In the documentary Lo and Behold, he told Elon Musk that he’d be happy to go on a one-way trip to Mars. Musk would prefer to offer round-trips. See the story HERE.
At the end of Wild Blue Yonder, Herzog says, “We thank NASA for its sense of poetry.”
In the book Werner Herzog: A Guide for the Perplexed, he tells David Cronin:
There are so many possibilities up there for fresh images, and I always thought it would be better to send up a poet instead of an astronaut; I would be the first to volunteer. I did actually once seriously consider applying to NASA to be on one of their missions. Space travel is unfinished business for me, though these days I wouldn’t be allowed. You need a complete set of teeth to get inside a spaceship.
In Cave of Forgotten Dreams, Herzog gains rare access to the caves housing the oldest known human paintings and documents what only a handful of people living today have seen in person and what would undoubtedly be irreparably damaged if it were exposed to human breath and touch.
In Encounters at the End of the World, Herzog says:
The National Science Foundation had invited me to Antarctica even though I left no doubt that I would not come up with another film about penguins.
The rules for the humans are do not disturb or hold up the penguin. Stand still and let him go on his way. And here, he’s heading off into the interior of the vast continent. With 5,000 kilometers ahead of him, he’s heading towards certain death.