Guest: Alfred Zaehringer. Topics: rocket science, rocket equation, Mars, chemical rockets, space tourism, low cost space access. Al Zaehringer returned to The Space Show to discuss his two books. Al was the editor of "Rocketscience: The Journal of the Detroit Rocket Society, Inc. 1947-1952," which is available from http://www.apogeebooks.com. This is a must have reference book, one of the very best of its kind. Apogee also rereleased his earlier book, "Rocket Science." We started the interview with Al telling us about the Detroit Rocket Society, some of the leaders who were part of it, and some stories from some of the people whose work is in the Journal. We then moved forward to questions about achieving low cost space access, chemical rockets, markets in space, drivers for the cost of a launch, fuel and more. Al was as blunt, outspoken and factual on this show as he was on his two appearances back in early 2005. We talked to him about his experiments in trying to manipulate the rocket equation and more. Listen to what he had to say about this and much more. We discussed the future of chemical rockets, the space industry, space advocacy, leadership, policy, regulation, and even nuclear rockets and the space elevator. In response to a listener phone call, we talked at length about amateur rocketry during the early days of the Detroit Rocket Society and today. And we discussed the best way to do Point A to Point B transportation. Is it better to scale up from suborbital or to scale down from true orbital? Listen to what Al had to say about this subject. We talked about many other space engineering, propulsion, and rocket issues. If you have questions or comments for Al Zaehringer, you can email him direct at janmay@comcast.net .