Welcome to Hard Talk on the BBC World Service with me, Stephen Sacco. My guest today can lay claim to be one of the greatest living explorers, having completed three space missions and a recently completed underwater journey to the bottom of the earth.

In the process, Cathy Sullivan became the first American woman to walk in space and played an

important role in the launch of the Hubble Space Telescope, which has proved to be an

invaluable window into deep space. For all of her adventures, Ms. Sullivan has always been first and

foremost a scientist. She trained as an Earth scientist, and after leaving

NASA spent a period as chief administrator of the U.S. Oceanic and Atmospheric Agency. She's been a key

player in debates about the impacts of climate change and the importance of respecting scientific data.

So who better then to provide a perspective on the

prospects for humanity both on our own planet and far beyond? Kathy Sullivan joins me now from Columbus, Ohio.

Welcome to Hard Talk. Thanks. Great to be with you. You, I think, can be described as a scientist and explorer,

but I'm wondering what comes first for you. Is it the science or is it the adrenaline-filled

adventure? Well, I would say it's the exploration. I've never really been all that much of an

adrenaline junkie. But exploring has always intrigued me from my youngest days,

watching Mercury astronauts and Jacques Cousteau and reading about all the people in National Geographic.

I just thought their opportunity to go exotic places and learn all sorts of things fascinated me.

And I wanted some of that in my life.

Well, I'll tell you what fascinates me about that, that you don't really feel that

adrenaline is your thing, because you've put yourself into circumstances both far above the

earth and right at the bottom of the earth, where, frankly, you're in life or death situations.

Surely adrenaline has to be part of it. Well, I don't do those things for the rush of the adrenaline.

I do them because of where

they let me go, what they let me learn. Sometimes the challenge, you know, can I fly an airplane

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