Types of Spaceships: Past, Present, and Future

This book is the seventh volume of "The Living in Space Series". Each volume focuses on one particular technology of living in space. In this book the focus is on spaceships used to access and travel in space. In my research I was pretty amazed at how many spaceships have been designed, the large number available in the current era, and that many more are already on the drawing boards. Some spaceships like the Space Shuttle seemed like a great idea back in the 1970s and 1980s.
But due to the compromises in design were very expensive for each flight and kind of dangerous too. Even though the Space Shuttle was flown for over 30 years it was eventually cancelled because of cost issues. The newer transportation systems focus on lowering costs through reusability. This will lead to a much better long term paradigm for expanding people's entry into space because of the lower costs reusability provides.
I also needed to determine what types of ships to include in this book. What is a valid spaceship? My decision was to use the Von Karmen Line which says that a spaceship flown higher than 50 miles (80 km) has entered space. Using the Von Karmen Line includes one manned device-the X-15 experimental rocket plane as a spaceship although most people wouldn't think so. Lastly, I've included some notional spaceship designs which might be used to travel to Mars or other bodies in the Solar System.