RD-0120 for SDHLV?

mikejz · Aug 23, 2005

Given the talk of the cost of SSMEs for a SDHLV, why has no one brought up the idea of using RD-0120 (Energia) engines? Seems that with the Atlas V we have proven the idea of Russian engines on American boosters. Outside of nationalist reasons, is there any good arugment against it? http://www.astronautix.com/engines/rd0120.htm

propforce · Aug 23, 2005

<blockquote>In reply to:<hr />There is the "Man Rating" game and the paper trail that requires. Would Energia play that game? <hr /></blockquote> Aerojet has indeed brought up and is marketing aggressively on the RD-0120 for SDLV. Technically the RD-0120 is produced by Chemi-automatik design bureau (CADB) licensed to Aerojet for marketing in the U.S. It is a 'timex' (takes a licking and keeps on ticking) version of SSME. It produce a slightly less thrust than the SSME (440K vs. 470k lbf) but has a higher vacuum Isp than the SSME (455 vs. 452 sec). It uses a common preburner and, in the Russian tradition, a single shaft for both turbopumps. It uses channel wall cooling technology which proved to be more robust and reliable (and Rocketdyne is trying to duplicate), and has demonstrated a quick re-start in as short as 20 minute during ground hot firing. However; I doubt that it will be accepted as a SDLV engine mainly for political reason, but also practically that we only know so much about the engine, the metallurgy properties, and how it operates. Look at another Russian engine as example, the RD-180, imported by P&W 10 yrs ago with the promise to duplicate its production here in the U.S. for EELV. Ha !! <img src="/images/icons/laugh.gif" /> I doubt those folks in West Palm Beach, FL have yet learn how to read Russian, let alone try to duplicate the design and manufacturing capabilities !! <div class="Discussion_UserSignature"> </div>

publiusr · Feb 9, 2006

RS-68 or the SSME derived RS-25(?)

john_316 · Feb 9, 2006

Hey if we had to we could use Boeings engines as pointed out and even a TRW engine if it went to Kerosene (clean sheet design). Who cares about the RD-120? I sure don't... Do we have to import all our rocket technology? I mean aren't our engineers and technicians good enough for the select few people who want all russian designs? I mean come on.... <img src="/images/icons/smile.gif" />

frodo1008 · Feb 10, 2006

As the SDLV is goin gto be both just a cargo carrier (and therefore does not have to be man rated), and is not going to be reuseable, then I would think that the RS-68 which is a VERY inexpensive engine, that currently develops 665 K of thrust would be a most excellent choice, I have heard from some of my friends at Rocketdyne, that Boeing (and now Pratt & Whitney) has seriously considered upgrading the RS68 to the million pound thrust class!! Even using five of these RS68, 665 K engines along with four SRB's would give far MORE thrust fo such a vehicle than even the mighty Saturn V had!!

qso1 · Feb 10, 2006

The RD-0120 was probably not mass produced in sufficient numbers to benefit from economies of scale. The Energia rocket certainly did not benefit from economies of scale as only two were launched. Furthermore, the Energia's last launch was 1988, almost 20 years ago and by 1993, production of the Energia was cancelled along with the Buran. Probably only a couple more Energias were built but never flown. <div class="Discussion_UserSignature"> My borrowed quote for the time being:There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened. </div>

no_way · Feb 10, 2006

<blockquote>In reply to:<hr />I mean aren't our engineers and technicians good enough.. <hr /></blockquote> The "old guard" definitely have lost their touch. Thats why fresh blood with the likes of XCOR et al should be massively encouraged.

publiusr · Mar 17, 2006

Please. The old guard is still better than the XCOR toys. Rocket racing my foot.

