New Space Race A few weeks ago I posted about the five major Chinese projects to develop reusable rockets, as they never seem to get much attention over here. Since that post, China has now successfully demonstrated 2 reusable rocket projects: • Their own cable catch barge • Folding landing legs (falcon 9 style) There are 3 other major Chinese rocket programs, and there are a lot of smaller minor programs behind those. China’s efforts are serious and progressing fast. What should be very obvious to anyone following SpaceX is that space (or rather Earth orbit) is really a numbers game. A space data center is actually not a “center” at all, it is a satellite constellation, it is not a single large object assembled in space it is a constellation of satellites much like Starlink already is. The way to think about it is that each satellite is basically 1 server rack. A single satellite is optimally around 150-250kW, which is EXACTLY where current AI racks are in the 2020s. So the fit seems fairly attractive even if you have to swallow the launch cost, and the lack of synchronicity that comes from being spread out in a constellation. Space data is solar powered and China already makes 95% of the world’s solar, so going after Elon is a very natural strategy for China, they already totally dominate one of the main industrial substrates, the solar cells. But space is only 1 branch of this story. Nvidia’s next gen rack technology Kyber moves to 800VDC, and to liquid cooling, this pushes rack power density to 600kW and possibly 1-1.5MW, well beyond the solar satellite optimal package size. At those power densities you start to go beyond what is optimal for a satellite and so the space data center window is opening in terms of access, just as Nvidia is moving chips toward something much denser. Chip tech is about to fork by heat sink. • Radiative cooling into deep space • Conductive/convective cooling into water This is why SpaceX needs their own silicon, this is Terafab is being built. Space chips need to run at higher temperatures to dissipate heat radiatively and be more energy efficient, whereas conductive and convective cooled chips just want to cram as much power and compute as possible into the synchronous operation horizon (the distance that light travels during 1 clock tick). For example at 3GHz clock speed light can travel 10cm between each tick of the clock, this is why fast chips must be small, and why a satellite constellation cannot run synchronous operations. Radiative cooling in space means distributed asynchronous compute. Liquid cooling at home means densified synchronous compute. So this new Space Race sits entirely on one side of the fork. Either way, China seems to be doing their fast follower thing here, and is following Elon into building a big space constellation of hot asynchronous chips in space. China has pre-built the solar fabs to support scaling and has 5 launch programs pushing to give them access, 2 of which are now demonstrated. Space silicon with high chip temperatures and limited energy budget, is not Nvidia’s direction, and the two tech forks lead to very different application strengths and weaknesses and different applications in that layer will fall under one fork or the other.