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Archive 1

Cleanup

I've made a few edits to begin to cleanup the article, including requests for more up-to-date information on the formal status of this development(?) or conceptual(?) program. Much more is needed. N2e (talk) 05:48, 13 December 2010 (UTC)

Raptor is an engine, not a rocket stage.

SpaceX's web site and presentations mention the raptor as a rocket engine, not a rocket stage.I suppose it could be both, though. Recommend this article be renamed Raptor (rocket engine). I see that there are web pages that mention it as being an upper stage, but these seem to be mistaken, and SpaceX's own web site would be a much more reliable source for what it actually is. --71.214.211.224 (talk) 15:13, 3 November 2010 (UTC)

That seems to be correct, it is an engine and not a rocket stage. Let's wait another week or two to see in anyone else wants to weigh in. If not, let's just rename the article per proposal by 71.214.211.224 above. N2e (talk) 05:43, 13 December 2010 (UTC)
I cant find mention of Raptor as an engine on SpaceX's web site can you give a link. If Raptor is the name of the engine then it would make sence to change the name but as Raptor would use diffent fuel to the merlin it would need a new stage which would proberly carry the same name so the stage should still be mentioned. 86.173.128.42 (talk) 01:10, 22 December 2010 (UTC)
I don't know of a source still available from the SpaceX website; SpaceX may have gone proprietary on some of their current advanced plans. The source in the article, from the AIAA Innovations in Orbit: An Exploration of Commercial Crew and Cargo Transportation conference held in June 2009, is the source I am familiar with, and where I first heard of the Raptor concept design. I'm glad the AIAA caught the talk on video. I have captured the quotation: "[SpaceX has] begun initial design of the Raptor LOX/Hydrogen upper stage, which dramatically increases payload performance."
But the important note to make is we still have no (zip, zilch, nada) source that indicates that "Raptor" is a rocket stage. We could speculate on the name for the stage, but this is Wikipedia so we can't, and should just go with what we have verifiable information for. So I think it is time to rename the article. Looking at other rocket engine articles, I would propose: Raptor (rocket engine). N2e (talk) 06:25, 22 December 2010 (UTC)

Hydrogen?

According to Musk they are working on a Methane engine.--92.225.133.101 (talk) 22:58, 4 September 2012 (UTC)

Could be. But it is not clear that any Methane engine they might be working on is the Raptor, and therefore may not belong in this article. If you have a source, please edit the article and update it with the facts. Cheers. N2e (talk) 04:45, 5 September 2012 (UTC)
 Done. November talk by Elon Musk has confirmed that Raptor is now a Methane/LOX propellant engine. And another editor has started by adding that claim to the article. N2e (talk) 03:12, 22 November 2012 (UTC)

Article move

Based on previous discussions on this Talk page since 2010, and now recent reliable sources confirming both that the SpaceX "Raptor" development project is an engine, not an upper stage—and that it will utiilize Methane/LOX as a propellant, not LH2/LOX—I am going to move the article to Raptor (rocket engine) from its existing article name Raptor (rocket stage). N2e (talk) 03:17, 22 November 2012 (UTC)

 Done N2e (talk) 15:29, 22 November 2012 (UTC)

"MCT is not a engine. Raptor is the next engine."

Elon Musk, November 2012: "MCT is not a engine. Raptor is the next engine. More details to be revealed next year!".

Looks like this supports the discussion above, from 2010, and the article should be renamed. As well, this info will need to be reflected in the article body. Cheers. N2e (talk) 07:10, 21 November 2012 (UTC)

Here's a timelink to where in the video he says that quote.--Craigboy (talk) 08:35, 8 March 2013 (UTC)

more press on the same topic

Substantially more information released to the public, October 2013

In recent news releases, a good bit of new information has been publically released by SpaceX about the Raptor engine, and the whole methane-based Raptor concept objective (inner solar system travel and exploration and colonization of Mars). I have updated the article with several aspects of the new information: mostly technical specs, testing plans, and the launch vehicle objectives of the new methane powered rockets.

