Even though explorers in the past traveled, for example, to the south or north pole, knowing they might never return, and thousands of immigrants moved to the US in the 18- and 1900's, knowing they would never see their homeland again, the human psyche has seemingly changed enough that a one-way ticket off the planet is not acceptable. According to psychologist Molly Dooley from Springfield, IL, it might take a major crisis on Earth for humans to seriously consider such a mission. “Usually it’s the disenfranchised that are willing to take those kinds of risks," she said. “When our present situation no longer works for us, we become more willing to take risks. The difference between the folks who are interested and those who aren’t is their attachment to their current situation."
The article raises some interesting questions, and the commenters add more insight. Link -via Metafilter