The Case For Data Centers In Space

Johnston says space could provide abundant solar energy as building new power projects on Earth becomes more constrained. He began exploring space businesses after seeing the launch capacity planned for Starship, then shifted from space-based solar to data centers: he says transmitting power to Earth would lose about 95% of it, while his team estimates space data centers could break even at launch costs near $500 per kilogram.

For its first spacecraft, Starcloud flew five GPUs, including an NVIDIA H100. Johnston describes using phase-change material to manage heat and ground testing to study radiation effects; the team also worked through software restarts after first contact. He says the spacecraft trained a model, ran Gemini, and performed inference on satellite imagery.

Johnston identifies heat removal in a vacuum and chip reliability under radiation as the main engineering challenges. Starcloud is developing deployable radiators and testing commercial components, while a SpaceX contract is intended to provide laser connectivity for its next 20 satellites. He describes a planned 10-kilowatt spacecraft for government and military customers, followed by a 200-kilowatt design, with the larger constellation and its capacity dependent on launch costs and Starship.

Johnston says investors initially rejected the idea, in part because they doubted launch costs would fall and found the concept difficult to picture. He credits his co-founders’ space engineering experience and says the team booked a rideshare launch the day after founding to create a concrete deadline. Early customers include government and military organizations, which could use onboard processing to turn large volumes of satellite imagery into information such as vessel locations.