RD-180: can the US make rocket engines?

This photo perfectly illustrates the absurdity of the question in the title of the article. However, the enthusiasm with which conspiracy theorists “expose NASA’s fraud” is consistent with the ignorance of their arguments. This article discusses one of them. According to which the United States depends on Russian rocket engines, as a result of which the Americans could not be on the moon (having made 6 landings + 3 more overflights) and did not even fly into space before the space shuttles. Although there are super-vigilant martial artists who have already reached them).

A natural question arises: since we do not consider the shuttles to be shot in Hollywood, on which engines did the Challenger, Discovery, Endeavor, Columbia and Atlantis ships make 134 flights in total (the Challenger crash at the start and the experienced Enterprise do not count)? Meanwhile, in addition to a pair of solid fuel boosters with a monstrous thrust of 1 225 tons each, the shuttle was launched into space with its three RS-25 rocket engines created by the legendary Roketdyne.

Just in case, it’s worth explaining: Russia has nothing to do with this rocket engine. In the 21st century, the Russian Federation does not produce or use hydrogen / oxygen engines at all, although the USSR managed to create such an engine. It was RD-0120, developed by the Voronezh NPO Himavtomatika and successfully tested in the second stage of the super-powerful Energia rocket. Technology that has been lost over the years of Putinism! Following the "logic" of the Moon-fighters, who deny the existence of the Saturn-5 rocket on the grounds that it is not being manufactured today, one could doubt the reality of Energy. However, both still existed, although the fate of Saturn 5 turned out to be more successful. We also note that all rights to the low-power hydrogen engine RD-0146, jointly developed by the NPO Himavtomatika and Pratt & Whitney, belong to the American company. Moreover, it is not produced in Russia.


RS-25 and RD-180

For a correct comparison with the RD-180, you need to divide the latter in half. In essence, it is a pair of engines in one "harness". The most critical and technologically complex unit in the LRE is a combustion chamber + nozzle. They must withstand heat from hot gases, as well as their pressure on the walls. If this very non-trivial problem is solved, then everything else is relatively easy to do. We also need a turbopump unit (TNA), which supplies fuel with preliminary pumping through a cooling jacket. In the F-1 engine, which stood at the 1st stage of Saturn-5, there was no cooling circuit. His very combustion chamber was recruited from tubes through which kerosene was supplied. This bold decision allowed Roketdyne to build a unique, single-chamber engine, which in many ways predetermined the success of the Apollo program.extremal-mechanics.org/archives/23662 it is appropriate to note that it appeared in the late 50s and was created with an eye on the US Air Force, but did not find application there. But NASA came in handy!

RD-180 has one turbopump unit for two combustion chambers, which gives a formal reason to consider it one engine. But nothing prevents us from dividing this assembly into two rocket engines, equipping each chamber with a separate TNA. This was done when two RD-181s were received from one RD-180, dividing the thrust in half. Interestingly, the RD-180, in turn, was similarly obtained as a result of "bisecting" the RD-170 propulsion system, which in Russia is considered the most powerful rocket engine in history. With a thrust of about 800 tons, it surpasses even the F-1 with its ~ 700 tons at ground level, but the RD-170 consists of four combustion chambers. This unit was assembled specifically for the carrier Energy (2 launches in 1987). After Russia's voluntary abandonment of this magnificent rocket and the reusable Buran ship (which became irreversible at the beginning of "rising from its knees"), the question arose about the use of the RD-170. Here

Now you can correctly compare the RS-25 and RD-180. The latter develops 187 tons of thrust per combustion chamber, while the RS-25 produces 182 tons at ground level. However, in a vacuum, this hydrogen liquid propellant rocket engine is slightly ahead of the kerosene RD-180 (223 tons versus 203 tons). Naturally, the specific impulse of RS-25 is greater (452 ​​sec in vacuum and 366 sec at ground level versus 338 sec and 311 sec in RD-180). In relation to the thrust to weight ratio, the Russian liquid propellant rocket engine looks better (78.4 versus 73.1), which, obviously, is associated with mass saving due to a single TNA for two combustion chambers.


Energy-Buran and RD-170 system

So, comparing the RD-180 with the RS-25 is already enough to refute the nonsense about the inability of the United States to make powerful rocket engines. The American engine has a fundamental difference - it is reusable. RS-25 can be repeatedly turned on / off at full throttle, which happened during the launch of space shuttles. In this case, the RD-180, like any other Russian liquid propellant rocket engine, is designed for only one space flight. In RuNet, you can find allegations that the RD-170 and 180 are reusable, but the grounds for such statements are not given.

Against the backdrop of such a spectacular superiority, claims that the scheduled maintenance is too expensive for the preparation of the RS-25 are ridiculous. If workers, engineers and scientists in the United States received the same beggarly handouts as in Russia, the cost of the shuttles and their launches would be much lower. This also partially explains the low cost of the RD-180, which cost the United States $ 10 million apiece (RS-25 is 5-6 times more expensive). Another reason is that Russia spent almost nothing on the development of rocket engines, trading in what it got for nothing from the USSR.

Deliveries of the RD-180 to the United States were carried out by a joint venture RD-Amross with headquarters in Florida, established by NPO Energomash and Pratt & Whitney. Back in 2002, it bought 101 engines, paying in advance for them. Apparently, these were the stocks of these rocket engines left over from the 90s. Thus, the States not only provided themselves with a cheap, reliable and powerful engine for a long time, but also deprived the Russian cosmonautics of development under its capabilities. RD-180 does not stand on our launch vehicles, and under it one could develop a more powerful and modern missile than the Proton-M. We can only blame our mediocre government for the fact that this did not happen.

