To move forward, what's required is a unified space agenda based on exploration, science, development, commerce, and security.

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.

I think it's inevitable that there will be Earthlings establishing a presence on Mars. And I would say that it would certainly take place by 2050 or shortly thereafter.

There's no guarantee that the United States will be around 200 years from now.

Unfortunately, pioneers will always pave the way with sacrifices.

I'm sure that there are places in the deserts in Australia that could be similar to where we might want to go on Mars.

I want to keep on the move, keep stimulated and challenged.