Cooling in Vacuum with Radiators

Philip Johnston is co-founder and CEO of Starcloud, a company building data centers in space to solve AI's power crisis. Starcloud has already launched the first NVIDIA H100 GPU into orbit and is partnering with cloud providers like Crusoe to scale orbital computing infrastructure.

As AI demand accelerates, data centers are running into a new bottleneck: access to reliable, affordable power. Grid congestion, interconnection delays, and cooling requirements are slowing the deployment of new AI data centers, even as compute demand continues to surge. Traditional data centers face 5-10 year lead times for new power projects due to permitting, interconnection queues, and grid capacity constraints.

In this episode, Philip explains why Starcloud is building data centers in orbit, where continuous solar power is available and heat can be rejected directly into the vacuum of space. He walks through Starcloud’s first on-orbit GPU deployment, the realities of cooling and radiation in space, and how orbital data centers could relieve pressure on terrestrial power systems as AI infrastructure scales.

Episode recorded on Dec 11, 2025 (Published on Jan 13, 2026)

In this episode, we cover: 

• [04:59] What Starcloud's orbital data centers look like (and how they differ from terrestrial facilities)
• [06:37] How SpaceX Starship's reusable launch vehicles change space economics
• [10:45] The $500/kg breakeven point for space-based solar vs. Earth 
• [14:15] Why space solar panels produce 8x more energy than ground-based arrays 
• [21:19] Thermal management: Cooling NVIDIA GPUs in a vacuum using radiators 
• [25:57] Edge computing in orbit: Real-time inference on satellite imagery 
• [29:22] The Crusoe partnership: Selling power-as-a-service in space 
• [31:21] Starcloud's business model: Power, cooling, and connectivity 
• [34:18] Addressing critics: What could prevent orbital data centers from working

Key Takeaways:

• Starcloud launched the first NVIDIA H100 GPU into orbit in November 2024 
• Space solar produces 8x more energy per square meter than terrestrial solar 
• Breakeven launch cost for orbital data centers: $500/kg 
• Current customers: DOD and commercial Earth observation satellites needing real-time inference 
• Target: 10 gigawatts of orbital computing capacity by early 2030s

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*Editing and post-production work for this episode was provided by The Podcast Consultant