Cambridge Discovery Education Interactive Readers are the next generation of graded readers - captivating topics, high-impact video, and interactive exercises designed to motivate and engage. From science fiction to actual space exploration, we have always been fascinated by our universe. Landing on the moon and exploring Mars aren't science fiction anymore. What will humans do in space next? Use the unique code inside the book to access the online reader, complete with videos and interactive exercises. Plus, download a free e-book version of the reader!