Liquid Rocket Engines Patents: Who Leads, Where Gaps Are 2026
- Filing has cooled since a 2021 peak of 15 records. the midpoint year of 2022 fell to 3, and the trend has stayed flat or declining since — though the most recent year is always undercounted due to publication lag.
- Concentration is heavy at the top. the top 5 assignees hold 44.3% of all 115 records in scope, and the top 10 hold 69.6%, leaving a long tail of single- or low-filing entrants.
- Nearly every record sits in F02K (jet & reaction propulsion). adjacent classes like spacecraft integration, additive manufacturing and non-positive-displacement pumps each carry a handful of records, marking where claim density thins out.
What the liquid rocket engine patent record actually shows
This landscape covers 115 published records filed between 2015 and mid-2026, drawn from filings that combine liquid or staged-combustion rocket engine terminology with claim language on turbopump design, combustion instability, regenerative cooling, throttling capability or reusability, classified under jet and reaction propulsion (F02K) and adjacent pump art (F04D). It is a narrow, claims-driven slice of propulsion patenting rather than a survey of the whole rocket industry.
Filing volume rose through the late 2010s, peaked in 2021, and has since flattened or declined into the most recent partial year. Receiving-office data shows the United States and Russia as the two largest jurisdictions, with China, South Korea, the EPO and WIPO trailing behind — a spread that reflects both state propulsion programmes and a newer cohort of commercial launch companies filing defensively around reusable, throttleable engine architectures.
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Filing trends and technology composition
Two views of the same 115 records: how filing activity has moved year over year, and how those records distribute across IPC subclasses.
A 2021 peak followed by a flat-to-declining trend
Annual filings rose from 6 in 2017 to a peak of 15 in 2021, then fell to 3 by the 2022 midpoint and have not recovered. Because publication typically lags filing by around 18 months, the final one or two years in this series will understate true filing activity — the decline is real but likely less steep than the raw count suggests.
F02K dominates; everything else is a thin adjacent layer
Every one of the 115 records in scope carries an F02K classification, which is expected given the search construction. Beyond that core, B64G (cosmonautics & spacecraft) appears in 7 records (6.1%), and additive manufacturing, powder metallurgy, electroplating, non-positive-displacement pumps and combustion chambers each appear in only one or two records apiece — thin enough that claim space there is largely open rather than occupied.
Shares are the percentage of the 115 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Liquid Rocket Engines with Eureka
This page is one run against one query. Ask Eureka your own question about liquid rocket engines and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this field
US20210190012A1 — Propulsion device for liquid propellant rocket engine
The filing describes a propulsion apparatus in which liquid propellant flows through a body housing an injector core, with at least one outlet discharging combustion gas and an injector positioned adjacent to that outlet so propellant moves between the frames of the body and the injector core.Filed by Perigee Aerospace, published 2021-06-24 — illustrative of injector/outlet geometry claims common in this dataset.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6619031B1 | Multi-mode multi-propellant liquid rocket engine | 74 |
| 2 | RU2232916C2 | Fuel nozzle of liquid-propellant rocket engine (versions) | 54 |
| 3 | US3897316A | Method for manufacturing a composite wall for a regeneratively cooled thrust chamber of a liquid propellant r… | 42 |
| 4 | US3699772A | Liquid propellant rocket engine coaxial injector | 39 |
| 5 | US9964073B1 | Liquid rocket engine with hybrid electric motor driven pump | 31 |
| 6 | EP1022454A2 | Liquid propellant rocket engine | 22 |
| 7 | JP1999229963A | Expander cycle structure in liquid rocket engine | 22 |
| 8 | US3780533A | Composite wall for a regeneratively cooled thrust chamber of a liquid propellant rocket engine | 17 |
| 9 | US3740946A | Momentum exchange throttling injector | 15 |
| 10 | CN101694189A | 液体火箭发动机超导电磁泵循环系统 | 14 |
Citation counts are drawn from the searched corpus and skew toward older filings; treat them as a signal of influence on later claim drafting, not a ranking of current commercial relevance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing strategy
Three read-throughs from the concentration, jurisdiction and citation data above.
The top of the field is dense, not diffuse
Just five assignees hold 44.3% of all records in scope, and the top ten hold 69.6%. A new entrant filing on core turbopump or combustion-chamber geometry is filing directly against incumbents who already hold multi-patent positions there.
Filing strategy splits along legacy state programmes and newer commercial entrants
The United States and Russia lead on volume, consistent with long-running state propulsion programmes, while South Korea, the EPO and WIPO show smaller but present filings — worth checking before assuming a single-jurisdiction clearance is sufficient.
