The flag is impossible to see from earth. There aren’t any telescopes capable of focusing on such a small object that far away. And no Hubble is not good enough.
The biggest telescope being built right now - Magellan - won’t even be able to focus on our flag. It’s simply too small. Too many variables, and the technology doesn’t even exist. We need to build something about 3 times the size of Magellan. That might sound easy, but we have no idea how to build a telescope that big.
May your using something different? :)