[Prospero]

It's the only way to travel in deep space within our technological capability. Anything beyond the moon that takes more than about three months puts humans into the four percent probability of "Radiation Exposure Induced Death" over the course of a lifetime. That's the outside limit NASA has today.

If you want to go to Mars (and return safely to the Earth) you need to get there and back a whole lot faster than the 900 day round trip needed for chemical rockets.

[cripplecreek]

Agreed. Time in space is a major issue. Personally I’ve turned toward the feeling that propulsion research should be our focus for now.