'Sean Dummy': Why is Elon Musk attacking the acting NASA chief?

Elon Musk is not a fan of NASA Acting Administrator Sean Duffy.

The SpaceX founder and CEO has hammered Duffy repeatedly on social media over the past few days, calling him "Sean Dummy" (which he later amended to "Sean 'Dangerously Stupid' Dummy") and claiming that Duffy "is trying to kill NASA."

Musk also posted the following poll question on X: "Should someone whose biggest claim to fame is climbing trees be running America's space program?" That's a nod to Duffy's lumberjack past; he was active in timber sports in his youth and held two world speed-climbing titles by the age of 30.

This barrage didn't come out of left field. It followed on the heels of Duffy's announcement that NASA will reopen competition for the Artemis 3 moon-landing contract, which SpaceX won in April 2021. The company plans to use a modified upper stage of its Starship megarocket for that mission, which will put astronauts down on the lunar surface for the first time since 1972. The current plan calls for Artemis 3 astronauts to launch atop a NASA Space Launch System rocket, then ride an Orion capsule to lunar orbit, where they'll meet up with Starship for the trip down.

Duffy, however, voiced concerns that Starship may not be ready on NASA's desired Artemis 3 timeline, which now features a 2028 launch target.

"I love SpaceX; it's an amazing company. The problem is, they're behind. They've pushed their timelines out, and we're in a race against China," Duffy said on Monday (Oct. 20) during an appearance on CNBC's "Squawk Box."

"The president and I want to get to the moon in this president's term, so I'm gonna open up the contract," he added. "I'm gonna let other space companies compete with SpaceX, like Blue Origin."

Musk did not seem happy about that. He responded by noting that Blue Origin has never delivered a "useful payload" to Earth orbit — something SpaceX has done hundreds of times — and then made a prediction: "SpaceX is moving like lightning compared to the rest of the space industry. Moreover, Starship will end up doing the whole moon mission. Mark my words."

Musk also responded in another, less substantive way, posting a meme on X asking Duffy why he is "gae."

Musk's beef with Duffy appears to extend beyond the Artemis 3 contract issue, however. The SpaceX chief has long backed fellow billionaire and private astronaut Jared Isaacman for NASA administrator — a post Isaacman was poised to secure until President Trump abruptly withdrew his nomination on May 31.

Trump himself nominated Isaacman but had a change of heart very late in the game, citing the tech entrepreneur's past donations to Democratic politicians and alleged close relationship with Musk. That decision resulted in Duffy taking the agency over in an acting capacity.

In a twist, Isaacman now appears to be back in the mix as a candidate for the top NASA job. But Duffy is keen to hold onto the position, according to both The Wall Street Journal and Ars Technica.

Both outlets also reported that Duffy may seek to fold NASA into the Department of Transportation, an agency also led by the former lumberjack and reality TV star. (Duffy was on the sixth season of MTV's "The Real World," which aired in 1997.)

Musk thinks this is a bad idea: He replied with the "100" emoji to a post by AstroForge CEO and founder Matt Gialich that reads, "No one wants this to happen. This would mark the beginning of the end for our nation's dominance in space."

And, in a post this morning (Oct. 22), Musk took the fight directly to Duffy yet again: "Having a NASA Administrator who knows literally ZERO about rockets & spacecraft undermines the American space program and endangers our astronauts."

The obvious but unsaid point of comparison is Isaacman, who funded, organized and commanded two private missions to Earth orbit, using SpaceX rockets and capsules. (Musk did distance himself from this comparison in another X post today, however, saying, "At this point, I am not advocating any particular candidate for NASA Administrator. I am just desperate for someone with a 3 digit IQ.")

Will Trump re-up Isaacman's nomination? Will Duffy get to take the "acting" modifier off his NASA job title? And how will Musk respond to any of these eventualities? Stay tuned; there could be much more drama ahead.

Editor's note: This story was updated at 3:28 p.m. ET on Oct. 22 to include a new X post from Musk, which reads, in part, "I am just desperate for someone with a 3 digit IQ."