Having said that, there is more info in the Space News article, on the financials for the Mississippi test facility, and more, should other editors want to read it, and consider its use in the article. Cheers. N2e (talk) 02:26, 26 October 2013 (UTC)

vacuum specific impulse is different from the specific impulse of a vacuum optimized version

The first stage version would have a sea level ISP of 321s and a vacuum ISP of 363s. The 380s number is for a physically different engine, which the citations are correct about, but this article was not. A vacuum optimized Raptor engine would be required for 380s ISP. Vacuum optimization means a larger expansion nozzle so the gasses expand more completely. The Merlin article makes this distinction correctly - sea level ISP is 282s, vac ISP is 311s, and the vacuum version of the engine is 340s. I don't think it's correct list stats side by side for physically different versions of the engine without making the distinction. ArbitraryConstant (talk) 23:30, 31 December 2014 (UTC)

I believe I understand your technical point, and it is a good one. If you can think of a good way to present that reality in the article, go for it. As long as there are verifiable reliable sources for each number, and those sources clarify which engine config the isp number is for, I see no problem with being explicit about this detail. N2e (talk) 05:21, 1 January 2015 (UTC)

New thrust numbers

From 2015-01-05 Reddit AMA with Elon Musk,

  • Q: Has the Raptor engine changed in its target thrust since the last number we have officially heard of 1.55Mlbf SL thrust?
  • A (Musk): Thrust to weight is optimizing for a surprisingly low thrust level, even when accounting for the added mass of plumbing and structure for many engines. Looks like a little over 230 metric tons (~500 klbf) of thrust per engine, but we will have a lot of them :)

From same AMA:

  • Q: In your recent MIT talk, you mentioned that you didn't think 2nd stage recovery was possible for the Falcon 9. This is due to low fuel efficiency of kerosene fuel, and the high velocities needed for many payloads (high orbits like Geostationary orbit). However, you also said that full reusability would be possible for the Mars Colonial Transporter launch vehicle.
What have you learned from flights of Falcon 9 that taught you
a) that reuse of its second stage won't be possible and
b) what you'll need to do differently with MCT to reuse its second stage.
  • A (Musk): Actually, we could make the 2nd stage of Falcon reusable and still have significant payload on Falcon Heavy, but I think our engineering resources are better spent moving on to the Mars system.
MCT will have meaningfully higher specific impulse engines: 380 vs 345 vac Isp. For those unfamiliar, in the rocket world, that is a super gigantic difference for stages of roughly equivalent mass ratio (mass full to mass empty).

I don't know how and if this information should be incorporated into the article. Perhaps as a footnote to existing numbers until something more official is released. -- ToE 12:12, 6 January 2015 (UTC)

I'd argue that Elon Musk is a fairly official source. It's verified that it was actually him in the AMA, which gives credentials. Would we trust a SpaceX twitter message as an official source? I'd try to find some better information, but I think if the twitter message is the only source available, it's worth using. If that's agreed upon, this should be the same case. Support on including the new figures in the article.Appable (talk) 20:30, 12 February 2015 (UTC)
It's been a few months since the comments above..., but I just looked in the article, and it appears to be covered. This is a new engine development project, and SpaceX' own internal statements show that they are looking at a number of different engine sizes as they optimize their design to meet their objectives. All quite normal, at least for private companies. After all, company design specs are proprietary to the company, unless they have some reason to publish them (to customers, or perhaps government regulatory autorities, etc.). Moreover, this engine is still early in development. SpaceX are working on the powerhead and so no doubt they will use any and all early test data, as well as their evolving engine design and manufacturing techniques, to modify the design before committing it to metal.
But if you have some info that isn't already reflected in the article where a variety of size/thrust specs are already mentioned, then by all means add it along with a citation. Cheers. N2e (talk) 20:53, 7 May 2015 (UTC)

Liquid methane

Why not refer to liquid methane as LCH4 for short? The following paper does so: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090004695.pdf — Preceding unsigned comment added by 89.77.157.164 (talk) 07:09, 13 June 2014 (UTC)

I'm guessing it is because we are writing for a general readership, not a readership that has necessarily taken Chemistry and is familiar with Chemical abbreviations and symbols. N2e (talk) 20:55, 7 May 2015 (UTC)

Hi. I checked on the following references and found them to be redirected to hobbyspace.com/blog address:

"Long term SpaceX vehicle plans" - [1] -Retrieved 2009-07-13
"Notes: Space Access'11: Thurs. - Afternoon session - Part 2: SpaceX"- [2] RLV and Space Transport News. 2011-04-07. Retrieved 2011-04-08
"SpaceX Raptor LH2/LOX engine" - [3] RLV and Space Transport News. 2011-08-08. Retrieved 2011-08-09.

