NASA's first J-2X engine rockets through first round of testing; development continues strong

Dec 22, 2011 By Jennifer Stanfield
NASA conducted a successful J-2X 500-second test firing on Nov. 9 at the A-2 test stand at Stennis Space Center. Credit: NASA/SSC

(PhysOrg.com) -- The best tech gift for propulsion engineers at the Marshall Space Flight Center in Huntsville, Ala.? It's NASA's first new human-rated rocket engine to be developed in 40 years. The J-2X engine -- highly efficient and versatile -- is a key component of the Space Launch System's second stage and will propel the nation's new heavy-lift launch vehicle beyond low-Earth orbit.

Using advanced technology, engineering processes and design, engineers at and Pratt & Whitney Rocketdyne in Canoga Park, Calif., are setting new records in rocket engine development with the first J-2X engine unit, dubbed E10001. During 2011, E10001 rocketed through its first ten tests probing engine performance and accumulated a total hot-fire test run time of 1,040 seconds at NASA's Stennis Space Center in southern Mississippi.

"E10001 got to 100 percent power in just four tests and achieved a full flight-duration test of 500 seconds in its eighth test -- quicker than any other U.S. engine program in history," said Tom Byrd, J-2X engine lead in the SLS Liquid Engines Office. "That provides a tremendous cost savings to the Space Program. It also validates that our design is solid and allows us to move farther in engine development quicker."

In this first year of testing, the J-2X team focused on characterizing basic components' performance, understanding integrated engine system performance during prestart, start, full power operation and shutdown, as well as demonstrating full mission duration.

Today's propulsion engineers are like high-tech Santa elves churning out toys for Christmas Day: strategic and focused. New engineering processes, along with design, analysis and development advances gleaned from numerous previous programs, have provided the J-2X engine team with a solid foundation to design, build and test the engine.

For example, the first J-2X engine has demonstrated high initial quality through manufacturing and assembly. High initial quality avoids costly and time-consuming re-works and re-designs that have historically typified building large engines. "For the J-2X engine, we’ve brought together a great suite of analytical models for loads, tolerances, structural integrity and assembly sequence," said Byrd. "Truly, we had little to no surprises assembling the E10001 test engine -- the components fit together like a glove -- and proved this new way really works for designing an engine."

Modern engineering tools and processes also enable a considerably shorter, more focused test schedule, saving a great deal of cost and time. The J-2X is totally redesigned from the heritage J-2 engine that flew humans to the moon in the 1960's and 1970's. And yet, over the coming years, the J-2X engine test program will need only five percent the number of tests required to develop the original J-2 engine. That’s about 150 tests now versus about 3000 then. The engineers who successfully got humans to the moon years ago clearly knew what they were doing, but today's engineers are equipped with all sorts of modern engineering tools, processes and lessons from the past -- and the SLS Program is the beneficiary in terms of an affordable engine development test program.

Byrd noted that this year's testing wasn't all smooth sailing. For example, a seal in the J-2X main oxidizer valve cracked and had to be replaced. The crack occurred because post-test operations did not adequately purge out the propellants in the engine main injector, leading to a "pop" after some tests, which damaged the seal. No other engine parts were damaged. The "pop" was eliminated by extending the duration of a post-test injector purge, which takes longer to clear out the propellants in the test configuration on the ground than in space. This was a relatively simple fix and the J-2X test program continued on.

Looking ahead, the team is geared up to test the engine's powerpack: the gas generator, oxygen and fuel turbopumps and related ducting and valves. This testing series will push the various components to operate over a wide range of conditions to ensure part integrity, demonstrate margin and better understand how the turbopumps operate.

In addition, the team will add a nozzle extension to the E10001 engine and make associated test stand modifications to see how the engine will perform at simulated altitude conditions where the atmospheric pressure is lower than on the ground. The J-2X is the second stage engine for the SLS heavy lift vehicle, so it starts and runs at altitude during flight.

In summer 2012, a new engine -- E10002 -- will be assembled and tested followed by a third engine, E10003, in 2013. A fourth engine will be assembled and tested in 2014.

"We'll continue to learn as we test, making incremental improvements to the new fleet of engines powering humans to new destinations like the moon, Mars and beyond," Byrd added.

Like Santa's elves, Marshall's propulsion engineers are staying focused for the big day when the Space Launch System is ready for deep space. Their gift of a new U.S. advanced will be a gift for all mankind -- powering exploration to new destinations in our solar system, discovering the unknown and improving life on Earth.

