Barbara Cohen, planetary scientist at NASA's Marshall Space Flight Center (MSFC), studies impact craters, especially those on Earth's Moon.

Where are you from?

I grew up in upstate New York, near Albany. I went to college at the State University of New York at Stony Brook, on Long Island, and then graduate school at the University of Arizona in Tucson, Ariz.

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

I wasn't particularly interested in science or space growing up. I enjoyed reading and creative writing more. But I did watch Carl Sagan's "Cosmos" with my family. I watched several episodes, but I only clearly remember one: the one with Voyager exploring Jupiter and Saturn -- I was blown away. It wasn't until several years later that I made the decision to pursue science as a career, but I think that "Cosmos" planted the seed.

Develop critical thinking skills. The ability to reason through any issue, whether in science or in life, makes you a better scientist, engineer and citizen.
- Barbara Cohen

How did you end up working in the space program?

The Marshall Space Flight Center (MSFC) didn't have any planetary scientists on staff so I joined NASA specifically to help with the Constellation program. The Constellation program was intended to send humans to the Moon to live there for extended periods of time. MSFC has been responsible for a lot of things related to the Moon: including the human lunar lander, the engineering documents describing the lunar environment, and the Lunar Reconnaissance Orbiter (LRO) and its companion, LCROSS. Now I work on new proposals for robotic spacecraft to return to the Moon and to visit other planets as well.

Who inspired you?

In high school, I had a chemistry teacher, Mrs. Fish, who made chemistry come to life for me -- something just clicked. As I pursued more science classes in high school and college, I had many excellent teachers who encouraged me.

My undergraduate advisor, Don Davis, showed me how to approach problems in planetary science using only my terrestrial geology skills. My graduate advisor, Tim Swindle, showed me how to really open up rocks and read their ages using isotopes. But I am most grateful to my network of friends and colleagues, who share their triumphs and disappointments -- I learn from them every day.

What is a Planetary Scientist?

A planetary scientist is someone who studies the solar system and the objects in it to understand how these objects formed and evolved to their present state. I'm most interested in the process of impacts -- we see evidence everywhere of objects colliding in the solar system. Sometimes the craters are small, like Meteor Crater on Earth, but sometimes they are enormous, like the South Pole-Aitken Basin on the Moon, which is 2,500 km across. If a crater that big formed on the Earth in the past, it may have seriously affected life as it was just beginning on our planet. So I try to use the rocks from different planets, moons and asteroids to better understand when these impacts happened and how they affected the rocks we see now.

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

Wow, there are so many. I've looked at lunar samples in a way no one has been able to do before, being the first to characterize their minerals and ages. I've gotten to see pictures of Mars fresh off one of the rovers. I've gone to Antarctica to collect new meteorites. I've seen rocket and space shuttle launches in person. I love my job -- I get to learn something new every day.

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

Keep your eyes open for new opportunities. Always ask for what you need. Say 'yes' a lot. And make sure you really love it, because it's a lot of hard work and long hours, but I find it very rewarding.

What do you do for fun?

I love to travel, especially to warm tropical places for scuba diving. I like being outside -- walking, hiking and rowing. My partner and I like to get together with friends to play strategy-based board games. I've been a potter for a long time now as well -- I love to make beautiful and functional pieces like bowls.

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

As I said above, I wasn't interested in science for a long time -- until high school, in fact. But before that, I was interested in learning. I learned a lot about language, history, math, and art. All these things add up to becoming a critical thinker -- which to me is the most important skill to have of all. So my advice is to develop critical thinking skills. The ability to reason through any issue, whether in science or in life, makes you a better scientist, engineer and citizen.