Electrospray Thruster Extractor Film for Arc Fault Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrospray thrusters face challenges with emitter failures due to arcing events caused by slight misalignments and tolerance errors, leading to cascade failures in large-scale arrays, which are exacerbated by the need for individual power supplies for each emitter.
Innovation Solution
The thruster design includes a conductive film on the extractor electrode with aligned apertures, allowing partial ablation during arcing events to isolate faulty emitters, maintaining the array's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large-scale arrays with thousands to millions of emitters are used to generate necessary acceleration, then thrust capability is improved, but probability of cascade failures increases
Solution Approach 1:
The extractor electrode is segmented into multiple electrically isolated segments, each serving a specific region of the emitter array. When an arc occurs, it is confined to a localized segment rather than propagating through the entire electrode, thus preventing cascade failures while maintaining overall system functionality.
Solution Approach 2:
Dielectric barriers are introduced as intermediary elements between emitters and the extractor electrode. These barriers prevent direct arcing by providing electrical isolation, allowing the system to operate at higher voltages necessary for thrust generation without suffering from cascade failures.
2Reliability
If individual power supplies are provided for each emitter to ensure localized failure isolation, then reliability is improved, but device complexity increases
Solution Approach 1:
Multiple emitters are electrically connected in parallel to a single power supply through the segmented extractor electrode structure. This merging approach maintains failure isolation capability while dramatically reducing the number of power supplies needed, as each segment can serve multiple emitters simultaneously.
Solution Approach 2:
The segmented extractor electrode structure serves multiple functions: it provides electrical isolation between regions, maintains voltage distribution across multiple emitters, and confines arc propagation. This multi-functionality eliminates the need for individual power supplies while preserving reliability.
3Ease of manufacture
If emitters are manufactured and aligned within finite tolerance, then ease of manufacture is improved, but arcing events due to misalignment increase
Solution Approach 1:
Dielectric barriers are placed beforehand between emitters and the extractor electrode to cushion against misalignment issues. These barriers provide a safety margin that prevents arcing even when alignment tolerances are exceeded, allowing easier manufacturing without compromising reliability.
Solution Approach 2:
The design accepts that misalignment will occur and converts this potential harm into a benefit by using dielectric barriers to contain arcs locally. Rather than trying to eliminate misalignment, the system uses it as an opportunity to demonstrate the effectiveness of localized failure containment.
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 prevents cascade failures by isolating faulty emitters, ensuring the thruster continues to operate despite individual emitter failures, and allows for integration on existing spacecraft architectures.
Implementation Method 1
The conductive film has a thickness such that an electrical short between the extractor electrode and the ionic fluid emitted from a respective tip of the array of tips ablates a portion of the conductive film along the aperture of the plurality of apertures aligned with the respective tip of the array of tips
Implementation Method 2
Electrospray is a process in which a fluid meniscus subject to strong electric fields deforms into a sharp cone-like structure that sheds charge from its apex
Implementation Method 3
Each of these electrospray emitters in turn requires a strong electric field generated over tens to hundreds of micrometers of distance from an emitter tip to a downstream electrode
Data Source
AI summary
An electrospray thruster includes an emitter including an array of tips, each tip of the array of tips being configured to emit ionic liquid, and an extractor electrode spaced from the emitter and comprising a conductive film, the conductive film having a plurality of apertures, the plurality of apertures being aligned with the array of tips of the emitter. The conductive film has a thickness such that an electrical short between the extractor electrode and the ionic fluid emitted from a respective tip of the array of tips ablates a portion of the conductive film along the aperture of the plurality of apertures aligned with the respective tip of the array of tips