Humanity is destined to explore, settle, and expand outward into the universe.

Space architectures capable of supporting a permanent human presence on Mars are extraordinarily complex, with many different interdependent systems.

Only a large-volume market like space travel can attack the barrier of high costs.

Absolutely the United States should lead in space, for the survival of the United States. It's inspiring for the next generation. If we lose leadership, then we'll be using Chinese capability to inspire Americans.

There may be aliens in our Milky Way galaxy, and there are billions of other galaxies. The probability is almost certain that there is life somewhere in space.

We need to have people up there who can communicate what it feels like, not just pilots and engineers.

One of the major problems with long-term deep space human flight is the requirement for radiation shielding.

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

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