SpaceX Raptor

{{Short description|SpaceX family of liquid-fuel rocket engines}} {{Use dmy dates|date=January 2022}} {{Infobox rocket engine | image = SpaceX sea-level Raptor at Hawthorne - 2.jpg | image_size = | caption = A Raptor 1 rocket engine ready for transport outside SpaceX's factory in Hawthorne, California | name = SpaceX Raptor | country_of_origin = United States | manufacturer = SpaceX | associated = SpaceX Starship | status = In production | type = liquid | oxidizer = LOX | fuel = CH{{sub|4}} | mixture_ratio = 3.6 (78% O{{sub|2}}, 22% CH{{sub|4}})<ref>{{Cite web|last=Sierra Engineering & Software, Inc.|date=18 June 2019|title=Exhaust Plume Calculations for SpaceX Raptor Booster Engine|url=https://www.faa.gov/space/stakeholder_engagement/spacex_starship/media/Appendix_G_Exhaust_Plume_Calculations.pdf|access-date=17 September 2021|page=1|quote=The nominal operating condition for the Raptor engine is an injector face stagnation pressure (Pc) of 3669.5 psia and a somewhat fuel-rich engine O/F mixture ratio (MR) of 3.60. The current analysis was performed for the 100% nominal engine operating pressure (Pc=3669.5 psia) and an engine MR of 3.60.|archive-date=20 October 2021|archive-url=https://web.archive.org/web/20211020054702/https://www.faa.gov/space/stakeholder_engagement/spacex_starship/media/Appendix_G_Exhaust_Plume_Calculations.pdf|url-status=live}}</ref><ref>{{Cite web|last=Space Exploration Technologies Corp.|date=17 September 2021|title=Draft Programmatic Environmental Assessment for the SpaceX Starship/Super Heavy Launch Vehicle Program at the SpaceX Boca Chica Launch Site in Cameron County, Texas|url=https://www.faa.gov/space/stakeholder_engagement/spacex_starship/media/Draft_PEA_for_SpaceX_Starship_Super_Heavy_at_Boca_Chica.pdf|url-status=live|access-date=17 September 2021|website=faa.gov|publisher=FAA Office of Commercial Space Transportation|page=12|quote=Super Heavy is expected to be equipped with up to 37 Raptor engines, and Starship will employ up to six Raptor engines. The Raptor engine is powered by liquid oxygen (LOX) and liquid methane (LCH4) in a 3.6:1 mass ratio, respectively.|archive-date=17 September 2021|archive-url=https://web.archive.org/web/20210917182019/https://www.faa.gov/space/stakeholder_engagement/spacex_starship/media/Draft_PEA_for_SpaceX_Starship_Super_Heavy_at_Boca_Chica.pdf}}</ref> | cycle = Full-flow staged combustion | pumps = 2 turbopumps | description = | combustion_chamber = 1 | nozzle_ratio = {{ubl |34.34 (sea-level),<ref>{{Cite web|last=Sierra Engineering & Software, Inc.|date=18 June 2019|title=Exhaust Plume Calculations for SpaceX Raptor Booster Engine|url=https://www.faa.gov/space/stakeholder_engagement/spacex_starship/media/Appendix_G_Exhaust_Plume_Calculations.pdf|access-date=17 September 2021|page=1|quote=The subject engine uses a closed power cycle with a 34.34:1 regeneratively-cooled thrust chamber nozzle.|archive-date=20 October 2021|archive-url=https://web.archive.org/web/20211020054702/https://www.faa.gov/space/stakeholder_engagement/spacex_starship/media/Appendix_G_Exhaust_Plume_Calculations.pdf|url-status=live}}</ref> |80 (vacuum)<ref>{{cite episode|series=Everyday Astronaut|network=Youtube|last=Dodd|first=Tim|author1-link=Everyday astronaut|language=en-US|url=http://youtube.com/watch?v=SA8ZBJWo73E|minutes=4|title="Starbase Tour with Elon Musk [PART 2]"|date=7 August 2021|access-date=23 February 2024|archive-date=17 February 2024|archive-url=https://web.archive.org/web/20240217202310/https://www.youtube.com/watch?v=SA8ZBJWo73E|url-status=live}}</ref> }} | thrust = '''Raptor 1:''' {{cvt|185|t-f|MN lb-f|lk=on|sigfig=3}}<ref>{{Cite web |last=Bergin |first=Chris |date=2022-01-23 |title=Raptor 2 testing at full throttle on the SpaceX McGregor test stands |url=https://www.nasaspaceflight.com/2022/01/raptor-2-starbase-update/ |access-date=2022-03-22 |website=NASASpaceFlight.com |language=en-US}}</ref> '''Raptor 2:''' {{ubl |{{cvt|230|t-f|MN lb-f|sigfig=3}}<ref name="everydayastronaut">{{cite episode|series=Everyday Astronaut|network=Youtube|last=Dodd|first=Tim|author1-link=Everyday astronaut|language=en-US|url=https://www.youtube.com/watch?v=ALiNmzoo1_E|title=Raptor 1 VS Raptor 2: What's New // What's Different|date=14 July 2022|access-date=15 July 2022|archive-date=15 July 2022|archive-url=https://web.archive.org/web/20220715072551/https://www.youtube.com/watch?v=ALiNmzoo1_E|url-status=live}}</ref> (sea-level) |{{cvt|258|t-f|MN lb-f|sigfig=3}}<ref name="sx20200524">{{Cite web |title=Starship : Official SpaceX Starship Page |url=https://www.spacex.com/vehicles/starship/ |url-status=live |archive-url=https://web.archive.org/web/20200522145915/https://www.spacex.com/vehicles/starship/ |archive-date=22 May 2020 |access-date=24 May 2020 |publisher=SpaceX}}</ref> (vacuum) }} '''Raptor 3:''' {{cvt|250|t-f|MN lb-f|sigfig=3}} (sea-level) {{cvt|275|t-f|MN lb-f|sigfig=3}} (vacuum) <ref name = "sx20260512">{{Cite web |title=SpaceX: Starship V3 |url=https://www.spacex.com/updates#starship-v3 |url-status=live |publisher=SpaceX}}</ref> | thrust_at_altitude = | throttle_range = 40–100%<ref name="musk20200817b">{{cite tweet |user=elonmusk |first=Elon |last=Musk |author-link=Elon Musk |number=1295553672454311941 |title=Max demonstrated Raptor thrust is ~225 tons & min is ~90 tons, so they're actually quite similar. Both Merlin & Raptor could throttle way lower with added design complexity. }}</ref> | thrust_to_weight = '''Raptor 1:''' 88.94 '''Raptor 2:''' 141.1 '''Raptor 3:''' 163.9 | chamber_pressure = {{ubl | {{ convert| 330| bar |psi |abbr=on }} }} | specific_impulse_vacuum = '''Raptor:''' {{convert|350|isp|km/s|abbr=on}} '''Vacuum Optimized:''' {{convert|380|isp|km/s|abbr=on}}<ref name="raptor-sep-2019-isp">{{cite tweet |user=elonmusk |first=Elon |last=Musk |author-link=Elon Musk |number=1171118891671490560 |title=Sea level Raptor's vacuum Isp is ~350 sec, but ~380 sec with larger vacuum-optimized nozzle |archive-date=25 September 2019 |archive-url=https://web.archive.org/web/20190925065050/https://twitter.com/elonmusk/status/1171118891671490560 |url-status=live}}</ref> | specific_impulse_sea_level = {{convert|327|isp|km/s|abbr=on}}<ref name="SpaceX20180917"/> | total_impulse = | mass_flow = {{ubl | ~{{convert|650|kg/s|lb/s|abbr=on}}:<ref>At 2.23{{nbsp}}MN thrust and 350{{nbsp}}s specific impulse</ref> | {{ubl | style = margin-left:1.6em; | ~{{convert|510|kg/s|lb/s|abbr=on}}, O{{sub|2}}<ref name=mr>78% O{{sub|2}}, 22% CH{{sub|4}} mixture ratio</ref> | ~{{convert|140|kg/s|lb/s|abbr=on}}, CH{{sub|4}}<ref name=mr /> }} }} | burn_time = Varies | capacity = | dimensions = | length = {{convert|3.1|m|abbr=on}}<ref>{{Cite web |url=https://www.spacex.com/starship |title=Starship | SpaceX |access-date=2 October 2019 |archive-date=30 September 2019 |archive-url=https://web.archive.org/web/20190930163150/https://www.spacex.com/starship |url-status=dead }}</ref> | diameter = {{convert|1.3|m|abbr=on}}<ref name=youtube-makinglifemulti/> | dry_weight = '''Raptor 1:''' {{convert|2080|kg|abbr=on}} '''Raptor 2:''' {{convert|1630|kg|abbr=on}} '''Raptor 3:''' {{convert|1525|kg|abbr=on}} | used_in = }}

'''Raptor''' is a family of rocket engines developed and manufactured by SpaceX. It is the third rocket engine in history designed with a full-flow staged combustion fuel cycle, and the first such engine to power a vehicle in flight.<ref name=":2">{{cite episode |series=Everyday Astronaut |network=Youtube |last=Dodd |first=Tim |author1-link=Everyday astronaut |language=en-US |date=2019-05-25 |title=Is SpaceX's Raptor engine the king of rocket engines? |url=https://everydayastronaut.com/raptor-engine/ |access-date=2023-05-22 |archive-date=22 May 2023 |archive-url=https://web.archive.org/web/20230522144323/https://everydayastronaut.com/raptor-engine/ |url-status=live }}</ref> The engine is powered by cryogenic liquid methane and liquid oxygen, a combination known as methalox.

