Misses the real issue
"We don’t know much about radiation shielding and protecting humans, frankly..."
The problem isn't the VARB, it's the intense ambient radiation from the Sun and extrasolar cosmic rays that humans would be exposed to once they got past low-Earth orbit that's the real issue. At the moment no one has an answer for that in production. An Orion crew could survive a few months at most outside the protection of Earth's magnetic field. What's really needed is a magnetic sheild that a craft would generate itself, but Orion's power systems wouldn't come close to providing the energy required for that -- even after we figure out how to generate make such a sheild (which is probably decades off). The other popular option is to use an envelope filled with water or waste to surround a ship's occupants with a protective layer. I think they've estimated they'd need around a meter deep of water or ice for that, again clearly outside Orion's "architecture". Maybe they could mine for lead on the Moon or in the Asteroid Belt and use mass drivers to get it into orbit for melting down and forming into protective plating, but then you're back to the problem of accelerating (and decelerating) the spacecraft around the solar system with all that additional mass.
Orion is a dumb idea. Always was. SpaceX's Falcon and other commercial craft can get us into low-Earth orbit. Deep space exploration is going to require a quantum leap in technology and the ships we build once that's in place are going to look more like 2001's fusion-powered Discovery than the Apollo CM.
P.S. Learned recently that our solar system actually happens to be travelling through a particularly radioactively "hot" area of the Milky Way just now, making intersteller travel even more... unhealthy than interplanetary jaunts around the Sun. Point is, we've got a long way to go yet and there's a mountain of basic research that still needs to be done. The money wasted on Orion could be used for that kind of research, if our politicians could just look a bit past their own selfish ambitions.
Biting the hand that feeds IT
