Paving the Way for Reliable Electrospray Propulsion through Materials Science and Design
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wangari_cwangari_phd_aa_2025_thesis.pdf
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73.34 MB
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Author(s)
Wangari, Charity
Advisor(s)
Lozano, Paulo
Date Issued
February 2026
Publisher
Massachusetts Institute of Technology
Abstract
Electrospray propulsion systems operate by accelerating charged particles from a liquid meniscus through extractor electrode apertures using electrostatic forces. These engines, such as those developed at the Massachusetts Institute of Technology, require immediate and reliable access to ionic liquids to function effectively. Their core design typically includes porous substrate emitters for fluid transport and single-use regulators beneath the emitters to isolate and meter liquid flow during operation. However, key limitations in these components motivate the work presented in this thesis. First, the coarse granularity of porous materials produces irregular tip geometries, which contribute to unpredictable emission patterns and reduced thrust performance. Moreover, current fabrication methods often yield inconsistent emitter shapes across arrays, undermining emission repeatability. Second, the closed-capillary structure of existing single-use valves prevents repeated actuation, making them unsuitable for systems requiring pre-launch testing or multiple operational cycles. To overcome these limitations, this work explores the use of electroactive polymers — such as Nafion™ — to create ultra-smooth emitter surfaces that enable more stable and directional ion emission. Additionally, a new class of reconfigurable open-channel valves is developed, leveraging electrowetting to allow for repeatable, on-demand liquid actuation. Together, these innovations advance the reliability and controllability of electrospray propulsion systems and lay the groundwork for broader application of polymer-based substrates and open microfluidic components in spaceflight or other technologies.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
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