SpaceX's super-heavy-lift rocket Starship uses Raptor engines in its Super Heavy booster and in the Starship second stage.<ref name="sx-pug202003">{{cite web|date=March 2020|title=Starship Users Guide, Revision 1.0, March 2020|url=https://www.spacex.com/sites/spacex/files/starship_users_guide_v1.pdf|url-status=dead|archive-url=https://web.archive.org/web/20200402122214/https://www.spacex.com/sites/spacex/files/starship_users_guide_v1.pdf|archive-date=2 April 2020|access-date=18 May 2020|work=SpaceX/files|publisher=SpaceX|quote=SpaceX's Starship system represents a fully reusable transportation system designed to service Earth orbit needs as well as missions to the Moon and Mars. This two-stage vehicle — composed of the Super Heavy rocket (booster) and Starship (spacecraft)}}</ref> Starship missions include lifting payloads to Earth orbit and is also planned for missions to the Moon and Mars.<ref name="sn20131025">{{cite news|last=Leone|first=Dan|date=25 October 2013|title=SpaceX Could Begin Testing Methane-fueled Engine at Stennis Next Year|newspaper=Space News|url=http://www.spacenews.com/article/launch-report/37859spacex-could-begin-testing-methane-fueled-engine-at-stennis-next-year|url-status=dead|access-date=26 October 2013|archive-url=https://archive.today/20131025232611/http://www.spacenews.com/article/launch-report/37859spacex-could-begin-testing-methane-fueled-engine-at-stennis-next-year|archive-date=25 October 2013}}</ref> The engines are being designed for reuse with little maintenance.<ref>{{Cite news |last1=Neff |first1=William |last2=Steckelberg |first2=Aaron |last3=Davenport |first3=Christian |date=9 January 2023 |title=The rockets NASA and SpaceX plan to send to the moon |url=https://www.washingtonpost.com/technology/interactive/2023/nasa-sls-spacex-starship-rockets/ |url-status=live |archive-url=https://web.archive.org/web/20230417053038/https://www.washingtonpost.com/technology/interactive/2023/nasa-sls-spacex-starship-rockets/ |archive-date=17 April 2023 |access-date=28 August 2023 |newspaper=The Washington Post}}</ref>

== Design == Raptor is designed for extreme reliability, aiming to support the airline-level safety required by the point-to-point Earth transportation market.<ref name="sn20171015raptor">{{cite news |last=Foust |first=Jeff |date=15 October 2017 |title=Musk offers more technical details on BFR system |url=http://spacenews.com/musk-offers-more-technical-details-on-bfr-system/ |url-status=live |archive-url=https://archive.today/20210307190214/https://spacenews.com/musk-offers-more-technical-details-on-bfr-system/ |archive-date=7 March 2021 |access-date=15 October 2017 |work=SpaceNews |quote=[initial flight testing will be with] a full-scale ship doing short hops of a few hundred kilometers altitude and lateral distance ... fairly easy on the vehicle, as no heat shield is needed, we can have a large amount of reserve propellant and don’t need the high area ratio, deep space Raptor engines. ... 'The engine thrust dropped roughly in proportion to the vehicle mass reduction from the first IAC talk,' Musk wrote when asked about that reduction in thrust. The reduction in thrust also allows for the use of multiple engines, giving the vehicle an engine-out capability for landings. ... Musk was optimistic about scaling up the Raptor engine from its current developmental model to the full-scale one. 'Thrust scaling is the easy part. Very simple to scale the dev Raptor to 170 tons,' he wrote. 'The flight engine design is much lighter and tighter, and is extremely focused on reliability.' He added the goal is to achieve 'passenger airline levels of safety' with the engine, required if the vehicle is to serve point-to-point transportation markets.}}</ref> Gwynne Shotwell claimed that Raptor would be able to deliver "long life... and more benign turbine environments".<ref name="shotwell201503317">{{cite web |last=Shotwell |first=Gwynne |date=17 March 2015 |title=Statement of Gwynne Shotwell, President & Chief Operating Officer, Space Exploration Technologies Corp. (SpaceX) |url=http://docs.house.gov/meetings/AS/AS29/20150317/103135/HHRG-114-AS29-Wstate-ShotwellG-20150317.pdf |url-status=live |archive-url=https://web.archive.org/web/20160128041905/http://docs.house.gov/meetings/AS/AS29/20150317/103135/HHRG-114-AS29-Wstate-ShotwellG-20150317.pdf |archive-date=28 January 2016 |access-date=11 January 2016 |work=Congressional testimony |publisher=US House of Representatives, Committee on Armed Service Subcommittee on Strategic Forces |pages=14–15 |quote=SpaceX has already begun self-funded development and testing on our next-generation Raptor engine. ... Raptor development ... will not require external development funds related to this engine.}}</ref><ref name="nsf20161003" />

=== Full-flow staged combustion === {{Related article|Liquid-propellant rocket#Engine cycles}}left|thumb|Simplified full-flow staged combustion rocket diagram Raptor is powered by subcooled liquid methane and subcooled liquid oxygen in a full-flow staged combustion cycle. This type of combustion is a twin-shaft staged combustion cycle that uses both oxidizer-rich and fuel-rich preburners. The cycle allows for the full flow of both propellants through the turbines without dumping any unburnt propellant overboard.

Full-flow staged combustion is a departure from the more traditional "open-cycle" gas generator system and LOX/kerosene propellants used by its predecessor Merlin.<ref name="fg20121122">{{cite news |last=Todd |first=David |date=22 November 2012 |title=SpaceX's Mars rocket to be methane-fuelled |url=http://www.flightglobal.com/news/articles/spacexs-mars-rocket-to-be-methane-fuelled-379326/ |url-status=live |archive-url=https://web.archive.org/web/20131030143636/http://www.flightglobal.com/news/articles/spacexs-mars-rocket-to-be-methane-fuelled-379326/ |archive-date=30 October 2013 |access-date=5 December 2012 |newspaper=Flightglobal |quote=Musk said Lox and methane would be SpaceX’s propellants of choice on a mission to Mars, which has long been his stated goal. SpaceX’s initial work will be to build a Lox/methane rocket for a future upper stage, codenamed Raptor. The design of this engine would be a departure from the "open cycle" gas generator system that the current Merlin 1 engine series uses. Instead, the new rocket engine would use a much more efficient "staged combustion" cycle that many Russian rocket engines use.}}</ref> Before Raptor, no full-flow staged combustion engine had ever been used inflight and only two designs had progressed sufficiently to reach test stands: the Soviet RD-270 project in the 1960s, a full scale test engine and the Aerojet Rocketdyne Integrated Powerhead Demonstrator in the mid-2000s, which only demonstrated the powerhead.<ref name=":2" /><ref name="hackaday201902">{{cite news |last=Nardi |first=Tom |date=13 February 2019 |title=The "impossible" tech behind SpaceX's new engine |url=https://hackaday.com/2019/02/13/the-impossible-tech-behind-spacexs-new-engine/ |url-status=live |archive-url=https://web.archive.org/web/20210204044128/https://hackaday.com/2019/02/13/the-impossible-tech-behind-spacexs-new-engine/ |archive-date=4 February 2021 |access-date=15 February 2019 |work=Hackaday}}</ref><ref name="nsf20161003" /><ref name="nsf20140307" /> RS-25 engines (first used on the Space Shuttle) used a simpler form of staged combustion cycle.<ref>{{cite web |title=Space Shuttle Main Engines |url=http://www.nasa.gov/returntoflight/system/system_SSME.html |url-status=live |archive-url=https://web.archive.org/web/20151210183632/http://www.nasa.gov/returntoflight/system/system_SSME.html |archive-date=10 December 2015 |access-date=6 March 2013 |publisher=NASA}}</ref> Several Russian rocket engines, including the RD-180<ref name="fg20121122" /> and the RD-191 did as well.<ref name="nsf20161003">{{cite news |last=Belluscio |first=Alejandro G. |date=3 October 2016 |title=ITS Propulsion – The evolution of the SpaceX Raptor engine |url=https://www.nasaspaceflight.com/2016/10/its-propulsion-evolution-raptor-engine/ |url-status=live |archive-url=https://web.archive.org/web/20210126012458/https://www.nasaspaceflight.com/2016/10/its-propulsion-evolution-raptor-engine/ |archive-date=26 January 2021 |access-date=3 October 2016 |work=NASASpaceFlight.com}}</ref>

Full-flow staged combustion has the advantage that the energy produced by the preburners, and used to power the propellant pumps, is spread among the entire fuel flow, meaning that the preburner exhaust driving the propellant turbopumps is as cool as possible, even cooler than other closed engine cycles that only preburn one propellant. This contributes to a long engine life. In contrast, an open-cycle engine in which the preburner exhaust bypasses the main combustion chamber tries to minimize the amount of propellant fed through the preburner, which is achieved by operating the turbine at its maximum survivable temperature.

