One of the things I’ve wondered is, if you can build a spacecraft that uses focus fusion as its main drive, why couldn’t you also use a DPF power plant solely for generating a magnetic “force-field” for shielding the spacecraft from radiation, similarly to the way Earth’s magnetic field shields us? Sure, it would make the spacecaft much larger, but, who cares? Space is big. While you are at it, why not have another for rotating the living quarter to provide artificial gravity so that calcium doesn’t leach from bones and muscles don’t atrophy?
