Carried over from the
russian news thread.
http://www.brookings.edu/research/o...sian-military-modernization-us-response-pifer
United Launch Alliance wound up using Russia’s engines because they were more advanced and cheaper than what was available in the U.S., Michael Gass, chief executive officer of the joint venture, told senators during the subcommittee hearing on March 5. Those engines are employed in one of two rockets used for military satellite launches.
“We have kind of fallen behind in advanced technology,” Gass said. “When we went to Russia, there were things that they were doing,” he added, that “our textbooks said was impossible.”
http://www.bloomberg.com/news/artic...b-at-rival-shows-u-s-space-reliance-on-russia
I think everybody in the space industry agree on russian rocket engines being a step ahead of anything else.
TL;DR version:
Russian engines are not the special snowflakes they are made out to be. The Russians engines in question are soviet-era and the Russians are not investing in new ones heavily. American engines are better in several categories and come in more varieties than Russian engines and the Americans are also heavily investing in brand new engines while the Russians stagnate.
Full Version:
Russian rocket engine technology is way overhyped. They do produce some awesome engines but they also produce a lot of crappy ones. There is a massive political backdrop to the above quotes that you have to understand. Absent this political context, you are missing a huge part of the overall story.
Backdrop:
After the USSR dissolved, there was a big push from the political and economic spheres to engage with Russia. On the political side, there was a desire to get Russia 'on our team' by increasing trade links. There was also a massive desire to prevent disgruntled and unemployed Russian rocket scientists from going to work for shifty 3rd world regimes or even terrorist organizations.
On the economic side, there was the desire to buy cheap stuff from Russia while the going was good. These two forces converged and created an atmosphere where buying Russian rocket engines was not only desirable, but
encouraged.
Lockheed Martin and Aerojet took the initiative and began buying up very high-performance Russian rocket engines. Lockheed Martin chose the RD-180 engine (which dates to the USSR's space shuttle program) for their Atlas III/V launch vehicles and this launch vehicle/engine combination has proven extremely reliable. Aerojet chose to begin importing NK-33 engines (which were literally produced in the 1960's/70's for the Soviet moon program and then stored in a warehouse) to market them to American rocket builders. Unfortunately, these have proven very unreliable and wound up causing Orbital ATK's Antares launch vehicle to explode several seconds after liftoff.
Fast Forward to the Present Political Climate
There has been over the last decade a growing concern among some US politicians over the importation and use of Russian rocket engines, particularly for US national security launches. They want this use to stop on the grounds that if Russian-American relations continue to deteriorate, the Russians may simply cut off supplies of the engines, which would make launching many spy satellites very difficult.
To that end, year over year, Congress has provided funds to ULA (the successor to Lockheed Martin's space launch business which markets the Atlas V) to study the production of RD-180's in the US (which is allowed per the ULA/Energomash contract) or to design a new American-designed/built engine. ULA has then year over year flushed those funds down the toilet.
Further aggravating the situation, ULA receives about a
$1 billion subsidy from the US government every year just to keep their doors open. This made sense when ULA was the only company able to launch US national security payloads but doesn't make sense now that SpaceX can do the same and there are other American launch companies on the cusp of joining the club. So you have essentially a company that not only is propped up by the US government but also wastes funds allocated to enable it to produce an American-made engine to replace their Russian ones.
Eventually, Congress enacted a ban on the further importation of Russian engines for national security launches but allowed ULA to keep their current stockpile of Russian engines for national security launches and also allowed them to continue importing Russian engines for civilian launches (NASA, commercial satellites, etc). ULA hated this and they took a series of highly controversial moves aimed at getting Congress to reverse itself:
1) They shifted engines that had been set aside for national security launches to civilian launches - thus artificially depleting the stockpile that was set to last them until 2019 or so.
2) They flat-out refused to bid on a recent national security launch contract, thus making SpaceX the sole provider of launches for these mission types using a thinly-veiled accounting pretext which has since been dis-proven. Essentially, they were trying to say, "You don't want to play by our rules then fine, we won't play at all". No one in the government wants a single launch provider anymore and ULA is trying to play into those fears by making SpaceX the de facto sole launch provider. This is ironic considering ULA was for over a decade the sole launch provider for national security missions.
3) They have refused to privately fund on a long-term basis the design of a new rocket that is intended to replace their current rockets while simultaneously gobbling up federal funds to design an American rocket engine to replace the RD-180. In other words, they are using taxpayer dollars to build new engines without using any funds to design a new rocket to accept them. They are in essence creating 'orphan' engines without a use.
The end result is that pretty much everyone in Congress who doesn't have ULA in their district is pissed off. However, a Congressman who does have ULA in their district was able to put in a policy rider in a defense spending bill that lifted the Russian engine ban and got it passed (and it had to pass or the government would have shut down). So now there are many people decrying this latest dirty trick and many more people decrying the overall stupidity of the situation.
So when you see people talking about the 'greatness of Russian engines', you have to realize that their statements are as much about justifying the choices of ULA as it is about the engines themselves. Also of note: ULA regularly employees retiring USAF/US Gov personnel who were previously responsible for buying ULA rockets and this practice has severely tilted many among the top brass in the USAF into a pro-ULA stance and has even been the cause of criminal/civil investigations.
To address some specific points -
“We have kind of fallen behind in advanced technology,” Gass said. “When we went to Russia, there were things that they were doing,” he added, that “our textbooks said was impossible.”