Explore further: NASA seeks proposals for commercial Mars data relay satellites

More information: For more information on the J-2X engine, visit: www.nasa.gov/mission_pages/j2x/index.html

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User comments : 13

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Nanobanano
not rated yet Dec 22, 2011
Being able to model everything ahead of time on a modern, multi-core super computer has it's advantages.
Husky
3.3 / 5 (3) Dec 22, 2011
Wouldn't it be better if they use their current tight budget to focus on the scientific payload and buy the faretickets from SpaceX ?
_nigmatic10
not rated yet Dec 22, 2011
Wouldn't it be better if they use their current tight budget to focus on the scientific payload and buy the faretickets from SpaceX ?


Not if spacex buys first.
LKD
not rated yet Dec 22, 2011
I'm curious, if someone can explain, why they are building 1 engine a year? Instead of say; developing a single engine then building 10 of them once all the kinks are cleared up.
Nanobanano
4.3 / 5 (3) Dec 22, 2011
I'm curious, if someone can explain, why they are building 1 engine a year? Instead of say; developing a single engine then building 10 of them once all the kinks are cleared up.


This is still prototyping.

I don't guess you'd make 10 of something this expensive until you know the new model works.

The paragraph below the one you are refering to "incremental improvements".

Making 10 copies of each "incremental improvement" before all the kinks are out would then be 10 times as expensive...

Unlike software, you can't "patch" an engine design once you have it made. Well, not easily anyway. If you need a change to any component that is going to significantly change it's shape, length, or width, then it probably won't fit back where it belongs, which means you'll need to re-design the entire system from scratch.

Ok, hopefully it's not quite that bad, but you get the idea. This isn't Star Trek. You can't just make everything work in 30 minutes like LaForge does...
Sonhouse
5 / 5 (4) Dec 22, 2011
Wouldn't it be better if they use their current tight budget to focus on the scientific payload and buy the faretickets from SpaceX ?

The engine the Marshall people are developing are way way more powerful than anything from SpaceX, a true heavy lifter like Apollo's Saturn but more efficient, cheaper and more reliable.
ShotmanMaslo
3.7 / 5 (3) Dec 22, 2011
Wouldn't it be better if they use their current tight budget to focus on the scientific payload and buy the faretickets from SpaceX ?


Yes, it would. Current rockets are chronically underused anyway.

Its not done because US space program is headed by politicians and lobbyists, not actually competent rocket scientists and economists.. :(
dschlink
3 / 5 (2) Dec 22, 2011
I don't see any reason to man-rate the heavy lifter, other than maximizing the number of NASA technicians required for a launch. Building a heavy lifter that was focused on cargo would cut years and billions of dollars off the project. I guess that covers the three reasons they are man-rating everything.
nononoplease
5 / 5 (1) Dec 23, 2011
That's a pretty good point. It would probably be a lot less expensive to man rate exactly one highly efficient/safe rocket that only gets people to LEO. For missions outside LEO you could launch the interplanetary craft with the heavy lift and then dock with the astronauts already waiting in orbit.
LKD
not rated yet Dec 23, 2011
Ok, hopefully it's not quite that bad, but you get the idea.


You missunderstand me. The question is why are they making 4 prototypes? Wouldn't you be better served making 1 or 2 prototype and developing 1 till it works as desired, then make more? Instead, it seems that they are developing an engine to specification, and when successful, throwing it aside then building an entire new one and moving to the next goal.

I would like to understand the development process thought pattern a little better because I seem to be unaware of something significant to justify this procedure.
James_A
2 / 5 (1) Dec 23, 2011
ISNT IT AMAZING WHAT WE DEVELOPED 50 YEARS AGO IS STILL CONSIDERED ONE OF THE MOST REMARKABLE FEATS EVER THE J2 WAS AND INCREDIBLE ENGINE AND NOW WE WILL MAKE IT BETTER
plasticpower
not rated yet Dec 27, 2011
They should concentrate on making these rockets reusable. It's a shame that each one of these engines is single use. We know how to make reusable rocket engines, and yet we continue to build and discard them with every launch. They aren't cheap..
Beerbarian
not rated yet Dec 27, 2011
They should concentrate on making these rockets reusable. It's a shame that each one of these engines is single use. We know how to make reusable rocket engines, and yet we continue to build and discard them with every launch. They aren't cheap..


I think that has a lot more to do with the intended purpose of the rocket engine... This design is intended for heavy cargo lifts to high orbit or beyond. The space shuttle has reusable engines because it never leaves LEO and is itself a manned rocket which needs to stay in one piece for the sake of the puny humans on board. As for the SRB's used during space shuttle launch, they are nothing like this engine because they are solid boosters, not liquid fueled, and therefore more durable.