Russia's Energomash company will send on Wednesday a batch of four rocket engines for U.S. Atlas rockets under a contract with Lockheed Martin.

"Four five-ton engines in special containers will be loaded on trailers and delivered to the Sheremetyevo airport. They will be later transported on board an An-124-100 cargo aircraft to the United States," Energomash said on Tuesday.

The Russian-made RD-180 liquid-fuel engine uses an extremely efficient, high-pressure staged combustion cycle. It is considered the best in its class worldwide.

Rights to employ the RD-180 were acquired by General Dynamics Space Systems Division (later purchased by Lockheed Martin) in the early 1990s for use in the Evolved Expendable Launch Vehicle (EELV) and the Atlas program.

The RD-180 was first deployed on the Atlas III carrier rocket in May 2000 and powered 28 Atlas-family delivery vehicles since then.

Energomash has produced 46 RD-180 engines for the Atlas rockets so far.

The next Atlas launch is scheduled for September 20, 2010.