How bad would it be if GPS satellites were shot down?

Losing GPS isn’t an X-risk, but would create a huge disaster on the scale of Covid-19 or bigger.Hi! From 2020 - 2023 I was one of the early employees at Xona Space Systems, a company working on essentially a next-generation version of GPS. I ended up learning a lot about how GPS works and what it’s used for, and (due to my personal interest in effective altruism) ended up doing some research into what would happen if today’s GPS systems suddenly failed. This post is the product of that research. I discuss:What could kill GPS: it would be a tempting early target in a war between superpowers, or it could possibly be taken down by superhuman AI’s cyber-hacking capabilities. On the bright side, it’s probably safe from even very large solar storms.If GPS was destroyed, how bad would this be? I describe all the major areas in civilian life that would be disrupted (mostly summarizing some government reports).Then I try to crunch some very rough, vague numbers. It looks like losing GPS would (by itself) be an economic hit to the USA perhaps equivalent to a few billion dollars a day. On a very broad, vibes-based level, this might feel approximately as disruptive and frustrating as the Covid-19 pandemic, albeit it would be a disaster with a very different character. Of course, GPS probably wouldn’t be destroyed in isolation, but in the larger context of a terrible and destructive great-power war, so everything would in fact be much worse.This post got too long, so I split it in half. If people like this one, then I hope to finish up a second post wherein I’ll discuss:GPS isn’t just for civilian life! The whole reason it would be such a tempting target in warfare is that it also has extreme military usefulness. I describe the various military functions of GPS (JDAMs, yes, but also they were originally quite important for atomic warfare), and speculate a little bit about the military strategy of who wins versus loses if all the GPS systems get blown up. Trying to quantify this