'It seems crazy': SpaceX's orbital data centre bet tests physics and finance

SpaceX ( SPCX ) has sold investors on a trillion-dollar vision of millions of solar-powered satellites in orbit, packed with the chips needed to power AI.

The promise is a new market in orbital data centres — and a bid by Elon Musk's company to dominate a critical layer of the AI economy.

SpaceX, which made its blockbuster stock market debut in June, expects to begin launching orbital data centres into space as soon as next year. Its 407ft-tall rocket known as Starship is central to this plan.

"This is not some sort of far-future, distant thing," Musk told investors this month.

But company filings, technical documents and interviews with aerospace engineers suggest the company needs to solve three significant interlocking problems to achieve this at scale: how to launch rockets cheaply at unprecedented cadence, cool power-hungry computers in a vacuum, and regularly replace them with the latest chip technology.

The company's own IPO filing makes clear how speculative its bet remains. "Many of our initiatives . . . including those to develop orbital AI compute at scale . . . involve significant technical complexity, unproven technologies or technologies that do not exist, and such initiatives may not achieve commercial viability," it wrote.

The logistical challenges of such an endeavour were "tremendous", said Christopher Smith, a senior aerospace engineer at UC Berkeley's Space Sciences Laboratory.

To maintain a constellation of 1mn satellites, dubbed Starmind by SpaceX, Smith calculated that the company would need to launch more than nine of its Starship rockets a day. The calculation assumes that the chips in its orbital data centres would need to be replaced every five years, and that each rocket could carry 60 satellites.

Starship was built to carry far more, and significantly larger, satellites than previous launch vehicles, bringing down the cost of taking cargo to space. But it has yet to demonstrate full reusability and has failed on several test flights.

It has so far only completed eight successful launches in total, while SpaceX's most prolific rocket, the Falcon 9, launched 165 times last year, a rate of one every two days.

SpaceX wrote in its IPO filing that it would eventually "be able to scale to thousands of [Starship] launches per year", but did not say when it would reach that figure.

"It seems feasible that an initial constellation of AI satellites will be deployed by 2028," said George Lordos, a space systems architect and lecturer at the Massachusetts Institute of Technology. "The question is the scale of that constellation."