New competition for Elons Mars colony: Asgardia - The Space Nation Both share this problem: http://phys.org/news/2016-10-mars-bound-astronauts-chronic-dementia-galactic.html Although Earths magnetic field protects Asgardia from most of radiation. Another study about radiation in space Apollo Astronaut Study Reveals Greater Heart Risk for Deep-Space Travelers To stop radiation lot of mass is needed. Lifting this mass from Moon with fuel made on the Moon is easier than from Earth. We need moon base before we can build anything really large in space. Asgardia would be good client for BFR.