Manned US missions to the International Space Station (ISS) aboard the Atlas V launch system and Boeing's newly developing capsule will be carried out using Russia's RD-180 engines, the Energomash space and rocket engine director said.

General Director Igor Arbuzov told RIA Novosti on Friday the first unmanned test launch of the heavy-lift Atlas V vehicle with Boeing's Crew Transportation System (CTS) capsule is expected in 2017.

The Atlas V CST's manned test launch is expected in 2018, he added. "The crew had already been selected and is being trained. It was determined that the Atlas V manned program will be implemented using the Russian RD-180 engines," Arbuzov said.

He pointed out that the RD-180's and Atlas V's tried and tested performance gives confidence that manned launches could take place within specific time frames.

"Moreover, one can say with confidence that no other engine in the world except the RD-180 is ready for manned launches as part of the Atlas V rocket," the Energomash director stressed.