SpaceX founder Elon Musk has mocked Blue Origin founder Jeff Bezos' moon plans saying they make no sense.
Amazon CEO Bezos had described his vision of humans living on miles-long, orbiting space stations called "O'Neill colonies", named after physicist Gerard O'Neill, who first floated the concept.
"Makes no sense. In order to grow the colony, you'd have to transport vast amounts of mass from planets/moons/asteroids. Would be like trying to build the US in the middle of the Atlantic Ocean," Musk, who is also the CEO of Tesla, tweeted.
The remark comes after Bezos attended a conference in Washington where he discussed his ambitious roadmap for Blue Origin to create a "sustained human presence" - housing up to a trillion people - on the Moon, the report added.
Earlier in May, Bezos unveiled a new Moon-lander called "Blue Moon" after three years of development, along with a smaller rover at the Walter E. Washington Convention Centre.
"We must return to the Moon - this time to stay. We're ready to support @NASA in getting there by 2024 with #bluemoon," Blue Origin had tweeted.