Thanks for that I had forgotten about the Blockstream satellite network. So lets assume everything else is gone would BTC really be able to run and produce new blocks with just that small satellite network?
I'm having difficulty imagining this scenario because I don't think much would work if those cables were cut.
If you imagined having an international banking scheme that relies on planes, the economy has probably already crashed.
I think the Internet could probably be launched off satellites if something like this happened so things would be less interrupted/interruptable - but satellite Internet is slow. Blockstream could probably be better resourced than the Internet for doing the downloads too (with the satellite internet being used to query if the chain is still trustworthy and the longest). Blockstream can't receive transactions too so that might be a problem (or it couldn't when I last checked).
Thankfully, the cables wrap fully around the earth and if part of a cable is broken it can be repaired (it's not like they actually take up the entire cable and relay a new one in its place, they can float the broken part of the cable up to the surface and fix only the bit that needs fixing there - it's locatable by echo location).