NASA Has No Clear Use for the J-2X That It Once Needed
NASA’s J-2X Engine To Be Mothballed After Testing, Aviation Week
“NASA’s J-2X engine, once considered the pacing item for the next U.S. human-rated rocket, will go on the shelf after development testing wraps up next year because it will be years before the engine is needed to push humans toward Mars. While the agency is actively seeking other missions for the heavy-lift Space Launch System (SLS) in the planetary science and military arenas, most of the human flights it has in sight for the big new rocket probably can be accomplished with an upper stage powered by the RL-10 engine instead of the J-2X. “The J-2X for certain [design reference missions] is somewhat overpowered,” said Todd May, NASA’s SLS program manager.”
NASA MSFC Solicitation: J-2X Design, Development, Test and Evaluation (2006)
“NASA/MSFC has a requirement for the design, development, test, and evaluation (DDT&E) of an engine to support the Crew Launch Vehicle (CLV) Upper Stage and the Cargo Launch Vehicle (CaLV) Earth Departure Stage (EDS). The engine, a J-2 (Saturn Heritage engine) derivative, will be a 250,000 pound thrust class human-rated engine and is planned to support a human launch of the CLV in 2012.”
Pratt & Whitney Rocketdyne Awarded $1.2 Billion NASA Contract for J-2X Ares Rocket Engine (2007)
“Pratt & Whitney Rocketdyne (PWR), a United Technologies Corp. (NYSE: UTX) company, was awarded a NASA contract valued at $1.2 billion to design, development and test a J-2X engine that will power the upper stages of the Ares I and Ares V launch vehicles.”
This is absolutely infuriating!
$1.2 billion pissed away…
$1.2 billion – that is a very conservative number.
That was just the first award. It is likely more than $2 billion.
Unfreakingbelievable…..smh
The J-2X could be quite useful immediately if NASA partnered with industry to leverage it inside of a powerful upper stage on top of launchers that are already flying, instead of betting it all on SLS. Dennis already mentioned that possibility
B Kutter of ULA has written that J2X does not make since economically, and /or there is not a government customer out there for it.
A over powered upper stage will cause to much G forces on a payload that has deployed its solar panels is what I see engineers posting most often,
Ditto the comment you see in the article…………………………
I do feel your sentiment Mr Kavanagh, I am glad that this program was not canceled 70% through and I am glad to see more money “wasted” on this through next year, we might change our minds, or the people of the future will thank us for engineering work and for this test article being preserved.
maybe Dennis would agree with at lest that?
A common family of upper stage engines with EELV and SLS does make since (RL-10) but this was not in the end why this decision was made.
thank you NASA for not killing this test program in till its completion! I do not believe you knowingly wasted my 1.2 Billion, after all is there not a claim that some new J2X technology will find its way into any new SSME?
but then agian a new SSME and F1X might be better replaced by a clean sheet EELV/new space beast? strike that congress has voted otherwise……………………………..
I am a big fan of the J2-X and since it is throttleable I don’t see why it can’t be further used.
Absolute Bollox!
Dennis,
thanks for your comment,
over at dat other forum I see allot of convo in regards to this issue along with a number of DRM’s that discuss this issue,
DRM’s that seem to state that “overpowerd” is a reference to two things,(1) can the JX2 be throttled down to the point that my deployed solar arrays survive the g forces?
if not then I need a battery that can with stand possible abort scenarios that force me to wait for deployment of said solar arrays.( and boil off ect ect)
Kutter et al would not agree with you, however I was one who emailed him with the hope that the J2x could be an EELV upper stage. this is why I am glad the test program will last into the next year
.I am engine agnostic with funding I do like the theory that all of these engines can find duel uses.
but the funding is not there………………to save our J2X
Dennis your article said not to cling to pet projects………………………….no matter what the pet project that might be.
I am love this quarter with methane gelled in LH2 as a bridge between spaceX Methane Merlin and Delta V super heavy and the SLS CBC and methane gelled in LH2 fuel depot but I know this will not be funded…………………. so this is my pet project I will have to give up
(2) Dennis, this one I am still learning to articulate, it has to do with gravity loss and sizing and weight of the engine, Ben and Mjeriee I think do a better job of explaining this
back to the funding question,
commonality with the interim upper stage with Delta V for the test flight is exciting to me with the rl-10, we are human rating this!
Atlas, human rating!
some sort of Delta sls CBC human rated!
Centaur( with atlas), human rated!
Dennis you speak of clinging to pet projects, human rating spaceX and most ULA products are in the works, this might be a better use of funds then J2X, at least for now
Dennis you also mention the F1 X as a common EELV engine, I am not sure if I see the funding or politics behind that?
will the F1X also absorb S1.2 billion just to be discarded a decade from now?
I did really enjoy your article!
