At the height of the sanctions against Russia, the Americans perfectly understood that in some places they could not do without Russian imports. For example, without the RD-180 rocket engine - a smaller copy of the Soviet RD-170 engine, on which the United States still launches its Atlas rockets into space.
About 40 years have passed since the creation of the RD-170 rocket engine, but no worthy competitors have been created for it. According to Western design bureaus, RD-170 is the ceiling of technical progress in liquid-propellant rocket engines, and foreign journalists called it "the crown of the thousand-year history of rocket engines."
Tsiolkovsky was right
The founder of cosmonautics, Konstantin Tsiolkovsky, proposed using a liquid fuel engine in rockets as early as 1903. But after the First World War, the development of rocket fuels based on nitrocellulose began.
Although no one thought to give up liquid fuel engines. In 1926, American Robert Goddard launched a liquid-fueled Nell rocket. In 2.5 seconds, she climbed 12 meters. In 1933, Friedrich Zander created a similar OP-2 rocket using liquid oxygen with gasoline in the USSR.
Unlike solid fuel, the liquid engine was very capricious. Therefore, many designers did not see potential in it. Until Wernher von Braun, along with Walter Thiel, sent their V-2s to London in 1944. These missiles had a liquid-propellant jet engine (LRE). True, Brown himself believed that he squeezed everything possible from the engine design.
In a liquid-propellant engine, the combustion chamber nozzle is exposed to colossal temperatures. A further increase in power would simply melt the metal of the nozzle. The option of cooling the nozzle from the inside was difficult, because the walls had to be made thinner for heat removal. But if the metal is thin, then it will not withstand the pressure and will also collapse.
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The solution to the problem was found in the 50s of the XX century in the USSR and the USA almost simultaneously. The nozzle began to be made of two bodies, placed one in the other, between which the coolant circulated. Ideally, the fuel itself. After all, liquid oxygen boils at a temperature of -183 °. In this case, the inner thin wall was cooled with fuel, and the outer thick one did not allow the chamber to explode from pressure.
In 1960, in the USSR, under the leadership of designers Sergei Korolev and Valentin Glushko, an intercontinental ballistic missile R-7 was created, on which an engine was installed on the components "liquid oxygen - kerosene". On April 12, 1961, it was this rocket that threw the Vostok-1 spacecraft, piloted by cosmonaut No. 1 Yuri Gagarin, to Earth's orbit.
Dash to the Moon
After the first flight into space, the two superpowers joined another race - the lunar one. As a result, the Americans were the first to reach the Moon, but the USSR also had its own groundwork. Although the relevance of a flight to the moon for Moscow has disappeared, it was decided to be the first to master Mars or Venus.
This required a heavy interplanetary ship with a powerful and reliable engine. In the early 1960s, OKB-1 under the leadership of Sergei Korolev launched a program to create N-1 liquid-propellant jet engines. But all four N-1 launches suffered a fiasco, and in 1974 the N-1 program was closed.
The program for the creation of the reusable space system Energia - Buran has become more promising. Academician Valentin Glushko was appointed general designer of NPO Energia. He believed that the best means of putting the Buran spacecraft into orbit would be the Energia launch vehicle (PH), which instead of the two solid-propellant boosters, supposed earlier, would have four launch accelerators with RD-170 engines.
The idea of the RD-170 oxygen-kerosene engine also belongs to Glushko, but in 1976 the team of the Energomash Design Bureau under the leadership of Vitaly Radovsky began to refine it. The highlight of the design was that the region of maximum temperatures ran along the axis of the combustion chamber, and "at the edges" was much "colder". This made it possible to increase the power without the risk of destroying the nozzle. But even before the fuel entered the chamber, the self-igniting components were mixed right in the pipeline. The nozzle itself was made of a unique nickel alloy that can withstand an aggressive mixture with a pressure of 270-300 atmospheres. As a result, the world's most powerful engine with 20 million horsepower was created!
The RD-170 turned out to be 5.5% more powerful than the American single-chamber F-1 engine, while it was almost one and a half times smaller in size. At the same time, the RD-170 is more economical, since it is built according to the closed cycle scheme, while the F-1 implements a simpler, but less efficient open cycle. Although the characteristic "economical" is rather arbitrary: in one RD-170 chamber with a diameter of only 380 millimeters, 600 kilograms of fuel burns per second.
On August 25, 1980, the first test of the RD-171 engine (the RD-170 version for the Zenit rocket) took place. After that, there were dozens of tests until May 15, 1987, the first successful launch of the Energia launch vehicle with RD- engines took place. 170 in the first stage. And on November 15, 1988, the first and, alas, the last space flight of the "Buran" spacecraft launched into orbit by the "Energia" launch vehicle was carried out. It was the swan song of the Soviet cosmonautics.
The mask never dreamed of
The design of the RD-170, for its characteristics, aroused admiration even among the Americans. They could not understand: how is this possible ?! In Soviet times, the design of the engine was classified, but after the collapse of the USSR, the United States wanted to get the same powerful engine.
In the 1990s, NPO Energomash, which produced the RD-170, found itself in a difficult economic situation. And the American proposal made it possible to preserve the enterprise. But in the USA there was a law preventing the supply of imported products to strategic industries. Then, by order of the American company Pratt & Whitney, Energomash allegedly developed a new engine - RD-180. Although in fact it was a half-engine RD-170 - for the Americans, the power of the RD-170 was excessive. The sale in the USA of the RD-180 was made through RD-Amros (RD-AMROSS), a joint venture between Pratt & Whitney and NPO Energomash. It was Amros that owned the patent rights for this engine. It turned out that the legal development is half American, half Russian. But in fact, the RD-180 is a legacy of the Soviet space era.
Although, under the terms of the contract, the Americans were given all the technical documentation and the right to produce the engine at home, the Yankees were never able to assemble the RD-180. It turns out that documentation isn't everything. And although the liberals argue that the United States simply does not need it, they say, it is cheaper to buy it in Russia, it is not. Maybe when it comes to potatoes or oil, the saying is true, but the US prefers to collect strategic equipment for astronautics at home. They just couldn't.
Although in February 2019, Elon Musk said that the Raptor engine, manufactured by his company SpaceX, surpassed the RD-180 in terms of pressure in the combustion chamber, it would be naive to believe this without repeated tests. Therefore, the American company United Launch Alliance (ULA) once again signed a contract with the Russian NPO Energomash for the supply of RD-180 engines until 2020. And Musk, although he tries, has not proved his competitiveness with Soviet cosmonautics 40 years ago.
Prokhor EZHOV