mattblack · Mar 17, 2006

They'd be better off uprating the RS-68s ISP for fuel efficiency if used for the CaLV heavy lifter. Because, as shuttle_guy has pointed out before, the RS-68 is a much heavier and thirstier engine (higher thrust and lower ISP will do that) than the RS-25 (SSME) and so the use of the RS-25 for the CaLV is a trade off for the most payload. For a corestage with RS-68s, 3x RS-68s is the optimum amount, otherwise for say, 4x RS-68, you'd have to stretch the corestage tankage far more for those thirsty motors, pushing the height of the CaLV taller than a Saturn V!! 1): Cluster of 5x RS-25: Weight -- 37,500 pounds. Thrust Sea Level -- 1.96 million pounds. ISP (vacuum) -- 450 seconds. 2): Cluster of 3x RS-68s: Weight -- 42,000 pounds. Thrust (sea L.) -- 1.95 million pounds. Vacuum ISP -- 420 seconds. See what I mean? 5x RS-25s weigh less, are more efficient, and give slightly more thrust. If they were to use 4x RS-68s, sure the thrust would go to 2.6 million pounds but the corestage would run out of fuel far sooner, so you'd want to "stretch" the corestage to compensate, which as I said would make the CaLV taller than a Saturn V. Also, the RS-68 in it's current configuration needs to burn off a big "belch" of hydrogen before liftoff, which is what gives the Delta IV Heavy a scorched look after liftoff. Ugh! Scary!! Also, 5x RS-25 gives you more engine-out capability in Abort-To-Orbit scenario during the loss of an engine. With 3x RS-68 you'd lose ONE THIRD of your thrust during an engine-out with much greater chance of loss of mission. The only way to use the RS-68 is to try find the money to develop an 1-million pound thrust uprated version with no burn-off characteristics, and then only in the long run would you save money over disposable RS-25s, for a negligible amount more payload. Seems to be little point (at least in the short term). It's all in h <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

danwoodard · Mar 17, 2006

>>See what I mean? 5x RS-25s weigh less, are more efficient, and give slightly more thrust. The bottom line is cost and reliability of the full system, not just Isp. Just look at the SSME engine bell. It's made of hundreds of brazed tubes, which taper from about 5mm at the bottom to the size of a piece of spaggheti at the top. Every one has to have H2-proof welds into header rings at both ends. The injector plate is surely the most complex ever fabricated. Even assuming a very optimistic cost of $38M each, as was done for the Shuttle C, five such engines would be $190 million. Today $250M would be more realistic. And that's just the engines! The RS-68 has only 10% as many parts as the SSME, and the channel-wall cooling avoids the very expensive fabrication from welding together individual tubes. />>Also, the RS-68 in it's current configuration needs to burn off a big "belch" of hydrogen before liftoff, which is what gives the Delta IV Heavy a scorched look after liftoff. Ugh! Scary!! I'm not sure why cosmetics are an issue.

mattblack · Mar 17, 2006

>>The bottom line is cost and reliability of the full system, not just Isp<< Yes, I know. But performance is also an issue and the RS-25 has that over the RS-68 in relative terms. Still, as you say, if cost becomes the issue, then they might go to 3x RS-68 to save money for a slight perfomance penalty. Which, as I reiterate, could be reduced by upgrading the RS-68 which is certainly do-able (but $$?). Regenerative-cooled nozzle would be the least of this. />>Also, the RS-68 in it's current configuration needs to burn off a big "belch" of hydrogen before liftoff, which is what gives the Delta IV Heavy a scorched look after liftoff. Ugh! Scary!! I'm not sure why cosmetics are an issue.<< Er, no... (Matt scratches head) 'cosmetics' as you put it has nothing to do with it. The scorching part is the worry, particularly as it pertains to man-rating and safety for the SRM skirts: Do we really want to wrap lots of insulation round the base of those 5-Segment monsters? <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

