You are assuming humanity will never again make any innovation, advancement or discovery in technology to protect astronauts against radiation. Forgive for saying that is being short-sighted as you can get.

I’m sorry but you are wrong. GRRM came out with this idea. Look the last ‘Inside the Episode’ where D&D tell how they convinced GRRM to tell them about Hodor and how shocked they were to find out. Nice article though.