I would like to see a NTR space act agreement( my idea) if NASA technology directorate gave up a pony of $2 to 3 million. could this work with DOE as a partner? could we get Darpa to get in on the act?
would any commercial interests come up with 40%
Thanks, I really think that NTR will be built when we have the industrial infrastructure ON THE MOON, to support it.
I like NTR but the dysfunction that we have today would require a lot of fixing at a lot higher pay grade than what is going to happen.
Could this be SLS cancellation, phase 1? (he asked with fingers tightly crossed)
I wonder how much this will hurt Aerojet if they’re not going to be building any J2-X engines. Somewhat ironic that they can sell upgraded, refurbished decades-old Russian engines to a US buyer, but their brand new US-designed and -built engines are to be “mothballed.” Who would have predicted that?
This won’t hurt Aerojet at all. Remember J-2 is a Rocketdyne program (Canoga Park, CA) where their bread and butter is RS-68 and SSME. J-2 is a small development program, and is built on normal industrial machines that can be used any engine they make, almost no special tooling is involved.
RL-10 is a Pratt & Whitney engine (West Palm Beach, FL) where they only do this engine, import the RD-180 and do some other light manufacturing for other Rocketdyne engines. With the announcement that XCOR is designing an LOX/H2 engine for ULA, the RL-10 may be in trouble.
Remember, J-2 has 10x the thrust of RL-10, and less Isp. While engine ground qualification is important, the engine still has to be integrated with a complete stage and flight qualified too. More issues will arise during stage integration and testing, and yet more will arise during flight qual. Ending the program at this point makes sense if you aren’t going to integrate it into a specific stage.
It’s great to have building blocks lying around that you can integrate into your system like Legos. Inspiration Mars is using this approach and Apollo did it with the RL-10, F-1, tanks for the S-I stage (Juno and Vanguard) and other portions. This approach lets you go to the Moon in less than a decade, but you end up spending a billion or so on every program without a well defined use for things.
If you ask me, we should rebuild the Saturn I, it used the RS-27 (in an earlier form) and RL-10s, both engines that have remained in continuous production since the 60s. It had a capsule on top, and a service module with it, all capabilities we are trying to rebuild now.
Barely less Isp, 451 vs 448 from what I see.
Modern RL-10s get Isps of more like 465, but the best part is this: they are already in serial production! You don’t have to flight qualify anything else, and you can leverage several decades of operations and technology investment. No new produciton lines, no new qual testing, no new test stands… just reuse the building blocks you have. Sadly, we can’t seem to do that in this industry.
If you have a heavy payload, like a LEM+CSM, then fine, several J-2s are the way to go. But when was the last time we needed that lifting capability? Unless you have an entire Mars mission on a single large departure stage, you might not need it. (BTW, I think the large Mars mission is precisely why you WANT the J-2… but I’d like to see us make our hardware investment decisions wisely. And I’m always disappointed.)
Ok I see the RL-10B-2 for the Delta IV gets 462 Isp, and the RL-10A-4-2 for the Atlas V gets 451 Isp. But understand your points and agree.
The capsule version was only used with the Saturn 1B, which used a single J-2 as the upper stage. With a J2-X you get about 4-5,000 lbs more mass to orbit.
Dennis, you certainly can get more mass with the J-2 version with the S-IVB. My complaint is that we never seem to do “good enough” engineering: RL-10 be used on unmanned AND manned vehicles? ABSOLUTELY NOT! Everyone has to have their own engines on their own stages and no one can reuse engines or stages on any other program.
A block II Saturn I would be just fine for getting an Apollo capsule to orbit… but that would have meant we reused RS-27s and RL-10s from other program, and we as an aerospace community can never seem to get over the “not invented here” disease.
You’d need that extra lift if you wanted to convert the SIB into something that’s in any way reusable, which I hope is the way of the future for all LVs bigger than sounding rockets. The thin skin of the original means you build it just in time, use it once, and throw it away. I’d like to see those days go away. On the flip side, replacing the electronics and sensors with new tech would probaby save considerable mass.
And just how much money have we wasted on this? Wasn’t the test stand alone at least $400M? More proof that CxP was an insanely poorly constructed money pit. This was never affordable and it took NASA until now to acknowledge this reality. Oh, and by the way – there are no other payloads for SLS and everyone knows it. DoD has stated emphatically that they have no need for anything that large and science doesn’t have the $1-3B per launch or need for it either. More empty attempts to justify a program that is only hurting space development. Why doesn’t AvWeek reporter identify any of these issues? Oh yea, they are beholden to big aero dollars for advertisers. So sad.
Can we use the test stand for other hydrogen engines? One would hope.
J-2 is utterly useless, it only makes sense if you depart from LEO directly instead of through L1/L2. And departing from LEO directly is stupid. If they had spent money on RL-60, then *that* could have been useful. But even that is not at all critical. RL-10 is just fine.
