NASA’s J2-X Engine Kicks Off 2012 With Powerpack Testing

Space Launch System
This image is from a 2008 cold flow test campaign conducted at NASA's Marshall Space Flight Center for the J-2X engine program. The next-generation engine was selected as part of the Space Launch System architecture that will once again carry humans into deep space. Photo Credit: NASA

BAY ST. LOUIS, Miss. — A new series of tests on the engine that will help carry humans to deep space will begin next week at NASA’s
Stennis Space Center in southern Mississippi. The tests on the J-2X engine bring NASA one step closer to the first human-rated liquid
oxygen and liquid hydrogen rocket engine to be developed in 40 years.

Tests will focus on the powerpack for the J-2X. This highly efficient and versatile advanced rocket engine is being designed to power the upper stage of NASA’s Space Launch System, a new heavy-lift launch vehicle capable of missions beyond low-Earth orbit. The powerpack comprises components on the top portion of the engine, including the gas generator, oxygen and fuel turbopumps, and related ducts and valves that bring the propellants together to create combustion and generate thrust.

“The J-2X upper stage engine is vital to achieving the full launch capability of the heavy-lift Space Launch System,” said William
Gerstenmaier, NASA’s associate administrator for the Human Exploration and Operations Mission Directorate. “The testing today
will help insure that a key propulsion element is ready to support exploration across the solar system.”

About a dozen powerpack tests of varying lengths are slated now through summer at Stennis’ A-1 Test Stand. By separating the engine
components — the thrust chamber assembly, including the main combustion chamber, main injector and nozzle — engineers can more
easily push the various components to operate over a wide range of conditions to ensure the parts’ integrity, demonstrate the safety
margin and better understand how the turbopumps operate.

“By varying the pressures, temperatures and flow rates, the powerpack test series will evaluate the full range of operating conditions of the engine components,” said Tom Byrd, J-2X engine lead in the SLS Liquid Engines Office at NASA’s Marshall Space Flight Center in
Huntsville, Ala. “This will enable us to verify the components’ design and validate our analytical models against performance data,
as well as ensure structural stability and verify the combustion stability of the gas generator.”

This is the second powerpack test series for J-2X. The powerpack 1A was tested in 2008 with J-2S engine turbomachinery originally
developed for the Apollo Program. Engineers tested these heritage components to obtain data to help them modify the design of the
turbomachinery to meet the higher performance requirements of the J-2X engine.

“The test engineers on the A-1 test team are excited and ready to begin another phase of testing which will provide critical data in
support of the Space Launch System,” said Gary Benton, J-2X engine testing project manager at Stennis.

J-2X is being developed for Marshall by Pratt & Whitney Rocketdyne of Canoga Park, Calif.

For more information on the J-2X engine, visit:

For more information on the Space Launch System, visit:



  1. Now that the Orion Multi Purpose Crew Vehicle has passed all its tests. It should not be long that (EFT-1) will be able to take place in late 2014. Then the Space Launch System can be biult by 2017. Then back to the Moon and onto Mars b 2025.

  2. The thought of a Saturn 5 type rocket is awesome but the cost of the SLS ($41 billion by the time it is all said and done) is a waste. Congress has mandated this to keep old Shuttle jobs around but we could do a lot of other things with 41 billion. Also the heavy lift is not going to be ready until 2030. The Spacex Falcon 9 can do the job for a lot less and a lot sooner. Either way SLS or Falcon it will be great to get back into something other than low earth orbit again,,,just wish it was sooner.

    • From where you get the 2030 number–certainly not NASA. According to NASA, the date for SLS is 2021-2023, though the Agency would like to move that number to an earlier date. Perhaps you’re thinking of the 130 mT variant? But NASA wants to move that launcher’s development up as well.

      Falcon 9 is a low-end medium-lift rocket with a LEO (28° inclination) payload capacity of 9,000 kg. It’s GTO is a paltry 2,400 kg. The Delta IV Heavy, by comparison, can loft 22,950 kg into LEO and 13,130 GTO. Even at its lowest rating, the SLS will embarrass both launchers with its 70,000 kg LEO payload capability. That means a 70 mT SLS will do in one mission what would take a Falcon 9 or a Delta IV Heavy over 7 and 3 launches each. But that makes sense–the Falcon 9 was developed with NASA COTS money to resupply ISS, not build a new space station and certainly not to go to the Moon.

      To put this in terms that people can get their arms around, Falcon 9 can only loft part of an ISS Destiny Module, a Delta IV Heavy could loft 1 1/2, and a 70 mT SLS could loft nearly 5. With the 130 mT SLS, just 4 launches would put up 15% more mass than the total of the ISS at 450 mT.

      Given the huge payload potential of the SLS and what that would mean for the national space program and for DoD, why do you count SLS a waste? I think I and many others see the SLS is just what the space program needs to get out of LEO in a meaningful way while offering really big payloads to LEO. That makes it a win-win.

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