it's the same deal with space travel.... the only viable shield is gigatons of lead or a magnetic field

space is a brutal place, intense vacuum, radiation everywhere, and magnetic fields dancing aronud like sumbiches

the only way we survive into the future beyond our current disaster cycle is by sheer luck and/or we have enough energy to encapsulate ours living areas with magnetic fields strong enough to deflect the radiation and hold up against the magnetic fluxes of the space around us

that basically means either antimatter or something else similarly nearly limitless