Growth has not continued past its 2021 peak
Several of the most active historical assignees show zero filings in the latest year tracked. That does not mean the technology is exhausted — it is more consistent with a maturing claim base where incumbents are defending existing positions rather than filing new ones.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to liquid rocket engines, with the prior art for and against each one.
Who holds the claim positions
The ranking behind this page covers 60 companies, counted in records — not a top-50 or top-100 list, but the complete set the dataset returns. A single leader holds 16 records; by fifth place that falls to 8, and by tenth to 5, which is the shape of a field with a dense head and a long tail.
One filer sits well ahead of the field
The leading assignee's 16 records outpace the fifth-ranked filer's 8, indicating a single dominant claim position rather than a tightly bunched top group.
Co-assignment is limited and concentrated
Only 10 co-assignee pairs appear across the dataset, and the strongest pairing recurs 16 times between the same two related entities — co-filing here looks like an individual-inventor-to-entity relationship rather than a broad joint-venture pattern.
Most filers appear once or twice
Below the top ten, filing counts drop quickly, consistent with commercial launch entrants and research institutes each protecting a narrow slice of engine architecture rather than building a broad portfolio.
| Assignee | Recent year | YoY |
|---|---|---|
| Bolotin Nikolai Borisovich | 0 | — |
| BOLOTIN NIKOLAJ BORISOVICH | 0 | — |
| Korea Aerospace Research Institute | 0 | — |
| PLA Strategic Support Force Aerospace Engineering University | 0 | — |
| SPECIAL AEROSPACE SERVICES LLC | 0 | — |
| OTKRYTOE AKTSIONERNOE OBSHCHESTVO NPO EHNERGOMASH IMENI AKADKA V P GLUSHKO | 0 | — |
| Varlamov Sergei Evgenievich | 0 | — |
| VARLAMOV SERGEJ EVGENEVICH | 0 | — |
Where to take this analysis
This page surfaces the shape of the field; deciding where to file or challenge requires drilling into specific claims.
Check freedom-to-operate against the top holders
With 44.3% of records held by five assignees, a new filing on core combustion chamber or turbopump geometry should be checked against those specific portfolios before drafting.
Explore assignee portfoliosMap the under-claimed adjacent classes
Additive manufacturing, powder metallurgy and electroforming each appear in only one or two records — worth a deeper prior-art pull before assuming the space is clear.
Run a white space searchCommon questions about liquid rocket engine patents
The dataset's assignee ranking shows a single leader with 16 records, well ahead of the fifth-ranked assignee at 8 and the tenth at 5. The top 5 assignees combined hold 44.3% of all 115 records in scope, and the top 10 hold 69.6%, so filing activity is concentrated at the top with a long tail of entities holding one or two records each. Anyone assessing freedom to operate should start with that concentrated group rather than treating the field as evenly distributed.
Filing peaked at 15 records in 2021 and had fallen to 3 by the 2022 midpoint, with the trend staying flat or declining since. Part of this apparent decline is a data artefact: publication typically lags filing by around 18 months, so the most recent one to two years in any patent trend are always undercounted. The genuine slowdown is likely real but less steep than the raw year-by-year counts suggest.
Every record in this dataset carries an F02K classification (jet and reaction propulsion), since that was the anchor of the search. Smaller shares touch B64G (cosmonautics and spacecraft, 6.1% of records), additive manufacturing, powder metallurgy, electroplating, non-positive-displacement pumps and combustion chambers — each appearing in only one or two records. That thinness in the adjacent classes is where claim space remains comparatively open.
The United States leads with 39 records, followed by Russia at 31 and China at 22. South Korea, the European Patent Office and WIPO's PCT route each see single-digit counts. That split reflects both established state propulsion programmes in the US and Russia and a newer wave of commercial filings, and it means a clearance search limited to one jurisdiction will miss a meaningful share of relevant prior art.
US20210190012A1, filed by Perigee Aerospace and published in 2021, claims a propulsion apparatus for a liquid propellant rocket engine built around an injector core inside a body, with an outlet discharging combustion gas and an injector positioned adjacent to that outlet so propellant moves between the body frame and injector core frame. It is representative rather than uniquely dominant, but its injector/outlet geometry claims illustrate the kind of structural claim language that recurs across this dataset's most-cited records. Teams designing injector assemblies should review its specific claim boundaries directly rather than relying on the abstract alone.
Combustion instability appears as one of the claim-language anchors used to build this dataset, alongside turbopump design, regenerative cooling, throttling capability and reusability, but the evidence here does not break out a separate count for combustion instability alone. The most-cited records include multiple injector and combustion chamber patents, suggesting sustained citation influence in that area even without a standalone class figure. A targeted sub-search restricted to combustion-instability claim language would be needed to size that slice precisely.
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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.