Lumen Orbit, a startup backed by Y Combinator, has raised over $10 million to develop data centers in space. It plans to support AI training in a way that’s both energy-efficient and scalable, and will launch its first demo satellite in 2025 as part of Nvidia’s Inception program.
In a recent whitepaper, Lumen Orbit explains that space-based data centers can make use of high-intensity, 24/7 solar power without being affected by the day/night cycle or atmospheric interference. This approach, they claim, would result in energy costs “22 times lower than today’s energy prices.”
Their vision for the setup is ambitious, involving large radiators to dissipate heat, which would be about half the size of the corresponding solar arrays. “Within the compute modules, either direct-to-chip liquid cooling or potentially two-phase immersion cooling is required to achieve high power densities and a space-efficient rack setup,” the whitepaper states. Heat from the modules would transfer to radiators via “several cooling loops, using two-phase systems where practical.” Lumen Orbit believes this setup could achieve power efficiency on par with the latest hyperscale data centers on Earth.
The company also makes some bold comparisons for cost savings. Lumen Orbit estimates that a 40MW data center on land operating for a decade would incur around $167 million in expenses for power, cooling, and infrastructure. In contrast, they argue that a space-based setup could cost only $8.2 million. Their breakdown includes $2 million for solar arrays, $5 million for launching the compute module, and $1.2 million for radiation shielding.
However, these estimates come with a few big assumptions. The setup would require the largest solar array ever deployed in space, far bigger than the 120kW array currently on the International Space Station. Lumen’s design relies on cost predictions for solar cells at around $0.03 per watt, as noted in a whitepaper by Longi. But this figure doesn’t factor in the extra protection space-based cells need against radiation. As the European Space Agency points out, a bare solar cell would only last a few days in space, so most arrays are shielded with a thin layer of glass, which adds cost, weight, and can impact performance.
Launch costs are another wildcard in Lumen’s calculations. The company’s $8.2 million estimate assumes a launch cost of $30 per kilogram. Currently, costs are closer to $1,520 per kilogram with Falcon Heavy rockets. SpaceX’s Starship could potentially bring that down to around $150 per kilogram, and maybe even as low as $10-30 per kilogram if both the booster and upper stage become reusable and production costs decrease. However, these cost reductions aren’t guaranteed.
Lumen Orbit’s large satellite would also need “highly responsive spacecraft maneuverability for collision avoidance,” which isn’t included in their cost estimates. The whitepaper acknowledges that hardware will degrade faster in space and become outdated quickly, particularly given the fast pace of AI developments. While the modules are designed to be replaceable, the $8.2 million figure only accounts for a single launch. Without human maintenance, failure rates could be higher than on Earth, requiring additional launches for replacements.
Data centers are evolving to meet increasing global demand, with innovative placements on land, underwater and now in space. On land, traditional data centers house vast servers in controlled environments, often near population hubs to reduce latency and optimize user access. Underwater data centers, such as those explored by companies like Microsoft, Subsea Cloud and Highlander utilize ocean depths for natural cooling, which can significantly reduce energy costs and environmental impact. Meanwhile, space-based data centers, though in the early stages, can handle data-intensive tasks like satellite communications. Together, these diverse environments demonstrate a shift toward more sustainable, resilient, and high-performance data infrastructure.
While Lumen Orbit’s plans are exciting, there are significant hurdles to overcome in terms of cost, technology, and logistics. For their vision of a space-based data center network to become a reality, the company will need to tackle these challenges head-on.
