StarCloud aims to start by providing GPU compute to other satellites, then build larger orbital facilities. Johnston says constant sunlight could supply power, while radiators would release heat into space without using fresh water. He argues this could reduce pressure on Earth’s electricity grids and water supplies.
Inside The Startup Launching AI Data Centers Into Space
Speaker
Philip Johnston, co-founder of StarCloud, describes the company’s effort to build orbital data centers during a visit to its Redmond, Washington headquarters with Y Combinator.
Johnston studied applied math and theoretical physics and began his career in software. His team first explored space-based solar power, but estimated launch costs would need to fall to about $50 per kilogram for the idea to break even. After accounting for energy lost when beaming power to Earth, they shifted to sending data centers into orbit, with an estimated break-even launch cost of $500 per kilogram.
StarCloud says it designed, built, and tested its first satellite in 15 months. The roughly 60-kilogram spacecraft carries an NVIDIA H100, and the team built its compute module, antennas, power system, and thermal hardware in-house while contracting Astro Digital to make the satellite bus. Johnston identifies radiation shielding and a deployable radiator as key engineering challenges.
StarCloud joined Y Combinator in summer 2024, after three application attempts, under the name Lumen Orbit. Johnston says YC encouraged the founders to discuss the larger ambition of serving data centers beyond satellite customers. Co-founder Addi brings data center and SpaceX software experience, while CTO Ezra has a decade of satellite design experience and a PhD in engineering.
Starcloud-1 launched on November 2 with the first NVIDIA H100 deployed in space. The company planned tests including model training, inference, and running Gemini, though the transcript describes these as future demonstrations. Johnston says a planned second satellite would have at least ten times the first satellite’s capability, use NVIDIA Blackwell GPUs, and add high-bandwidth optical links.
Takeaways
- Estimate the economics of a new infrastructure model early; StarCloud compared launch-cost break-even points for two concepts.
- Choose an initial customer use case that can validate technology before pursuing a much larger market.
- Identify the engineering constraint that could decide feasibility; StarCloud emphasizes heat dissipation and deployable radiators.
- Pair expertise across the system: compute software, data center operations, satellite structures, and thermal design.
- Separate completed milestones from planned demonstrations when assessing a technically ambitious product.
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What was claimed 18
- foundedPhilip Johnston founded Starcloud
“Philip Johnston, the co-founder and CEO of Starcloud”
0:39inThe Case For Data Centers In SpaceYouTube Verified2 sources· Talk
- featureStarcloud: Builds orbital data centers, initially to provide GPU compute to other satellites and later to compete with terrestrial data centers on energy cost.
“We are building data centers in space, initially to provide GPU compute to other satellites”
YouTube Unverified1 source· Talk
- uses
“We'll be the first to run Gemini from Google on there.”
YouTube Unverified1 source· Talk
- uses
“our first satellite to have an H100 from NVIDIA on board”
YouTube Unverified1 source· Talk
- metricStarcloud: Aims to build 40-megawatt orbital data centers weighing about 100 tons.
“extremely large, full 40-megawatt data centers. It's about 100 tons.”
YouTube Unverified1 source· Talk
- launchedStarcloud launched Starcloud-1
“you launched Starcloud-1 in November 2025”
4:38inThe Case For Data Centers In SpaceYouTube Verified2 sources· Talk
- metricStarcloud: Initially called Lumen Orbit when the founders pitched YC in summer 2024; accepted on the third attempt.
“In the summer of 2024, Philip and his co-founders pitched the idea to YC. They got in on their third attempt. Back then, they were called Lumen Orbit.”
YouTube Unverified1 source· Talk
- previously atprincipal software engineer
“then he was with SpaceX as a principal software engineer”
YouTube Unverified1 source· Talk
- previously at
“My co-founder Addi spent 20 years building data centers at Microsoft”
YouTube Unverified1 source· Talk
- previously at
“He worked on NASA's Lunar Pathfinder mission”
YouTube Unverified1 source· Talk
- role at
“My co-founder Ezra, who's our CTO”
YouTube Unverified1 source· Talk
- metricStarcloud: Designed, built, ready, and tested its first satellite in 15 months.
“We went from founding to having the satellite designed, built, ready, and tested in 15 months.”
YouTube Unverified1 source· Talk
- builtStarcloud built Starcloud-1
“We went from founding to having the satellite designed, built, ready, and tested in 15 months.”
YouTube Unverified1 source· Talk
- usesStarcloud uses Astro Digitalcontracted to build the satellite bus
“We contracted Astro Digital, one of the bus manufacturers, to build the bus.”
YouTube Unverified1 source· Talk
- usesStarcloud-1 uses
H100“Starting with the world's first Nvidia H100 GPU deployed in space”
YouTube Unverified1 source· Talk
- featureStarcloud: Second satellite planned to have optical terminals for continuous high-bandwidth, low-latency connectivity.
“24/7 high-bandwidth connectivity with very low latency all the time”
YouTube Unverified1 source· Talk
- uses
“it will fly Nvidia's Blackwell architecture”
YouTube Unverified1 source· Talk
- metricStarcloud: Second satellite planned to be at least 10 times more powerful than the first and to fly NVIDIA Blackwell architecture.
“at least 10 times more powerful than the first satellite, and it will fly Nvidia's Blackwell architecture.”
YouTube Unverified1 source· Talk
