preimert1; I'm sorry if you perceive my comment as hi-jacking. It certainly was not my intent.

Radiation Pressure applications for so called light sail propulsion is a very real, highly technical, and effectively demonstrated means of travel throughout space. But the Planetary Society has had little success in their efforts towards it's development and demonstration. It's been recognized since at least Maxwell, and HG Welles first proposed the concept as space propulsion in the 1890's (?). IKARUS by the Japanese in 2010, has been the most successful actual project to date and there are a number of projects by different groups scheduled for the next couple of years that offer a great deal more to the development and demonstration of the application than that of the Planetary Society.

Many in science and engineering perceive the work of Bill Nye and Carl Sagan before him through the Planetary Society and other efforts to that of increasing their own celebrity in their field of making personal profit from supposed scientific education. Both have been guilty of popularizing and espousing various specious theories best exemplified by different politically driven Climate Change scare tactic efforts. Bill Nye's job as the CEO of Planetary Society is to garner donations to the same and increase his celebrity and political influence. In general, his scientific acumen is quite a bit less than his media persona would imply, and he often damages more than helps the serious work on real science and the image of real scientists.