When I was a little kid, we only knew about our nine planets. Since then, we've downgraded Pluto but have discovered that other solar systems and stars are common. So life is probably quite prevalent.

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

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.

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

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

Armstrong described the lunar surface as 'beautiful.' I thought to myself, 'It's not really beautiful. It's magnificent that we're here, but what a desolate place we are visiting.'

We feel that this stands as a symbol of the insatiable curiosity of all mankind to explore the unknown.