As a former Apollo astronaut, I think it's safe to say that SpaceX and the other commercial developers embody the 21st century version of the Apollo frontier spirit.

As we move into the 21st century, there's what the Bible calls a 'quickening of the spirit.'

The 21st century simply means open century.

The great challenge of the twenty-first century is to raise people everywhere to a decent standard of living while preserving as much of the rest of life as possible.

I think the biggest problem of the 21st century is how to deal with minorities.

I think future generations will say the late 20th century and the early 21st century was a time of great convulsions and upheavals.