One more thing: This hope that a revolutionary technology is just around the corner is not something we can count on. Most of us on this list have been around long enough to know that the engineering hurdles that must be overcome for space travel are orders of magnitude beyond the engineering advancements we've seen leading up to and through the Industrial revolution, to the present day. Our cultural memory extends to times when we had nothing more than fire, wheels, and bronze, so of course a ramjet, computer and iPod seem futuristic. But there is still a LONG way to go before we can contemplate travels to exoplanets. You think risk is high going to Mars? "It's so very lonely, you're a thousand light-years from home..." -the Rolling Stones