I am very impressed by the fact that this is an actual Azure IP.

Even if we could scale to Cosmos web services we’re still stuck with IPv4

I'm not sure why people think space is "far away". Data centers (CDNs) in space would have 10ms ping times in basically the worst case (assuming a relatively high low earth orbit of 1000 km and hitting satellites at approximately 45 degrees elevation). In the best case they'll have ping times possibly as low as 3ms (satellites that happen to be directly overhead in their 400 km orbits).

You get direct connections to the servers without going through multiple local jumps and you aren't slowed down by the slower speeds of light in fiber.

Error correction, mass limits, and power generation are the difficult parts.