Talk:RS-25

Requested move 31 May 2019

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion. 

The result of the move request was: Moved. (closed by non-admin page mover)  SITH   (talk)   14:40, 7 June 2019 (UTC)

Space Shuttle main engine → RS-25 – The designation of "Space Shuttle Main Engine" has shifted from being the title of this engine to a descriptor, and it's a misleading one at that. With the SLS now using these engines, along with NASA's shift to using the RS-25 name, I think keeping the old SSME name is doing more harm than good. We don't call the F-1 the Saturn V main engine after all. It's much more concise to say, "the space shuttle used three RS-25s as its main engines," than it is to say, "the SLS will use four Space Shuttle Main Engines." One's a proper rocket engine name, the other's an application of said rocket engine.

Basically, calling this rocket by it's technical designation is far more concise, consistent, and precise than calling it by its former use. While the latter was justifiable when the one and only application of the RS-25 was as part of the space shuttle system, it no longer makes sense to use that designator as the engine's primary name. Anyone searching for "space shuttle main engine" on wikipedia will understand immediately why they were redirected to an article named "Rocketdyne RS-25," but someone unfamiliar with their use in the shuttle program might be confused why their query for "RS-25" redirects them to "space shuttle main engine." - Jadebenn (talk) 08:15, 31 May 2019 (UTC)


 * On further introspection, perhaps it would be more consistent to rename it to either RS-25 or Aerojet Rocketdyne RS-25. The former is consistent with RS-68, and the latter is the actual full name. Unsure if that requires a new request or not - Jadebenn (talk) 08:44, 31 May 2019 (UTC)


 * Changed rename request to RS-25. - Jadebenn (talk) 09:04, 31 May 2019 (UTC)


 * Support as per your reasoning. HurricaneGeek2002 (talk) 17:56, 31 May 2019 (UTC)
 * Support – Makes perfect sense, similarly to other articles about rocket engines. — JFG talk 14:38, 3 June 2019 (UTC)
 * Support The engine now applies to more than the Space Shuttle, so it's appropriate that the page title accounts for that. However, I think the phrase "Space Shuttle main engine" should continue to be used on Space Shuttle-related pages, as that is what the RS-25 was known as during the Space Shuttle era. Balon Greyjoy (talk) 14:48, 3 June 2019 (UTC)
 * I'm not against that. In articles where the space shuttle is being discussed, using the SSME name can make sense. It's just, like you said, that the article name should reflect the fact that the engine is no longer exclusive to the space shuttle system. - Jadebenn (talk) 16:32, 3 June 2019 (UTC)


 * The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

SLS Section
This section has severely out-of-date info and could probably use some love. - Jadebenn (talk) 08:39, 9 June 2019 (UTC)

Not much on design for reuse
I couldn't see how many STS launches they were designed to do between overhauls (3 I think) or how many launches in total they were designed or intended for. Which parts had to be specially designed so that the engine was reusable ? How much did the design for reuse, increase the development cost and the cost per engine ? - Rod57 (talk) 12:08, 12 February 2020 (UTC)
 * In 1970 the design goal for the SSME was 50 flights before replacement, but I'm not sure what they were eventually certified for.
 * The original Rocketdyne turbopump bearings were only lasting for 2 fights, replaced later by P&W turbopumps. - Rod57 (talk) 09:42, 22 November 2020 (UTC)

Role of Chamber Coolant Valve
Section 1.4.1 (Controller - Main Valves) mentions that the Chamber Coolant Valve (CCV) is 100% open at high throttle settings, "for maximum cooling," and is progressively closed at low throttle setting "for reduced cooling". This seems to contradict the schematic diagram of the engine in this same article (which is derived from various sources). The CCV appears to function as a bypass valve, bypassing the coolant plumbing and going straight to the preburners. Therefore, it appears (to this layman) that closing the CCV would actually increase the fuel flow through the nozzle and chamber cooling sections, as less fuel is able to bypass and would be then increasingly forced through the two sections of plumbing that provide cooling. If this is the case, my guess is that at lower thrust levels, the mass flow through the engine is less and therefore the regenerative cooling is reduced, so the CCV is closed to pick up the slack. Indeed, the source referenced at the end of section 1.4.1, reference 5, doesn't mention anything about "maximum cooling" or "reduced cooling," and simply states the valve positions for various throttle levels, which makes me think that these statements in the article are incorrect. Of course, I could be entirely wrong about this - perhaps someone more knowledgeable than me can elaborate. — Preceding unsigned comment added by 67.83.150.17 (talk) 17:09, 24 November 2021 (UTC)