The general director of Russia's leading manufacturer of rocket parts says Elon Musk's SpaceX is unlikely to achieve its ambitious goals.

In February, SpaceX announced plans to launch tourists into space by 2018.

Vladimir Solntsev, who runs Russia's RSC Energia, has publicly questioned whether SpaceX has a spacecraft capable of sending tourists on a weeklong trip around the moon as promised. It "would be difficult to carry out such a mission in 2018, and even in 2020," he says.

The Russian criticized SpaceX during an interview with TASS, a Russian news outlet.

"Nobody has yet even seen the designs," Solntsev said. "There's no launch vehicle, no spacecraft.The Crew Dragon spacecraft designed for missions to the ISS and Falcon 9 launch vehicle are a far cry from a spacecraft and a rocket that are needed for a mission towards the moon."

SpaceX and Musk remain steadfast, however, in their intentions to launch a crewed mission venturing past the moon for two private customers in 2018, as per the original announcement made in February of this year.