Why the workhorse RD-180 may be the future of US rocketry.
On the floor of Lockheed Martin's vast Waterton Canyon assembly plant outside Denver, it's easy to distinguish the Russian engines from the ones built in the US. The American models are sleek and shiny, packed with custom fittings and curvilinear piping. There's not a seam showing or a rivet out of place. The Russian engines inspire less confidence. Insulating foam spills like whipped cream from joints, weld lines scar brawny pipes, and some parts seem to be held together by baling wire.
But it's the Russian RD-180 that will power Lockheed's Atlas V rocket into space next May, delivering a communications satellite into orbit. The RD-180 engine, the product of a combined venture between Pratt & Whitney and Russian engine-maker NPO Energomash, is built for thrust, not looks. "The Russians don't worry about cosmetics or workmanship," says plant manager Steve Blake. "They build the thing and test the shit out of it. This engine cost $10 million and produces almost 1 million pounds of thrust. You can't do that with an American-made engine."
The RD-180's roots stretch back to the Second World War. Having survived Stalin's purges, V.P. Glushko - legendary Soviet rocketeer and founder of the company that would become NPO Energomash - made the Soviet Union's first liquid-fueled rocket engine, the RD-1, in 1943. Engineers continued to make refinements and upgrades throughout the early days of space exploration. Soviet technicians, working without the lavish budgets and specialized components enjoyed by their counterparts at NASA, built their machines from off-the-shelf parts, striving for maximum force and absolute reliability. Although Glushko died in 1989 (just before the Soviet Union also succumbed), NPO Energomash managed to stay alive.
Around the same time, American researcher Charles Vick, working out of the Alabama Space & Rocket Center in Huntsville, was digging into the secret history of the Soviet space program. At a conference in 1988, Vick told US government and industry officials that the Soviets had developed engines that were more powerful, more durable, and less expensive than those created by the best American engineering minds. "There was a tremendous amount of resentment and backlash," recalls Vick, now the chief of space policy at the Federation of American Scientists. "People said, 'That's impossible - I don't believe you.'"
Eventually, the US space industry came to realize that Vick's claims were, if anything, understated. In 1993, a group of American defense contractors visited the Moscow rocket factory. "We looked at the Russian stuff and did a number of calculations to understand what they were telling us," says Bob Ford, who headed the group and now directs Lockheed Martin's reusable launch vehicle. "It was eye-popping."
While the US finessed its rockets into orbit using lightweight materials with minuscule tolerances, the Russians went for brute force, drawing on every ounce of propulsion they could muster to lift their much heavier craft into space. The RD-180 is fueled by liquid oxygen and kerosene; most US engines use solid fuel or more expensive liquid hydrogen, which must be stored at around -420 degrees Fahrenheit.
The Russians employ what's known as a closed-cycle engine: The liquid-oxygen propellant is used in the pre-burner to power the machine's pumps, and then cycled at high pressure into the main combustion chamber, where it's burned with the rest of the fuel. Reusing the concentrated propellant from the pre-burner raises fuel efficiency to more than 95 percent. Until the space shuttle, US rockets had open-cycle engines, which dumped all incompletely burned fuel overboard.
Not only is the RD-180 more powerful than any of its American-made counterparts, but unlike US engines, it can be throttled up and down during flight, making for a much smoother and more efficient ride.
The Russians devised a number of other simple but ingenious strategies to increase reliability and keep costs down. They applied special coatings to internal machine parts to protect them from extreme heat, and routed kerosene around hot rocket nozzles to cool them down. More important, they emphasized what's known as "producibility," handing off designs early in the process to the engineers who were actually going to be building the stuff. "It's a European design philosophy," Ford explains. "Over there, engineers are trained to produce things that work."
If the Atlas V proves successful, the RD-180 may become the engine of choice for the US Air Force's Evolved Expendable Launch Vehicle program, which is charged with developing the military's next-generation disposable rockets. And this means that the success of future American space missions could be riding on an unsightly piece of machinery with MADE IN RUSSIA stamped on the side.
