The energy varies with the square of the velocity, so if you need five times the velocity, that's 25 times the energy.

We need to begin thinking about building permanence on the Red Planet, not just have voyagers do some experiments, plant a flag and claim success. Having them go there, repeat this, in my view, is dim-witted. Why not stay there?

Program Alarm, it's a 1202.

You can never tell when a commercial space venture will suddenly become viable.

Let's not spend resources that we don't need to be sending astronauts back to the moon. Let's not spend expensive resources on bringing people who have reached Mars back again. Prepare them to become a growing colony.

I'm not in favor of just taking short-term isolated situations and depleting our resources to keep our climate just the way it is today.

History gets reinterpreted as time goes on. Many times, the participants are lost in the retelling of the story.