j05h · Mar 17, 2006

>The bottom line is cost and reliability of the full system, not just Isp. Right there with you. Confuse me if i'm wrong, but isn't the "RS-25" vaporware? (quick check of astronautix.com confirms) The RS-68 actually exists and is on a flying rocket, the "simplified" SSME is just some cost-plus contractor's dream. The parts simplification on the RS-68 is impressive, and using any of the tooling from DeltaIV should improve costs. I agree w/ Dan's construction analysis: making the SSME radically cheaper is a non-starter. If you wanted to compare vaporware engines, how about the RS-25 against TRW's Low Cost Pintle Engine? />I'm not sure why cosmetics are an issue. Cosmetics are very much an issue, or we wouldn't fight over capsules-vs-spaceplanes. Looks mean a lot to some people. For similiar reasons, I doubt a tube-launched rocket would terribly popular with costumers. Josh <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

frodo1008 · Mar 17, 2006

I am going to support what you say here. The big issue is always reliability. The RS-25 is going to have to be essentially a new engine, even though it is derived from the SSME. It is going to have to go through a very large development program, which is going to be very expensive. I don't say it can't be done, I know the people at Rocketdyne, and even though I retired in 2000 I can still say they are indeed the best people in the world at what they do. However, they also make the far less expensive (and in some ways the even more robust, and therefore more reliable engine) RS68 engine. It is also a liquid hydrogen / liquid oxygen engine like the SSME, so its Isp is not that far from the SSME or the proposed RS-25. However, it is quite a bit heavier and has some what less performance, but in comparison to being only about 25% the cost of the SSME, it then becomes the winner for a pure heavy lift launch vehicle that does not need to be man rated. It would even be cheaper than the RS-25 (which would be cheaper than the original SSME, as it will not need to be man rated) because of the added development costs even cheaper in comparison to the initial RS-25's. In the 1960's we were developing the NOVA rocket, which would have made the great Saturn V look like a midget along side! I have at least a gut feeling that if the costs of the engines can be reduced by some 400 percent, and the engines are the most expensive elements of the system (at least for pure cargo vehicles), then the over all cost would still be far less than more expensive engines, even if this meant a bigger rocket over all! It also would seem that further iterations of NASA's base line seem to go along with this, as they no longer want the development time and costs for the single stick second stage that using an air started SSME (AKA RS-25) would entail. They now wish to use two already developed J2S engines from the 1970's instead. This would reduce both the costs and

propforce · Mar 17, 2006

"... I heard a report a few days ago that the RS-25 may be dropped from the heavy lift SDLV in favor of the RS-68. ..." I've heard the same rumor, plus that the diameter of CaLV will be bigger as well. <div class="Discussion_UserSignature"> </div>

mlorrey · Mar 17, 2006

How will doing this contribute to reductions in the cost of the engines? What is the price on the RS-68 now?

propforce · Mar 17, 2006

".... Confuse me if i'm wrong, but isn't the "RS-25" vaporware? (quick check of astronautix.com confirms)..." Actually the RS-25 designation is for the SSME. The "E" version would just happen to be the "expendable" version. I think the "D" version is the Block II version. "...If you wanted to compare vaporware engines, how about the RS-25 against TRW's Low Cost Pintle Engine? ..." What's the status of the TRW low cost pintle engine? Last time I've heard was that they've had the 250K thrust chamber demonstrator test at Stennis several years ago but have not heard of a pig squeak since. <div class="Discussion_UserSignature"> </div>

mlorrey · Mar 17, 2006

XCOR is also building its Xerus suborbital tourism and launch vehicle (boosting upper stages with payloads). They are also providing engines to other private launch companies. The XCOR folks have developed up to about 20,000 lb thrust engines so far (from their days at Rotary Rocket) and have developed demonstrably the most reusable low maintenance engines around.

