In addition to being a historian and political junkie I am also a Space nut. I was hugely disappointed to see the shuttle program shut down with its replacement being cancelled because we plan to rely on the private sector. I do plan on buying SpaceX stock if they ever have an IPO though. I ran across the below infographic on and decided to pass it along because I think the whole spaceplane concept is intriguing. Source All about our solar system, outer space and exploration