Billionaire Gina Rinehart's Hancock Prospecting has acquired a $US1 billion ($1.4 billion) stake in Elon Musk's rocket company SpaceX.

'We see SpaceX as a rare business: led by a truly exceptional person, technically exceptional and operating in sectors that are crucial, and with long-term potential,' Mrs Rinehart told the Wall Street Journal.

Mrs Rinehart is a big fan of Musk and met with him in 2024, the day after Donald Trump's election win.

'It gave me the opportunity to thank him for his loyal, steadfast support of President Trump despite all the lies and misrepresentations and worse that was thrown at the president (that's what real friendship is),' Mrs Rinehart said.

Mrs Rinehart praised Musk for his work with the Department of Government Efficiency (DOGE), where he led efforts to cut bureaucratic waste and government bloat before stepping down from the role in May 2025.

'[It was] a chance to congratulate Elon on his leadership to drive an office of government efficiency, to cut government waste, this being much needed in Australia too.

'Both countries are running huge debts, which leads to higher taxation, high interest and inflation, affecting us all, so it's very important to cut government waste as Elon advocates.'

On Friday, Musk became the world's first trillionaire after shares of SpaceX, soared in Wall Street's biggest initial public offering.

Musk says SpaceX, which he founded in 2002, is going public to raise money for ambitious projects including asteroid mining, deploying satellites and data centres in space, and eventually establishing a human colony on Mars.

He marked the opening of trading on Nasdaq by joining a ceremonial bell-ringing from Starbase, the South Texas home of SpaceX.

He reiterated his lofty goal 'to make life multiplanetary'.

'Not just a few astronauts, I mean literally you,' Musk said. 'Whoever you are watching this, SpaceX wants to be able to take you to the moon, take you to Mars and ultimately beyond.'

In addition to establishing a one-million-person Martian colony, the company has promised to save humanity by establishing other outposts in space, launching data centres the size of football fields into orbit, and outdoing rivals Anthropic and OpenAI in the race to make money from artificial intelligence.

To reach its goals, SpaceX needs billions more than it currently takes in from its rocket and satellite business. Between the start of 2025 and March 31, 2026, the company, formally known as Space Exploration Technologies Corp., lost $8.7 billion.

Musk made his initial fortune by creating two companies, Zip2 and PayPal, that netted him about $200 million upon their sale. He used that money to start SpaceX and invest in Tesla, defying the odds by creating a space company that figured out how to reuse rockets and a car company that made electric vehicles cool.