I followed up with HobbySpace publisher and editor Mr. Clark Lindsey about the links. He told me that old RLV News blog pages are no longer available for free. So Even if we put the new links, only people with a kind of subscription to NewSpaceGlobal.com will be able to access the pages. So I will remove these links and set the relevant texts as "citation needed". --Guyver (talk) 11:27, 20 August 2015 (UTC)

Thanks Guyver for all your work to clean this up. However, I believe the proper Wiki process for doing this is to leave the old/orginal link(s) that was/were supporting the statement, and tag the link with {{tl:dead link}}, or inside the cite template with the parm |deadurl=yes.
The principle is that some editor sourced it; if the source URL goes dead, or behind a paywall, then that reference to a source is just as valid in Wikipedia as a citation to, say, some obscure book that an author referenced from her bookshelf but is not available online. We keep the ref, even when it cannot be quickly reaccessed via the intertubz. Cheers. N2e (talk) 16:27, 4 September 2015 (UTC)
Thanks N2e for your explanation. I will do these kind of work properly in the future :) I want to bring back those links with "deadlink" tag but all of the links redirect to the same page - hobbtspace.com/blog - , I think those pages have new links which requires you to be a paid member to some service and old links are really invalid, you can not go the pages with these links even if you are a member. So does what you said about tagging "dead", apply to this kind of links too ? If so I update the page accordingly. Thanks again. --Guyver (talk) 18:05, 4 September 2015 (UTC)
Cool, Guyver. I appreciate the kind thoughts, and the constructive discussion.
On the substance, I think the idea (in the Wiki process) is to keep exactly the link that was valid (or reported to be valid by the editor who added that URL some months/years ago) along with the exact date that the editor accessed that link, but then add (also clarify) that the link is now a deadlink. I think that best keeps the history valid, for the good of the long-term historical use of the Wikipedia encyclopedia.
Having said that, it would be cool to find an editor who has a subscription; you might be able to find someone on the WP:WikiProject Spaceflight discussion page. Or who knows, maybe that site would consider giving one or two Wikipedia editors some sort of temporary (or longer) access to the archives to research it and clean up old links. Some of the many large commercial article repositories online (ones that normally charge big $$$ for access) are doing exactly that. Cheers. N2e (talk) 19:36, 5 September 2015 (UTC)
Guyver, one very useful tool in this situation is the Internet Archive's Wayback Machine, which stores historical snapshots of most URLs. The best practice when finding a dead link is to first search for it on the Wayback Machine, and if it is present you can simply add the archive link to the citation to restore it to working order. All of the HobbySpace links you removed were still available on the Internet Archive, so I have restored them with archive links. Now, a technically-savvy website owner can request that archived copies of their site be removed from the Archive at any time, and given your discussion with the editor of the site that may well take place. In the meantime, though, this helps preserve important sourcing information. 121.98.124.75 (talk) 11:25, 10 September 2015 (UTC)
121.98.124.75 Thank you very much, that will come in handy. Up until now, I had only used google's cache for website. --Guyver (talk) 09:50, 11 September 2015 (UTC)

First Raptor engine shipped to Texas for testing.

http://arstechnica.com/science/2016/08/spacex-has-shipped-its-mars-engine-to-texas-for-tests/?comments=1&post=31686107

"SpaceX appears to have taken a significant step forward with the development of a key component of its Mars mission architecture. According to multiple reports, during the Small Satellite Conference Tuesday in Logan, Utah, SpaceX President Gwynne Shotwell said the company has shipped a Raptor engine to its test site in MacGregor, Texas. A spokesman confirmed to Ars that the engine has indeed been moved to Texas for developmental tests."

I think that we should add that information to the article. Cheers..C: Dante 80 (talk) 08:34, 10 August 2016 (UTC)

Raptor on the test stand

Musk released two photos and tweeted various details of the engine today (via Twitter). I've updated the thrust spec for production engines in the article. Other data is also provided in that series of tweets. Very likely, one of the photos would meet fair use guidelines for use in this article. N2e (talk) 11:57, 26 September 2016 (UTC)

