propulsion system utilizing two power controllers and rotary switch assemblies that enable any thruster to be powered by either controller, with a movable rotatable shaft and high-reliability switches, allowing for flexible power distribution and isolation of thruster pairs, reducing the number of contact rings and mass, and using stepper motors for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay units are used to manage power distribution to ion thrusters, then power switching functionality is achieved, but the system becomes large, heavy, and costly
Solution Approach 1:
The patent combines multiple relay functions into a single rotary switch assembly that can connect any power controller to any ion thruster pair. This single assembly replaces what would traditionally require multiple separate relay units, significantly reducing mass while maintaining the ability to perform power switching and distribution functions.
Solution Approach 2:
The rotary switch assembly is designed to be universal, allowing any power controller to power any ion thruster pair through rotational positioning. This multi-functional design eliminates the need for dedicated relay units for specific thruster pairs, reducing overall system mass and complexity.
2Adaptability or versatility
If relay units are used to manage power distribution, then switching functionality is provided, but the system size and cost increase
Solution Approach 1:
The rotary switch assembly uses rotational movement to dynamically reconfigure connections between power controllers and ion thrusters. By rotating to different positions, the same physical assembly provides different connection configurations, enabling thruster isolation and power routing without requiring multiple static relay units that would occupy more space.
3Reliability
If multiple relay units are used for redundant subsystems, then failure tolerance is improved, but mass increases
Solution Approach 1:
The rotary switch assembly provides universal connectivity that enables redundant subsystem operation with fewer components. Any power controller can serve any ion thruster pair, creating inherent redundancy without requiring duplicate dedicated relay units for each subsystem, thus reducing mass while maintaining failure tolerance.
4Ease of operation
If traditional relay-based XRU is used, then power switching is achieved, but the number of switching elements increases system complexity
Solution Approach 1:
The patent merges multiple switching elements into a single rotary switch mechanism with contact rings and brushes. Instead of using many independent relays, one rotary switch assembly performs the switching function for multiple circuits simultaneously, reducing component count and simplifying the system while maintaining power routing flexibility.
Data Source
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AI summary
A gridded ion propulsion system comprising two power controllers, four ion thrusters, and two switch assemblies. One switch assembly is connected to the two power controllers and to two of the four ion thrusters. The other switch assembly is connected to the two power controllers and to the other two ion thrusters. Each switch assembly has first and second switching states which can be selected to enable either power controller to supply power to any one of the four ion thrusters. Each switch assembly comprises a respective movable body and a respective multiplicity of switches which change state in unison when the movable body changes position. For example, the movable body may be a rotatable hollow shaft driven by a stepper motor.