Deep|Space Compute: SPCX Could Reach 1 GW of On-Orbit Compute in 2028

Executive Summary

1. A thermal design is now in place: chips run hotter, and each satellite carries one NVL72 rack. SpaceX has disclosed AI1 at 250 kW peak and 175 kW average with a 160 m² radiator, but not the operating temperature. Working backward from our June radiator table, that implies a radiator surface of ~65–75°C and chip junction temperatures of 80–90°C. Our industry checks corroborate this: the space version runs its chips at junction temperatures of 80–90°C. That is feasible from an engineering standpoint, since chips in terrestrial racks often run above 80°C at full load, and the temperature itself is not a problem for the chips; the binding constraint is memory. In orbit, running hot is worth far more for heat rejection: in a vacuum, heat can only be shed by radiation, and radiative capacity rises with the fourth power of temperature. Rejecting heat at ~40°C, as is customary on the ground, would require 240–290 m² of radiator; by running hotter, a ~2 t satellite carries exactly one NVL72, a Starship carries ~40 satellites, and no on-orbit assembly is needed.