United Launch Alliance Selects Aerojet Rocketdyne’s RL10 Engine for Next-generation Vulcan Centaur Upper Stage

Commerical Crew Program (CCP) astronauts visit Aerojet Rocketdyne to see engine test. (Credit: NASA/Dimitri Gerondidakis)

CENTENNIAL, Colo., May 11, 2018 (ULA PR) – United Launch Alliance (ULA) today announced Aerojet Rocketdyne as a strategic partner for the RL10 upper stage engine for ULA’s next-generation Vulcan Centaur rocket following a competitive procurement process.

“ULA and Aerojet Rocketdyne have a long and successful history together that began with the first flight of our Atlas and Delta rockets in the 1960s,” said Tory Bruno, ULA president and CEO. “We could not be more pleased to have selected the proven and reliable RL10 to power our Vulcan Centaur upper stage.”

This partnership is a long-term agreement for Aerojet Rocketdyne to provide upper stage propulsion for the next decade. As part of this partnership, Aerojet Rocketdyne will provide RL10s and develop the RL10C-X, the next generation of the RL10 family. The RL10C-X will increase the use of additive manufacturing and introduce other advanced technologies to improve the quality, reliability, affordability and performance.

“Key determining factors to our selection included price and delivery schedule,” said Bruno. “We look forward to continuing our strong partnership to ensure a successful introduction of Vulcan Centaur.”

Over the course of nearly 60 years, more than 450 RL10 engines have flown on various ULA heritage vehicles with an unmatched record of mission success.

ULA continues its competitive procurement process for the booster engine and plans to make a down select soon.

With more than a century of combined heritage, United Launch Alliance is the nation’s most experienced and reliable launch service provider. ULA has successfully delivered more than 125 satellites to orbit that provide critical capabilities for troops in the field, aid meteorologists in tracking severe weather, enable personal device-based GPS navigation and unlock the mysteries of our solar system.

For more information on ULA, visit the ULA website at www.ulalaunch.com, or call the ULA Launch Hotline at 1-877-ULA-4321 (852-4321). Join the conversation at www.facebook.com/ulalaunch, twitter.com/ulalaunch and instagram.com/ulalaunch.

  • Lee

    Making decisions like this just keeps driving nails in ULA’s coffin. Pretty soon it will be done for good.

  • Michael Halpern

    There are a few reasons for this, other than the history of the RL-10 line, there’s politics in AJR’s favor, relying on 2 engines very much in development instead of 1 (BE-3U while mostly a modification of BE-3 is still not proven), engine certification requirements, relying on competitors for all their propulsion, familiarity with RL-10, and the need for Vulcan to be flying before New Glenn. The choice in upper stage propulsion is far from what will kill ULA, that is something that they are too late to change, their operational stance on reuse

  • Lee

    Didn’t say this choice would kill them. I said it was another nail in their coffin.

  • Henry Vanderbilt

    The BE-3U is awkwardly large for Vulcan ACES, and has significantly lower vac Isp than RL-10 – some tens of seconds, though the exact figure seems hard to come by – being a tap-off cycle engine. (430ish seconds, similar to the J-2, would be a reasonable guess.)

    I suspect ULA used the available competition to haggle out the best long-term deal for the RL-10 they could get, then went with it. Given ACES should have mission-flexibility capabilities no other upper stage can easily match, if ULA has to charge a bit of a premium to cover the best available engines, the people who need those capabilities will likely still buy ACES missions.

    (Too bad “best available engines” refers to an AJR rather than XCOR product, but it is what it is.)

  • duheagle

    Even a “cheaper” RL-10 is probably still going to have an 8-figure price tag. A single cheaper RL-10 for Vulcan’s version of Centaur help’s “Block 1” Vulcan’s economics relative to Atlas V. But putting four of the same engines on ACES – when, and if, ULA gets around to actually building it – is not going to be a good competitive move.

    This newest announcement is not about ACES. But, as you correctly point out, there isn’t a currently available cheaper alternative with equivalent figures of merit. Not a nice situation ULA finds itself in.

    Perhaps ULA has a secret fairy godmother who will see to it some scrappy start-up licenses the XCOR tech and quickly pushes it through to completion.

