Talk:RS-25/Archive 1

Diagrams
Perhaps the article could use some diagrams, instead of just pictures of the SSMEs. Image:Orbiter_main_propulsion_system.png Image:SSME_major_components.PNG Cjosefy 20:58, 19 July 2006 (UTC)

Rename to Space Shuttle Main Engine
Space Shuttle Main Engine is a redirect to Space Shuttle main engine. Shouldn't it be the other way around? Cjosefy 20:07, 18 September 2006 (UTC)

The SSME after the Shuttle era
Removed the following text from the section, as I'm fairly sure it's outdated (and indeed, it completely contradicts the rest of the section) but I could be wrong so if anyone disagrees and wants to fit that back in somehow, feel free. A new Crew Launch Vehicle, also known as ARES (Affordable REsponsive Spacelift) is in development. Three SSME are to be used on this vehicle. It is scheduled for a demonstration flight in 2010 and may see operation in 2018. --Cecilkorik 05:14, 8 December 2006 (UTC)

First throttling rocket engine
Honeywell describes the SSME as, "the first rocket engine capable of being throttled." If this is true, it should be prominently mentioned in the Introduction section. (sdsds - talk) 18:14, 9 August 2007 (UTC)


 * The statement is clearly incorrect, as the Reaction Motors XLR-99 used on the X-15 was throttleable, as was the Descent Propulsion System used on the Apollo Lunar Module. Both predate the SSME by decades. Joema 12:23, 12 August 2007 (UTC)

SSME Power Ratings
Can someone explain to me why(how) the SSME are normally flown at 104.5%? Doesn't 100% mean all/the whole thing. I mean when you eat 100% of a pizza, you've eaten the whole pizza. This question is just a question in general, I'm not questioning if the article is correct. I've seen this in many other places, I just don't understand it. Thanks Rocketmaniac 11:49, 13 November 2007 (UTC)


 * Made an effort to explain this in article. See "SSME thrust specifications" subheading. Joema 15:46, 13 November 2007 (UTC)

Re all the combustion & nozzle properties given in this article, would someone who has all the numbers please compile a consistent set of values for at least one of the SSME power ratings (100%, 104% or 104.5% -- which it is, I can't tell --, and 109%), in one list. My preference would be for the current launch power, which I understand is 104% (104.5% ?) of original design. I'd like to assign to my students a simplified supersonic nozzle computation based upon the numbers for the SSME. And perhaps also please make clear what specs are upgraded from original (e.g., throat area & combustion chamber pressure).

From perusing the references, I come up with the following (I'm trying to come up with a consistent set of numbers for today's launch values, which I understand are at 104% of reference power):

Nozzle throat area: 0.0600 m2 (from Ref 6, p.23; this nozzle throat area is 9% larger than the original, allowing a lower combustion chamber pressure; the first flight employing this new design was mission STS-89, in 1998, Ref "Space Shuttle Main Engine Enhancements")

Nozzle expansion ratio: 77.5 (Ref "NASA Shuttle Press Kit ...", p. 3)

Nozzle exit area: 4.67 m2 (don't have an original ref for this)

Combustion chamber pressure (104%): 19.6 MPa (Ref 6, p. 24)

Combustion chamber temperature (% power rating not known; maybe the same for all): approximately 6000 R (that's Rankines, as in 9/5 Kelvins; Ref 6, pp. 4, 23. Note, a value of 6000 F is quoted in the Introduction of the present article. Note 6000 F = 6460 R, not an insignificant difference. I don't know for certain which is correct, the present article or Ref. 6. I believe Ref 6 is correct, since it is a NASA technical report, and the value 6000 R appears in at least 2 places I have read. Furthermore, I see Rankine temperatures quoted in other places in the same report. Note, I see the same -- I believe, erroneous -- 6000 F value appears in Ref "The Roar of Innovation", 2002. I believe the value "6000 F" in the Introduction section of the present article is likely incorrect and should be changed to "approximately 6000 R" or "approximately 6500 F". Also, a more precise number would be appreciated.)

Design altitude: 60,000 ft (don't have an original ref for this)

Vacuum thrust (104%): 2.18 MN (Ref 6, p. 24, and "NASA Shuttle Press Kit ...")

