Orbital data center thermal management is a scale-dependent engineering challenge not a hard physics constraint with passive cooling sufficient at CubeSat scale and tractable solutions at megawatt scale

The Stefan-Boltzmann law governs heat rejection in space with practical rule of thumb being 2.5 m² of radiator per kW of heat. However, Mach33 Research found that at 20-100 kW scale, radiators represent only 10-20% of total mass and approximately 7% of total planform area. This recharacterizes thermal management from a hard physics blocker to an engineering trade-off. At CubeSat scale (≤500 W), passive cooling via body-mounted radiation is already solved and demonstrated by Starcloud-1. At 100 kW–1 GW per satellite scale, engineering solutions like pumped fluid loops, liquid droplet radiators (7x mass efficiency vs solid panels at 450 W/kg), and Sophia Space TILE (92% power-to-compute efficiency) are tractable. Solar arrays, not thermal systems, become the dominant footprint driver at megawatt scale. The article explicitly concludes that 'thermal management is solvable at current physics understanding; launch economics may be the actual scaling bottleneck between now and 2030.'