  • passinglurker

    We don’t know the fine print for all we know seeing the writing on the wall ajr may have actually written a deal that was competitive with blue origin’s offering. If this sounds technically impossible for ajr to cut price that fast keep in mind that this isn’t ajr’s only revenue stream. They could be eating the losses just to nail down the customers with plans to make rl10 profitable again as they go. One thing that’s different now is ajr seems to be getting the wiggle room to improve and iterate their design whereas before customers insisted they change nothing.

    Anyway that’s my 2 cents of baseless speculation. Interesting times these are.

  • Zed_WEASEL

    My take on the RL10C-X is that basically it is a new engine if they are manufacturing differently from the older RL10 variants along with adding new parts.

    Brings to mind the gestation of the RS-68 from the RS-25 and the J-2X from J-2 from AJR.

    Hope this is not a board decision make to appease the Alabama mafia over the head of Tory Bruno.

  • Henry Vanderbilt

    The industry could certainly use a propulsion house that’s lower cost and more responsive than AJR, yeah.

    Putting the pieces back together at this point, well, that would involve a middling chunk of patient capital and some considerable persuasion.

    And quite a bit of creative organizing. An engine company serving all interested transport companies is a hugely different thing than a transport company with a sideline in engines.

  • Henry Vanderbilt

    Yes, I’d agree there’s some risk in counting on AJR to produce a redesigned engine affordably, on performance, and on time. Not a great track record on delivering on those points lately.

  • duheagle

    An engine company serving all interested transport companies is a
    hugely different thing than a transport company with a sideline in
    engines.

    Splendidly and succinctly put, sir. AJR at least aspires to be the first of these. It’s main problem is that almost no one is any longer interested in its wares. XCOR had ambitions of moving into this same ecological niche, but wiped out in the clubhouse turn. Blue Origin is a good match to the second sort of entity you characterize. SpaceX could be another such, if it chose. But it has not chosen, at least thus far, to offer any of its hardware – especially engines – in an unbundled fashion.

    And, yes, I agree the prospects for semi-divine intervention anent upper stage engine supply look bleak. Looking at an illustration of Vulcan components on another forum (SpaceNews), I see that what is identified there as a “Centaur” upper stage has four engines, just like ACES is supposed to have. Perhaps the illustration in question is mislabeled as it also seems to show a detachable engine module which, it is my current understanding, won’t be implemented until about the same time as ACES on what we might as well call the “Block 2” Vulcan. Going to four RL-10’s on a non-ACES Centaur upper stage early on seems like an ideal way to kill the economics of Vulcan right out of the gate. I hope that isn’t what ULA is actually planning to do. It has a tough enough row to hoe as it is.

    I don’t know whether you know any “inside men at the skonk works” anent ULA, but given that your background and knowledge base in all matters rocket-related far exceeds my own, perhaps you could tell us all what’s actually what in terms of ULA and its latest intended development path for Vulcan.

  • Michael Halpern

    I would argue BFS can easily surpace ACES mission flexibility

  • Search

    Just look here https://www.ulalaunch.com/rockets/vulcan-centaur
    Vulcan’s initial upper stage will be Centaur with 4 RL-10s. ACES is “next generation”

  • Larry J

    While we know the price of an RL-10 is very high, we don’t know how much it costs AJR to build one. This is especially true for the newer versions they’re developing to be more competitive. When ULA had a monopoly on government launches and everything was cost-plus, AJR was under no pressure to lower their production costs because everything was just passed on to the taxpayers. Now that those days are coming to an end for ULA and AJR, they may have ways to seriously reduce the cost of building an RL-10.

  • passinglurker

    Indeed it’s certainly believable that AJR would cut into RL-10’s profit margin to some degree out of fear of losing OrbitalATK and ULA to to someone like Blue origin or ArianeSpace, but they are still a business they likely have a plan to increase or restore profitability to RL-10 down the road hence the increasingly aggressive redesign.

  • ThomasLMatula

    The problem with XCOR is they got hooked on space tourism and the Lynx instead of focusing on their strengths. I put it down as another victim, along with Spaceport America and Virgin Galactic, to the Space Tourism hype the Ansari X-Prize generated.

  • duheagle

    In retrospect, that certainly seems a defensible proposition.

  • duheagle

    Yeah, your link shows the same illustration SpaceNews used for its story. I wasn’t previously aware that the “Centaur” for Vulcan was going to diverge quite so much from the single-engine models currently flown on Atlas V and Delta IV or even the twin-engine version being readied for Dream Chaser. Well, now I know. Thanx.