Would the J-2X make a viable main engine for a reusable tug/ferry that flies between LEO and EML-1/2?
Delta-V EML-1 = 3.77 km/s, EML-2 = 3.43 km/s, return *2
What sort of payload could it carry?
Assuming the tug picks up propellant and cargo in LEO and returns empty. Maximum acceleration ~1g.
are my solar arrays deployed?
what are my G forces?
how much to make J2X throttlable ?
are clustered RL-10 simply cheaper?
engine out capability?
are my solar arrays deployed?
Yes, for the tug’s own solar arrays. Deployment of the cargo’s arrays will be different for different missions.
what are my G forces?
Low. I hope this is kept down to less than 4g. This may have to be the heavy tug.
Note: The Falcon Heavy intends to lift 53,000 kilograms (117,000 lb) to low Earth orbit.
how much to make J2X throttlable ?
are clustered RL-10 simply cheaper?
Someone else will have to answer those two questions.
engine out capability?
That could be negotiable.
edit:grammar
Andrew,
sorry I did not make my self clear,
will the tug or cargoes solar arrays be deployed while the J2X is firing?
this is the reason the J2X is being shelved……
You were perfectly clear. The solar arrays built into the tug would definitely be deployed when the J-2X was fired.
This is a reusable space tug so, unlike a launch vehicle, it does not have to work in the Earth’s atmosphere. Consequently making solar arrays survive 4g is EASY. You can buy 1g solar panels from your local hardware store. 4g panels may need to use similar techniques to aircraft wings.
p.s.
c/work at 4g/survive 4g/
Since a tug is basically a satellite that works in LEO it will already have batteries. So adding a few extra for the burn is possible. When the solar arrays stop vibrating the electricity can be used to recharge the batteries.
Well, J-2X really was a very specific solution to the problem of Ares-I’s lower stage only burning for about 120 seconds. It had to take a vehicle from deep within the atmosphere all the way up to orbit, requiring thrust over specific impulse as gravity losses were its biggest obstacle to overcome. Once you got a core that could take the upper stage to a reasonable ignition altitude, J-2X’s particular performance wasn’t really required anymore. What is needed is a higher-impulse engine for escape and deep-space manoeuvring burns.
What about for a first stage then? It looks like the J-2X has higher impulse and higher thrust than the J-2 but less thrust to weight since it’s significantly heavier. The Ariane 5’s Vulcain 2 is the highest thrust-weight of a hydrogen engine followed closely by the SSME. The RL-10 has just slightly higher thrust-weight than the J-2X and just slightly higher impulse. This is all just going by wikipedia’s numbers.
Well it’s a pretty fantastic accomplishment but really too bad we don’t have an immediate use for it. In a perfect world we’d have a continuously updated diverse stable of available rocket engine types to choose from. We’d be going to space a lot more then though.
“In a perfect world we’d have a continuously updated diverse stable of available rocket engine types to choose from”
Amen
ours is not that perfect world, sigh
In a perfect world we would have kept developing the X-33 / Venture Star. There was a lot more good than bad going on with the program. Next step is nuclear propulsion. It shows the greatest ISP than anything we are doing now; but America will not do it, … the Chinese will.
Yeah that too 🙂 Aerospike! Hopefully if the Chinese do, we will too, rather than having our politicians act all angry at them.
Possibly an LH2 upper stage for the Falcon? Now that it’s designed, what would the manufacturing cost be?
No use to SpaceX. For one, it’s not cost or manufacture-optimised and secondly, they are moving to Methalox with Raptor the first in this line. Approx sea level thrust of 650klbf.
Musk seems to have a bit of the “not-invented-here” attitude.
It has so far served him pretty well, though.
It’s too big and too propellent-hungry for something in the Falcon Heavy’s size range. Something closer to the Vinci or MB-60 would be better.
The Falcon Heavy lifting a pound of payload at 1/4th the price of SLS makes the shelving of the J2-X a moot point. NASA can now barely afford to pay for the construction of the SLS. There is no destinaion. Asteroid, Moon, Mars – two too costly and the third, involves moving a NEA into Earth orbit that hasn’t gain sufficient support inside NASA. I like the Asteroid Initiative concept but SLS is too late and costly. The adversity that challenges NASA holds a double edged sword – a replacement for the shuttle thats too costly and a quickly changing space industry. Unless advocates of NASA and exploitation of space speak up now and cancel SLS, it will be another dead end venture and unlike Shuttle it won’t be considered a technological marvel in any respect. Lets direct NASA funds to cutting edge tech. Today’s tech including robotics is changing the role of humans in space – to tourists to LEO and explorers awaiting real inter-planetary spacecraft. [& I do not work for SpaceX]