John M. Grunsfeld

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

“Our country... invests a tiny fraction of 1 percent in NASA, and this is what's so amazing to me, is with that small investment, we do so much for the country.”

“I was not really scared on my spacewalks. We practice so much and need to stay so focused that it has a calming effect on me. I do a kind of visualization and meditation in the airlock prior to going outside, to guide my first activities once I get out in space.”

“There are some things worthy of risking your life for.”

“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 humans are rapidly changing the planet. I've watched Amazonia as the rainforest has been cut down. That's something I've seen out the window. I'm very worried about that.”

“All space exploration is risky. As an astronaut, I had to decide each and every time I went to space whether or not to risk my life for the mission.”

“Are we alone? Many, many people on planet Earth want to know. We are on the cusp of being able to answer that question... because of the investments we're making in space technology.”

“All indications are that three and a half billion years ago, Mars looked like Earth. It had lakes. It had rivers. It had river deltas. It had snow-capped peaks and puffy clouds and blue sky. Three and a half billion years ago, it was a happening place. The same time on Earth, that's when life started. So did life start on Mars?”

“A lot of people get home from work and sink into a good chair, the place in their life where they feel most comfortable. I get that comfort in space, the place where I most feel like I belong.”

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

“Small bodies in our solar system, like comets and asteroids, help us understand how the solar system formed and provide opportunities to advance exploration.”

“Only by studying large numbers of people can we figure out, are astronauts dying at a higher rate of cancer, and what types of cancers, than other people?”

“To help enable the kind of science Hubble is performing makes my life worthwhile.”

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

“There's a perspective that I've gained as an astronaut that I didn't get from my science activities. In my science activities, I learned by the seat of my pants. Spending 17 years as an astronaut, I learned the NASA formalism of systems engineering as if my life depended on it. Literally.”

“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.”

“Our journey in going beyond our home planet is a human endeavor, and in the greatest tradition of exploration, past, present, and future spacefarers will continue to be enduring catalysts for inspiration in our quest to unravel the mysteries of the universe.”

“Absolutely the most fun thing to do in space and rewarding thing, in many ways, is to look back at planet Earth.”

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

“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.”