WASHINGTON, Oct 21 (Reuters) - Acting NASA chief Sean Duffy and billionaire Elon Musk on Tuesday traded barbs online over who should lead the space agency, a day after Duffy invited companies to compete with Musk’s SpaceX for a moon landing mission.

Elon Musk ignited a fierce public feud with Acting NASA Administrator Sean Duffy, calling him 'Sean Dummy' and suggesting he had a '2-digit IQ' in a dramatic series of posts on X.

Musk’s comments come one day after Duffy said he was in the process of reopening solicitations for a contract that had been awarded to SpaceX as part of the Artemis III project.

Sean Duffy, the Secretary of Transportation and acting administrator of NASA, appeared on CNBC on Monday to say that SpaceX had fallen behind in its effort to return Americans to the moon with the Artemis program. And SpaceX CEO Elon Musk was not happy about it.

SpaceX Chief Executive Elon Musk hurled insults at NASA’s acting administrator a day after complaints SpaceX was behind schedule on its Artemis lander.

NASA acting administrator Sean Duffy suggested SpaceX may not be taking NASA to the moon. Experts said it’s unlikely another company could step in and hit the 2027 goal.

Elon Musk criticizes government plan to merge NASA with DOT, calling it a threat to agency's independence and U.S. space leadership. Supports Jared Isaacman for leadership.

Elon Musk has criticised acting Nasa administrator Sean Duffy after remarks that SpaceX is “behind schedule” on the Artemis III lunar mission

Transportation Secretary and interim NASA Administrator Sean Duffy is reportedly gunning for the top space agency job.

Elon Musk voiced his disapproval of acting NASA administrator Sean Duffy Tuesday in a slew of messages donning him “Sean Dummy.”

The transportation secretary condemned the incidents as "absolutely unacceptable" and said he will "get to the bottom" of them.