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J-2X

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J-2X
A computer rendering of a J-2X.
Country of originUnited States
ManufacturerAerojet Rocketdyne
ApplicationUpper stageengine
AssociatedLVBlock IISpace Launch System(EDS)
PredecessorJ-2
StatusUnknown
Liquid-fuel engine
PropellantLiquid oxygen/liquid hydrogen
Mixture ratio5.5–4.5
CycleGas generator
Configuration
Nozzle ratio92:1
Performance
Thrust, vacuum1,307 kN (294,000 lbf)
Thrust-to-weight ratio55.04
Specific impulse,vacuum448 seconds (4.39 km/s)
Dimensions
Length4.7 metres (15 ft)
Diameter3 metres (9.8 ft)
Dry mass5,450 pounds (2,470 kg)
References
References[1][2]

TheJ-2Xis aliquid-fueledcryogenic rocket enginethat was planned for use on the Ares rockets ofNASA'sConstellation program,and later theSpace Launch System.Built in the United States byAerojet Rocketdyne(formerly,Pratt & Whitney Rocketdyne), the J-2X burnscryogenicliquid hydrogenandliquid oxygenpropellants, with each engine producing 1,307 kN (294,000 lbf) ofthrustin vacuum at aspecific impulse(Isp) of 448 seconds (4.39 km/s).[2]The engine's mass is approximately 2,470 kg (5,450 Lb), significantly heavier than its predecessors.[2]

The J-2X was intended to be based on theJ-2used on theS-IIandS-IVBstages of theSaturnrockets used during theApollo program,but as required thrust for the Ares I increased due to weight problems it became a clean-sheet design. It entered development in 2007 as part of the now-cancelledConstellation program.[2]Originally planned for use on theupper stagesof theAres IandAres Vrockets, the J-2X was later intended for use in theEarth Departure Stageof the Block 2Space Launch System,the successor to the Constellation program. The engine is intended to be more efficient and simpler to build than its J-2 ancestor, and cost less than theRS-25engine.[1]Differences in the new engine include the removal ofberyllium,a centrifugal turbo pump versus the axial turbo pump of the J-2, different chamber and nozzle expansion ratios, a channel-walled combustion chamber versus the tube-welded chamber of the J-2, a redesign of all the electronics, agas generatorand supersonic main injector based on theRS-68,[3]and the use of 21st-century joining techniques.[2][4]

Testing

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On 16 July 2007 NASA officially announced the award toPratt & Whitney Rocketdyne(PWR) of a $1.2 billion contract "for design, development, testing and evaluation of the J-2X engine",[5]and began construction of a new test stand for altitude testing of J-2X engines atStennis Space Centeron 23 August 2007.[6]

Component testing was undertaken between December 2007 and May 2008, with nine tests of heritage J-2 engine components at SSC in preparation for the design of the J-2X engine.[7]and on 8 September 2008 PWR announced successful testing of the initial J-2X gas generator design.[8]The completion of a second round of successful gas generator tests was announced on 21 September 2010.[9]

Starting in 2011, the full J-2X engine, derived from heritage and new designs, has undergone hot-fire tests.

  • June 2011: The first hot-fire test.[10]
  • November 2011: A test-firing lasting 499.97 seconds.[11]
  • June 2012: A test-firing lasting 1,150 seconds, during which the J-2X was throttled up and down.[12]
  • July 2012: A test-firing for 1,350 seconds (22+1⁄2minutes).[13]
  • December 2012: Final test-firing of thepowerpackassembly.[14]
  • Feb 2013: Testing of engine 10002 begins on test stand A2 for 6 tests.[15]
  • June 2013: Engine 10002 moved to test stand A1 for 7 further tests.[16]
  • Sept 2013: Final test-firing of engine 10002.[17]
  • Nov 2013: Testing of engine 10003 begins.[16]

Program status

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In October 2013, it was reported that work on the J-2X would pause following development testing in 2014, due to funding limitations, an expected delayed need for the engine's capabilities for piloted missions to Mars, and selection[18]of theRL10poweredExploration Upper Stagefor SLS.[19]

