Electrospray and Micropropulsion Patents: Who Leads, Gaps 2026
- 67.8% concentration. The top five assignees hold 61 of 90 records in scope — filing here is already dominated by a small group, not a wide field of independent entrants.
- 2018 was the peak. Filings hit 16 that year and have not returned to that level; 2021 to 2024 fell 83%, though 2025-2026 counts are still filling in under publication lag.
- B64G and F03H nearly tie. Spacecraft-systems claims (46.7% of records) and plasma/ion propulsion claims (45.6%) run almost neck and neck, while power conversion sits far behind at 12.2%.
Filing growth compares 2021 (6 records) with 2024 (1) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 90 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Electrospray and micropropulsion patents cover thruster designs that extract and accelerate charged ionic-liquid propellant through emitter arrays and extractor electrodes to generate micronewton-scale thrust — the propulsion class increasingly used for precise attitude control and station-keeping on small satellites and formation-flying constellations. This dataset spans 90 published records filed between 2015 and mid-2026, drawn from a search string anchored on electrospray, field-emission and colloid thruster claims combined with emitter-array fabrication, ionic-liquid propellant, extractor-electrode and micronewton-thrust language.
Filing activity is concentrated among a handful of research-linked and startup assignees, with United States filings dominating the receiving-office mix and PCT filings a distant second. Because publication trails filing by roughly 18 months, the most recent one to two years in any trend chart will understate actual filing activity.
Filing trends and technology composition
The two charts below track when electrospray and micropropulsion patents were filed and what technical subclasses they claim against, using the same 90-record denominator throughout.
Filing trend: a 2018 peak, then a pullback
Filings ran from 3 in 2017 up to a peak of 16 in 2018, then eased off; the 2021-to-2024 span alone fell 83%, from 6 records to 1. Treat 2025 and 2026 as incomplete rather than as evidence the field has stalled.
IPC composition: spacecraft systems and ion propulsion dominate
B64G (cosmonautics and spacecraft) and F03H (plasma and ion propulsion) each appear on close to half of all records — 46.7% and 45.6% respectively — while H01J (electron and discharge tubes) trails at 21.1% and power conversion (H02M) at 12.2%. Because records can carry multiple IPC classes, these shares sum to well over 100%.
Shares are the percentage of the 90 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Electrospray and Micropropulsion with Eureka
This page is one run against one query. Ask Eureka your own question about electrospray and micropropulsion and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US11801949B2 — Field emission propulsion system and method for calibrating and operating a field emission propulsion system
A field emission propulsion system for a spacecraft includes a control unit, a propulsion assembly, and a plurality of extractor electrode voltage sources. The propulsion assembly comprises a plurality of field emission propulsion units having an ion source with a plurality of ion emitters and extractor electrodes associated with the ion emitters and disposed in a field arrangement. The plurality of extractor electrode voltage sources, each associated with the extractor electrodes to control the same, are controlled by the control unit using an individual extractor electrode voltage.Filed by Morpheus Space and granted in 2023, this record claims per-emitter voltage control across a field-arranged extractor array — a calibration-and-operation layer that sits above the underlying emitter geometry.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20120144796A1 | Microfluidic electrospray thruster | 62 |
| 2 | US20020023427A1 | Micro-colloid thruster system | 39 |
| 3 | US6516604B2 | Micro-colloid thruster system | 35 |
| 4 | US20160297549A1 | Propellant tank and loading for electrospray thruster | 31 |
| 5 | WO2010036291A2 | Ionic liquid multi-mode propulsion system | 30 |
| 6 | US20160202131A1 | Method and Apparatus for Measuring Thrust | 29 |
| 7 | WO2011079138A2 | Microfluidic electrospray thruster | 27 |
| 8 | US20200102100A1 | Staging of ion propulsion thrusters | 24 |
| 9 | US20160010631A1 | Generating electrospray from a ferrofluid | 21 |
| 10 | US20190264666A1 | Propulsion systems including a sublimable barrier | 18 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside the searched corpus — read them as a signal of influence on later work, not as a ranking of current technical importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns stand out once the ranking, the trend and the IPC composition are read together.
A small group holds most of the claim space
The top five assignees account for 61 of the 90 records in scope, 67.8% of the field, and the top ten reach 85.6%. A new entrant is not filing into open territory at the system level — freedom-to-operate work has to map specifically against the leader's claim scope, not against the field in aggregate.
Filing activity has cooled from its 2018 peak
After peaking at 16 filings in 2018, the volume of new electrospray and micropropulsion patents fell sharply through 2021-2024, down 83% over that span. Several of the most active named assignees show zero filings in the latest complete year, though 2025-2026 figures are still incomplete under the usual publication lag.