    Doesn’t exactly give me a warm and fuzzy feeling about ULA’s competitive chances over the next few years though.

  • Henry Vanderbilt

    Disqus is now “detecting as spam” both my long detailed comments like the one you’re missing here, and also the short sweet ones like this.

    Disqus, please FIX THIS?!

  • Henry Vanderbilt

    Interesting. The illo accompanying the recent press release does show four engines on the upper stage. Got no more inside info than you these days, alas. My impression has been that Vulcan would be initially matched with a new two-engine Centaur version. And I came across a (how recent? can’t tell) ACES viewgraph that calls out 1-4 engines, presumably depending on the mission.

    My guess: It’ll depend on the mission, the general equation of course being that more engines/more thrust is better for maximizing payload to lower orbits, fewer engines/less thrust better for maximizing available delta-V for smaller payloads on longer/more-complex missions.

    And my view is that Vulcan/Centaur-then-ACES will be strongest in the higher-delta-V/more-complex missions market. FWIW.

    Hmm. Could showing four engines here have been part of an overall effort to convince AJR they’ll be buying lots of engines, to get per-engine price lower? A clever company might well foster such an impression while negotiating. Just a thought…

    As for XCOR’s propulsion-market ambitions, it is my observation that one problem they always had there was convincing potential propulsion customers that XCOR wouldn’t be unduly distracted by vehicle development. It was never in the slightest bit subtle that their first love was vehicle development.

  • Henry Vanderbilt

    OK, fixed, apparently, fingers crossed. Long reply reposted… Read it quick, before their demented spam-detect bot strikes again!

  • Henry Vanderbilt

    As I saw it, there was no “The” problem, there were multiple problems interacting in complex ways. And the Lynx was in fact one of their strengths, along with propulsion. (Not an unalloyed strength, no, or else they might not have hit the development snags and delays they did.)

    I was never a huge fan of tourism as a market, mind, but the only way we’d have found whether or not it was “hype” would have been for at least one of the vehicle developers to make it to operations in a timely manner. As for why nobody so far has done so, that’s a book, not a comments column…

    Meanwhile, it should be interesting to see how things develop when/if VG gets past flight test and if Blue decides they actually want to go after the market. Then we may finally see if there’s a there there.

  • Glad to see your 2 cents Henry. I’ve never worked with the West Palm folks, but seeing the PR for tests they kept doing at Stennis, I have to imagine this is a straightforward roundup of all the ideas that NASA has been funding/testing for the last few years. The engine’s been on the stand enough that it probably just requires the engineering hardware to be productionized and the qual program to be run. Certainly a lower hurdle to requal the upgrade to an existing engine that to get something brand new (AR-1) through the process.

  • duheagle

    Looks like we’ll just have to see what the Vulcan Centaur looks like when it gets to be a thing, not an illo.

    As to XCOR, it may be that the criticism that has often been leveled against SpaceX – that they have too many irons in the fire – was actually true for XCOR. That people were seriously making such a charge against SpaceX when it had 5,000, then 6,000 and now 7,000 employees always struck me as daft. But I don’t think XCOR’s payroll ever exceeded a couple hundred. Maybe it should have stuck to engines. But I think Lynx went forward not only because XCOR had always intended to do a vehicle at some point but also because companies pursuing vehicle programs have tended to be regarded as more real in some sense.

  • passinglurker

    Anything is easy when you think that big.

  • Henry Vanderbilt

    All companies have some limit on their engineering/development bandwidth, even SpaceX. Priorities have to be set and decisions made where the talent can best be applied, always. But yeah, companies with dozens of engineers and techs have a lot tighter limits than companies with thousands.

    FWIW, XCOR was explicitly intended to be a space transportation company right from the start. It was the primary focus, and it was also a significant element in recruiting talent. If you were on the team, you got a ride in the rocket when the time came. Never got there with Lynx, but pretty much everyone got a ride on the X-Racer back in ’08.

    I don’t know about “more real”, but in general vehicles are just generally seen as cooler than their engines. It was true in the aircraft business and it’s true in the spacecraft business.