{{CSS image crop |Image = Raptor 2 Full Flow Staged Combustion Cycle Estimate.svg |bSize = 480 |cWidth = 360 |cHeight = 325 |oTop = 15 |oLeft = 50 |Location = left |Description = Raptor 2 rocket engine cycle diagram with estimates from open-source information and analysis }} An oxygen-rich turbine powers an oxygen turbopump, and a fuel-rich turbine powers a methane turbopump. Both oxidizer and fuel streams are converted completely to the gas phase before they enter the combustion chamber.<ref name=":2" /> This speeds up mixing and combustion, reducing the size and mass of the required combustion chamber. Torch igniters are used in the preburners. Because of the high temperatures of the preburner exhaust, the main combustion chamber of Raptor 2 has no main igniter, which eliminate the need for Merlin's dedicated, consumable igniter fluid.<ref name="nsf20161003" /> Raptor 2 uses coaxial swirl injectors to admit propellants to the combustion chamber, rather than Merlin's pintle injectors.<ref>{{Cite journal |last1=Park |first1=Gujeong |last2=Oh |first2=Sukil |last3=Yoon |first3=Youngbin |last4=Choi |first4=Jeong-Yeol |date=May 2019 |title=Characteristics of Gas-Centered Swirl-Coaxial Injector with Liquid Flow Excitation |url=https://arc.aiaa.org/doi/10.2514/1.B36647 |journal=Journal of Propulsion and Power |language=en |volume=35 |issue=3 |pages=624–631 |doi=10.2514/1.B36647 |issn=0748-4658 |access-date=9 June 2019 |archive-date=4 February 2021 |archive-url=https://web.archive.org/web/20210204072538/https://arc.aiaa.org/doi/10.2514/1.B36647 |url-status=live |url-access=subscription }}</ref><ref>{{cite episode |title=Elon Musk Explains SpaceX's Raptor Engine! |url=https://www.youtube.com/watch?v=E7MQb9Y4FAE&t=573s |series=Everyday Astronaut |last=Dodd |first=Tim |author1-link=Everyday astronaut |network=Youtube |date=Jul 9, 2022 |language=en |access-date=17 February 2023 |archive-date=17 February 2023 |archive-url=https://web.archive.org/web/20230217151318/https://www.youtube.com/watch?v=E7MQb9Y4FAE&t=573s |url-status=live }}</ref>

=== Propellants === Raptor is designed for deep cryogenic propellants—fluids cooled to near their freezing points, rather than their boiling points, as is typical for cryogenic rocket engines.<ref name="issconf20150707">{{cite AV media |url=https://www.youtube.com/watch?v=hJD0MMP4nkM |title=Elon Musk comments on Falcon 9 explosion – Huge Blow for SpaceX |date=7 July 2015 |medium=video |time=39:25–40:45 |access-date=30 December 2015 |archive-url=https://web.archive.org/web/20150906075127/https://www.youtube.com/watch?v=hJD0MMP4nkM |archive-date=6 September 2015 |url-status=dead |people=Elon Musk, Mike Suffradini}}</ref> Subcooled propellants are denser, increasing propellant mass per volume<ref>{{Cite web |last=Fernholz |first=Tim |date=2016-02-29 |title=The "super chill" reason SpaceX keeps aborting launches |url=https://qz.com/627430/the-super-chill-reason-spacex-keeps-aborting-launches |url-status=live |archive-url=https://web.archive.org/web/20230522194002/https://qz.com/627430/the-super-chill-reason-spacex-keeps-aborting-launches |archive-date=22 May 2023 |access-date=2023-05-22 |website=Quartz |language=en}}</ref> as well as engine performance. Specific impulse is increased, and the risk of cavitation at inputs to the turbopumps is reduced due to the higher propellant fuel mass flow rate per unit of power generated.<ref name="nsf20161003" /> Cavitation (bubbles) reduces fuel flow/pressure and can starve the engine, while eroding turbine blades.<ref name=":3" /> The oxidizer to fuel ratio of the engine is approximately 3.8 to 1.<ref name="waitbutwhy-201508">{{Cite web |last=Urban |first=Tim |date=2015-08-16 |title=How (and Why) SpaceX Will Colonize Mars — Page 4 of 5 |url=https://waitbutwhy.com/2015/08/how-and-why-spacex-will-colonize-mars.html |access-date=2024-02-16 |website=Wait But Why |language=en-US|archive-url=https://web.archive.org/web/20150817120851/http://waitbutwhy.com/2015/08/how-and-why-spacex-will-colonize-mars.html/4 |archive-date=17 August 2015|quote= Musk: "''The critical elements of the solution are rocket reusability and low cost propellant (CH{{sub|4}} and O{{sub|2}} at an O/F ratio of ~3.6). And, of course, making the return propellant on Mars, which has a handy CO{{sub|2}} atmosphere and lots of H{{sub|2}}O frozen in the soil.''"}}</ref> Methalox burns relatively cleanly, reducing carbon build-up in the engine.

Liquid methane and oxygen propellants have been adopted by many companies, such as Blue Origin with its BE-4 engine, as well as Chinese startup Space Epoch's Longyun-70.<ref>{{Cite web |last=Jones |first=Andrew |date=19 January 2023 |title=Chinese startups conduct hot fire tests for mini version of SpaceX's Starship |url=https://spacenews.com/chinese-startups-conduct-hot-fire-tests-for-mini-version-of-spacexs-starship/ |url-status=live |archive-url=https://web.archive.org/web/20240223204348/https://spacenews.com/chinese-startups-conduct-hot-fire-tests-for-mini-version-of-spacexs-starship/ |archive-date=23 February 2024 |access-date=31 August 2023 |website=SpaceNews}}</ref>

=== Manufacturing and materials === Many components of early Raptor prototypes were manufactured using 3D printing, including turbopumps and injectors, increasing the speed of development and testing.<ref name="issconf20150707" /><ref>{{Cite web |last=Zafar |first=Ramish |date=2021-03-23 |title=SpaceX's 3D Manufacturing Systems Supplier For Raptor Engine To Go Public Through SPAC Deal |url=https://wccftech.com/spacexs-3d-manufacturing-systems-supplier-for-raptor-engine-to-go-public-through-spac-deal/ |archive-url=https://web.archive.org/web/20221105065404/https://wccftech.com/spacexs-3d-manufacturing-systems-supplier-for-raptor-engine-to-go-public-through-spac-deal/ |archive-date=2022-11-05 |access-date=2023-11-22 |website=Wccftech |language=en-US}}</ref> The 2016 subscale development engine had 40% (by mass) of its parts manufactured by 3D printing.<ref name="nsf20161003" /> In 2019, engine manifolds were cast from SpaceX's in-house developed SX300 Inconel superalloy, later improved to SX500.<ref name="casting-alloy">{{Cite web |title=''SpaceX Casting Raptor Engine Parts from Supersteel Alloys'' Feb 2019 |url=https://www.nextbigfuture.com/2019/02/spacex-casting-raptor-engine-parts-from-supersteel-alloys.html |url-status=live |archive-url=https://web.archive.org/web/20201026120552/https://www.nextbigfuture.com/2019/02/spacex-casting-raptor-engine-parts-from-supersteel-alloys.html |archive-date=26 October 2020 |access-date=22 October 2020}}</ref>

==History== [[File:SpaceX Merlin and sea-level Raptor at Hawthorne.jpg|thumb|upright=1.2|SpaceX's Merlin engine (left) compared to a sea-level Raptor 1 engine (right)]]

=== Conception === SpaceX's Merlin and Kestrel rocket engines use a RP-1 and liquid oxygen ("kerolox") combination. Raptor has about triple the thrust of SpaceX's Merlin 1D engine, which powers the Falcon 9 and Falcon Heavy launch vehicles.

Raptor was conceived to burn hydrogen and oxygen propellants as of 2009.<ref name="hs20090713">{{cite web |date=7 July 2009 |title=Long term SpaceX vehicle plans |url=http://www.hobbyspace.com/nucleus/index.php?itemid=13632 |url-status=dead |archive-url=https://web.archive.org/web/20100214144451/http://hobbyspace.com/nucleus/index.php?itemid=13632 |archive-date=14 February 2010 |access-date=13 July 2009 |publisher=HobbySpace.com}}</ref> SpaceX had a few staff working on the Raptor upper-stage engine at a low priority in 2011.<ref name="rlvst20110407">{{cite news |title=Notes: Space Access'11: Thurs. – Afternoon session – Part 2: SpaceX |url=http://www.hobbyspace.com/nucleus/index.php?itemid=28515 |access-date=8 April 2011 |newspaper=RLV and Space Transport News |date=7 April 2011 |url-status=dead |archive-url=https://web.archive.org/web/20120320030007/http://www.hobbyspace.com/nucleus/index.php?itemid=28515 |archive-date=20 March 2012}}</ref><ref name="stn20110808">{{cite news |title=SpaceX Raptor LH2/LOX engine |url=http://www.hobbyspace.com/nucleus/index.php?itemid=31534 |access-date=9 August 2011 |newspaper=RLV and Space Transport News |date=8 August 2011 |url-status=dead |archive-url=https://web.archive.org/web/20111102161312/http://www.hobbyspace.com/nucleus/index.php?itemid=31534 |archive-date=2 November 2011}}</ref>

In October 2012, SpaceX announced concept work on an engine that would be "several times as powerful as the Merlin 1 series of engines, and won't use Merlin's RP-1 fuel".<ref name="fg20121017">{{cite news |last=Rosenberg |first=Zach |title=SpaceX aims big with massive new rocket |url=http://www.flightglobal.com/news/articles/spacex-aims-big-with-massive-new-rocket-377687/ |access-date=17 October 2012 |newspaper=Flightglobal |date=15 October 2012 |archive-date=18 October 2012 |archive-url=https://web.archive.org/web/20121018120213/http://www.flightglobal.com/news/articles/spacex-aims-big-with-massive-new-rocket-377687/ |url-status=live }}</ref>

