Elon Musk takes aim at President Biden over SpaceX Inspiration4 snub

Fresh from his ongoing war of words with fellow billionaire Jeff Bezos, Elon Musk has fired a shot at US President Joe Biden, mirroring an attack by Donald Trump.

Musk, the CEO of SpaceX, was asked by a Twitter user why Biden hadn't acknowledged the four American astronauts who flew on the Inspiration4 mission.

That was the first mission in history to put an all-civilian crew into orbit around the Earth. They landed on Sunday after spending three days in space.

Musk replied: "He’s still sleeping", echoing former President Trump's "sleepy Joe" nickname for the man who beat him in the 2020 US election.

The jabs at the President didn't stop there. Some hours later he replied to a meme tweet that attacked Biden's relationship with unions, in this case the United Auto Workers (AUW) union.

The meme features a scene from the movie Alien, with one of the beings attached to someone's face. The alien was labelled 'UAW' and the person underneath 'Biden'.

Musk agreed, replying "seems that way".

The controversial Tesla CEO has previously criticised a Democrat bill giving incentives for consumers to buy electric cars built by unionised companies. Business Insider reported that Musk had also claimed, without evidence, that lobbyists for UAW and Ford had written the bill.

Meanwhile, Musk has personally donated US$50 million to the charity supported by the Inspiration4 mission.

Hayley Arceneaux, one of those who orbited the Earth, is a physician assistant at St Jude Children's Research Hospital and a pediatric cancer survivor. The mission is trying to raise US$200 million for the hospital.

"This brings tears to my eyes," she wrote after hearing of Musk's donation.

"Thank you Elon Musk for this generous donation toward our US$200 million dollar fundraising goal for St Jude!"