Why Is Heat the Hardest Part of a Data Center in Orbit?

Baiju Bhatt says dissipating heat is the thorniest part of a data center in orbit. In broad strokes, the satellite uses solar panels to generate power, GPUs for compute, supporting electronics, and a big heatsink that absorbs heat and then radiates it away. Large radiator sheets mean carting a bunch of mass and volume to space.

Two racks of GPUs are strictly worse when they are split apart, one in one room and another in a building across the street, than when they sit together. Two racks should be one big satellite rather than two smaller ones. How much radiator mass has to fly is the constraint that design has to beat.