=== Development === In November 2012, SpaceX founder and CEO Elon Musk announced that SpaceX was working on methane-fueled rocket engines, that Raptor would be methane-based,<ref name="fg20121120">{{cite news |last=Todd |first=David |date=20 November 2012 |title=Musk goes for methane-burning reusable rockets as step to colonise Mars |url=http://seradata.com/SSI/2012/11/musk_goes_for_methane-burning/ |url-status=dead |archive-url=https://web.archive.org/web/20160611083349/http://seradata.com/SSI/2012/11/musk_goes_for_methane-burning/ |archive-date=11 June 2016 |access-date=4 November 2015 |newspaper=FlightGlobal Hyperbola |quote="We are going to do methane." Musk announced as he described his future plans for reusable launch vehicles including those designed to take astronauts to Mars within 15 years, "The energy cost of methane is the lowest and it has a slight ''I''sp (Specific Impulse) advantage over Kerosene," said Musk adding, "And it does not have the pain in the ass factor that hydrogen has".}}</ref> and that methane would fuel Mars colonization.<ref name="nsf20140307">{{cite news |last=Belluscio |first=Alejandro G. |date=7 March 2014 |title=SpaceX advances drive for Mars rocket via Raptor power |url=http://www.nasaspaceflight.com/2014/03/spacex-advances-drive-mars-rocket-raptor-power/ |url-status=live |archive-url=https://web.archive.org/web/20150911235533/http://www.nasaspaceflight.com/2014/03/spacex-advances-drive-mars-rocket-raptor-power/ |archive-date=11 September 2015 |access-date=7 March 2014 |newspaper=NASAspaceflight.com}}</ref> Because of the presence of underground water and carbon dioxide in Mars atmosphere, methane, a simple hydrocarbon, could be synthesized on Mars using the Sabatier reaction.<ref>{{cite AV media |url=https://www.youtube.com/watch?v=vYA0f6R5KAI |title=GPUs to Mars: Full-Scale Simulation of SpaceX's Mars Rocket Engine |date=5 May 2015 |work=YouTube |access-date=4 June 2015 |archive-date=19 January 2016 |archive-url=https://web.archive.org/web/20160119113849/https://www.youtube.com/watch?v=vYA0f6R5KAI |url-status=live }}</ref> NASA analysis found in-situ resource production on Mars to be viable for oxygen, water, and methane production.<ref name="nasa20151108">{{cite web |last1=mmooney |date=8 November 2015 |title=In-Situ Resource Utilization – Mars Atmosphere/Gas Chemical Processing |url=http://sbir.nasa.gov/content/situ-resource-utilization-mars-atmospheregas-chemical-processing |url-status=dead |archive-url=https://web.archive.org/web/20160618142308/http://sbir.nasa.gov/content/situ-resource-utilization-mars-atmospheregas-chemical-processing |archive-date=18 June 2016 |access-date=2 June 2015 |website=NASA SBIR/STTR |publisher=NASA}}</ref>

In early 2014 SpaceX confirmed that Raptor would be used for both first and second stages of its next rocket. This held as the design evolved from the Mars Colonial Transporter<ref name="nsf20140307" /> to the Interplanetary Transport System,<ref name="sn20160927">{{cite news|url=http://spacenews.com/spacex-unveils-mars-mission-plans/|title=SpaceX's Mars plans call for massive 42-engine reusable rocket|last=Foust|first=Jeff|date=27 September 2016|work=SpaceNews|access-date=7 April 2018|quote=Musk stated it’s possible that the first spaceship would be ready for tests in four years... 'We’re kind of being intentionally fuzzy about the timeline,' he said. 'We’re going to try and make as much progress as we can with a very constrained budget.'|archive-date=18 September 2021|archive-url=https://web.archive.org/web/20210918121059/https://spacenews.com/spacex-unveils-mars-mission-plans/|url-status=live}}</ref> the Big Falcon Rocket, and ultimately, Starship.<ref name="sn20171015">{{cite news |first=Jeff |last=Foust |url=http://spacenews.com/musk-offers-more-technical-details-on-bfr-system/ |title=Musk offers more technical details on BFR system |work=SpaceNews |date=15 October 2017 |access-date=7 April 2018 |archive-date=7 March 2021 |archive-url=https://archive.today/20210307190214/https://spacenews.com/musk-offers-more-technical-details-on-bfr-system/ |url-status=live }}</ref>

The concept evolved from a family of Raptor-designated rocket engines (2012)<ref name="201211raptorSpecifics">{{cite news |last=Todd |first=David |title=Musk goes for methane-burning reusable rockets as step to colonise Mars |url=http://www.flightglobal.com/blogs/hyperbola/2012/11/musk_goes_for_methane-burning/ |access-date=22 November 2012 |newspaper=FlightGlobal Hyperbola |date=20 November 2012 |quote=''The new Raptor upper stage engine is likely to be only the first engine in a series of lox/methane engines.'' |archive-date=29 October 2013 |archive-url=https://web.archive.org/web/20131029184957/http://www.flightglobal.com/blogs/hyperbola/2012/11/musk_goes_for_methane-burning/ |url-status=live }}</ref> to focus on the full-size Raptor engine (2014).<ref name="tss20140321">{{cite AV media |url=http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |title=Broadcast 2212: Special Edition, interview with Gwynne Shotwell |date=21 March 2014 |medium=audio file |publisher=The Space Show |time=21:25–22:10 |access-date=22 March 2014 |archive-url=https://web.archive.org/web/20140322013556/http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |archive-date=22 March 2014 |url-status=dead |format=mp3 |id=2212 |quote=''our focus is the full Raptor size'' |people=Gwynne Shotwell}}.</ref>

In January 2016, the US Air Force awarded a {{USD|33.6 million}} development contract to SpaceX to develop a prototype Raptor for use on the upper stage of Falcon 9 and Falcon Heavy.<ref name="dod20160113">{{cite press release |title=Contracts: Air Force |url=https://www.defense.gov/News/Contracts/Contract-View/Article/642983 |date=13 January 2016 |work=U.S. Department of Defense |access-date=15 January 2016 |archive-date=15 January 2016 |archive-url=https://web.archive.org/web/20160115134349/http://www.defense.gov/News/Contracts/Contract-View/Article/642983 |url-status=dead }}</ref><ref name="sn20160113">{{cite news |title=Orbital ATK, SpaceX Win Air Force Propulsion Contracts |first=Mike |last=Gruss |url=http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/ |date=13 January 2016 |work=SpaceNews |access-date=15 January 2016 |archive-date=3 February 2016 |archive-url=https://archive.today/20160203182448/http://spacenews.com/orbital-atk-spacex-win-air-force-propulsion-contracts/ |url-status=live }}</ref>

The first version was intended to operate at a chamber pressure of {{convert|250|bar|MPa+psi}}.<ref name="musk20170929">{{cite web |date=29 September 2017 |title=Elon Musk speech: Becoming a Multiplanet Species |website=YouTube |url=https://www.youtube.com/watch?v=tdUX3ypDVwI |archive-url=https://web.archive.org/web/20180309212706/https://www.youtube.com/watch?v=tdUX3ypDVwI |archive-date=9 March 2018}} 68th annual meeting of the International Astronautical Congress in Adelaide, Australia</ref> As of July 2022, chamber pressure had reached 300 bars in a test.<ref name=":3" /> In April 2024, Musk shared the performance achieved by SpaceX with the Raptor 1 engine (sea level 185 tf, RVac 200 tf) and Raptor 2 engine (sea level 230 tf, RVac 258 tf) along with the target specifications for the upcoming Raptor 3 (sea level 280 tf, RVac 306 tf)<ref name=ars20240408>{{cite news |url=https://arstechnica.com/space/2024/04/elon-musk-just-gave-another-mars-speech-this-time-the-vision-seems-tangible/ |title=Elon Musk just gave another Mars speech; this time the vision seems tangible |last=Berger|first=Eric |date=8 April 2024 |access-date=2024-04-16 |work=Ars Technica}}</ref><ref name=sn20240406>{{cite news |url=https://spacenews.com/musk-outlines-plans-to-increase-starship-launch-rate-and-performance/ |title=Musk outlines plans to increase Starship launch rate and performance |last=Foust|first=Jeff |date=6 April 2024 |access-date=2024-04-16 |work=SpaceNews }}</ref> and said SpaceX would aim to ultimately achieve over 330 tonnes of thrust on the sea-level booster engines.<ref name=musk20240406>{{cite AV media |url=https://www.youtube.com/watch?v=OffMED-KXIs?t=1080 |title=Elon Musk SpaceX Presentation Leaves Audience Speechless |date=4 April 2024 |publisher=SpaceX |access-date=16 April 2024 |via=YouTube}}</ref>

Raptor 1 and 2 engines require a heat shroud to protect pipes and wiring from the heat of high-velocity atmospheric re-entry,<ref name=":3" /> while Raptor 3 is designed so that it does not require an external heat shield.<ref>{{Cite tweet |number=1776669097490776563 |user=SpaceX |date=April 6, 2024 |title=At Starbase, ElonMusk provided an update |access-date=November 13, 2024}}</ref>

=== Testing === [[File:SpaceX's Raptor oxygen preburner testing at Stennis (2015).jpg|thumb|right|Testing of the Raptor 's oxygen preburner at Stennis Space Center in 2015]] [[File:Raptor-test-9-25-2016.jpg|thumb|First test firing of a Raptor development engine on 25 September 2016 in McGregor, Texas]] Initial development testing<ref name="nasa201509">{{cite web |date=September 2015 |title=NASA-SpaceX testing partnership going strong |url=http://www.nasa.gov/sites/default/files/atoms/files/septemberlagniappe2.pdf |url-status=live |archive-url=https://web.archive.org/web/20151231200955/http://www.nasa.gov/sites/default/files/atoms/files/septemberlagniappe2.pdf |archive-date=31 December 2015 |access-date=10 January 2016 |work=Lagniappe, John C. Stennis Space Center |publisher=NASA |quote=''this project is strictly private industry development for commercial use'' |volume=10 |issue=9}}</ref> of Raptor components was done at NASA's Stennis Space Center,<ref name="sn20131025" /><ref name="pa20131023">{{cite news |last=Messier |first=Doug |date=23 October 2013 |title=SpaceX to Conduct Raptor Engine Testing in Mississippi |url=http://www.parabolicarc.com/2013/10/23/spacex-conduct-raptor-engine-testing-mississippi/ |url-status=live |archive-url=https://web.archive.org/web/20131024192458/http://www.parabolicarc.com/2013/10/23/spacex-conduct-raptor-engine-testing-mississippi/ |archive-date=24 October 2013 |access-date=23 October 2013 |newspaper=Parabolic Arc}}</ref> beginning in April 2014. Testing focused on startup and shutdown procedures, as well as hardware characterization and verification.<ref name="nsf20161003" />

SpaceX began testing injectors in 2014 and tested an oxygen preburner in 2015. 76 hot-fire tests of the preburner, totaling some 400 seconds of test time, were executed from April–August.<ref name="nasa201509" />