N2e, for the time being, pick one and go with fair use. Since these are closed door tests not open to the public (obviously), there would be no opportunity to otherwise obtain a freely licensed alternative. That said, the moment we're aware of SpaceX officially releasing an image under their CC0 license, we'll take it down. To that end, I've messaged Musk on Twitter to see if those images are intended to be CC0 as well. Maybe I'll hear back, but I'm not holding my breath. — Huntster (t @ c) 12:50, 26 September 2016 (UTC)
Someone has added one of those images to the article infobox. Not sure if all the licensing is straight vis a vis Wiki rules; but it's clearly the best image to have for today. Likely will be better non-twitter images released in the context of the speech slated for tomorrow. N2e (talk) 14:27, 26 September 2016 (UTC)
N2e, well this was...unanticipated. Musk affirmed the CC0 licensing rather quickly: https://twitter.com/elonmusk/status/780423473961115649. I'll get to work making sure both images are on Commons and set up properly. I'll post here when finished. — Huntster (t @ c) 15:13, 26 September 2016 (UTC)
Okay, images are up: File:Raptor-test-9-25-2016.jpg (already in article) and File:Raptor test firing, 2015-09-25.jpg. — Huntster (t @ c) 15:33, 26 September 2016 (UTC)

Comparison table

It would be nice if the table was sort-able.Doyna Yar (talk) 20:31, 27 September 2016 (UTC)

IAC 2016 talk

In this talk many details about both the vacuum and SL versions are unveiled. — Preceding unsigned comment added by Leonardorejorge (talk • contribs) 21:07, 27 September 2016 (UTC)

There are now (at least) two Raptor rocket engines under development

With the announcement this month (Jan 2016) that the USAF is going to contract with SpaceX to develop an upper stage Raptor engine (with USD33 million) that will also be methalox and use FFSC combustion cycle, there are now TWO Raptor rocket engines.

So the question is, over time, should this article become the overview article on the Raptor (rocket engine family) or should it become the article to describe only the one (full-size, for MCT, etc.) Raptor engine that SpaceX has been working on since approximately 2013, and began full-scale component testing in 2014-2015? Anyone have any thoughts? Cheers. N2e (talk) 15:51, 18 January 2016 (UTC)

Well, leave it until we know more about the different Raptors, but i think later becoming rocket engine family makes sense. SirKeplan (talk) 03:43, 19 January 2016 (UTC)
I've stubbed out a new article for the partially-USAF-funded prototype engine: Raptor prototype upper-stage engine. So that project can be just summarized in this article—which has been done, it seems—with the detail put in its own article. N2e (talk) 13:36, 28 January 2016 (UTC)

In my view, with the substantial additional new info released by Musk in late September, it is no longer clear (to me) if we have necessarily a separate engine for the USAF engine contract, where the US government military was going to pay 1/3 of some subset of development costs for a possible Falcon 9 and Falcon Heavy upper stage engine test on a ground test stand.

Now that Musk has released more data on the Raptor for the ITS launch vehicle, the question is: Do we have any source that clarifies that the two engines are not the same engine? (Before Sep, all we had was that no source indicated that they were one and the same. Now is unclear.) N2e (talk) 17:33, 1 October 2016 (UTC)

Test stand Raptor size

Dear Huntster (t @ c), the Raptor in the test stand is a scaled down version and next week an article will be discussing its thrust and turbomachinery power. Let's not keep this edit war, please. – Baldusi (talk) 15:23, 30 September 2016 (UTC)

Baldusi, this is not edit warring. The "scaled down" thing was not sourced, and I've seen no evidence of it being such. I'm not doubting you, and if an article comes out next week supporting that, I'm all for it. — Huntster (t @ c) 02:14, 1 October 2016 (UTC)

It appears that different sources are reporting different things on this, even in news stories written some days after the Musk reveal. I've updated the article to reflect this uncertainty on the size of the engine. Cheers. N2e (talk) 13:36, 12 October 2016 (UTC)

The NSF article was pretty clear: they first talk about the 2014 prototype that was tested in Stennis, then they move on to the full-scale version tested on a dedicated stand in McGregor. I have updated the text accordingly. Self-reverted after reading it again; still unclear. — JFG talk 15:03, 6 November 2016 (UTC)

Real versions?