In September 2022, the components of the J-2X was put up for auction on GSA Auctions, likely confirming the cancellation of the program.[20]

See also

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References

[edit]
Wikimedia Commons has media related toJ-2X (rocket engine).
  1. ^ab"J-2X Engine".Aerojet Rocketdyne. Archived fromthe originalon 12 January 2014.Retrieved9 January2014.
  2. ^abcdeMark Wade (17 November 2011)."J-2X".Encyclopedia Astronautica. Archived fromthe originalon 12 December 2011.
  3. ^"The J-2X Upper Stage Engine: From Design to Hardware. Thomas Byrd, Deputy Manager, J-2X Upper Stage Engine Element Ares Projects Office Marshall Space Flight Center Huntsville, AL 35812"(PDF).
  4. ^William D Greene (4 June 2012)."J-2X Extra: What's in a Name?".NASA. Archived fromthe originalon 9 November 2010.Retrieved11 June2012.
  5. ^"NASA Awards Upper Stage Engine Contract for Ares Rockets".NASA. 16 July 2007. Archived fromthe originalon 1 August 2020.Retrieved17 July2007.
  6. ^"NASA's Stennis Space Center Marks New Chapter in Space Exploration".NASA. 23 August 2007. Archived fromthe originalon 4 April 2012.Retrieved26 February2012.
  7. ^"NASA Successfully Completes First Series of Ares Engine Tests".NASA. 8 May 2008. Archived fromthe originalon 6 April 2012.Retrieved26 February2012.
  8. ^"Pratt & Whitney Rocketdyne Completes Successful Test of J-2X Gas Generator".Pratt & Whitney Rocketdyne. 8 September 2008. Archived fromthe originalon 9 August 2009.
  9. ^"Pratt & Whitney Rocketdyne Completes Latest Round of Tests on J-2X Gas Generator"(Press release). Pratt & Whitney Rocketdyne. September 21, 2010.RetrievedDecember 10,2022.
  10. ^Morring, Frank."First J-2X Hot-Fire Test Could Come Next Week".Aviation Week.Archivedfrom the original on 28 October 2020.Retrieved19 June2011.
  11. ^"NASA Test Fires Engine for Giant New Rocket".Space. 9 November 2011.Retrieved26 February2012.
  12. ^"NASA Surpasses Test Facility Record with J-2X Powerpack Test".National Aeronautics and Space Administration. 8 June 2012.Retrieved10 June2012.
  13. ^"A Summer of Records for Engine Testing".National Aeronautics and Space Administration. 26 June 2012.Retrieved26 June2012.
  14. ^"Beating Heart of J-2X Engine Finishes Year of Successful Testing".National Aeronautics and Space Administration. 13 Dec 2012. Archived fromthe originalon 17 December 2012.Retrieved14 Dec2012.
  15. ^"NASA Set for New Round Of J-2X Testing at Stennis Space Center".National Aeronautics and Space Administration. 11 Feb 2013.Retrieved6 Feb2014.
  16. ^ab"J-2X Progress: November 2013 Update".National Aeronautics and Space Administration. 15 Nov 2013.Retrieved6 Feb2014.
  17. ^"One Final Test for J-2X Engine No. 10002".National Aeronautics and Space Administration. 5 Sep 2013.Archivedfrom the original on 2021-12-21.Retrieved6 Feb2014.
  18. ^Bergin, Chris (12 October 2014)."NASA lines up Exploration Upper Stage workhorse for SLS".NASASpaceflight.RetrievedNovember 8,2014.
  19. ^"NASA's J-2X Engine To Be Mothballed After Testing".Aviation Week and Space Technology magazine. 4 Oct 2013. Archived fromthe originalon 2 November 2013.Retrieved29 Oct2013.
  20. ^"GROUP 1 COMPONENTS TO ASSEMBLE J2X ROCKET ENGINE".RetrievedSeptember 12,2022.
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