By early 2016, SpaceX had constructed an engine test stand at their McGregor test site in central Texas for Raptor testing.<ref name="nsf20161003" /><ref name="sn20131025" /> The first Raptor was manufactured at the SpaceX Hawthorne facility in California. By August 2016 it was shipped to McGregor for development testing.<ref name="ars20160810">{{cite news |last1=Berger |first1=Eric |title=SpaceX has shipped its Mars engine to Texas for tests |url=https://arstechnica.com/science/2016/08/spacex-has-shipped-its-mars-engine-to-texas-for-tests/ |access-date=17 August 2016 |publisher=Ars Technica |date=10 August 2016 |archive-date=18 August 2016 |archive-url=https://web.archive.org/web/20160818221504/http://arstechnica.com/science/2016/08/spacex-has-shipped-its-mars-engine-to-texas-for-tests/ |url-status=live }}</ref> The engine had {{convert|1|MN|abbr=on}} thrust.<ref name="musk20200817c">{{Cite tweet |number=1295498964205068289 |user=elonmusk |title=SN40 is about to be tested & has several upgrades over 330 bar engine. For reference, 330 bar on Raptor produces ~225 tons (half a million pounds) of force. |first=Elon |last=Musk |author-link=Elon Musk |date=18 August 2020}}</ref> It was the first-ever full-flow staged combustion methalox engine to reach a test stand.<ref name="nsf20161003" />

A subscale development engine was used for design validation. It was one-third the size of the engine designs that were envisioned for flight vehicles.<ref name="nsf20161003" /> It featured {{convert|200|bar|MPa+psi}} of chamber pressure, with a thrust of {{convert|1|MN|abbr=}} and used the SpaceX-designed SX500 alloy, created to contain hot oxygen gas in the engine at up to {{convert|12000|psi|bar+MPa}}.<ref name="casting-alloy" /> It was tested on a ground test stand in McGregor, firing briefly.<ref name="nsf20161003" /> To eliminate flow separation problems while testing in Earth's atmosphere, the test nozzle expansion ratio was limited to 150.<ref name="nsf20161003" />

By September 2017, the subscale engine had completed 1200 seconds of firings across 42 tests.<ref name="nsf20180809">{{cite news |last=Gaynor |first=Phillip |date=9 August 2018 |title=The Evolution of the Big Falcon Rocket |url=https://www.nasaspaceflight.com/2018/08/evolution-big-falcon-rocket/ |url-status=live |archive-url=https://web.archive.org/web/20180817161710/https://www.nasaspaceflight.com/2018/08/evolution-big-falcon-rocket/ |archive-date=17 August 2018 |access-date=17 August 2018 |work=NASASpaceFlight.com}}</ref>

SpaceX completed many static fire tests on a vehicle using Raptor 2s, including a 31 engine test (intended to be 33) on 9 February 2023,<ref>{{Cite news |last=Chang |first=Kenneth |date=2023-02-09 |title=SpaceX Test Fires 31 Engines on the Most Powerful Rocket Ever |url=https://www.nytimes.com/2023/02/09/science/spacex-starship-static-fire.html |access-date=2023-02-09 |work=The New York Times |language=en-US |issn=0362-4331 |archive-date=17 April 2023 |archive-url=https://web.archive.org/web/20230417183647/https://www.nytimes.com/2023/02/09/science/spacex-starship-static-fire.html |url-status=live }}</ref> and a 33 engine test on 25 August 2023.<ref>{{Cite tweet |number=1695158759717474379 |user=SpaceX |title=Super Heavy Booster 9 static fire successfully lit all 33 Raptor engines, with all but two running for the full duration. Congratulations to the SpaceX team on this exciting milestone! |author-link=SpaceX |date=25 August 2023}}</ref> During testing, more than 50 chambers melted, and more than 20 engines exploded.<ref name=":3">{{cite episode |title=Elon Musk Explains SpaceX's Raptor Engine! |url=https://www.youtube.com/watch?v=E7MQb9Y4FAE |access-date=2024-02-17 |series=Everyday Astronaut |last=Dodd |first=Tim |author1-link=Everyday astronaut |network=Youtube |date=July 9, 2022 |language=en-US |website=youtu.be |archive-date=14 February 2023 |archive-url=https://web.archive.org/web/20230214090838/https://www.youtube.com/watch?v=E7MQb9Y4FAE |url-status=live }}</ref>

SpaceX completed its first integrated flight test of Starship on 20 April 2023. The rocket had 33 Raptor 2 engines, but three of those were shut down before the rocket lifted off from the launch mount. The flight test was terminated after climbing to an altitude of ~39 km over the Gulf of Mexico. Multiple engines were out before the flight termination system (FTS) destroyed the booster and ship.<ref name="spacex-starship-flight-test-2023">{{cite web |title=Starship Flight Test |url=https://www.spacex.com/launches/mission/?missionId=starship-flight-test |access-date=28 April 2023 |website=SpaceX |archive-date=14 April 2023 |archive-url=https://web.archive.org/web/20230414172859/https://www.spacex.com/launches/mission/?missionId=starship-flight-test |url-status=live }}</ref>

On the second integrated flight test, all 33 booster engines remained lit until boostback burn startup, and all six Starship engines remained lit until the FTS was activated.<ref>{{Citation |title=Full Replay: SpaceX Launches Second Starship Flight Test | date=18 November 2023 |url=https://www.youtube.com/watch?v=uOI35G7cP7o |access-date=2023-11-30 |language=en |archive-date=22 November 2023 |archive-url=https://web.archive.org/web/20231122021359/https://www.youtube.com/watch?v=uOI35G7cP7o |url-status=live }}</ref><ref name=":45" />

On the third integrated flight test, all 33 booster engines once again remained lit until main engine cutoff, and then following hot-staging, 13 successfully relit to perform a boostback for full duration.<ref name=":4">{{Cite web |date=March 14, 2024 |title=Starship's Third Flight Test |url=https://www.spacex.com/launches/mission/?missionId=starship-flight-3 |access-date=May 20, 2024 |website=SpaceX.com}}</ref> On the booster's landing burn, only 3 engines of the planned 13 lit, with 2 shutting down rapidly, the other remained lit until the booster was destroyed ~462 metres above sea level.<ref name=":4" /> The ship successfully kept all 6 engines lit until second stage / secondary engine cutoff without issues, however a planned in-space Raptor re-light was cancelled due to rolling during coast.<ref name=":4" />

The seventh flight test featured the first reflown Raptor engine,<ref>{{Cite web |last=Foust |first=Jeff |date=January 4, 2025 |title=SpaceX to test vehicle upgrades and payload deployment on next Starship flight |url=https://spacenews.com/spacex-to-test-vehicle-upgrades-and-payload-deployment-on-next-starship-flight/ |access-date=24 May 2025 |website=SpaceNews}}</ref> which was successfully flown during Super Heavy Booster 14's ascent burn and was recovered after its successful catch by the launch tower. A further 29 raptors were reflown on B14 for Starship's ninth test flight.<ref>{{Cite web |title=Starship's Ninth Flight Test |url=https://www.spacex.com/launches/mission/?missionId=starship-flight-9 |access-date=24 May 2025 |website=SpaceX – Launches}}</ref>

=== Starship === {{Main|SpaceX Starship}}

==== Original configuration ==== [[File:BFR in flight (cropped)-2018 version.png|thumb|Big Falcon Rocket during ascent (artist's concept)]] In November 2016, Raptor was projected to power the proposed Interplanetary Transport System (ITS), in the early 2020s.<ref name="nsf20161003" /> Musk discussed two engines: a sea-level variant (expansion ratio 40:1) with thrust of {{convert|3050|kN|lbf|abbr=on}} at sea level  for the first stage/booster, and a vacuum variant (expansion ratio 200:1) with thrust of {{convert|3285|kN|lbf|abbr=on}} in space. 42 sea-level engines were envisioned in the high-level design of the first stage.<ref name="nsf20161003" />

Three gimbaling sea-level Raptor engines would be used for landing the second stage. Six additional, non-gimbaling vacuum-optimized Raptor Vacuum engines would provide primary thrust for the second stage, for a total of nine engines.<ref>{{Cite web |author1=Wall |first=Mike |date=2016-09-27 |title=SpaceX's Elon Musk Unveils Interplanetary Spaceship to Colonize Mars |url=https://www.space.com/34210-elon-musk-unveils-spacex-mars-colony-ship.html |url-status=live |archive-url=https://web.archive.org/web/20211203101057/https://www.space.com/34210-elon-musk-unveils-spacex-mars-colony-ship.html |archive-date=3 December 2021 |access-date=2023-05-22 |website=Space.com |language=en}}</ref><ref name="nsf20161003" /> Raptor Vacuums were envisioned to contribute a specific impulse of {{convert|382|isp|m/s|abbr=on}}, using a nozzle extension.<ref name=":0">{{Cite web|last=Musk|first=Elon|date=27 September 2016|title=SpaceX IAC 2016 Announcement|url=http://www.spacex.com/sites/spacex/files/mars_presentation.pdf|url-status=dead|archive-url=https://web.archive.org/web/20160928040332/http://www.spacex.com/sites/spacex/files/mars_presentation.pdf|archive-date=28 September 2016|access-date=27 September 2016|website=Mars Presentation|publisher=SpaceX}}</ref>

