Elon Musk has announced plans for one of the biggest sales of stock to the public ever for a space company currently losing billions of dollars year.

Documents filed on Wednesday (local time) show Musk’s SpaceX lost US$2.6 billion from operations last year on US$18.7 billion in revenue, and the losses kept piling up at the start of this year, too.

Still, the initial public offering is expected to rank among the largest ever, possibly surpassing the current title holder, Saudi Aramco, the oil giant that went public seven years ago.

The prospectus did not put a dollar figure on the amount Musk hopes to raise but various reports have put it at US$75 billion or so.

The company has said the money will help to finance projects to put men on the moon and maybe some day Mars in his quest to make making humans an intergalactic species as it faces existential threats that could wipe out civilisation.