The Strange Cold War History of the Soviet Engines in the Antares Rocket

When an Antares rocket went up in a huge fireball last week at the Wallops Flight Facility in Virginia, observers looking to quickly assign blame for the crash pointed their fingers in a surprising direction: Russia. The culprits, they speculated, were the Russian-made NK-33  engines used to power the rockets. Decades old and relics of ...

Joel Kowsky/NASA via Getty Images
Joel Kowsky/NASA via Getty Images

When an Antares rocket went up in a huge fireball last week at the Wallops Flight Facility in Virginia, observers looking to quickly assign blame for the crash pointed their fingers in a surprising direction: Russia. The culprits, they speculated, were the Russian-made NK-33  engines used to power the rockets. Decades old and relics of the Cold War, these obscure machines turned into a political tool. With relations between Moscow and the West at their lowest point since the Cold War’s end, of course the Russian bogeyman could be spotted lurking in the shadows of this Virginia disaster.

But where did these engines come from? And how did they end up on an American rocket that is one of the main competitors to Paypal co-founder Elon Musk’s dreams of commercial space dominance?

The answer lies in the obscure history of another failed rocket. In the depths of the Cold War, the Soviet Union suddenly and unexpectedly found itself losing the space race. After beating the Americans off the starting block by putting the first satellite in space and first achieving manned space flight, the United States was racing toward the moon. The Russians, it turned out, were missing the huge moon rocket necessary to sling men and materiel more than 200,000 miles from the earth.

Not that they didn’t try. The Soviet answer to America’s Saturn rocket was dubbed the N-1 and represented a massive experiment in rocket science. Lacking huge rocket engines and the manufacturing capability to build them, the Soviets constructed a gargantuan rocket whose first stage was powered by 30 smaller rocket engines.

That engine was dubbed the NK-33 and represented a marvel of rocket science. Liquid-fueled rockets function by mixing a hydrocarbon — typically kerosene — with oxygen that then ignites in a combustion chamber. By raising the pressure in the combustion chamber, it is possible to generate even more thrust from that violent reaction. To do so, a pre-burner is used to pump the fuel at higher speeds. The Soviet innovation was to “close” this cycle and funnel the exhausts from the pre-burner into the combustion chamber. Previously, those exhausts had been vented to the engine’s side, wasting energy and possible power.

The NK-33’s design did something that American engineers thought had been impossible. Closing the cycle created a precarious balance within the rocket engine that operated at the edge of physics, producing previously unheard of efficiency and power.

But the N-1 was a doomed project. Early versions of the rocket blew up shortly after take-off, and its designers failed to produce a reliable version. To give a sense of both the rocket’s scale and its ambitions, one of the N-1 crashes resulted in what is believed to be one of the largest non-nuclear explosions to have ever taken place on earth.

The Soviets had lost the race to the moon, and the technological marvel that was the NK-33 was mothballed and stashed away in a Russian warehouse where the engines sat unused for decades.

It was only after the Soviet Union collapsed that American engineers realized what a treasure they had in Russia’s rocket stores. The Soviets, it turned out, had managed to construct rocket engines that were in many ways more capable than their American counterparts. “We looked at the Russian stuff and did a number of calculations to understand what they were telling us,” Bob Ford, a Lockheed Martin engineer who traveled to Russia to learn about Soviet rocket engines, told Wired in 2001. “It was eye-popping.”

American rocket engineers quickly realized that they could buy Soviet engines on the cheap and repurpose them in their own rockets. Refurbished and outfitted with more modern technology and electronics, the NK-33 is now used in Orbital Sciences’ Antares rocket, and the bigger, more powerful RD-180 is used in the Atlas rocket.

For a sense of the power of one of these engines, see this video of an NK-33 being test fired by NASA. (The NK-33 is also known as the AJ26, in its refurbished and slightly modernized form.)

But America’s dependence on Russian rockets has now turned into a political flashpoint. The RD-180 is manufactured in the United States under license, and some observers fear that Russia might deny its renewal as relations between Moscow and Washington continue their downward slide.

And for entrepreneurs like Musk, this political subplot to the story of these Russian super-engines represents a business opportunity. “One of our competitors, Orbital Sciences, has a contract to resupply the International Space Station, and their rocket honestly sounds like the punch line to a joke,” he told Wired in 2012. “It uses Russian rocket engines that were made in the ’60s. I don’t mean their design is from the ’60s-I mean they start with engines that were literally made in the ’60s and, like, packed away in Siberia somewhere.”

Last week, he was singing a very different tune:

Musk is currently battling for control of the rapidly growing commercial space industry, and the quality of rocket engines is one key front on which that war is being waged. Musk’s SpaceX makes an engine that is similar to the NK-33 and is called the Merlin. It represents the workhorse of his space fleet, and if Musk is able to convince his customers — primarily the U.S. government — that he has built a superior machine, he will be well on his way to crushing his competition.

According to Brian Weeden, the technical adviser for the Secure World Foundation and a space policy expert, Musk has a point in his arguments against the NK-33. Musk’s Merlin engine is made in-house in his company’s facilities, and SpaceX has a much better sense of the engine’s strengths and weaknesses. And like the Soviets, Musk plans to use several of these smaller engines to power his heavy-lift rocket.

Left unsaid is that an engine made by Soviet engineers in the 1960s is effectively competing with a brand-new American design. The NK-33 is by some measures more powerful than the Merlin, and its continued use is a testament to the quality of the old design.

And these old rocket engines are helping keep Musk’s competitors in the game. Orbital Sciences’ expertise lies in satellite design and manufacture, not rockets. The use of the NK-33 offers Orbital Sciences entry into the market at a low price-point. “I would look at this in the context of a business decision made by one U.S. space company,” Weeden said.

In fact, the NK-33 isn’t the only foreign component in Orbital Sciences $200 million Antares rocket. Its first stage is manufactured by a Ukrainian firm, the KB Yuzhnoye design bureau.

But the most telling aspect of Orbital Sciences’ dependence on Russian space technology can be found out at Wallops, a facility on the Virginia coastline, where some signs are posted in both English and Russian:

Elias Groll is a staff writer at Foreign Policy. Twitter: @EliasGroll

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