Building the First Data Centers in Space

Philip Johnston is the co-founder and CEO of Starcloud, the company building data centers in space. In November 2025, Starcloud launched an Nvidia H100 GPU into orbit and trained the first large language model in space. They've since raised $200 million, hit a billion-dollar valuation just 17 months after YC demo day and filed with the FCC to deploy 88,000 more satellites. In this episode, Philip walks us through their wild origin story, the engineering challenges behind the StarCloud-1, why they booked a SpaceX launch before they even knew what they were building and how data centers in space make sense both economically and politically. Transcript: https://www.ycrootaccess.com/p/starcloud-solving-ais-energy-problem Chapters: 00:00 - First thing every space company should do 01:06 - Why data centers in space 01:40 - The Starbase trip that started it 02:59 - Asteroid mining, space hotels, and the ideas they passed on 03:25 - Why space-based solar doesn't work 04:43 - Launching Starcloud-1 05:41 - Cooling an H100 in an ice bath at 5AM 06:24 - The separation video 07:25 - First contact and the satellite that kept restarting 10:00 - The two hardest problems: heat and radiation 11:30 - Testing GPUs in a particle accelerator 12:43 - Automotive parts instead of space-grade 13:49 - "The dumbest thing I've ever heard" 14:24 - What 100 VCs got wrong 18:32 - The path to 20 gigawatts in space 20:25 - First customers 21:10 - Designing a GPU for space with NVIDIA 22:50 - A Bitcoin miner in orbit 23:41 - Why hard tech suddenly got popular with VCs 25:18 - Inside the Benchmark round 26:37 - Their hiring strategy 27:48 - How to be contrarian but right 30:29 - Recruiting co-founders before having an idea 31:25 - What if data centers get banned on Earth? 32:26 - Data center myth busting 34:49 - Advice for hard tech founders Apply to Y Combinator: https://www.ycombinator.com/apply Work at a startup: https://www.ycombinator.com/jobs

Philip JohnstonguestGarry Tanhost

Aug 5, 202636mWatch on YouTube ↗

EPISODE INFO

Released: August 5, 2026
Duration: 36m
Channel: Y Combinator
Watch on YouTube: ▶ Open ↗

EPISODE DESCRIPTION

Philip Johnston is the co-founder and CEO of Starcloud, the company building data centers in space. In November 2025, Starcloud launched an Nvidia H100 GPU into orbit and trained the first large language model in space. They've since raised $200 million, hit a billion-dollar valuation just 17 months after YC demo day and filed with the FCC to deploy 88,000 more satellites. In this episode, Philip walks us through their wild origin story, the engineering challenges behind the StarCloud-1, why they booked a SpaceX launch before they even knew what they were building and how data centers in space make sense both economically and politically. Transcript: https://www.ycrootaccess.com/p/starcloud-solving-ais-energy-problem Chapters: 00:00 - First thing every space company should do 01:06 - Why data centers in space 01:40 - The Starbase trip that started it 02:59 - Asteroid mining, space hotels, and the ideas they passed on 03:25 - Why space-based solar doesn't work 04:43 - Launching Starcloud-1 05:41 - Cooling an H100 in an ice bath at 5AM 06:24 - The separation video 07:25 - First contact and the satellite that kept restarting 10:00 - The two hardest problems: heat and radiation 11:30 - Testing GPUs in a particle accelerator 12:43 - Automotive parts instead of space-grade 13:49 - "The dumbest thing I've ever heard" 14:24 - What 100 VCs got wrong 18:32 - The path to 20 gigawatts in space 20:25 - First customers 21:10 - Designing a GPU for space with NVIDIA 22:50 - A Bitcoin miner in orbit 23:41 - Why hard tech suddenly got popular with VCs 25:18 - Inside the Benchmark round 26:37 - Their hiring strategy 27:48 - How to be contrarian but right 30:29 - Recruiting co-founders before having an idea 31:25 - What if data centers get banned on Earth? 32:26 - Data center myth busting 34:49 - Advice for hard tech founders Apply to Y Combinator: https://www.ycombinator.com/apply Work at a startup: https://www.ycombinator.com/jobs

SPEAKERS

Philip Johnston
guest
Co-founder and CEO of Starcloud, building space-based data centers.
Garry Tan
host
President and CEO of Y Combinator and co-host of The Light Cone.

EPISODE SUMMARY

In this episode of Y Combinator, featuring Philip Johnston and Garry Tan, Building the First Data Centers in Space explores starcloud’s plan to power AI with orbital solar data centers Starcloud argues terrestrial AI compute is hitting energy, permitting, and political constraints, while space offers abundant solar power if launch costs fall enough.

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