Making sure AI chips don’t overheat in space

Project Suncatcher is Google’s moonshot to launch solar-powered AI into Earth’s orbit. But operating TPU clusters in space creates a massive hurdle.

On Earth, cooling chips means blowing air over heat sinks. In the vacuum of space, there is no air.

In this video, Google researchers share the thermal engineering challenge of moving heat, using heat pipes, pumped fluid loops, and thermal vacuum chambers.

00:10 – How do we cool AI chips in space?

01:05 – How do heat pipes and fluid loops move heat to radiators?

01:26 – How do thermal vacuum chambers simulate space on Earth?

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Space simulation for hardware testing is performed using a thermal vacuum chamber (1:26). This specialized equipment replicates the two most critical conditions found in the orbital environment:

Vacuum Environment: By removing air from the chamber, engineers simulate the lack of atmosphere in space, which eliminates the possibility of convective cooling (31:00).
Thermal Environment: The chamber allows researchers to control temperatures to mirror the extreme thermal conditions a spacecraft will encounter while operating in orbit (1:33).

Before launching hardware, teams place the integrated payload into these chambers to conduct functional tests, observing how the electronics and cooling systems—such as heat pipes and pumped fluid loops—react to the harsh realities of space (1:36 – 1:45).

Cooling AI chips in space requires a complete shift from traditional air cooling to radiation heat transfer because the vacuum of space lacks air. Through its Google Project Suncatcher initiative, Google is tackling this immense thermal hurdle for its Tensor Processing Units (TPUs) by replacing standard fans with advanced conduction and radiation mechanisms designed for orbital data centers. [1, 2, 3]

Key Cooling Technologies for Space AI

Thermal Interface Materials & Heat Pipes: A layer of malleable thermal material connects the chips directly to aluminum and copper heat pipes. This conducts highly concentrated heat away from the core processors. [1, 4]
Pumped Fluid Loops: These systems actively transport thermal energy from the inner “guts” of the spacecraft out to the external body. [1, 3]
Extensive Radiator Surfaces: In a vacuum, heat can only dissipate via electromagnetic waves emitted by radiators. Because a compact TPU generates thousands of watts while radiators only dissipate a few hundred watts per square meter, satellites require meters of radiator surface area per chip. [1, 2]
Intermittent Duty Cycles: Due to the large discrepancy between how fast the chips generate heat and how fast radiators can release it, the TPUs cannot run continuously. They operate in brief spurts of about 15 minutes and then shut down to allow the cooling system to catch up. [4, 5]

Before taking these systems to orbit, engineers validate the hardware on Earth inside a thermal vacuum chamber, which simulates both the extreme temperatures and the airless environment of space. [1, 2]