Is It Really Impossible To Cool A Datacenter In Space?
Why Hacker News recommends it
HN points to it as a convincing energy-budget analysis in debates over space datacenters, while debating its assumptions.
What it is
Scott Manley explains the thermal balance of spacecraft and how a satellite could be configured to radiate away the heat from datacenter-scale computing in space. His rough numbers suggest it is feasible.
Recommended by 2 HN commenters across 2 different months, 2026 to 2026.
What Hacker News said
Recommends db48x · 2026-05 · on “Starship V3”
It’s very easy to overestimate the difficulty of cooling things in space, unless you actually run the numbers. So please follow along as Scott Manley runs the numbers: < [this video] >. Basically a Starlink v3 satellite has an estimated power budget of 20kW. Add in the heat absorbed from the environment (both directly from sunlight and reflected off of the Earth) and you’ll find that it must reject about 22kW of heat. That’s a fair amount, but at 65°C it can radiate it all away just using it’s own surface area! No radiator required at all! Of course the power density of computer racks has been going up over the years. If you want to reach 100kW per satellite then they will need a modest radiator,
Recommends jauntywundrkind · 2026-06 · on “Cooling in Space”
I went in wanting this to look real bad. But the Scott Manley video alas has sort of convinced me this is pretty feasible, that the energy budget is quite doable. [this video] I do think this is a pretty generous estimate he ends up at. I don't think emissivity is perfectly well dealt with. I don't know if his earth reflection emissivity includes the high energy thermal transfer from particles that do exist on the near vacuum (exosphere be hit, ya'll) or if that matters. But his figures seem ballpark correct & my concerns are at best marginal.
Cites YZF · 2026-05 · on “Starship V3”
[this video] "Is It Really Impossible To Cool A Datacenter In Space?" - Scott Manley tl;dr -> not impossible.
Cites roer · 2026-05 · on “SpaceX S-1”
I don't see how that would lessen their concerns? Exactly because space is a vacuum, cooling is harder since you can't do convection. The math still checks out though. Scott Manley did a video on it, and the top comment has some corrections: [this video]
Cites jauntywundrkind · 2026-06 · on “Cooling in Space”
He starts with something hot today but viable, 80C. And he goes on to cite and discuss a M*sk tweet about hotter, 97C, and what that density that enables. [this video] and [this video]
Cites keeganpoppen · 2026-06 · on “SpaceX to buy Cursor AI coding agent operator Anysphere for $60B”
it actually is not that impossible, and in fact can be done in a form factor not that different from Starlink satellites: [this video]
Critical shagie · 2026-04 · on “SpaceX Files to Go Public”
The bit that I wasn't entirely sold on with his analysis was that he was working on 1 satellite per rack [this video] (YouTube auto transcribe) > ... but how do you scale this up right 20 kow used to be enough to power a full rack of computer gear but we're seeing predictions now of 100 kilowatts per rack and that's just one rack in a data center racks right the 48U 19in rack which is you know big and it's just dense with computers how does that fit into a flat satellite well it turns out that like 19in rack is about 50 cm wide it's about 1 m deep per unit and if you've got a 24 1/2 square meter satellite and you take all your one U units and stack them ... One rack per satellite doesn't seem lik