Decades after the end of the space race, an American rocket took off from Cape Canaveral. This was a routine launch to send a communications satellite into orbit, but the situation was an historic first. The rocket in question was driven by a powerful Russian engine unlike any ever built in the States. Although this particular engine was new, the design dated back to the space age.
By the early 1960s, the Russians were leaps and bounds ahead of the United States in terms of space exploration. They had already launched Sputnik and sent Yuri Gagarin to orbit the Earth. All in all, the Russians seemed poised to send a man to the moon. Russian technology had the Americans worried enough to spy on them with satellites, and the images that came back revealed something spectacular. Out in the Kazakh desert, the Russians were building an enormous causeway and two launch pads. As it turns out, the US had every reason to be worried.
The Russian space program was largely controlled by one man, Sergey Pavlovich Korolyov. It was his design workflow that made the Russians so successful. Instead of spending thousands of hours at the drawing board, they would simply build rockets, fly them, and improve them based on the result. Once President Kennedy announced the Americans’ intent to put a man on the moon by the end of the decade, the race was on. Korolyov was well aware of the awesome amount of rocket power required to send a man to the moon. Because of this, he sought a new manufacturer for rocket engines, and he found one in Nikolai Kuznetsov.
In a Saturn V rocket engine, liquid oxygen and kerosene fuel are pumped separately into the engine at high pressure. They first travel through a pre-burner, which dumps exhaust into the air. Korolyov and Kuznetsov designed a closed-cycle engine that would recycle the pre-burner exhaust back into the system instead of wasting it. For the first N-1 launch, the rocket was powered by 30 of these closed-cycle engines, each running at about 1/6 of the thrust of a Saturn V engine. Whether you’re shaking or nodding your head at how awesomely dangerous this design is, you’re right. An issue with any one engine is likely to cause an explosive chain reaction in the other engines.
Change of the Guard
Korolyov died in 1966, and rocket engineer Vasily Mishin took over the program. The first N-1 rocket was assembled beginning in early 1967 and stood 35 stories tall. Tensions were high in February 1969 as the Russians geared up for the first unmanned launch. The N-1 took off from the launch pad and things were looking good. About a minute into the flight, some metallic debris got into one of the engines and the rocket exploded.
Over the next few months, the team made improvements and scheduled another launch for early July 1969, just a few weeks before the Apollo 11 mission. The N-1 took off and promptly crashed down on the launchpad with incredible force. Although the success of Apollo 11 effectively ended the space race, Mishin and Kuznetsov persevered. Improvements were made on the NK-33 including the addition of filters to keep debris out of the engines. Test launches continued until the Kremlin canceled the program and ordered the destruction of all N-1 rockets in an effort to keep a lid on the technology. Some of the parts were used to build pigpens.
A Forest of Engines
After the end of the Cold War, American engineers started hearing about secret rocket technology developed in the 1960s by the Russians. Engineers from Aerojet and Lockheed were eventually invited to check it out. Kusnetsov took them far out into the desert to a large warehouse where more than 60 of the closed-cycle engines had been sitting secretly in storage.
Aerojet wanted to prove the power and capabilities of the engines and they were allowed to take one back to Sacramento for testing in October 1995. It did everything they said it would do and hit all the advertised benchmarks. Shortly thereafter, work began on a new engine, the RD-180. It would be twice as big as the NK-33, with five times the thrust of a jumbo jet.
The RD-180 was not a slam dunk design, however. Because of the closed-cycle design, the engine created very high combustion that was hot enough to melt the engine metal. A new, high-temperature stainless steel was created by the RD-180’s designer, NPO Energomash, and the RD-180 successfully launched an Atlas III rocket in May of 2000.
Thanks for the tip, [M]!
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