Re: Prometheus to Mars
Hmm, if getting to Mars through VASIMR would take much less time, this would expose the crew to far less sun and cosmic radiation than a 6 months long trip. A nuclear rocket would reduce exposure, thanks to the time saved.
Yes, it's going to be more expensive than a chemically propulsed rocket, but such a rocket will already be extremely expensive anyway. So a fraction more, will that make such a difference? I'm not sure.