This is a great expansion pack for FSX very authentic and realistic and fun. What I personally found that makes this great it¿s the first airplane into space and X-15 expansion series exceeded my X-speculations, I also liked the many models you get to try out it also has fully functional instrument panels and the old gauges. Plus the systems simulate just about every step and procedure required in a typical X-15 mission. In my opinion it¿s a thumbs up. I recommend this to anyone who likes the idea of flying the early prototypes of the X models