What is unusual about Mercury's core? Why does Venus have fewer craters than Mercury? What would astronauts need to survive on Mercury or Venus? The books in the Astronaut Travel Guides take you on a virtual journey through our solar system, and beyond. Discover the facts about your destination, as well as information on what you need to take with you, and who you might choose to come along. You can even read exclusive interviews with a real astronaut and astronomer to learn tips for studying and living in space!