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

Retain the vision for space exploration. If we turn our backs on the vision again, we're going to have to live in a secondary position in human space flight for the rest of the century.

Space travel for everyone is the next frontier in the human experience.

When the time comes to start building deep space transports and refueling rocket tankers, it will be the commercial industry that steps up, not another government-owned, government-managed enterprise.

I think both the space shuttle program and the International Space Station program have not really lived up to their expectations.

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