propforce · Mar 17, 2006

"... How will doing this contribute to reductions in the cost of the engines?..." Significant cost avoidance (not reduction since NASA didn't have the budget planned there in the first place) for the non-recurring engineering & manufacturing development of the RS-25E and certification, and a "projected" recurring cost reduction of the RS-25E acquisition. More important, this represents a significant RISK reduction of the CLV/ CaLV schedule which is the most important in saving NASA manager jobs. "...What is the price on the RS-68 now? ..." Not as expensive as the SSME but more expensive than a bicycle. <div class="Discussion_UserSignature"> </div>

mattblack · Mar 17, 2006

CaLV bigger diameter? I'd doubt that: It'd mean throwing away the E.T. tooling and going for a clean-sheet design. Bad idea, development cost-wise. And as for the RS-25 SSME derivative being "vaporware", well, only if the engine they were based on didn't exist at all which is clearly not the case. Also, the cost issue is slightly moot from one point of view: the CaLV is never going to have a very high flight rate anyway. At best, one extra mission per year than the peak Apollo-era Saturn V flight rate. If you know and accept that going into this thing, it'll be understandable and do-able. <div class="Discussion_UserSignature"> One Percent of Federal Funding For Space: America CAN Afford it!! LEO is a Prison -- It's time for a JAILBREAK!! </div>

trailrider · Mar 17, 2006

"I've heard the same rumor (substituting the RS-68 for the RS-25's) , plus that the diameter of CaLV will be bigger as well." So, does that mean three (3) RS-68's vice the five (5) RS-25's? Also, how much of a diameter increase for the vehicle? And what does that do to utilizing the existing tooling, transport barges (if any), and infrastructure, AGE, etc.? Sounds like a "clean sheet" booster! Using 3 engines instead of 4 or 5 sounds almost like an attitude control nightmare. Ad Luna! Ad Ares! Ad Astra! (Ad anywhere beyond LEO, #&*^%#!!!, but lets get something off the drawing boards and onto and then off the pad!)

propforce · Mar 17, 2006

"... That is surprizing. That means the ET tooling could not be used. ..." It's just a rumor. I can not verify how good it is yet. <div class="Discussion_UserSignature"> </div>

j05h · Mar 17, 2006

>Actually the RS-25 designation is for the SSME. The "E" version would just happen to be the "expendable" version. I think the "D" version is the Block II version. Eh, I had thought the SSME was RS-24. Whatyever the designation, the "low cost" version doesn't yet exist. />What's the status of the TRW low cost pintle engine? Last time I've heard was that they've had the 250K thrust chamber demonstrator test at Stennis several years ago but have not heard of a pig squeak since. Not sure, but I think they hot-fired a 650k version of the engine in 2001. TRW's simple engines have flown many times, but the TR-106 was canned when the Space Launch Initiative was shelved. They still have the designs and could probably build a motor in any size you wanted, if you've got the cash. It reads like great tech, directly descended from the Apollo Lunar Descent modules. http://www.astronautix.com/engines/tr106.htm Josh <div class="Discussion_UserSignature"> <div align="center">We need a first generation of pioneers. </div> </div>

mikejz · Mar 17, 2006

Retooling needed? Are they trying to get this program cancelled?

frodo1008 · Mar 17, 2006

I am admittedly a little confused on this myself. I would just make an educated guess that the diameter of the end of the nozzle of the respective engines and the amount of swivel of the engines would be the determining factors of how large an area that would be needed for a certain amount of engines. The exit diameter of the SSME I could find, at some 94 inches (just two inches shy of 8 feet), but I could not find the same diameter for the RS58. As I remember (it has been 6 years since my retirement) the maximum diameters are quite similer. If anyone knows this I would think that it would help here. One possible way to estimate this is that the Delta IV Heavy with three in line RS68's (and I would think that a triangular configuration would have an even smaller footprint) is used with the common booster cores all being the same diameter. And the Common Booster Core of the Delta IV is a whole lot smaller than the diameter of the ET! If this would be any indication I would think that the RS68 would have no problem with the much larger ET diameter. But I must admit that this is just a logical guess, and may not be correct! A TRW engine of the same thrust would also have about the same diameter. These are all circular nozzle engines, and the same thrust would make the engines about equal in size. Knowing what these engines consist of it is difficult for me to imagine anyone getting an engine in the 500k thrust range down much lower than the $7 million for each RS68! This would make five RS68's less than even one SRB or even one SSME!

mikejz · Mar 17, 2006

Of course, while not in design vouge, they could also adopt an Atlas model with dropping engines.

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