Mars is far more attractive as an outpost colony for earthlings than the moon is.

It was designed to have an impact on the stalemate over Mutually Assured Destruction with the Soviet Union. Us reaching the moon convinced Gorbachev and other leaders that the Soviet Union couldn't compete with the U.S., so they revised their agenda. But people have short memories.

Timing has always been a key element in my life. I have been blessed to have been in the right place at the right time.

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

I think we need to move to the moons of Mars and learn how to control robots that are on the surface. It's not the impatient way of getting there, but Mars has been there a long time.

Every couple of years, we could dispatch people from Earth to Mars.

My first inclination is to be a bit skeptical about the claims that human-produced carbon dioxide is the direct contributor to global warming.