SpaceX, Elon Musk’s rocket and satellite company, announced last June that it had set its I.P.O. price at $135 per share, preparing for what could become the largest stock market debut in history. The company was expected to begin public trading Friday under the ticker symbol SPCX.

SpaceX plans to sell more than 555 million shares and raise around $75 billion, giving the company a valuation of $1.77 trillion. If successful, the offering would break the previous I.P.O. record set by Saudi Aramco, which raised more than $29 billion in 2019. The huge offering could also make Musk even wealthier and turn thousands of current and former SpaceX employees into millionaires.

Musk founded SpaceX in 2002 and has since developed partly reusable rockets and the Starlink satellite internet service. The company also works with NASA and other federal agencies.

SpaceX’s financial report has raised questions among investors. SpaceX lost more than $4.9 billion last year because of increased spending on A.I., although its revenue rose 33 percent to $18.7 billion.

Some investors have questioned whether SpaceX is really worth more than $1.7 trillion, according to…. They are also unsure whether Musk’s ambitious plans such as putting A.I. data centers into orbit and building factories on the moon are realistic. Senator Elizabeth Warren has raised concerns about the company’s financial projections as well. Others, however, remain excited about the offering and see it as another opportunity to bet on Musk’s ability to change industries.