The section on putative Raptor versions strikes me as contradicting the sources. First of all, the naming "ER40", "ER50" etc. is nowhere to be found, so we should strike it as WP:OR, and second I can only find sources mentioning TWO versions: the sea-level and vacuum versions, differing only by their nozzle. This is the same situation as with Merlin 1D and Vacuum, which are considered ONE engine. Hence my suggestions:

  • Revert the page name to Raptor (rocket engine), not "family"
  • List only the two official versions and don't assign them arbitrary names
  • Mention the prototype variants (e.g. the scaled-down model tested in 2014 or the 150-ratio nozzle potentially used to test the vacuum version on Earth) within the discussion of the engine development or under the corresponding production version

Looking forward to your input before proceeding. — JFG talk 15:25, 6 November 2016 (UTC)

Yeah, let's get some eyes on this. I believe that some source that User:Baldusi pointed me at showed that there was a exp ratio 40 engine for sea-level Earth use on the ITS launch vehicle and a very similar-but-slightly-different ER nozzle for the second stage spaceship and tanker since the optimizing condition was landing on Mars (very low pressure, with atmospheric lower than Earth) plus maneuvering etc. use in the lower-pressure higher-altitude atmosphere of Earth (or Mars); even though both spacecraft would briefly be used during the final landing burn at (near-sea-level, higher pressure) Earth landings, but that the ER=50 nozzle would perform better (Isp) and be "tough enough" to handle the back pressures etc. of landing on a flat surface (whereas the ER=40) engines are used only over an open flame trench where the back pressure is considerably less. Baldusi, R U there?
As for whatever descriptive terms are used, since the expansion ratios are the differing factor, and this is a technical article, they can be described non-technically as "sea level nozzle" and "vacuum nozzle", but listing the exp. ratio in the descriptor seems a fine and perfectly encyclopedic way to describe them. Just as long as we don't say, in wikiprose, that "SpaceX calls them the "ER40" model etc. In other words, we are writing prose for an encyclopedia, and lots of such prose is descriptive, rather than pure quotations of source material, and as such, we could, in fact, use the descriptive characteristic that is unique to describe the several different engine versions: expansion ratio 40, expansion ratio 50, expansion ratio 200, or ER40, ER50, ER200. At least, that is my take.
But, yes, if we can't find a WP:V source for the ER50 engine, then that part would go, and only what is in decent sources would be used here. N2e (talk) 17:00, 6 November 2016 (UTC)
Not sure where User:Baldusi has been; we all get busy with our non-WP life. But I think it is worth making the point that, based on current sourced information, it seems rather clear that Raptor is an engine class name for a number of different models of large methalox rocket engines. Nothing in the reliable sources indicates it is merely a single engine. N2e (talk) 15:14, 27 November 2016 (UTC)
Yes, I'm sorry that I haven't been around but my line of works and family life sometimes leave no material time to contribute here. I don't think that I pointed out the ER40 sources, I did for the isp figures. But from all the speculation and calculations that I've seen around, I only see inconsistencies. For example by measuring the presented graph, which were supposedly based on engineering models, you get different ER and diameters for first and second stage atmospheric optimized Raptors. Also, they are just now getting empirical result on a sub-scale demonstrator.
So, I'm pretty sure that Raptor should be considered for now as a moving target, and more of a project. This is normal for SpaceX, as if you try to get the specs on Merlin 1 you'll go from an ablative design with less thank 95klf to a 170klf regen engine. Even the Merlin 1D has changed its specs at least three times. So I would simple try to reflect the inconsistency of avaialable analysis, the culture of constant optimization and the early stage of development. I'm sorry but SpaceX is very jealous of its propulsion information and I couldn't get more than what's publicly available. Baldusi (talk) 15:41, 27 November 2016 (UTC)
Thanks for getting over here with a comment Baldusi. So with no reliable source for teh ER50 expansion ratio engines for the two spacecraft, I've removed that statement from the article prose. And when some years of ground tests are complete, and early flights, SPaceX will undoubtedly be updating all of these specification, specs that are only, as of now, based on CAD models of engines using CFT models for all of the low-atmospheric pressure specs.N2e (talk) 00:48, 30 November 2016 (UTC)

Musk did an AMA on BFR yesterday, and included some Raptor specs and other info

The CEO of SpaceX did an AMA (Ask Me Anything) limited to the topic of BFR yesterday. Includes statements about being easy to scale the engine to 170 tons, and on designed-in vehicle reliability from various engine aspects (RUD shielding; number of engines in the design, etc.)

While what he said is clearly a primary source, it is likely able to be used to back up certain facts in the BFR article since they are the utterances of a corporate CEO who is speaking about and making public statements about, a development program that said company is funding at present.