In September 2017 Musk said that a smaller Raptor engine—with slightly over half as much thrust as the previous designs—would be used on the next-generation rocket, a {{cvt|9|m|adj=on}}-diameter launch vehicle termed Big Falcon Rocket (BFR) and later renamed Starship.<ref>{{Cite web |author1=Wall |first=Mike |date=2017-09-29 |title=Elon Musk Wants Giant SpaceX Spaceship to Fly People to Mars by 2024 |url=https://www.space.com/38313-elon-musk-spacex-fly-people-to-mars-2024.html |url-status=live |archive-url=https://web.archive.org/web/20230603022809/https://www.space.com/38313-elon-musk-spacex-fly-people-to-mars-2024.html |archive-date=3 June 2023 |access-date=2023-05-22 |website=Space.com |language=en}}</ref> The redesign was aimed at Earth-orbit and cislunar missions so that the new system might pay for itself, in part, through economic spaceflight activities in the near-Earth space zone.<ref name="issR&Dconf20170719-49:48">{{cite AV media |url=https://www.youtube.com/watch?v=BqvBhhTtUm4&t=8m50s |title=Elon Musk, ISS R&D Conference |date=19 July 2017 |last=Musk |first=Elon |medium=video |location=ISS R&D Conference, Washington DC, USA |time=49:48–51:35 |access-date=21 September 2017 |archive-url=https://web.archive.org/web/20210204053231/https://www.youtube.com/watch?v=BqvBhhTtUm4&t=8m50s |archive-date=4 February 2021 |url-status=live |quote=''the updated version of the Mars architecture: Because it has evolved quite a bit since that last talk. ... The key thing that I figured out is how do you pay for it? If we downsize the Mars vehicle, make it capable of doing Earth-orbit activity as well as Mars activity, maybe we can pay for it by using it for Earth-orbit activity. That is one of the key elements in the new architecture. It is similar to what was shown at IAC, but a little bit smaller. Still big, but this one has a shot at being real on the economic front.'' |people=}}</ref> With the much smaller launch vehicle, fewer Raptor engines would be needed. BFR was then slated to have 31 Raptors on the first stage and 6 on the second stage.<ref name="sn20170929">{{cite news|last=Foust|first=Jeff|date=29 September 2017|title=Musk unveils revised version of giant interplanetary launch system|work=SpaceNews|url=http://spacenews.com/musk-unveils-revised-version-of-giant-interplanetary-launch-system/|access-date=1 October 2017|archive-date=30 September 2017|archive-url=https://archive.today/20170930093331/http://spacenews.com/musk-unveils-revised-version-of-giant-interplanetary-launch-system/|url-status=live}}</ref><ref name="nsf20161003" />

By mid-2018, SpaceX was publicly stating that the sea-level Raptor was expected to have {{convert|1700|kN|lbf|abbr=on}} thrust at sea level with a specific impulse of {{convert|330|isp|m/s|abbr=on}}, with a nozzle exit diameter of {{convert|1.3|m|ft|abbr=on}}. Raptor Vacuum would have specific impulse of {{convert|356|isp|m/s|abbr=on}} in vacuum<ref name="nsf20180809" /> and was expected to exert {{convert|1900|kN|lbf|abbr=on}} force with a specific impulse of {{convert|375|isp|m/s|abbr=on}}, using a nozzle exit diameter of {{convert|2.4|m|ft|abbr=on}}.<ref name="nsf20180809" />

In the BFR update given in September 2018, Musk showed a video of a 71-second fire test of a Raptor engine, and stated that "this is Raptor that will power BFR, both the ship and the booster; it's the same engine. [...] approximately a 200 (metric) tons engine aiming for roughly 300 bar chamber pressure. [...] If you had it at a high expansion ratio, has the potential to have a specific impulse of 380."<ref name="SpaceX20180917" /> SpaceX aimed at a lifetime of 1000 flights.<ref>{{cite magazine |last=O'Callaghan |first=Jonathan |date=31 July 2019 |title=The wild physics of Elon Musk's methane-guzzling super-rocket |url=https://www.wired.co.uk/article/spacex-raptor-engine-starship |url-status=live |archive-url=https://web.archive.org/web/20210222232043/https://www.wired.co.uk/article/spacex-raptor-engine-starship |archive-date=22 February 2021 |access-date=5 September 2019 |magazine=Wired}}</ref> [[File:Starship SN20 getting a tile inspection.jpg|thumb|Starship SN20 has its tiles inspected]] === Proposed Falcon 9 upper stage === In January 2016, the United States Air Force (USAF) awarded a {{USD|33.6 million}} development contract to SpaceX to develop a Raptor prototype for use on the upper stage of the Falcon 9 and Falcon Heavy. The contract required double-matching funding by SpaceX of at least {{USD|67.3 million}}.<ref name="dod20160113" /><ref name="snd20160113">{{cite news |date=13 January 2016 |title=SpaceX, Orbital ATK + Blue Origin Signed On By SMC For Propulsion Prototypes |work=Satnews Daily |url=https://www.satnews.com/story.php?number=1825850188 |url-status=live |access-date=7 February 2016 |archive-url=https://web.archive.org/web/20210204060021/https://www.satnews.com/story.php?number=1825850188 |archive-date=4 February 2021}}</ref> Engine testing was planned for NASA's Stennis Space Center in Mississippi under US Air Force supervision.<ref name="dod20160113" /><ref name="sn20160113" /> The USAF contract called for a single prototype engine and ground tests.<ref name="dod20160113" />

In October 2017 USAF awarded a {{USD|40.8 million}} modification contract for a Raptor prototype for the Evolved Expendable Launch Vehicle program.<ref name="dod20171019">{{cite web |date=19 October 2017 |title=Contracts: Air Force |url=https://www.defense.gov/News/Contracts/Contract-View/Article/1348379/ |url-status=dead |archive-url=https://web.archive.org/web/20180207005519/https://www.defense.gov/News/Contracts/Contract-View/Article/1348379/ |archive-date=7 February 2018 |access-date=6 February 2018 |work=U.S. Department of Defense Contracts press release |quote=''Space Exploration Technologies Corp., Hawthorne, California, has been awarded a $40,766,512 modification (P00007) for the development of the Raptor rocket propulsion system prototype for the Evolved Expendable Launch Vehicle program. Work will be performed at NASA Stennis Space Center, Mississippi; Hawthorne, California; McGregor, Texas; and Los Angeles Air Force Base, California; and is expected to be complete by April 30, 2018. Fiscal 2017 research, development, test and evaluation funds in the amount of $40,766,512 are being obligated at the time of award. The Launch Systems Enterprise Directorate, Space and Missile Systems Center, Los Angeles AFB, California, is the contracting activity (FA8811-16-9-0001).''}}</ref> It was to use liquid methane and liquid oxygen propellants, a full-flow staged combustion cycle, and be reusable.<ref name="sn20160113" />

=== Production === In July 2021, SpaceX announced a second Raptor production facility, in central Texas near the existing rocket engine test facility. The facility would concentrate on serial production of Raptor 2, while the California facility would produce Raptor Vacuum and new/experimental Raptor designs. The new facility was expected to eventually produce 800 to 1000 rocket engines each year.<ref name="dallasnews202107">{{cite news |date=10 July 2021 |title=Elon Musk says SpaceX's next Texas venture will be a rocket engine factory near Waco |work=Dallas Morning News |url=https://www.dallasnews.com/business/technology/2021/07/10/elon-musk-says-spacexs-next-texas-venture-will-be-a-rocket-engine-factory-near-waco/ |url-status=live |access-date=11 July 2021 |archive-url=https://web.archive.org/web/20210711024016/https://www.dallasnews.com/business/technology/2021/07/10/elon-musk-says-spacexs-next-texas-venture-will-be-a-rocket-engine-factory-near-waco/ |archive-date=11 July 2021}}</ref><ref name="spacex20210710">{{cite tweet |user=elonmusk |first=Elon |last=Musk |author-link=Elon Musk |number=1413909599711907845 |title=We are breaking ground soon on a second Raptor factory at SpaceX Texas test site. This will focus on volume production of Raptor 2, while California factory will make Raptor Vacuum & new, experimental designs |archive-url=https://web.archive.org/web/20210710200424/https://twitter.com/elonmusk/status/1413909599711907845|archive-date=10 July 2021 |url-status=live}}</ref> In 2019 the (marginal) cost of the engine was stated to be approaching {{Usd|1 million}}. SpaceX planned to mass-produce up to 500 Raptor engines per year, each costing less than {{Usd|250000}}.<ref>{{cite web |url=https://www.spacex.com/vehicles/starship/ |title=SpaceX – Starship |website=SpaceX |access-date=December 29, 2023 |quote=Starship is the fully reusable spacecraft and second stage of the Starship system. |archive-date=22 May 2020 |archive-url=https://web.archive.org/web/20200522145915/https://www.spacex.com/vehicles/starship/ |url-status=live }}</ref>

== Versions == Raptor has evolved significantly since it was revealed. {| class="wikitable" |+SpaceX rocket engines (sea-level, atmosphere and variant)<ref name="Raptor1&2">{{Cite tweet|author=SpaceX|user=SpaceX|number=1819795288116330594 |title=Performance stats of previous versions: Raptor 1 (sea level variant) Thrust: 185tf Specific impulse: 350s Engine mass: 2080kg Engine + vehicle-side commodities and hardware mass: 3630kg Raptor 2 (sea level variant) Thrust: 230tf Specific impulse: 347s Engine mass: 1630kg Engine + vehicle-side commodities and hardware mass: 2875kg Raptor 3 is designed for rapid reuse, eliminating the need for engine heatshields while continuing to increase performance and manufacturability |date=2024-08-03|language=en-US}}</ref><ref name="Raptor3">{{Cite tweet|author=SpaceX|user=SpaceX|number=1819772716339339664 |title=Raptor 3 (sea level variant) Thrust: 280tf Specific impulse: 350s Engine mass: 1525kg Engine + vehicle-side commodities and hardware mass : 1720kg |date=2024-08-03|language=en-US}}</ref> !Version !Mass (kg) !Thrust (t) !Chamber pressure (bar) !Specific impulse (s) !Engine only TWR |- |Raptor 1 |2080 |185 |250 |350 |89 |- |Raptor 2 |1630 |230 |300 |347 |141 |- |Raptor 3 |1525 |250 |330 |350 |164 |}

