Powering AI from space, at scale

Engineers from the School of Engineering and Applied Science have developed a novel design for solar-powered data centers that will orbit the earth and could realistically scale to meet the growing demand for AI computing while reducing the environmental impact of data centers.

Reminiscent of a leafy plant, with multiple, hardware-containing stems connected to branching, leaflike solar panels, the design leverages decades of research on “tethers,” ropelike cables that naturally orient themselves under the competing forces of gravity and centrifugal motion. This architecture could scale to the thousands of computing nodes needed to replicate the power of terrestrial data centers, at least for AI inference, the process of querying tools like ChatGPT after their training concludes.

Unlike prior designs, which typically require constant adjustments to keep solar panels pointed toward the sun, the new system is largely passive, its orientation maintained by natural forces acting on objects in orbit. By relying on these stabilizing effects, the design reduces weight, power consumption, and overall complexity, making large-scale deployment more feasible.

“This is the first design that prioritizes passive orientation at this scale,” says Igor Bargatin, associate professor in mechanical engineering and applied mechanics at Penn Engineering and the senior author of a paper describing the system. “Because the design relies on tethers—an existing, well-studied technology—we can realistically think about scaling orbital data centers to the size needed to meaningfully reduce the energy and water demands of data centers on Earth.”

Proposed in the early days of the space age, tethers are essentially long, flexible cables that behave in unique ways once in orbit. Pulled taut by the competing forces acting on orbiting objects—Earth’s gravity and the centrifuge-like effect of orbital motion—tethers naturally align themselves, with one end pulled earthward and the other extending towards space.

In the Penn design, thousands of identical computing nodes would be connected along a tether, forming a long, vertical chain in orbit. Each node would carry computer chips, solar panels, and cooling hardware, creating a modular structure. “Just as you can keep adding beads to form a longer necklace,” says Bargatin, “you can scale the tethers by adding nodes.”

Read more at Penn Engineering.