[Skunkleton]

I make no claims about my reading comprehension. That last bit seemed too narrow to me. Once you have all the bits in orbit, shielding doesn’t seem too onerous. Is the claim that even space-space shielding + reactor is too heavy to be worth the advantage of the nuclear drive?

[marsokod]

No, they are saying that the nuclear drive shall be reserved to a shuttle that remains in space. At that point, it makes much more sense as you can really use the nuclear drive to its full capabilities.

> If we need the full performance advantage of nuclear propulsion, we should design a spaceship that is intended for it from the get-go. It never lands, only going from orbit to orbit, so there is no need for heat shielding, flaps, high thrust engines, thick steel structure or aerodynamic shaping requirements.

[simonh]

In space if you’re careful you only need a plate of shielding between the drive and the crew/cargo section.

[GordonS]

Isn't radiation from cosmic rays going to require very heavy shielding?

[simonh]

Sure, but that's got nothing to do with any additional requirement due to your propulstion system.