Elon Musk has responded on social media to criticism of SpaceX's orbital data center cooling, arguing that heat is easier to shed in space than on Earth. In a vacuum, heat can only leave through radiation, in the form of infrared, because there is no air or water to carry it away.
The reply followed a comment by Shaun Maguire, a partner at Sequoia Capital, which Musk answered with «much easier to cool in space». Musk wrote that an aluminum radiator facing away from the Sun can emit about 1,300 watts per square meter, because it mostly sees cosmic background radiation at about three degrees above absolute zero. The Sun is the decisive variable: its energy heats the equipment, so components that must shed heat have to point away from it.
In Musk's calculation, the radiator must be far larger than the solar panels. «Solar panels generate 250 W/m², so you should expect them to have 5 times the area of the radiator», he wrote, adding that most of the satellite's mass is solar panels.
Radiative heat transfer follows the Stefan-Boltzmann Law, which links emitted heat to the emissivity and area of a surface, the Boltzmann constant, and the temperatures of the object and its surroundings. Coated aluminum radiators have higher infrared emissivity than solar panels, which is the basis of Musk's argument.
The project sits within a broader plan. SpaceX describes a constellation called Starmind with up to one million satellites, organized in clusters of about ten units linked by roughly 10 terabits of bandwidth. According to sources, the first satellites could begin deployment as soon as late 2027, built at the Gigasat factory in Bastrop, Texas. The first design is called AI1 and would sit in a sun-synchronous orbit to stay in sunlight.
The idea has critics. In February, OpenAI's Sam Altman called putting data centers in space «ridiculous» in the current landscape, while saying they could matter later. On X, one commenter noted that a vacuum insulates heat and that heat can only be dissipated by radiation, making such data centers unlikely.
Musk has also said that almost all computing for future superintelligence will be in space, clarifying that «overwhelmingly» means about 100%. These remain his forecasts; the cooling figure is a physical estimate, not an experimental result.
Impact on the Italian market
None of the sources points to a direct effect on the Italian market. The subject concerns the technical feasibility of an infrastructure that today exists only in plans.
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