=== Raptor Vacuum === Each version of the engine has a corresponding Raptor Vacuum (RVac) variant<ref name="space20200924">{{cite tweet |user=SpaceX |number=1309317126130339845 |title=Completed a full duration test fire of the Raptor Vacuum engine at SpaceX's rocket development facility in McGregor, Texas |archive-date=18 November 2020 |archive-url=https://web.archive.org/web/20201118090130/https://twitter.com/SpaceX/status/1309317126130339845 |url-status=live}}</ref> with an extended, regeneratively-cooled nozzle for higher specific impulse in space. The vacuum-optimized Raptor targets a specific impulse of ≈{{cvt|380|isp|m/s}}.<ref name="raptor-sep-2019-isp"/> A full-duration test of version 1 of Raptor Vacuum was completed in September 2020 at McGregor.<ref name="space20200924" /> The first in-flight ignition of a Raptor Vacuum was on S25 during the second integrated flight test.<ref name=":45">{{Cite web |date=2023-11-21 |title=SpaceX – Launches |url=https://www.spacex.com/launches/mission/?missionId=starship-flight-2 |url-status=live |archive-url=https://web.archive.org/web/20231121034547/https://www.spacex.com/launches/mission/?missionId=starship-flight-2 |archive-date=November 21, 2023 |access-date=2023-11-21}}</ref>

=== Raptor 2 === thumb|A NASA employee standing between two Raptor 2 Vacuum engines (background) and a Raptor 2 sea-level (foreground). Raptor 2 is a complete redesign of the Raptor 1 engine.<ref name=":1">{{Cite web |date=2021-10-11 |title=Ship 20 prepares for Static Fire – New Raptor 2 factory rises |url=https://www.nasaspaceflight.com/2021/10/ship-20-static-fire-new-raptor-2-factory/ |url-status=live |archive-url=https://web.archive.org/web/20211016203607/https://www.nasaspaceflight.com/2021/10/ship-20-static-fire-new-raptor-2-factory/ |archive-date=16 October 2021 |access-date=2022-02-12 |website=NASASpaceFlight.com |language=en-US}}</ref> The turbomachinery, chamber, nozzle, and electronics were redesigned. Many flanges were converted to welds, while other parts were deleted.<ref name="nsf20220211">{{cite news |last1=Mooney |first1=Justin |last2=Bergin |first2=Chris |date=11 February 2022 |title=Musk outlines Starship progress towards self-sustaining Mars city |url=https://www.nasaspaceflight.com/2022/02/starships-self-sustaining-city-mars/ |access-date=12 February 2022 |work=NASASpaceFlight |archive-date=10 March 2022 |archive-url=https://web.archive.org/web/20220310040749/https://www.nasaspaceflight.com/2022/02/starships-self-sustaining-city-mars/ |url-status=live }}</ref> Simplifications continued after production began. On 10 February 2022, Musk showed Raptor 2 capabilities and design improvements.<ref name="nsf20220211" /><ref>{{Citation |title=Starship Update | date=10 February 2022 |url=https://www.youtube.com/watch?v=3N7L8Xhkzqo |access-date=2022-02-12 |language=en |archive-date=11 February 2022 |archive-url=https://web.archive.org/web/20220211183758/https://www.youtube.com/watch?v=3N7L8Xhkzqo |url-status=live }}</ref>

By 18 December 2021, Raptor 2 had started production.<ref>{{Cite tweet |number=1472054278613254147 |user=elonmusk |title=Each Raptor 1 engine above produces 185 metric tons of force. Raptor 2 just started production & will do 230+ tons or over half a million pounds of force. |first=Elon |last=Musk |author-link=Elon Musk |date=18 December 2021 |access-date=20 November 2022 |language=en}}</ref> By November 2022, SpaceX produced more than one Raptor a day and had created a stockpile for future launches.<ref name="Isaacson2023" /> Raptor 2s are produced at SpaceX's McGregor engine development facility.

Raptor 2s were achieving {{cvt|230|t-f|lbf|lk=on}} of thrust consistently by February 2022. Musk indicated that production costs were approximately half that of Raptor 1.<ref name=nsf20220211/>

=== Raptor 3 === Raptor 3 is aimed to ultimately achieve {{cvt|300|t-f|MN|lk=on}} of thrust in the booster/sea-level configuration.<ref name=sn20240406/><ref name=musk20241231>{{cite tweet|first=Elon|last=Musk|author-link=Elon Musk|user=elonmusk|number=1873986963407344069|title=It has more than twice the thrust already. When Raptor reaches 300 tons of thrust at liftoff, which Raptor 3.x can probably do (certainly Raptor 4 will), then it will have 10k metric tons of thrust at liftoff, which is 22.5M lb-F, almost exactly three times Saturn V.}}</ref> As of August 2024, it had reached a maximum of 280 tf, with a mass of 1525 kg and {{val|350|ul=bar}} chamber pressure in ground testing, though as of 2025 operational pressure has only been announced as high as 330 bar.<ref name="350 bar">{{Cite tweet |number=1657249739925258240 |user=elonmusk |title=Raptor V3 just achieved 350 bar chamber pressure (269 tons of thrust). Congrats to @SpaceX propulsion team! Starship Super Heavy Booster has 33 Raptors, so total thrust of 8877 tons or 19.5 million pounds. |first=Elon |last=Musk |author-link=Elon Musk}}</ref> During an update in May 2026, SpaceX revealed that Raptor 3 engines nominally produced 250tf (275tf for vacuum variant) of thrust.<ref name="sx20260512">{{Cite web |title=SpaceX: Starship V3 |url=https://www.spacex.com/updates#starship-v3 |url-status=live |publisher=SpaceX}}</ref>

The main goal of Raptor 3 was to eliminate protective engine shrouds by moving the majority of the plumbing and sensors into the engine's main structure,<ref name="ars20240408" /><ref name="musk20240406" /> taking advantage of the already present regenerative cooling. On 2 August 2024, Raptor 3 SN1 was revealed.<ref name="Raptor3SN1">{{cite tweet |user=elonmusk |first=Elon |last=Musk |author-link=Elon Musk |number=1819551225504768286 |title=Raptor 3, SN1}}</ref> The reduction in externally visible components resulted in the CEO of United Launch Alliance, Tory Bruno mistakenly accusing SpaceX of revealing a "partially assembled" engine while comparing it to "fully assembled" engines.<ref>{{cite tweet |first=Tory |last=Bruno |author-link=Tory Bruno |user=torybruno |number=1819819208827404616 |title=They have done an excellent job making the assembly simpler and more producible. So, there is no need to exaggerate this by showing a partially assembled engine without controllers, fluid management, or TVC systems, then comparing it to fully assembled engines that do.}}</ref><ref>{{cite tweet |number=1821674726885924923 |user=Gwynne_Shotwell |title=Works pretty good for a “partially assembled” engine |first=Gwynne |last=Shotwell |author-link=Gwynne Shotwell}}</ref>

Many bolted joints in Raptor 2 have been eliminated/replaced by single parts and/or welds. However, this makes servicing more difficult, as some parts may lie beneath welds.<ref name="tea20240622">{{cite AV media |url=https://www.youtube.com/watch?v=aFqjoCbZ4ik |title=First Look Inside SpaceX's Starfactory w/ Elon Musk |date=5 June 2024 |medium=video |time=41:50–42:18 |access-date=24 June 2024 |people=Elon Musk, Tim Dodd}}</ref>{{rp|42:19–45:50}}

On May 22, 2026, the twelfth flight test of Starship demonstrated the first flight of Raptor 3 engines. One of the vehicle's 33 Raptor 3 engines shut down prematurely during launch, but despite the engine-out, the vehicle achieved its planned trajectory. On the “boostback” burn, not all the engines ignited, and those that did shut down less than 20 seconds into the planned minute-long burn.<ref>Faust, Jeff (May 22, 2026). "[https://spacenews.com/spacex-launches-first-starship-v3/ SpaceX launches first Starship V3]", ''Space News''. Retrieved May 24, 2026.</ref>

=== LEET === In October 2021, SpaceX initiated an effort to develop a conceptual design for a new rocket engine with the goal of keeping cost below {{Usd|1000}} per ton of thrust. The project was called the 1337 engine, to be pronounced "LEET" (after a coding meme).<ref name="Isaacson2023">{{cite book |last1=Isaacson |first1=Walter |author-link=Walter Isaacson |title=Elon Musk |title-link=Elon Musk (Isaacson book) |date=12 September 2023 |publisher=Simon & Schuster |isbn=978-1-9821-8128-4 |pages=389–392 |language=en}}</ref>

Although the initial design effort was halted in late 2021, the project helped define an ideal engine, and likely generated ideas that were incorporated into Raptor 3. Musk stated then that "We can't make life multiplanetary with Raptor, as it is way too expensive, but Raptor is needed to tide us over until 1337 is ready."<ref name="Isaacson2023" />

In June 2024, the LEET concept was clarified as a total tearup of the Raptor 3 design, with Musk stating that SpaceX will "probably do that at some point. ... [Raptor 3] looks like a LEET engine, but its way more expensive because it still has printed parts, for example."<ref name=tea20240622 />

