NASA’s acting Administrator Sean Duffy seems to have provoked the ire of Elon Musk.
Musk, the founder and CEO of SpaceX, took aim at Duffy on Tuesday in a flurry of social media posts, attacking his intelligence and recent efforts at the helm of the space agency.
“Sean Dummy is trying to kill NASA!” Musk wrote on X, which he also owns, using an insulting nickname to refer to the acting administrator. In a separate post, he said: “The person responsible for America’s space program can’t have a 2 digit IQ.”
Musk’s posts came after Duffy announced on Monday that in NASA’s quest to return astronauts to the moon — and to do so before China puts its own bootprints there — the agency is open to using moon landers from competitors to SpaceX.
NASA’s plan had been to use SpaceX’s next-generation Starship rocket system, which is in development, to land on the lunar surface.
In his posts on Tuesday, Musk even created a poll for his X followers to weigh in, asking: “Should someone whose biggest claim to fame is climbing trees be running America’s space program?” One response option read, “Yezz, chimps skillz rūl!” while the other was, “Noo, he need moar brainz!”
As of Tuesday afternoon, the poll had nearly 110,000 votes.
SpaceX won a $2.9 billion contract in 2021 to use its Starship rocket system to land two astronauts on the lunar surface for NASA’s Artemis III mission, which is slated to launch in 2027.
But Musk’s rocket company has fallen behind schedule with its testing and development of Starship, and the vehicle suffered a string of explosive failures earlier this year.
At the same time, political pressure has mounted as the space race with China heats up. The country, which aims to land its astronauts on the moon by 2030, has already sent two robotic rovers to the lunar surface and conducted key tests of a new rocket that would be used for crewed moon missions.
In appearances Monday on Fox News and CNBC, Duffy said NASA will open up the Artemis III contract and solicit other moon lander proposals from rival space companies to help the U.S. stay competitive with China.
“We’re not going to wait for one company,” Duffy said on CNBC’s “Squawk Box” on Monday. “We’re going to push this forward and win the second space race against the Chinese.”
Duffy added that he and President Donald Trump are eager to have astronauts back on the moon within Trump’s second term.
Duffy called out Blue Origin, the space launch company started by Amazon founder Jeff Bezos, as an example of a SpaceX competitor that could offer its own technology.
The comments appeared to anger Musk.
In his Monday posts, Musk cast doubt on whether any other commercial space company could meet such an aggressive deadline.
“SpaceX is moving like lightning compared to the rest of the space industry,” he wrote. “Moreover, Starship will end up doing the whole Moon mission. Mark my words.”
SpaceX is indeed far ahead of its rivals — it already conducts regular missions for NASA to carry astronauts and cargo to and from the International Space Station.
In response to Musk’s post, Duffy wrote on X: “Love the passion. The race to the Moon is ON. Great companies shouldn’t be afraid of a challenge. When our innovators compete with each other, America wins!”
But on Tuesday, Musk’s online tirade got personal, as he called into question Duffy’s competence to run NASA. Although Duffy is leading the agency temporarily, a Wall Street Journal report on Monday suggested that he is jockeying to keep the role, in addition to his duties as transportation secretary.
The Journal reported that Duffy has been battling it out with billionaire Jared Isaacman, who may be emerging again as a potential pick for NASA administrator. Trump pulled Isaacman’s nomination in May, shortly before his expected confirmation vote, after what the president described as “a thorough review of prior associations.” (Trump did not provide details, but some Republicans had raised concerns that Isaacman had previously donated to Democrats.)
Musk had backed Isaacman, who flew on two private SpaceX missions into orbit.
Bethany Stevens, press secretary for NASA, told NBC News that President Trump had asked Duffy to talk to potential administrator candidates, and that the interim head was “happy to help by vetting people and giving his honest feedback.”
“Sean is grateful that the President gave him the chance to lead NASA,” Stevens in a statement. “At the President’s direction, Sean has focused the agency on one clear goal — making sure America gets back to the Moon before China. Sean said that NASA might benefit from being part of the Cabinet, maybe even within the Department of Transportation, but he’s never said he wants to keep the job himself.”
The White House did not immediately respond to a request for comment.
The timing of the Isaacman drama in May coincided with an ugly, public spat between Trump and Musk, which preceded the SpaceX CEO’s exit from the White House as a special government employee. Musk’s departure was tense — he criticized Trump’s One Big Beautiful Bill, calling it a “massive, outrageous, pork-filled Congressional spending bill” and a “disgusting abomination” that would add to the budget deficit.
Trump picked Duffy in July to be the interim administrator of NASA.
