The SpaceX founder put Bezos on blast in an early Thursday tweet, claiming the Blue Origin founder's plans to construct futuristic space colonies was half-baked. Bezos has previously 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 USA in the middle of the Atlantic Ocean!" Musk wrote in response to a Twitter user who asked for his opinion on "O'Neil structures."
The snarky remark comes after Bezos attended a conference in Washington, D.C., where he discussed his ambitious roadmap for Blue Origin to create a "sustained human presence" — housing up to a trillion people — on the Moon, according to Business Insider.
The Amazon chief introduced a mock-up of his own planned lunar lander for Blue Origin earlier this month.
He said Blue Origin will land a robotic ship ("Blue Moon") the size of a small house, capable of carrying four rovers and using a newly designed rocket engine and souped-up rockets. It would be followed by a version that could bring people to the moon along the same timeframe as NASA's proposed 2024 return.
"This is an incredible vehicle and it's going to the moon," he said with confidence.
It didn't take long for Musk to call Bezos out at that time, too.
The 47-year-old tweeted a screenshot on May 9 of a New York Times article with the headline: "Jeff Bezos unveils Blue Origin’s vision for space, and a moon lander." The image featured Bezos standing in front of the company's "Blue Moon" spacecraft.
But Musk's screenshot of the article appeared to be altered. Instead of reading “Blue Moon,” the word “moon” was crossed out and the word “balls” was added in.
“Oh stop teasing, Jeff,” Musk quipped in the tweet.
Fox Business' Kathleen Joyce and The Associated Press contributed to this report.