This makes me oddly depressed. The mere idea that the X-33 will not fly is troubling. Mostly, because of the Mars Lander fiasco, NASA is not seen in the brightest of lights anymore. The delays in developing the X-33 are mostly safety based (which makes sense if anyone remembers a slight problem in 1986 with the Challenger...), but these delays are not giving NASA credibility. They need one project to work, and to work well. The International Space Station is still in development, and can't save them yet...