This is seriously overblown. What Gass is specifically referring to is the oxygen-rich combustion cycle used by both the RD-180 and NK-33. This means that the engines uses an excess amount of oxygen during combustion which essentially makes the specific impulse (think of it like the MPG rating of a car) higher. The trade off is that oxygen-rich cycles are extremely corrosive and do nasty things to engines. The Russians figured out the metallurgy required to make this work and as a result have produced some very efficient rocket engines.
However great this appears, it's only part of the story. For a lower-stage engine (which the RD-180 and NK-33 are), it is much more important to have a high thrust to weight ratio (more power) than to have a more efficient one. So while the
RD-180 is very efficient and is pretty powerful, it's T/W ratio is only decent at about ~80:1. This is nothing special although the engine has proven highly reliable with 66 perfect flights. *Note this last bit for later.
On the other hand, the
NK-33, which is also oxygen-rich (and therefore highly efficient) has a much higher T/W ratio of about 137:1. This is the second highest T/W ratio of any engine which is truly awesome until you realize that it has only flown on 5 flights (total of 10 engines) and failed on 1 of them. This gives it a reliability of only 90% (1 engine failed on the 5th flight, not both engines, so 1 out of 10 engines has failed). This is not so great. *Note this last bit for later.
Now let's look at some American counterparts -
The
Merlin 1C/D/FT variants have flown on 21 flights, each using 9 engines on the first stage. (I am not counting the Merlin Vacuum variants for the upper stages but you should note that including them would actually make the statistics even better. I am also not counting Falcon 1 flights, which again would make the statistics better.) In those 21 flights, only 1 single Merlin engine failed. So the success to failure ratio is 189:188 for the engines which is over 99% reliable. *Compare this to the 100% and 90% success to failure ratios above.
At the same time, the Merlin has a decent specific impulse (lower than the RD-180 and NK-33 but not terrible) but a much higher T/W ratio of over 180:1 (the FT variant is unpublished but higher than the C/D variants which come in at 180:1). This is the highest T/W ratio of any liquid rocket engine, ever, and as previously noted, much more important than specific impulse for lower stages.
It is also significantly cheaper than both the RD-180 and NK-33, which is one of the primary justifications for ULA/Orbital ATK for using them. (Worthy of note: The launch failure last year of a Falcon 9 was not caused by the engine and the one engine that did fail in an earlier flight was compensated for by the 8 other engines of the Falcon 9)
The
RS-68A engine, (produced by Aerojet Rocketdyne) is an advanced Hydrogen/Oxygen rocket engine. It's worth pointing this out because the Russians have not built very many engines of this type and none of their current launch vehicles use them. This engine gets a ridiculously high specific impulse compared to all of the above, though it's T/W ratio is kind of crappy at ~53:1.
The
Space Shuttle Main Engine (SSME -also by Aerojet Rocketdyne) has an even higher specific impulse than the RS-68A and the same T/W ratio.
Finally, both SpaceX and Blue Origin are now building Methane/Oxygen engines which no one has ever launched with before.
To summarize:
Russian engines are highly efficient but have spotty reliability. There cost advantage is also dubious at best and their T/W ratios are not that impressive on the engines they have that don't explode. Additionally, while the Russians can claim to be the only producers of Oxygen-Rich Combustion Cycle engines, they have not ever produced Hydrogen/Oxygen or Methane/Oxygen engines on a regular basis or for lower stages which the US now has and is developing more of. It should be noted that the Russians do have plans for a Hydrogen/Oxygen engine but it is yet to be flown and the US has had this technology since the 60's when they flew these types of engines on the Saturn V.
I am completely discounting all of the hypergolic engine types that both the US and Russians use as the US isn't importing them from Russia and is such out of consideration. I am also not counting the as-of-lately dismal Russian record of launch failures of Russian vehicles as again, that's outside the context of this conversation.
I wouldn't call Russian equipment outdated. Their SAMs are the best in the world, the new T-14 tank looks pretty state-of-the-art, their planes are generally excellent, and they're hoping to introduce the AK-12 to service (though assault rifle design matters very, very little in the grand scheme of things).
I can't speak to the much more important factors of training, command, intel, and logistics, and Russia certainly has huge stockpiles of outdated equipment, but their new stuff is no joke.
This excelence is visible in the military field too, with russian ICBMs, antiship misilles and particullarly SAMs being top notch and in many cases with ranges, ceiling and speeds way ahead of western ones. West has yet to build something as the SA-21 system.
In other fields though i have the feeling they continue lacking respect western counterparts. For instance air warfare. Russian aircraft being awesome and all, the important thing today is information. Detect and not to be detected. With current weapons once you are detected you are mostly toast. (i know i know they thought the same in vietnam, but now it is true) And it is not all about stealth but the whole scenery awareness thing. Sensors, to say it in a word. So in case of a war in the air i would root for the rusky planes but would put all my money in the western equiped side.
Their SAMs are great but I wouldn't say they are the best in the world. They are also severely behind on cruise missile and smart bomb technology which I would argue are much more important in any conceivable war today because let's face it, there aren't many countries that both have decent air forces that are realistically going to go to war.
Their jets are also very old and in addition to lacking stealth, lack the kind of sophisticated electronics that western jets have. As with smart bombs and cruise missiles, I would argue that the electronics in modern aircraft are even more important than the aircraft themselves as they effectively multiply the utility of the aircraft they have. The T-14 tank is yet to be massed produced and for all we know, it is simply catching up to where western tanks now are technologically. Again, it's the electronics in western tanks that makes them much more effective, not bigger guns or thicker armor.
Disclosure:
I'm not anti-Russian space or military hardware. I deeply respect the systems that they have. But in particular when it comes to their space hardware, there is a lot of misconceptions that westerners have for them.
