There's no question that if we stay on planet Earth and never leave, that eventually we'll be wiped out. — John M. Grunsfeld Copy Share Image
Life outside of Earth is probably going to be really hard to find. — John M. Grunsfeld Copy Share Image
A deep ocean under the icy crust of Ganymede opens up further exciting possibilities for life beyond Earth. — John M. Grunsfeld Copy Share Image
Science at NASA is all about exploring the endless frontier of the Earth and space. — John M. Grunsfeld Copy Share Image
What we do at NASA is inspiring. It's reaching, it's visionary, and it inspires people on Earth to try hard things. — John M. Grunsfeld Copy Share Image
Absolutely the most fun thing to do in space and rewarding thing, in many ways, is to look back at planet Earth. — John M. Grunsfeld Copy Share Image
The truth is, every single rocket launch off of planet Earth is risky. — John M. Grunsfeld Copy Share Image
After my spacewalks, I am quite exhilarated but also tired, similar to a workout on Planet Earth. — John M. Grunsfeld Copy Share Image
I believe that the future of humans, and the future of Earth, depends on space exploration. That's not a French problem, or… — John M. Grunsfeld Copy Share Image
The strangest thing I've found is that when I got to space, I felt more comfortable in space that I've ever been… — John M. Grunsfeld Copy Share Image
Are we alone? Many, many people on planet Earth want to know. We are on the cusp of being able to answer… — John M. Grunsfeld Copy Share Image
Once we get beyond Mars, which formed from the same stuff as Earth, the likelihood that life is similar to what we… — John M. Grunsfeld Copy Share Image
Because of Hubble and other telescopes, we've now discovered that there are probably planets around every star, or virtually every star. There… — John M. Grunsfeld Copy Share Image
Here on Earth, we're exposed to asteroids hitting the Earth, eventual changes in the Sun, changes in the Earth's climate, things we're… — John M. Grunsfeld Copy Share Image
The most striking thing to me about human space flight and my own personal experience is that I've seen dramatic changes on… — John M. Grunsfeld Copy Share Image
I'm absolutely compelled for NASA to send international astronauts to Mars to find out if Mars ever harbored life. — John M. Grunsfeld Copy Share
The most striking thing to me about human space flight and my own personal experience is that I've seen dramatic changes on Earth. We… — John M. Grunsfeld Copy Share
At the age of six, I declared that I wanted to be an astronaut. My mother thought that was just fine, as it would… — John M. Grunsfeld Copy Share
I can't imagine anywhere I'd rather be than outside the space shuttle in my space suit next to the Hubble Space Telescope. — John M. Grunsfeld Copy Share
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. — John M. Grunsfeld Copy Share
I see no difference between scientific exploration and human exploration. — John M. Grunsfeld Copy Share
Being an astronaut, there are not a lot of things that have really shocked me in my life. — John M. Grunsfeld Copy Share
I kind of feel like I found my cause in life servicing the Hubble Space Telescope. — John M. Grunsfeld Copy Share
One of the things that happens in space is that there is a fluid shift. You get a lot of extra pressure, and it… — John M. Grunsfeld Copy Share
The things I like to do involve a lot of mental focus, a combination of physical and mental challenge. That is what mountain climbing… — John M. Grunsfeld Copy Share
