The SpaceX board granted Musk one billion restricted shares of Class B common stock on top of his existing stake of roughly 5 billion shares, worth roughly $700 billion at the expected IPO valuation of $1.75 trillion.

The new shares, potentially worth an additional $600 billion or more, only vest if SpaceX hits two conditions: its top market capitalization milestone of $7.5 trillion, and the creation of a permanent human colony on Mars with at least one million inhabitants. 

The prospectus answers a question on Wall Street’s mind: why SpaceX is going public this way at all. Three months before filing, Musk merged his AI company xAI and his social media platform X into SpaceX, in a deal that valued the rocket company at $1 trillion and the AI company at $250 billion. That merged company, set to rock public markets next month, seemed Frankenstein-ish, but the filing’s own mission statement shows that the seemingly mismatched parts have a single purpose.

“For the entirety of its existence,” the filing reads, “human civilization has lived on a single celestial body: Earth. The current paradigm, in which human civilization is confined to one planet, exposes humanity to existential threats that are unpredictable and uncontrollable on a planetary scale.”

A few sentences later, it adds:  “We do not want humans to have the same fate as dinosaurs.”

SpaceX is a Mars company, and everything else is built as infrastructure for the trip.

Mars colonization, the goal Musk has chased since he was a boy reading Asimov, requires much more than rockets. It requires robots—to build habitats, carry out agriculture, produce fuel, and build all the infrastructure needed to keep humans alive in an environment that’s trying to kill them. It requires the robots to run on AI that can operate on Mars itself, since there’s a communications lag with Earth. And it requires enormous amounts of capital, since none of this technology exists yet.

The merger gave Musk all three pieces under one roof. xAI on its own, loaded down with debt, could not raise the capital to build the AI infrastructure that such a colony would require. SpaceX on its own had no AI business. The idea,  as the filing shows, is that the new company can use Starlink’s revenue plus SpaceX’s launch business to subsidize the AI buildout, and use xAI’s technology to make Mars actually governable at scale.

Who will pay for the rest of it? That’s what the IPO is for. SpaceX’s launch business doesn’t seem to need public capital, with Starlink alone generating more than $11 billion in revenue last year. But the Mars-supply-stack as a whole needs more money than even a profitable rocket company can produce.

Public capital has to fund this layer: the Starship production scale-up needed to move what would be millions of tons of cargo to Mars and to produce the orbital AI compute satellites SpaceX says it will begin deploying as early as 2028. The S-1 hints at this throughout, including a stated goal of deploying space-based AI data centers powered by the sun starting in 2028.

SpaceX claims that for this suite of technologies, there’s a total addressable market of $28.5 trillion, roughly the current size of the U.S. economy. Of that, $26.5 trillion sits in AI. The space and connectivity businesses most people generally associate with the company account for less than $2 trillion combined.

Whether public market investors have an appetite for funding something this risky is a separate question. The Mars timeline is estimated on a range from multi-decades to never. 

Paul Sutter, a NASA advisor and Johns Hopkins research scientist, wrote in Scientific American that Musk’s Mars timeline doesn’t correspond to a real plan. “It’s like announcing a camping trip on your next available weekend,” Sutter wrote, “without having purchased any camping supplies. And your car is in the shop. And has exploded.”

Plus, the combined company posted a $4.3 billion net loss in the first quarter alone, according to the filing. The drag came almost entirely from xAI, which was folded into SpaceX in the February merger. The AI segment generated $818 million in revenue but lost $2.5 billion on operations, while spending $7.7 billion on capital expenditures—mostly Nvidia GPUs, which the company leased from its own board member. Plus if you add a $1.9 billion accounting charge from paying off xAI’s old debt early, then the bulk of the net loss is SpaceX absorbing xAI’s balance sheet. Starlink and the launch business stayed profitable.

The prospectus opens with an epigraph from Musk himself, set above the corporate mission statement:

“You want to wake up in the morning and think the future is going to be great—and that’s what being a space-faring civilization is all about. It’s about believing in the future and thinking that the future will be better than the past,” he wrote. “And I can’t think of anything more exciting than going out there and being among the stars.”