John M. Grunsfeld

When people left on the Oregon Trail from St. Louis, they knew that only a fraction of them would make it to the West Coast. But they went anyway.

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

I have dedicated my life to answering the great scientific questions of our time and to the incredible adventure of space exploration.

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.

As a young boy growing up on the South Side of Chicago, I was inspired by the nascent space age.

Regardless of what dreams you have, work very hard, play very hard, and have fun.

The '60s were a remarkable time because several things were happening at once. Men were leaving planet Earth, kids were breaking into the television age, and I was able to see Neil Armstrong walking on the moon.

Here we were, the only seven humans in space, repairing a telescope whose only purpose is to enrich the minds of people on planet Earth and increase our understanding of the workings of the universe. I can think of no better peaceful use of space for all humankind.

InSight will get to the 'core' of the nature of the interior and structure of Mars, well below the observations we've been able to make from orbit or the surface.

Going to Mars would make NASA great again.

I look forward to working with the NASA team to help enable new discoveries in our quest to understand our home planet and unravel the mysteries of the universe.

Science at NASA is all about exploring the endless frontier of the Earth and space.

The biggest honor is to be an astronaut. It's such a tremendous privilege to be able to represent humankind in our quest to explore space.

I have had the privilege to be a member of many high-performance teams at NASA, both on and off the planet.

Once in a while, the universe lets you be free alone and in peace.

I got lucky and got assigned to Hubble.

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

When I first went to Hubble, as an astronomer and as a scientist, it was a dream come true. And as an astronaut, the Hubble missions are premiere missions because Hubble is so important to science, so important to humanity, that it's just a very special event. But as an astronomer, it was sort of the holy grail of missions.

A deep ocean under the icy crust of Ganymede opens up further exciting possibilities for life beyond Earth.

Getting a team of scientists on Mars could be transformative.