Our family was very fond of the University of Iowa. We thought it was a good place to go.

I think we need someone in a responsible political position to have the courage to say, 'Let's terminate human spaceflight.'

My position is that it is high time for a calm debate on more fundamental questions. Does human spaceflight continue to serve a compelling cultural purpose and/or our national interest? Or does human spaceflight simply have a life of its own, without a realistic objective that is remotely commensurate with its costs? Or, indeed, is human spaceflight now obsolete?

These days, it's really been uninteresting except when disasters occur.

Certainly one of the most enthralling things about human life is the recognition that we live in what, for practical purposes, is a universe without bounds.

I am never as clear about any matter as when I have finished writing about it.

I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.