Space is not just going up and coming back down again. Space is getting into orbit and being there, living there, establishing a presence, a permanence.

There were about six years when there was not one American who went into space. We shouldn't do that again.

Before deciding what to do about national space policy, Obama set up an outside review panel of space experts, headed up by my friend Norm Augustine, former head of Lockheed Martin and a former government official.

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

Trips to Mars, the Moon, even orbit, will require that we provide astrotourists with as many comforts from home as possible, including paying each other.

When we set out to land people on the surface of Mars, I think we should as a nation, as a world, commit ourselves to supporting a growing settlement and colonization there. To visit a few times and then withdraw would be an unforgivable waste of resources.

Unfortunately, kids are led to believe things are easier to achieve than they really are.