Astrobiology, an interdisciplinary science catalyzed by NASA, brings together researchers in a wide variety of fields, including astronomy and astrophysics, Earth and planetary sciences, microbiology and evolutionary biology, and cosmochemistry.

Where are you from?

I am from Greenwich, Conn. which makes me a Connecticut Yankee, and it gives me an excuse to talk quickly. Since 1987, when I left Rhode Island, I have called the San Francisco Bay Area home. (OK, I was born in New York City, but I think I have lost most of the accent.)

Scientific curiosity should be like an itch—you can't sleep at night until you find the right answer.
- Lynn Rothschild

Describe the first time you made a personal connection with outer space.

I looked up at the stars, as everyone does. However, I first developed a real fascination for the space program during the Apollo missions leading to the incredible events of the manned Moon landings. (We called it "manned" in those days, but today we call it "human space exploration.")

In particular I remember being fascinated by Apollo 8, the first manned craft to orbit the moon, and of course Apollo 11 when the first humans set foot on another body in space. I was 12, and at a summer camp in Maine (Arcadia) when the moon landing took place. This camp, for the most part, didn't have electricity and certainly not a television. However, I knew the director had a television away from the campers, and so I started a campaign to somehow stay up and see the televised landing. The very enlightened director, who had a love for the stars and must have also shared my excitement, at the last minute decided it was so important that the entire camp of well over 100 girls should get up in the middle of the night and hike with flashlights to where there was one small, black and white television. By 2:00 in the morning the director and I were the only ones left in the room, still transfixed by the enormity of the event. Since that historic night I have met both of these Apollo 11 superstars -- Neil Armstrong and Buzz Aldrin -- and I still stand in awe of their achievements. The danger of this landing was brought home to me a few years ago after seeing the draft of speeches that President Nixon had prepared to give if the astronauts had to be abandoned to perish on the moon.

How did you end up working in the space program?

Well, if you had asked me when I was a biology major in college, or even a Ph.D. student in molecular biology, I would never have imagined that I would work in the space program. That changed when I gave a seminar on my Ph.D. thesis work about chloroplast evolution at Harvard and learned from Andy Knoll that NASA had a long-standing interest in early evolution. After all, how can we understand the evolution of life in the universe, or discover whether we are alone in the cosmos, without a deep understanding of the one place we have data -- planet Earth. Within a year I had an application in hand for a fellowship at NASA, which was followed by a call from NASA in the middle of winter asking me if I wanted to look for life on Mars, go to the Antarctic and move to California. Well, what would you say?

Who inspired you?

Some kids are motivated to go into science because of a scientist or teacher who inspires them, and perhaps someone will be inspired by this interview. I have been extremely fortunate in having had a series of excellent mentors at nearly all stages in my career. When I was young, my father, grandfathers and two terrific teachers encouraged me in science. As I mature, I realize how important it is to thank them, as they gave so much of themselves to help me achieve.

Science is so incredibly compelling that in my case I was also inspired by protists -- unicellular eukaryotes such as paramecia. They grabbed my interest and have never let go. And Charles Darwin always inspires me.

What is an astrobiologist?

The field focuses on three of humankind's most fundamental questions: Where do we come from?, Where are we going? and Are we alone? Thus, an astrobiologist tackles one or more of these questions. Because all of these are so multidisciplinary, astrobiologists start out in one of more of the traditional science disciplines -- biology, geology, chemistry and astronomy. The field of astrobiology also includes engineers and some social scientists, who look at the ethical implications of astrobiology.

Tell us about a favorite moment so far in your career.

A nice, quiet afternoon behind a microscope with a cool field sample is my idea of relaxation. Elation comes from fresh data -- whether it confirms your original hypothesis or not -- as long as it is clear. Also, the moments when, suddenly, doors are opened to you, such as being asked for advice by the NASA administrator, being promoted by your center director, having an offer to fly an experiment to 100,000 feet on a balloon -- or 400,000 feet on a rocket -- spending the night in Windsor Castle, being filmed for television, or speaking at the Vatican Observatory -- how can you beat these for career excitement? After all, scientists are human too.

What advice would you give to someone who wants to take the same career path as you?

Be passionate about what you do. Scientific curiosity should be like an itch -- you can't sleep at night until you find the right answer or at least the next step. Read and study broadly, which is very easy to do in this era of the Internet. Ask interesting questions, pursue them and find mentors who will guide you.

What do you do for fun?

Music. Right now we are doing some serious bagpiping in our family (but my son will always be better than me). I also enjoy swimming, canoeing, photography and traveling (although much of it is job related).

If you were talking to a student interested in science and math or engineering, what advice would you give them?

In any of the fields, learn the most you can. Learn to be critical of the data, including when results should be challenged and when they should be accepted. With the Internet, talk radio and blogging, one must understand that not all information or opinions are of equal quality. If you are interested in becoming an astrobiologist in particular, at a minimum take evolutionary biology, microbiology or other biodiversity courses, molecular and cell biology, biochemistry, earth science, astronomy and planetary science.