Jeff Foust, in a good bio of NASA Administrator appointee Michael Griffin, reproduces a quote from the man that is worthy of framing:

"What the U.S. gains from a robust, focused program of human space exploration is the opportunity to carry the principles and values of western philosophy and culture along with the inevitable outward migration of humanity into the solar system,” he said. Such an effort, he noted, would be similar to the influence the British Empire had because of its mastery of the seas. “Can America, through its mastery of human space flight, have a similar influence on the cultures and societies of the future, those yet to evolve in the solar system as well as those here on Earth? I think so, and I think our descendants will consider it to have been worth twenty cents per day."