Startups are eyeing the market for space tourism, and NASA is discovering habitable planets. On this edition of River to River , host Ben Kieffer talks with the co-authors of Vacation Guide to the Solar System , a book that imagines an interplanetary vacation. In the book, co-authors Olivia Koski and Jana Grcevich take real data from NASA and other sources to create a whimsical and accurate picture of what it would really be like to travel our solar system. Destination Mars: "Who hasn't dreamt