The RD-180 engine is placed on the 1st stage of the Atlas-V carrier. This is a product of the evolution of the Atlas-Centaur family that NASA has used since the early 70s (Pioneer 10 and 11 probes, which first reached Jupiter and Saturn, after which left the solar system, were launched by Atlas-Centaur rockets in 1972 and 1973). In 1977, the Titan-III with the same Centaur overclocking module worked on epic missions Voyager 1 and 2.

From the beginning of operation to the present, the United Launch Alliance (ULA) company has carried out 79 Atlas-V rocket launches www.wikiwand.com/en/Atlas-5#/Atlas_V launch vehicles_ Atlas_V. Almost half of them - 38 fell on military needs: early warning satellites, spy satellites, etc. The nearest - the 80th launch is scheduled for July 17, 2019 ... also for military purposes. For all this, the "energy superpower" received $ 1 billion, including kickbacks to "effective managers." It is worth noting that Russia lost its own, satellite constellation of the early warning system in the process of rising from its knees extremal-mechanics.org/archives/14681 .


Left Atlas-V, right Atlas-II (100% American rocket)

Does it look like the US dependence on the Russian Federation, inspiring our cheers-patriots? It should also be borne in mind that NASA did not have an urgent need to modify its Atlas-II (in Atlas-III and almost immediately in Atlas-V). The installation of the RD-180 at the 1st stage increased the launch mass and size of the rocket by ~ 20%, the carrying capacity increased slightly more. However, heavy versions of Atlas-V take off due to not so much RD-180 as solid propellants. And if someone believes that without our engine NASA would not have built a heavy rocket, then I will have to disappoint him.

The Delta-4 Heavy carrier, flying on its RS-68 engines, significantly exceeds the payload capacity of not only the (most powerful) Atlas-V 551, but also our Proton-M. The payloads put by these missiles into geostationary orbit are 6.6 tons, 3.85 tons and 3.7 tons, respectively. At the same time, they are able to put 28.4 t, 18.85 t and 23.7 t into a low, near-earth orbit.

It can be seen that the most powerful rocket in the 21st century is the Delta-4 Heavy. Falcon Heavy is already on its heels, but it is still in the testing phase (albeit very successful). This rocket, roughly speaking, is three times stronger than Proton-M. It flies on its own Space-X Merlin-1D engines, using solid-fuel boosters at launch. Merlin-1D develops about 90 tons of thrust, but, as you can see, the thrust of the 1st stage engine is not a critical indicator when creating heavy rockets. Although 90 tons is not so little in the light of the question of whether the United States can do rocket engines. In addition, Merlin-1D runs on kerosene, so do not be amazed by the fantasies that at least they cannot do kerosene engines. Even as they know how, simply hydrogen is the most efficient fuel!

Thus, with a Delta-4 carrier from the beginning of the 21st century, NASA did not need a heavy, single-use rocket, if you do not take into account the economy. And Atlas-V is better because of the low cost of the RD-180 engine (RS-68 is estimated at $ 15 - $ 20 million, there are 3 of them on Delta-4 Heavy), and also because the operation of hydrogen / oxygen RS-68 is more expensive than kerosene / oxygen RD-180. In addition, the heavier Delta-4 is naturally more expensive than the lighter Atlas-V. From an economic point of view, the modification of the Atlas-II rocket with the installation on the 1st stage of the RD-180 engine paid off. America saved money in outer space without reducing flight frequency and without losing quality, while Russia remained with old missiles, giving its most powerful rocket engine to an overseas partner. In fact, in the 21st century, the Russian Federation lost its independence in space and turned into a junior partner of the United States,



And what is the RS-68, created by the same Aerojet Roketdyne? This hydrogen liquid propellant rocket engine is no less, and the most powerful engine today, if you do not engage in tricks with the summation of the thrust from several combustion chambers. RS-68 develops 289 tons at sea level and 307 tons in vacuum. But it is not reusable, so it is much cheaper than the RS-25. The myth that the RD-180 and RD-170 are the most powerful rocket engines is finally destroyed along with the myth that the United States is dependent on Russian engines.

In 2012, Roketdyne invited NASA to install a modified F-1 engine (the same one that "did not exist") on a promising, superheavy SLS carrier. In the F-1B variant, he was supposed to develop 800 tons of thrust at sea level. In this case, it was supposed to radically alter the cooling system of the nozzle with exhaust gases from TNA. In order to restore the handling skills of this rocket engine in 2013, its low-thrust launches were even carried out. However, NASA did not support this idea, which could give a second life to the fiery engine of Saturn-5.

In 2005, Roketdyne suggested that NASA build an RS-84 kerosene engine with a thrust of 470 tons, but also did not find support. Currently, Roketdyne, on its own initiative, has developed the AR-1 engine, capable of developing about 250 tons of thrust. An installation of two twin AR-1s could replace the RD-180 with an Atlas-V rocket, but competition among manufacturers of liquid-propellant rocket engines makes it difficult to make a final choice, so the engine is still in the testing phase.

The final touch to the picture, in which "the United States depends on the Russian Federation." Blue Origin created a Blu-Engine-4 methane engine with a thrust of 240 tons to replace a pair of such rocket engines with an RD-180. Space-X is testing the same methane Raptor. The problem is not that there is nothing to replace the RD-180, but that it is difficult to choose one of several options, what exactly to change it for. It is clear that, with all the bureaucratic puffs of time, in the near future the United States will get rid of the RD-180, because Congress insists on it.