Vacuum specific impulse (104%): 453.4 sec (Ref 6, p. 24)

Note, in compiling the above I have found the most useful references to be Ref 6: "Report of the SSME Assessment Team", 1993; and "NASA Shuttle Press Kit SSME Reference", publication date unknown (I can find no publication date within this reference).

Prfssr (talk) 06:04, 15 March 2010 (UTC)

Return to Ares V
Hey, I found this website just a few days ago. Nasaspaceflight.com It talks about how NASA engineers are actually going reconsider their original plans and put SSMEs on Ares V Core stage. Should this be included in the article? --68.60.67.149 (talk) 00:13, 30 December 2008 (UTC)

Number produced and when production ended
The article doesn't seem to state how many SSMEs were produced, nor when production ended. These are key bits of info needed for completeness. I've thus re-rated the article for WikiProject Space as class=C. (sdsds - talk) 03:35, 24 June 2009 (UTC)

The cost of each SSME is approximately
Recent edits added a sentence to the Introduction section that begins, "The cost of each SSME is approximately...." Not only is the value given dubious, this entire formulation of SSME costing is inadequate, since the cost per engine is highly dependent on the number of engines ordered. (sdsds - talk) 01:05, 19 November 2010 (UTC)

Removed list of missions
The following unlabeled list of (apparently) all shuttle missions up to 2006 really doesn't seem to belong in an article on the Space Shuttle main engine. Perhaps it should be a separate list article, if there isn't one already.

Based on a P&W handout, SSME missions up to 2006:


