South Korea's Methane Rocket Engine Upstages U.S. Developments

A South Korean company has developed and ground-tested a regeneratively-cooled, liquid oxygen/methane rocket engine that produces 20,000-30,000 lb. of thrust, bringing quick-response space-launch vehicles closer to reality.

The culmination of a 10-year development program, this "Chase-10" engine was fired at full thrust for 10 sec. on Mar. 15 at a test facility in Seosan, approximately 90 mi. southwest of Seoul. Measured thrust was about 20,000 lb. force, using a non-optimized nozzle. This marked the first time C&Space, the developer, had run a fully integrated prototype--including turbopump, gas generator and regeneratively-cooled combustion chamber--at full power, program officials say.

Methane engines offer superior performance and much cleaner operation than today's kerosene powerplants, but liquid-methane rocket technology isn't as mature. "Basically, nobody's put the money into developing methane [engines]," says a senior launch-industry official. Kerosene powerplants "were already out there, and they worked."

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The Chase-10, developed by C&Space, is a 22,000-lb.-thrust LOX/methane rocket engine with a regeneratively-cooled combustion chamber and nozzle.

"Across the board, liquid methane is better [than current rocket fuels]," says James Petty, president of JP Rocket Engine Co. "It offers a higher Isp [specific impulse] and burns more efficiently than kerosene, especially with regenerative cooling. [Methane is] much more stable than hydrogen, doesn't require heavily insulated tanks, and doesn't have the materials-compatibility issues that hydrogen does. The U.S. just hasn't spent enough money on advancing rocket-propulsion technology--and methane competes with the status quo."

However, NASA showed its continuing interest in this technology by recently awarding a $10.4-million contract to Alliant Techsystems to develop a 7,500-lb.-thrust LOX/methane propulsion system. Contract options call for ATK also to design and build a heavier prototype with multiple-restart features.

NASA-Marshall and the Air Force Research Laboratory, XCOR Aerospace and Orbitec have all built and test-fired methane engines as well. These tend to be at the research and development stage, and typically are gas-pressure-fed systems. The C&Space engine appears to be far more mature than any of the U.S.-developed alternatives--the Chase-10 is already a full-up, production-ready engine, C&Space officials say, with a turbopump and regeneratively-cooled combustion chamber and nozzle.

Until recently, the C&Space engine's existence and maturity have been largely unknown. The South Korean government launched the program in 1996, when Hyundai sent engineers to Moscow under a long-term technology-transfer agreement. Russia and South Korea were partnered to develop a new high-performance rocket engine that could be manufactured and tested in the Republic of Korea. By late 2004, a prototype 22,000-lb.-thrust combustion chamber and turbopump system had been built and tested, but a new administration dropped the project. Instead, the Korean Aerospace Research Institute decided a kerosene engine would power its new KSR-3 sounding rocket.

Its principal researcher, Kyoung-ho Kim, formed C&Space under Vitzro, a Korean company specializing in electrical equipment. Backed by Vitzro funding, C&Space brought the Chase-10 engine to production-ready status and plans to build even larger versions.

The 22,000-lb.-thrust Chase-10 rocket engine--augmented by reusable hybrid solid-rocket boosters--is designed to launch up to 1,000-lb. satellites into low Earth orbit for $1,500-2,000/lb. Its robust combustion chamber is designed to handle 30,000 lb. thrust, says David Riseborough, a C&Space research engineer. The engine can be throttled from 60-100%, but cannot be restarted inflight. An inflight-restart capability, and a fully gimbaled nozzle system, are being incorporated to meet a specific vehicle's needs, Kim adds.

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An integrated prototype of C&Space's methane-fueled rocket engine was tested at full thrust for 10 sec. on Mar. 15. It produced about 20,000 lb. of thrust.

The motor has a 50-cycle design life, with turbine bearings replaced after three cycles. Initial cost will be about "$2-3 million--about 50-75% [that] of a kerosene motor," says David J. Fawcett, president of AirBoss Aerospace Inc., a U.S. company marketing the methane engine with C&Space.

For space tourism applications, AirBoss also is designing a delta-wing launch vehicle that uses the Chase-10 engine. C&Space will fabricate the single-pilot aircraft, enabling suborbital tourism flight profiles to about 100 km. (328,000 ft.) altitude.

A satellite-launch version of the same reusable manned vehicle would add two strap-on solid-rocket boosters, each with about 50,000 lb. thrust.

While NASA and space tourism companies may embrace methane rocket engines for their high-performance, clean-burning and reusability features, the U.S. Air Force wants quick-turnarounds, or "operationally responsive launch." C&Space and AirBoss predict the Chase family of LOX/methane engines would enable mission-to-mission turnarounds of about 6 hr., with actual times dependent on what else a flight vehicle might require.

"If you had an unfueled, staged vehicle on the pad, it could be ready to launch in about 1.5 hr.," Fawcett says. "From the call that says, 'I need something in orbit,' to being on-station, I envision [a methane-powered system] doing it in about 4 hr." Actual "scramble" and turnaround times depend heavily on the site's complete launch and payload-handling infrastructure, as well as processing procedures, he notes.

Because C&Space and AirBoss have just started marketing efforts, no U.S. rocket "airframer" has selected the Chase-10 methane engine yet. A flight-certified, reusable LOX/methane Chase-10 engine can be delivered to a customer about nine months after receipt of an order, Kim says. Any customization that necessitates additional testing would stretch delivery time to about 12 months.