    XCOR definitely had the potential to become a serious propulsion company – turned down at least one major opportunity to do so – but never the willingness to focus on propulsion to the degree necessary. And once the Curacao group made a large investment with the specific expectation that they would become a major operator of Lynx, becoming primarily a propulsion company was no longer even a theoretical option.

    Oh well, history now. Meanwhile, good luck to ULA!

  • Henry Vanderbilt

    I read Mulready’s book recently on various P&W advanced engine developments, including the RL-10. Two points come to mind, that there was some very sophisticated thinking going into those engines, and that it all happened over fifty years ago. IE, most of the people involved are not just retired, but dead.

    Which is by way of pointing out that one can get into all sorts of trouble redesigning an old machine for modern materials and production methods if there turn out to be things about how the old version worked that one doesn’t really entirely understand as well and deeply as one believes.

    One can then compound that trouble when the urge to make just a leetle improvement here and there creeps in.

    On the evidence, AJR hit those rocks hard on the NK-33/AJ-26 to AR-1 evolution. Can they avoid them on RL-10? One might hope so. We’ll see.

  • My understanding was the AR1 is a De Soto (Rocketdyne) engine, not a Sacramento (Aerojet) engine (which kinda miffed the Sacramento folks since they were the ones who bought PWR). So I don’t think there is much NK-33 heritage to those. My understanding was that those engine had a number of issues, including being martensitic and thus susceptible to stress corrosion cracking – maybe not an issue if you use them right away, but if you store them for a few decades…

    Mulready’s book is a great read and the RL-10 is an incredible machine. I have to imagine that loss of tribal knowledge is part of the reason they keep putting the RL-10 on the stand, to make sure the team thoroughly understands it. And that’s why you go through qual in the first place, to qualify the engineering changes and the manufacturing processes. If they have a robust test program for qual, I have no doubt they’ll find any hidden demons.

  • Henry Vanderbilt

    Most likely so – but then we circle back around to, in how much time, for how much money? I guess we’ll see.

  • Michael Halpern

    it is also far less expensive ACES was a good idea but its too late. maybe something similar will happen in a methalox fed form to ride empty on bfs, the problem with hydrolox is that it takes up so much extra space that its isp isn’t useful in most situations compared to SEP, and its density and thrust is so poor that it sucks at high thrust applications, you generally either need high thrust, or high isp, and often you are constrained in mass and/or volume.

  • passinglurker

    I’m gonna need some sources cited cause I’ve always understood quite the opposite that being that Hydrolox is about the best combination of thrust and isp you can aquire for interorbital maneuvers short of nuclear propulsion especially when using balloon tanks like ACES as hydrogen weighs very little and needs very little in most mixture ratios yet still tops metholox isp by 75-100 m/s. Hydrogen technologies like handling, insulation, and balloon tanks are of course very difficult to develop but once you have them there is no reason not to use them. Methalox though great for liftoff is simply either mars centric or a shortcut once in space.

  • Michael Halpern

    If you are just looking at chemical propulsion hydrolox has the best isp, but it’s very hard to get to orbit with it alone can’t think of a hydrolox rocket that can do it without SRBs and it takes up so much space its useless for station keeping hence why satellites almost always use either hydrazine or sep, its low density results in horrible twr because of tank mass, it is essentially only good for orbit raising in practice. Let’s look at the size difference between sls and FH, if you took off the SRBs sls wouldn’t get off the ground, despite having 4 of the second most powerful LH2 engines ever built

  • passinglurker

    “can’t think of a hydrolox rocket that can do it without SRBs”
    Delta 4H, H3 30, and technically CZ-5 doesn’t use “SRB’s” either but that’s just me being facetious. Sometimes its a bad choice and its too late to turn around like you fear but other times its the same logic as kerolox upper stages that its just cheaper to plumb a pad for only one set of propellants and cope with the drawbacks.

    As for the rest of your issues. Often times hydrolox in the design is of no consequence because the rocket needs to be wide for bulky voluminous payloads. One of F9’s biggest drawbacks is its volume limits. Of course it plays that to a strength saving money on transit but its still a limit once you reach the pad. As for station keeping once you have it why not use it this is why ACES incorporates IVF technology and either way I don’t see payloads using methalox either so that isn’t really fair criticism, and finally I think you are exaggerating the twr thing yes it exists but its not as bad as you make it out to be especially once you are in space and especially especially if you are using balloon tanks like ACES

  • Michael Halpern

    And how successful is the delta IV line? In terms of cost

  • passinglurker

    Initially or presently? You know there is more to the logistics and economics of a launch vehicle than just the choice of propellant. It’s just not that cut and dry.