 * SN-2005 5
 * STS-1, STS-2, STS-3, STS-4, STS-5
 * SN-2006 5
 * STS-1, STS-2, STS-3, STS-4, STS-5
 * SN-2007 5
 * STS-1, STS-2, STS-3, STS-4, STS-5
 * SN-2011 7
 * STS-9, STS-51J, STS-61B, STS-33, STS-31, STS-41, STS-50
 * SN-2012 22
 * STS-6, STS-7, STS-8, STS-41B, STS-41C, STS-51A, STS-51C, STS-51D, STS-51G, STS-51I, STS-35, STS-43, STS-45, STS-53,STS-60, STS-67, STS-74, STS-79, STS-83, STS-86, STS-90, STS-93
 * SN-2015 9
 * STS-6, STS-7, STS-8, STS-41B, STS-61C, STS-40, STS-44, STS-49,STS-52
 * SN-2017 14
 * STS-6, STS-7, STS-8, STS-51J, STS-61B, STS-27, STS-49, STS-53,STS-57, STS-61, STS-65, STS-66, STS-70, STS-75
 * SN-2018 12
 * STS-9, STS-41D, STS-51A, STS-51C, STS-51D, STS-51G, STS-51I,STS-61C, STS-54, STS-56, STS-58, STS-59
 * SN-2019 19
 * STS-9, STS-51J, STS-61B, STS-26, STS-28, STS-36, STS-38, STS-37,STS-48, STS-50, STS-54, STS-57, STS-61, STS-65, STS-70, STS-76,STS-83, STS-86, STS-93
 * SN-2020 6
 * STS-41C, STS-41G, STS-51B, STS-51F, STS-61A, STS-51L
 * SN-2021 6
 * STS-41D, STS-41G, STS-51B, STS-51F, STS-61A, STS-51L
 * SN-2022 8
 * STS-26, STS-29, STS-28, STS-32, STS-38, STS-40, STS-42, STS-47
 * SN-2023 5
 * STS-41G, STS-51B, STS-51F, STS-61A, STS-51L
 * SN-2024 7
 * STS-32, STS-35, STS-43, STS-45, STS-53, STS-56, STS-58
 * SN-2026 6
 * STS-39, STS-42, STS-47, STS-68, STS-74, STS-80
 * SN-2027 7
 * STS-30, STS-34, STS-36, STS-38, STS-40, STS-42, STS-46
 * SN-2028 11
 * STS-26, STS-29, STS-28, STS-32, STS-35, STS-43, STS-45, STS-59,STS-68, STS-71, STS-72
 * SN-2029 15
 * STS-27, STS-30, STS-34, STS-39, STS-44, STS-47, STS-55, STS-51,STS-62, STS-64, STS-63, STS-69, STS-75, STS-80, STS-84
 * SN-2030 10
 * STS-27, STS-30, STS-34, STS-36, STS-39, STS-44, STS-49, STS-52,STS-65, STS-66
 * SN-2031 17
 * STS-29, STS-33, STS-31, STS-41, STS-37, STS-48, STS-50, STS-55,STS-51, STS-62, STS-64, STS-67, STS-73, STS-79, STS-84, STS-87,STS-93
 * SN-2032 7
 * STS-46, STS-60, STS-71, STS-74, STS-80, STS-84, STS-90
 * SN-2033 9
 * STS-46, STS-54, STS-56, STS-61, STS-59, STS-68, STS-67, STS-79,STS-94
 * SN-2034 9
 * STS-52, STS-57, STS-51, STS-60, STS-66, STS-71, STS-75, STS-81,STS-94
 * SN-2035 3
 * STS-63, STS-69, STS-76
 * SN-2036 3
 * STS-70, STS-72, STS-78
 * SN-2037 5
 * STS-73, STS-77, STS-82, STS-94, STS-87
 * SN-2038 3
 * STS-73, STS-77, STS-82
 * SN-2039 4
 * STS-72, STS-78, STS-85, STS-87
 * SN-2040 4
 * STS-77, STS-82, STS-86, STS-91
 * SN-2041 5
 * STS-78, STS-81, STS-85, STS-90, STS-88
 * SN-2042 3
 * STS-81, STS-85, STS-91
 * SN-2043 7
 * STS-89, STS-95, STS-103, STS-101, STS-97, STS-100, STS-108
 * SN-2044 7
 * STS-89, STS-88, STS-99, STS-106, STS-98, STS-105, STS-111
 * SN-2045 8
 * STS-89, STS-95, STS-92, STS-102, STS-105, STS-110, STS-113,STS-121
 * SN-2047 6
 * STS-91, STS-96, STS-106, STS-98, STS-104, STS-109
 * SN-2048 4
 * STS-95, STS-92, STS-110, STS-112
 * SN-2049 7
 * STS-96, STS-103, STS-101, STS-97, STS-100, STS-108, STS-107
 * SN-2050 5
 * STS-88, STS-99, STS-108, STS-111, STS-113
 * SN-2051 4
 * STS-96, STS-104, STS-110, STS-112
 * SN-2052 5
 * STS-99, STS-106, STS-98, STS-105, STS-121
 * SN-2053 5
 * STS-103, STS-92, STS-102, STS-109, STS-107
 * SN-2054 6
 * STS-101, STS-97, STS-100, STS-111, STS-114, STS-121
 * SN-2055 1
 * STS-112
 * SN-2056 6
 * STS-102, STS-104, STS-109, STS-113, STS-107, STS-114
 * SN-2057 1
 * STS-114
 * SN-2107 5
 * STS-33, STS-31, STS-41, STS-37, STS-48
 * SN-2109 17
 * STS-41B, STS-41C, STS-41D, STS-51A, STS-51C, STS-51D, STS-51G,STS-51I, STS-61C, STS-55, STS-58, STS-62, STS-64, STS-63, STS-69,STS-76, STS-83 — Preceding unsigned comment added by Dfeuer (talk • contribs) 04:44, 18 August 2011 (UTC)
 * I just found List of space shuttle missions, which is much more useful than the list I just cut. Dfeuer (talk) 05:54, 18 August 2011 (UTC)

This seems like an error: SN-2056 6 is listed as being used in STS-107, which was destroyed. How could it have been used in STS-114? — Preceding unsigned comment added by 50.43.36.11 (talk) 02:54, 27 September 2011 (UTC)
 * I'm agreeing with Dfeuer in believing the above list does not belong in the article. It is trivia that is of no significance. If you feel differently. Discuss it here before putting it in the article.--71.214.211.30 (talk) 20:02, 5 October 2011 (UTC)

SMTE (aka RS-25)
Will someone knowledgeable care to mention the proposed SMTE variant? I wouldn't think it would need an article of its own, but it would be good to give a brief history of the idea. Thanks! 131.252.209.128 (talk) 05:59, 27 June 2009 (UTC)


 * Also, the article needs to be rewritten from the perspective of the engine being used for multiple launch vehicles/systems, since a version is now planned for use on the SLS. --71.214.214.251 (talk) 21:46, 14 September 2011 (UTC)