I think humans will reach Mars, and I would like to see it happen in my lifetime.

We really didn't devote a lot of time to investigating the scariest aspects of our flight. It was more challenging and productive to concentrate on the remedies, and leave things that couldn't be solved to happen without thinking about them. There is a morbid human curiosity associated with tragic death-producing events. Though naturally, this needs to be kept in perspective.

Mars is there, waiting to be reached.

The honor you have given us goes not to us as a crew, but to ... all Americans, who believed, who persevered with us. What Apollo has begun we hope will spread out in many directions, not just in space, but underneath the seas, and in the cities to tell us unforgettably what we will and must do. There are footprints on the moon. Those footprints belong to each and every one of you, to all mankind. They are there because of the blood, sweat, and tears of millions of people. Those footprints are the symbol of true human spirit.

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

It's time to open the space frontier to citizen explorers.

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