  • Michael Halpern

    True but the fact is hydrolox is propellant of last resort, if you need a good mix of thrust and isp Methalox is your best bet, your choice in propellant decides how big your tanks have to be for a given target lift, liquid hydrogen also requires special materials to store, entry level physics like it but engineering its more trouble than its worth

  • passinglurker

    This may be true for booster stages, and startups with no heritage to draw on but once you already have the materials, technology, engineering, and infrastructure developed and paid for (say over 50 years ago?) There is little reason not to use it ergo we have ACES. Hydrolox has enough thrust that you are not futility spiraling out like sep and enough isp that you’re not so easily stone walled by the tyranny of the rocket equation. Now couple that with the superior mass fraction of balloon tanks.

    For someone with this sort of heritage like ula hydrolox is the best choice for upper stages and beyond they already have the expertise and infrastructure in areas that would be too lengthy and costly for someone without military or bezos pockets to try to catch up.

  • Michael Halpern

    Lh2 also boils easily meaning your tanks need heavy insulation, at the end of the day, most of the impulse you gain from LH2 is eaten up by how heavy LH2 tanks have to be

  • Michael Halpern

    For a given surface area of your tank with the insulation, your adding more mass compared to any other propellant, in short lived upper stages its fine, similarly in sub orbital boosters its fine, but if you are either trying to get to orbit or land in which case you want high TWR, are already in orbit and need to station keep or adjust your orbit in which case you need isp in a small amount of space (LH2 fails there) or high density in a simple propulsion system that makes up for isp in accurate and powerful thrust, LH2 is a jack of all trades master of none propellant outside of conventional upper stages. It’s ONE advantage is that refuces the work the first stage has to do

  • passinglurker

    Tory bruno said aces has an orbit life on the order of years like I said once you have the tech (ivf, light weight insulation solutions, etc…) It’s dumb not to use it.

  • Michael Halpern

    Unless you have stuff that works better, we have the tech for horse drawn carriages, doesn’t mean it makes sense to use them

  • Michael Halpern

    As for on orbit life, seeing as ACES generates power by burning boiloff, there might not be much left by that point not enough to be useful ACES assumes that the orbit will be revisited, in practice except for GEO this is rarely the case

  • passinglurker

    You do know what IVF is right? Seriously though you’re just repeating technical challenges off note cards at this point none of this is insurmountable ula and others have already cracked these problems.

  • passinglurker

    Hydrolox has challenges but when surmounted it is better on orbit so in a sense you got it backwards methalox is the horse. “It’s so easy they drive themselves, self repair, self fuel, self fabricate why would everyone go through the trouble and expense of automobile infrastructure when you have horses?” This is essentially the augment you are making for methalox what you are suggesting is that an automobile manufacturer go back to horse buggies cause all the cool kids are doing it.

  • passinglurker

    You clearly don’t get it. IVF saves a massive amount of mass replacing independent sub systems like hydrazine, helium, and batteries with hydrolox which out weighs the mass you put back in for insulation and slows boiloff to a crawl. Hydrolox is the best for an ivf system because of its crazy efficient for power, station keeping, and pressureization as a result they can store the overwhelming bulk of the propellants on orbit for years if needed not just the empty bottle.

  • Michael Halpern

    Except it doubles the size of your system at least, why should I use Hydrolox for station keeping when I have ion engines?

  • Michael Halpern

    No it isn’t on orbit ion engines are better,

  • Michael Halpern

    If hydrolox was so great why don’t satellites use it? The answer is because it’s piss poor at handling what they need

  • passinglurker

    Pfft ahahaha sure if you are in no hurry, aren’t trying to lift through the radiation belts to much, and have no isru plans they have their time and place just like how hydrolox has a time and place, and metho/kerolox have their time and place etc…

  • passinglurker

    Satellites aren’t using metholox either. Anyway commercial space is expensive once you have something reliable it’s hard to get the players with the funding to try new things. This is why storables achieved and held popularly for so long despite other developments.

  • Michael Halpern

    No but they are using ion engines and hydrazine, you also don’t want to leave an upper stage in orbit for too long let alone close to a satellite, they are known for exploding