Here is one non-news source summary of some of Musk's statements:

Would imagine some bits of these statements will be covered in secondary source news media in the coming days. Cheers. N2e (talk) 12:55, 15 October 2017 (UTC)

Source

18 June 2009: First public mention of the Raptor engine design program

Here is the first public mention of an engine design program for an engine called Raptor. "We've begun initial design on the Raptor Lox/Hydrogen upper stage, which dramatically increases payload performance," at 4:54 in the video, in a talk given by SpaceX Max Vozoff at an AIAA conference (AIAA Innovations in Orbit: An Exploration of Commercial Crew and Cargo Transportation) on 18 June 2009. Video published 1 July 2009. YouTube recording, published by AIAA.

SpaceX seems to have subsequently decided to tighten down information release on their advanced (post-Merlin) engine development efforts, and didn't say much more until 2012. Cheers. N2e (talk) 03:11, 10 May 2018 (UTC)

Inconsistent F1 Engine Thrust-to-weight Ratio

The "Comparison to other engines" table lists the F1 engine's thrust to weight ratio as 83, this is inconsistent with the ratio listed on other pages. The F1's wiki page lists it as 94.1 and the comparison of rocket motor page lists it as 90.6 (though this is for the "F1A"). Pulu (talk) 14:31, 3 August 2018 (UTC)

Needs update

SpaceX is working on a single version for now (sea-level-like), a vacuum version might be added later. The pressure went up again, the sea-level engine now has a higher I_sp than the previous vacuum version. Some numbers here. --mfb (talk) 04:08, 20 September 2018 (UTC)

I've got a possible citation for the Raptor specific impulse, if some guesswork is allowed

"I realized that a methane-oxygen rocket engine could achieve a specific impulse greater than 380." - Elon Musk

http://money.cnn.com/2013/11/21/leadership/steve-jobs-elon-musk.pr.fortune/index.html

NortySpock (talk) 19:19, 24 November 2013 (UTC)

I'd go ahead and add it to the article, as the current citation does not support the 380 claim at all. N2e (talk) 05:38, 26 November 2013 (UTC)
Musk released a tweet today confirming the 382 s figure as a goal, following first test(s) of Raptor on a test stand. N2e (talk) 11:58, 26 September 2016 (UTC)

I wouldn't worry too much about an exact number. Elon Musk and his entire SpaceX tend to exaggerate the truth when it come to the capabilities of their technology. Maybe adding a Circa number next to it for clarification. -SuperSonicFlow

Given the Nozzle ratio of 40 and the combustor pressure off 300 bar, the vacuum ISP for the first stage will most likely not exceed 355 s. In order to achieve 375s, you could increase the combustion pressure a bit, and choose an expansion ratio of around 150, thus leading to a nozzle of around 2.5 m diameter. Geometrically, you could fit six nozzles into a stage with a diameter of 9 m, but it is probably on the upper end of what is technically possible. — Preceding unsigned comment added by 195.37.61.178 (talk) 12:56, 31 May 2019 (UTC)

Source

Merge with Raptor prototype upper-stage engine

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.
The result of the discussion is merge. --Soumyabrata (talk • subpages) 10:10, 31 December 2019 (UTC)

Since the upper stage engine is a development from this program, since this article is already labeled "family" (indicating more than one specific model) and since the upper stage article is so short, has redundancies (things repeated not just in the lead and body, but at multiple points in the short body), and is unlikely to grow much larger, I don't think we need two separate articles when a section here can cover it. oknazevad (talk) 14:16, 16 December 2018 (UTC)

