“It [traveling to Mars] is important for our future. If the dinosaurs had a space program, they'd still be here.”
In a Reddit IAmA. http://www.reddit.com/r/IAmA/comments/r62jp/iama_nasa_astronaut_that_recently_returned_to/c437ubd (2012)
An earlier similar quotation can be found in:
The dinosaurs became extinct because they didn't have a space program. And if we become extinct because we don't have a space program, it'll serve us right!
By Larry Niven As quoted by Arthur C. Clarke in "Meeting of the Minds : Buzz Aldrin Visits Arthur C. Clarke" by Andrew Chaikin (27 February 2001) http://web.archive.org/web/20010302082528/http://www.space.com/peopleinterviews/aldrin_clarke_010227.html
Help us to complete the source, original and additional information
Related quotes

As quoted by Arthur C. Clarke in "Meeting of the Minds : Buzz Aldrin Visits Arthur C. Clarke" by Andrew Chaikin (27 February 2001) http://web.archive.org/web/20010302082528/http://www.space.com/peopleinterviews/aldrin_clarke_010227.html

“People should be travelling to Mars and doing it in our lifetime.”
Page 9
Conversation: Elon Musk on Wired Science (2007), Foreword to Marc Kaufman's Mars Up Close: Inside the Curiosity Mission https://books.google.com/books/about/Mars_Up_Close.html?ido6XaCwAAQBAJ&hlen. National Geographic. ISBN 978-1-4262-1278-9.

"Meeting of the Minds : Buzz Aldrin Visits Arthur C. Clarke" by Andrew Chaikin (27 February 2001) http://web.archive.org/web/20010302082528/http://www.space.com/peopleinterviews/aldrin_clarke_010227.html
2000s and posthumous publications

Page 10
Conversation: Elon Musk on Wired Science (2007), Foreword to Marc Kaufman's Mars Up Close: Inside the Curiosity Mission https://books.google.com/books/about/Mars_Up_Close.html?ido6XaCwAAQBAJ&hlen. National Geographic. ISBN 978-1-4262-1278-9.

“If we found life on Mars, it would change everybody's view of our place in space.”
[NewsBank, Mike Anton, Los Angeles Times, The Seattle Times, Seattle, Washington, Fully loaded robot heading off to Mars, November 20, 2011]

“Dinosaur fossils? God put those here to test our faith.”
Source: Revelations (1993)
Context: I think God put you here to test my faith, dude. Does that bother anybody else—the idea that God might be … fucking with our heads? I have trouble sleeping with that knowledge. Some prankster God running around, [pantomimes digging] "We'll see who believes in Me now! I am the Prankster God. I am killing Me!"

Crucible of Creativity (2005)
Context: Putting a new feature into a program is important, but refactoring so new features can be added in the future is equally important. The ability to do things in the future is something that I consider suppleness, like clay your hands that accepts your expression. Programs and documents get brittle very quickly. Wiki imagines a more dynamic environment where we accept change...