Systems claims and propulsion-physics claims run in parallel
B64G (spacecraft systems) and F03H (plasma and ion propulsion) each touch roughly half of all records, meaning most filings pair a spacecraft-integration claim with a thruster-physics claim rather than filing narrowly in one lane. Power conversion (H02M, 12.2%) and spraying/atomising (B05B, 6.7%) are claimed far less often relative to the core physics.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to electrospray and micropropulsion, with the prior art for and against each one.
Who is filing, and where the field is still open
The ranked leaders are a mix of university research offices, a government defence lab, and a small number of commercial thruster makers — a pattern consistent with a technology still moving out of lab-scale demonstration into flight hardware.
One assignee sits well ahead of the field
The leading assignee holds 27 records versus 4 at fifth place and 3 at tenth — a steep drop-off that marks this as a leader-plus-long-tail field rather than one with several evenly matched incumbents.
Most named assignees appear only a handful of times
Beyond the top ten, filing counts drop into single digits quickly. That long tail includes university tech-transfer offices and smaller propulsion startups filing narrowly around specific emitter or feed-system designs rather than broad system claims.
Co-filing is limited and concentrated on two organisations
Only 6 co-assignee pairs appear in the dataset, and the strongest links both involve the same aerospace corporation paired with named individual inventors — a pattern of internal inventor credit rather than cross-company joint development.
| Assignee | Recent year | YoY |
|---|---|---|
| Massachusetts Institute of Technology (MIT) | 0 | -100% |
| ACCION SYSTEMS INC | 0 | — |
| California Institute of Technology (Caltech) | 0 | — |
| Technische Universität Dresden (TU Dresden) | 0 | — |
| MORPHEUS SPACE GMBH | 0 | — |
| The Regents of the University of Michigan | 0 | — |
| The Government of the United States, as represented by the Secretary of the Air Force | 0 | — |
| Aerojet General Corporation | 0 | — |
Where to take this next
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, white-space filing, or tracking a competitor.
Map claims against the top assignee
With one assignee holding 27 of 90 records, a freedom-to-operate review should start there rather than against the field average.
Run a claim comparison in Eureka →Test the under-claimed sub-areas
Capillary feed geometry and startup transient control show lighter claim density than the core physics classes — worth a novelty check before drafting.
Search white space in Eureka →Watch for the 2025-2026 catch-up
Publication lag means the apparent 2021-2024 decline may partly reverse once 2025-2026 filings finish publishing.
Track new filings in Eureka →Common questions about electrospray and micropropulsion patents
One assignee leads the ranked field with 27 records, well ahead of the fifth-place holder at 4 and the tenth-place holder at 3. The leading names include university research offices such as MIT and Caltech, a US Air Force-affiliated filer, and commercial thruster makers including Accion Systems, Busek and Morpheus Space. Because the top five assignees together account for 67.8% of all 90 records in scope, competitive tracking should focus on that small group rather than the full ranked list of 23 companies.
Filings peaked at 16 in 2018 and have declined since, with the 2021-to-2024 span alone falling 83% from 6 records to 1. That said, 2025 and 2026 figures are still incomplete because publication typically lags filing by around 18 months, so the true recent trend is likely stronger than the raw chart shows. Anyone using this data for a strategic call should treat the last one to two years as provisional rather than confirmed decline.
US11801949B2, assigned to Morpheus Space and granted in 2023, claims a field emission propulsion system with a control unit that sets an individual extractor-electrode voltage for each emitter in a field-arranged array. The claim scope centres on per-emitter voltage calibration and control rather than on emitter geometry or propellant chemistry itself. Anyone designing a competing thruster with individually addressable extractor voltages should review this claim set specifically rather than assume it only covers Morpheus's own hardware configuration.
The IPC composition shows heavy claim density in spacecraft systems (B64G, 46.7% of 90 records) and plasma/ion propulsion physics (F03H, 45.6%), but much lighter coverage in power conversion (H02M, 12.2%) and spraying/atomising mechanisms (B05B, 6.7%). Sub-areas named directly in the search scope but rarely dominant in the IPC breakdown — capillary propellant feed design and emitter startup transient control — look under-claimed relative to the core physics. A first claim there would likely need to be narrow and mechanism-specific rather than a broad system claim, given how crowded the top-level spacecraft and propulsion classes already are.
United States filings dominate this dataset at 56 of the records with a known receiving office, followed by WIPO PCT filings at 20 and EPO filings at just 5. That pattern reflects where the leading assignees — largely US universities, a US government lab, and US-based startups — are headquartered and where their primary commercial and government customers sit. A filer targeting European or Chinese markets specifically would be filing into comparatively thin coverage there, which cuts both ways: less prior art to clear, but also less established licensing infrastructure.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.