Physics

Good points.

I wonder what the dose would look like to a square metre, framed in human reference terms. Better or worse than medical imaging. That would require figuring out photon flux, above 750nm. But there is also relativistic cross section changes happening, so does that affect the flux?

I'm reminded of a first year physics prof that suggested we figure out how fast we'd need to go to fit through the head of a needle (in a vacuum).

The redundant computing this is a fantastic invention. I'm aware that SpaceX is using off-the-shelf computers for this instead of the longstanding tradition to use only "rad hardened hardware", preferring to rely on multiple redundancy for weight and cost savings. Without knowing the flux at 0.95c though, it'd be hard to estimate how well the strategy would work :)