Self-Adjusting Gap System for Charge Mitigation and Monitoring
Electrical and Electronics
Self-Adjusting Gap System for Charge Mitigation and Monitoring (GSC-TOPS-365)
Revolutionary Contactless Solution for Controlled Discharge and Measurement
Overview
NASA scientists working on the Plankton, Aerosol, Cloud, and ocean Ecosystem (PACE) mission identified a critical risk to measurement devices: uncontrolled electrical discharges from surface charging during auroral charging events over polar ice regions. Rotating components on the satellite are especially vulnerable to charge build-up. The extreme sensitivity of PACE’s instrumentation eliminates traditional solutions, like slip rings, which degrade over time due to repeated discharges. These discharges not only risk damaging critical components but could also compromise the accuracy of mission data. To protect the sensitive instruments and ensure reliable operation, a novel method was needed to mitigate surface charging.
Innovators at NASA’s Goddard Space Flight Center have developed a novel self-adjusting gap (SAG) system for mitigating and monitoring surface charge. The SAG system is a revolutionary approach to non-conductive bearings. Not only is the system capable of mitigating discharge related risks, but also acts a sensor to measure charging on isolated components. It is self-adjusting, passive, robust, and more precisely controllable than existing technologies.
The Technology
Fixed-point or spark-plug discharge systems are challenging to set up and maintain, often suffering from performance degradation or failure as repeated discharges damage and alter contact points. Similarly, contact-based solutions like slip rings can introduce torque drag and create contamination particles over time as materials wear down. The SAG system eliminates these problems with its innovative contactless design, proven to cycle reliably tens of thousands of times without failure. In testing, this system survived approximately 25,000 times the expected mission charge cycles.
The SAG system consists of a flexure, discharge point, and bleed circuit that controls the voltage, location and current at which a discharge occurs. The flexure is electrically isolated from the rest of the stationary body forcing the discharge current to go through the bleed circuit. This provides the ability to protect sensitive electronics from a sudden field collapse or ground plane disturbance. The flexure is able of taking different forms depending on the application and desired characteristics allowing for a scalable system, modifiable for various mission parameters. Additionally, the SAG system is passive until needed, requiring no active electronics unless used as a sensor. Due to its contactless nature, the SAG system simplifies live wear testing, significantly lowering costs compared to traditional mechanisms. Unlike fixed-point systems, it does not require precise dynamic clearances, making it more tolerant to launch loads and reducing the severity of electrical discharge events.
Although designed for space and planetary exploration applications, the SAG system may also be valuable for terrestrial use cases for monitoring charging of electrically isolated components where charge buildup may occur or where grounding isn’t possible. The SAG System is at technology readiness level (TRL) 6 (system demonstration in relevant environment) and is available for patent licensing.
Benefits
- Contactless: Unique design minimizes wear and tear, mitigates the risk of contamination, and ensures reliable performance over time.
- Robustness: Built with aerospace-grade materials and designed for intermittent use, the system offers exceptional durability and an extended operational lifespan.
- Scalable: With low complexity and high adaptability, the system can be easily scaled for applications ranging from CubeSats to the International Space Station (ISS).
- Versatility: Beyond charge mitigation, the system’s integrating sensing capabilities function as a voltage measurement device and a torque electric field meter.
- Low-Cost: Simple design without need for advanced components.
Applications
- Aerospace: Scalable design for satellites and spacecraft to mitigate charge and protect sensitive components.
- Automotive: Enabling charge measurement and mitigation in electric vehicle shafts.
- Power Generation: Mitigating charge in wind turbines or other situations where grounding is not possible.
- Energy Storage: Preventing charge buildup in advanced battery systems or flywheel energy storage.
- Robotics: Managing charge in autonomous systems with rotating joints, such as robotic arms or drones.
Technology Details
Electrical and Electronics
GSC-TOPS-365
GSC-18981-1
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