84 Quotes by John M. Grunsfeld

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.

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.

When I grew up as a kid, we didn't know there were any other planets outside of our own solar system. It was widely speculated that planet formation was an incredibly rare event and that it's possible that other planets just don't exist in our galaxy, and it's just this special situation where we happen to have planets around our sun.

Because of Hubble and other telescopes, we've now discovered that there are probably planets around every star, or virtually every star. There are solar systems around most stars. And the fact that we're here on a planet, Earth, means that it's likely there's lots of other Earths out there.

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.

Science fiction has been an inspiration to generations of scientists and engineers, and the film series 'Star Wars' is no exception.

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.

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

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.