Per Oknazevad. This article is about the entire family, and there's no real reason to have a separate article about a single variant. — Huntster (t @ c) 15:23, 17 December 2018 (UTC)
I'd be inclined to see, from reliable and verifiable sources, exactly what happened with that upper-stage prototype program that the US government paid for. We know that SpaceX started the Raptor engine, on methalox propellant, by Oct/Nov 2012 per sources in the article. We know they did this with private capital. We know they were testing the entire powerhead (turbines and preburners, just without a main combustion chamber) by 2014. We know the USAF got on that bandwagon in early 2016 with a $33 million dollar contract for SpaceX to build them a specific upper stage engine for the Falcon 9 upper stage; and that SpaceX had to put in private capital to the tune of 2x that amount (so $67 million). I don't think we have currently a great source that says what part of (which of any planned contract milestones) got met/achieved against that US gvmt one off contract. We do know that the US came back in late 2017, and gave another contract (~$40 million), for some different set of milestones USAF wanted in an engine prototype. I don't think we have yet had any editor find/add the sources to say which of the milestones on that second contract where achieved, and when.
Making this the primary article for all of the detail on those gvmt contracts, rather than merely a place for summary info while the other article contains the detail, would conflate US gvmt funding of one particular thing or demo/prototype engine design for c. $73mm with the overall engine development program which is, with these size engines, multiple protoypes, and typically 7+ year development/test cycles often costing upwards of $1 billion.
In short, I'd be against conflating a one-off contract with the US government for a specific prototype upper stage engine with the entire/overall Raptor development program, without clear sourcing that showed how that contract work fed the overall Raptor program, and not just a one-off US government need (at a time when the US Congress was throwing large amounts of money at US rocket engine companies, and through many times that much $$$ at other US rocket engine companies of the older / cost-plus contracting model of rocket engine development. Does anyone have such sources? N2e (talk) 16:45, 1 January 2019 (UTC)
Since there's no clear plan to equip any launcher with the scaled upper-stage Raptor engine, I support Oknazevad's idea. We can clarify all the details about private and gov't funding in this article. In short, I'd say we don't need a separate article whose only meaning of existence is to emphasize SpaceX's efficiency. PSR B1937+21 (talk) 09:59, 3 January 2019 (UTC)
Agree to merge. No upshot to keeping a forked article. — JFG talk 16:51, 7 February 2019 (UTC)
Merge. No point in having two articles on the same rocket engine. Biglulu (talk) 23:37, 3 March 2019 (UTC)
Oppose the merge—Just seems to me to be a one-off special contract prototype engine for the US Air Force, so that the US government could have an upper stage design methalox engine in their stable, but was just a prototype, and it never went into flight test, let alone production. We don't have many specifications on the engine, and thus cannot really place it well comparatively with any other methalox engine designs. It is notable as is, there are a number of news articles about it, and it meets WP:GNC. Best to keep it as a separate article for that one-off prototype rocket engine. N2e (talk) 02:07, 28 March 2019 (UTC)
@N2e: Thanks for your rationale, but you are the only editor opposing the merge, therefore I think we should go ahead, per WP:1AM. — JFG talk 08:52, 15 April 2019 (UTC)
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

What materials are used

Article doesn't seem to say what the major components of the engine are made from (Inconel?) and what parts are 3D printed and of what materials. Are the sea level and vacuum nozzles a niobium alloy like on the Merlin engines ? - Rod57 (talk) 01:18, 22 October 2020 (UTC)

Engine manifold is cast SX300 (later SX500) like Inconel.[1] - Rod57 (talk) 01:33, 22 October 2020 (UTC)

Any copper or bronzes ? The failing engines on SN8 had a green exhaust just before the crash landing. - Rod57 (talk) 21:35, 10 December 2020 (UTC)

From a Musk tweet (after SN8) that the nozzle bell is copper channels sleeved in inconel. - Rod57 (talk) 14:19, 18 December 2020 (UTC)

References

  1. ^ SpaceX Casting Raptor Engine Parts from Supersteel Alloys Feb 2019

Ignition method

Isn’t the ignition method also an important statistic?

It uses a basically oversized spark plug. BTW, please remember to sign your messages. Singularities421 (talk) 19:38, 17 August 2021 (UTC)

under development?

At what point does Raptor switch from "under development" to "operational"? There are 29 of them hanging off the bottom of BN4 today, and various test articles have flown 8(?) times. Must we wait until a Raptor reaches LEO? -Arch dude (talk) 22:32, 14 September 2021 (UTC)

"Comparison of engines is strictly not allowed in articles"

A recent edit made a significant change and put this in the comment on the edit. What WP does this reference?War (talk) 02:43, 15 September 2021 (UTC)

Hi, its me. I going to add the table back, I cannot remember to find the table MOS anywhere that mention this. CactiStaccingCrane (talk) 02:58, 19 September 2021 (UTC)

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Reason of reduction of cavitation risk.

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.[30]

It looks to me that the risk of cavitation reduction increase is incorrect or at least not sourced properly. Going to the cited source, it does not say anything like that. The actual reason is because the actual cause of cavitation is when local pressure is lower than the vapor pressure. Lower temperature reduces the vapor pressure. — Preceding unsigned comment added by 69.181.215.242 (talk) 19:23, 14 October 2021 (UTC)

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