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

We must still think of ourselves as pioneers to understand the importance of space.

By venturing into space, we improve life for everyone here on Earth - scientific advances and innovations that come from this kind of research create products we use in our daily lives.

I was lucky enough to have been born on this planet earth, in this admirable country of the United States of America.

Certainly, I've never wanted to live on past achievements.

Before deciding what to do about national space policy, Obama set up an outside review panel of space experts, headed up by my friend Norm Augustine, former head of Lockheed Martin and a former government official.

Everyone who's been in space would, I'm sure, welcome the opportunity for a return to the exhilarating experiences there.