Space VLBI is a thing already! Seems to have been around for a while [0][1]. I imagine that the challenge with during EHT-style VLBI in space is downlink bandwidth... there's just no way to get the petabytes of data they talk about down from a satellite. It's already so much data that it's easier to fly hard drives around the world than to send it over the internet, so the transfer would probably take ages over a microwave link. Maybe with laser communication in the near future but even then... it's a lot of data.

Resolution-wise, the angular resolution is inversely proportional to the farthest baseline, as given by the Rayleigh criterion. [2] To get twice the resolution, you "just" need to double the size of your baseline (and do that in both dimensions, otherwise the angular resolution will be different in x & y). We've maxed out the Earth's baseline, so it seems like orbital radio telescopes are the only way to better resolution. Pretty exciting!

[0] - https://www.jpl.nasa.gov/missions/space-very-long-baseline-i...

[1] - https://asd.gsfc.nasa.gov/blueshift/index.php/2016/07/25/thi...

[2] - https://en.wikipedia.org/wiki/Angular_resolution