== Comparison to other engines == {{Main|Comparison of orbital rocket engines}}

{| class="wikitable sortable" ! scope="col" |Engine ! scope="col" |Rockets ! data-sort-type="number" scope="col" |Thrust ! data-sort-type="number" scope="col" |Specific impulse, vacuum ! nowrap="nowrap" data-sort-type="number" scope="col" |Thrust-to- weight ratio ! scope="col" |Propellant ! scope="col" |Cycle |- |Raptor 3 sea-level | Super Heavy, Starship | {{cvt|2750|kN|lbf}}<ref name="Raptor3" /> | {{cvt|350|isp|m/s}}<ref name="Raptor3" /> | 200 | rowspan="2" |{{chem|LCH|4}} / LOX (subcooled) | rowspan="2" |Full-flow staged combustion |- |Raptor 3 vacuum | Starship | {{cvt|{{#expr:280*9.80665*380/350 round -1}}|kN|lbf}}<ref name="Raptor3" /> | {{cvt|380|isp|m/s}}<ref name="raptor-sep-2019-isp" /> | 120 (at maximum) |- |Merlin 1D sea-level |Falcon booster stage |{{cvt|914|kN|lbf}} |{{cvt|311|isp|m/s}}<ref>{{cite web|title=Merlin 1C|url=http://www.astronautix.com/engines/merlin1c.htm|archive-url=https://web.archive.org/web/20110411134903/http://www.astronautix.com/engines/merlin1c.htm|url-status=dead|archive-date=11 April 2011|access-date=2 November 2013|publisher=Astronautix.com}}</ref> |176<ref name="quora-M1Dquestion">{{cite web|last=Mueller|first=Thomas|author-link=Tom Mueller|date=8 June 2015|title=Is SpaceX's Merlin 1D's thrust-to-weight ratio of 150+ believable?|url=https://www.quora.com/Is-SpaceXs-Merlin-1Ds-thrust-to-weight-ratio-of-150+-believable/answer/Thomas-Mueller-11|access-date=9 July 2015|quote=The Merlin 1D weighs 1030 pounds, including the hydraulic steering (TVC) actuators. It makes 162,500 pounds of thrust in vacuum. that is nearly 158 thrust/weight. The new full thrust variant weighs the same and makes about 185,500 lbs force in vacuum. You can do the math! BTW, I believe most other engines don't include the thrust vector control actuators in their {{abbr|F|force}}/W numbers.}}</ref> | rowspan="2" |RP-1 / LOX (subcooled) | rowspan="2" |Gas generator |- |Merlin 1D vacuum |Falcon upper stage |{{cvt|934|kN|lbf}}<ref name="sxf9ProductPage20160930">{{cite web|title=SpaceX Falcon 9 product page|url=http://www.spacex.com/falcon9|access-date=30 September 2016|archive-date=15 July 2013|archive-url=https://web.archive.org/web/20130715094112/http://www.spacex.com/falcon9|url-status=dead}}</ref> |{{cvt|348|isp|m/s}}<ref name="sxf9ProductPage20160930" /> |180<ref name="quora-M1Dquestion" /> |- |Blue Origin BE-4 |New Glenn, Vulcan |{{cvt|550000|lbf|kN|order=flip}}<ref name="sn20140917">{{cite news|last1=Ferster|first1=Warren|date=17 September 2014|title=ULA To Invest in Blue Origin Engine as RD-180 Replacement|work=Space News|url=http://www.spacenews.com/article/launch-report/41901ula-to-invest-in-blue-origin-engine-as-rd-180-replacement|url-status=dead|access-date=19 September 2014|archive-url=https://archive.today/20140918114236/http://www.spacenews.com/article/launch-report/41901ula-to-invest-in-blue-origin-engine-as-rd-180-replacement|archive-date=18 September 2014}}</ref> | {{convert|339|isp|m/s|abbr=on}}<ref name="RD-171b">{{cite web|title=RD-171b|url=https://forum.nasaspaceflight.com/index.php?topic=39674.msg1504802#msg1504802|access-date=13 May 2023}}</ref> | |{{chem|LCH|4}} / LOX | rowspan="6" |Oxidizer-rich staged combustion |- |Energomash RD-170/171M |Energia, Zenit, {{nowrap|Soyuz-5}} |{{cvt|7904|kN|lbf}}<ref name="RD-171">{{cite web|title=RD-171M|url=http://www.npoenergomash.ru/eng/dejatelnost/engines/rd171m/|access-date=30 June 2015|work=NPO Energomash}}</ref> |{{cvt|337.2|isp|m/s}}<ref name="RD-171" /> |79.57<ref name="RD-171" /> | rowspan="4" |RP-1 / LOX |- |Energomash RD-180 |Atlas III, Atlas V |{{cvt|4152|kN|lbf}}<ref name="RD-180">{{cite web|title=RD-180|url=http://www.npoenergomash.ru/eng/dejatelnost/engines/rd180/|access-date=30 June 2015|work=NPO Energomash|archive-date=4 December 2015|archive-url=https://web.archive.org/web/20151204180544/http://www.npoenergomash.ru/eng/dejatelnost/engines/rd180/|url-status=live}}</ref> |{{cvt|338|isp|m/s}}<ref name="RD-180" /> |78.44<ref name="RD-180" /> |- |Energomash RD-191/181 |Angara, Antares |{{cvt|2090|kN|lbf}}<ref name="RD-191">{{cite web|title=RD-191|url=http://www.npoenergomash.ru/eng/dejatelnost/engines/rd191/|access-date=7 April 2016|work=NPO Energomash}}</ref> |{{cvt|337.5|isp|m/s}}<ref name="RD-191" /> |89<ref name="RD-191" /> |- |Kuznetsov NK-33 |N1, {{nowrap|Soyuz-2-1v}} |{{cvt|1638|kN|lbf}}<ref name="NK-33">{{cite web|title=NK-33|url=http://www.astronautix.com/engines/nk33.htm|archive-url=https://web.archive.org/web/20020625124013/http://www.astronautix.com/engines/nk33.htm|url-status=dead|archive-date=25 June 2002|access-date=1 April 2015|publisher=Astronautix.com}}</ref> |{{cvt|331|isp|m/s}}<ref name="NK-33" /> |136.66<ref name="NK-33" /> |- |Energomash RD-275M |Proton-M |{{cvt|1832|kN|lbf}} |{{cvt|315.8|isp|m/s}} |174.5 |{{N2O4|link=yes}} / UDMH |- |Rocketdyne RS-25 |Space Shuttle, SLS |{{cvt|2280|kN|lbf}} |{{cvt|453|isp|m/s}}<ref>{{cite web|title=SSME|url=http://www.astronautix.com/s/ssme.html|archive-url=https://web.archive.org/web/20161228143022/http://astronautix.com/s/ssme.html|url-status=dead|archive-date=28 December 2016|access-date=25 October 2021|publisher=Astronautix.com}}</ref> |73<ref>{{cite web|title=Encyclopedia Astronautica: SSME|url=http://www.astronautix.com/s/ssme.html|archive-url=https://web.archive.org/web/20161228143022/http://astronautix.com/s/ssme.html|url-status=dead|archive-date=28 December 2016|access-date=25 October 2021}}</ref> |{{LH2}} / LOX |Fuel-rich staged combustion |- |Aerojet Rocketdyne RS-68A |Delta IV |{{cvt|3560|kN|lbf}} |{{cvt|414|isp|m/s}} |51<ref>{{cite web|title=Encyclopedia Astronautica: RS-68|url=http://www.astronautix.com/r/rs-68.html|archive-url=https://web.archive.org/web/20161228054251/http://astronautix.com/r/rs-68.html|url-status=dead|archive-date=28 December 2016|access-date=25 October 2021}}</ref> |{{LH2}} / LOX |Gas generator |- |Rocketdyne F-1 |Saturn V |{{cvt|7740|kN|lbf}} |{{cvt|304|isp|m/s}}<ref>{{cite web|title=F-1|url=http://www.astronautix.com/engines/f1.htm|url-status=dead|archive-url=https://web.archive.org/web/20131109232214/http://www.astronautix.com/engines/f1.htm|archive-date=9 November 2013|access-date=2 November 2013|publisher=Astronautix.com}}</ref> |83 |RP-1 / LOX |Gas generator |- | ISRO SCE-200 |LVM3, NGLV |{{cvt|2030|kN|lbf}} |{{cvt|335|isp|m/s}} |77 |RP-1 / LOX |Oxidizer-rich Staged combustion |}

==References== {{Reflist|36em|refs= <ref name=SpaceX20180917>{{Cite web|url=https://www.youtube.com/watch?v=zu7WJD8vpAQ|title=First Lunar BFR Mission|last=Musk|first=Elon|date=17 September 2018|website=YouTube|quote=And this is the Raptor engine that will power BFR both the ship and the booster, it’s the same engine. And this is approximately a 200-ton thrust engine that’s aiming for roughly a 300-bar or 300-atmosphere chamber pressure. And if you have it at a high expansion ratio it has the potential to have a specific impulse of 380.|time=45:30|access-date=19 September 2018|archive-date=11 February 2020|archive-url=https://web.archive.org/web/20200211143203/https://www.youtube.com/watch?v=zu7WJD8vpAQ|url-status=live}}</ref> <ref name=youtube-makinglifemulti>{{cite web |last1=Musk |first1=Elon |url=https://www.youtube.com/watch?v=tdUX3ypDVwI&t=22m34s |website=youtube.com |title=Making Life Multiplanetary |publisher=SpaceX |access-date=29 September 2017 |date=29 September 2017 |archive-date=18 March 2021 |archive-url=https://web.archive.org/web/20210318092716/https://www.youtube.com/watch?v=tdUX3ypDVwI |url-status=live }}</ref> }}

== External links == {{Commons category|Raptor (rocket engine)}} *[https://www.youtube.com/watch?v=e7kqFt3nID4 SpaceX Raptor Engine Test on 25 September 2016], ''SciNews'', video, September 2016. *[http://on-demand.gputechconf.com/gtc/2015/video/S5398.html GPUs to Mars: Full-scale Simulation of SpaceX's Mars Rocket Engine], Adam Lichtl and Steven Jones, GPU Technology Conference, spring 2015. *[https://www.twitter.com/artzius/status/1371479013798084609 unofficial Raptor engine log infographic]. {{SpaceX}} {{Rocket engines}}

{{DEFAULTSORT:Raptor}} Category:Rocket engines using methane propellant Category:SpaceX rocket engines Category:Rocket engines using full flow staged combustion cycle Category:Rocket engines of the United States Category:SpaceX Starship