Let's Plan to Leave: Combine new propulsion drive plus breathable Rhea atmosphere. Mix and Stir.

When you combine this story about a cutting edge engine that can get you to Mars in 39 days and a possible breathable atmosphere on the Saturn moon of Rhea...well, I think we can all start making plans. Um, how breathable is that air on Rhea? Wouldn't you get irradiated? Could you live a couple of hours?