We currently can't block enough radiation to make space travel safe for humans in long term situations unless we are blessed with the calmest of space weather based on some recent news about the long term effects on the kidneys in the conditions of space travel (source, I believe the research still needs to be corroborated https://phys.org/news/2024-06-astronauts-kidneys-survive-roundtrip-mars.pdf )

We're still not at the Star Trek radiation screen level, unfortunately. So I'm not confident we can isolate this well enough. Earths magnetic field and atmosphere do a lot of work for us, and we still cannot replicate their function well enough to make it safe for humans long term. And this is a project that was put underground because it was more sensitive than humans.