Hubble has really opened our eyes to what the universe is made of, its structure, and has helped us learn how little we know about the universe.

If I could live in space, I would definitely do that.

I'm absolutely compelled for NASA to send international astronauts to Mars to find out if Mars ever harbored life.

I thrive with high-performance challenges in front of me.

I'm an incurable romantic. But I'm not an adrenaline junkie.

We need to move off the planet. And Mars is the next best place.

Sometimes astronauts feel a little ill or get minor scrapes. I trained as a crew medical officer to do basic treatment.

The things I like to do involve a lot of mental focus, a combination of physical and mental challenge. That is what mountain climbing is.

The Martian atmosphere is very thin. It's like our atmosphere at 100,000 feet.

At the age of six, I declared that I wanted to be an astronaut. My mother thought that was just fine, as it would encourage me to learn science, and besides, there really was no chance I would ever actually become an astronaut.

We're being very careful that we don't send a spacecraft to Mars with the intention of detecting Martian life - and find out that we detected the Earth life that we took with us.

Being an astronaut, there are not a lot of things that have really shocked me in my life.

The first thing to know about space food - it is the ambiance; it is the environment. It is not the food.

I don't particularly want to jump out of an airplane with a parachute if I don't have to. I don't want to go bungee jumping. I like adventure with a real purpose that I can buy into.

What we do at NASA is inspiring. It's reaching, it's visionary, and it inspires people on Earth to try hard things.

One of the things that happens in space is that there is a fluid shift. You get a lot of extra pressure, and it fills your sinuses, and the horseradish is a miracle worker for cleaning that out.

Life outside of Earth is probably going to be really hard to find.

I think it's really a sign of great American strength that we do invest the money we do in technology, in these hard projects, in NASA.

Getting a team of scientists on Mars could be transformative.

Hubble uniquely has been able to look in the atmosphere of a planet orbiting a nearby star and figure out what's in that atmosphere.

The surface of Mars is bathed in ultraviolet light, bathed in radiation. Mars's magnetic field is essentially gone, so the surface of Mars is essentially sterilized.

There are some things worthy of risking your life for.

The best would be to fly in space with family and friends.

I got lucky and got assigned to Hubble.