I've been remiss in my book-reviewing! Here are four recommended space nonfiction series that would make excellent additions to any children's library.
For ages 5-7: The Exploring Space series includes six 24-page books by Martha Rustad: The Milky Way, Black Holes, Constellations, Space Stations, Space Vehicles, and NASA. They take a story-style approach to each subject: rather than cramming pages with disconnected facts, there are a couple of simple sentences on left-hand pages and one very large, well-chosen photo on the facing page. The three engineering books are more informative than the three astronomy books. I think the best book in the series is NASA; it does a good job of explaining how the U.S. explores space, why we send robots to some places and humans to others, and so on.
For ages 7-11: The Universe Rocks series includes four 32-page books by astrophysicist Raman Prinja: To the Planets and Beyond, Stars and the Dust That Made Us, Galaxies and the Runaway Universe, and Spacecraft and the Journey into Space. I am always initially suspicious of books that have two-page fact-crammed spreads -- usually, they rehash the same old facts you can get in any other nonfiction book -- but Prinja's fact selection is terrific, with up-to-date science and the latest discoveries about the universe. For instance, the Saturn section in the Planets title talks about Titan's lakes, the great northern storm on Saturn, with perfectly chosen, recent photos. Each book also includes three hands-on activities; I didn't try any of them, but they appeared to be well-explained (each activity is given two full pages, with thorough explanations of both how to perform the experiment or demonstration and what the lesson was supposed to be) and would likely work as written. I was pleased to see that the spacecraft book includes our LightSail as an example of future tech.
For ages 8-10: The Astronaut Travel Guides series includes eight 48-page titles by five authors: The Sun, Mercury and Venus, Earth, The Moon, Mars, Jupiter and the Outer Planets, Stars and Galaxies, and Comets, Asteroids, and Meterors. The last one was written by none other than Stuart Atkinson, an occasional guest blogger here. In keeping with the series' title, the books are partially written in the second person and treat their subjects as though you, the reader, were planning a visit. It makes the text much more engaging than many fact-filled nonfiction books I've seen. The Earth book is particularly good, a thorough introduction to Earth science for younger readers. Interspersed with fact-filled sections are interviews with people working in space careers, like rover driver Scott Maxwell in the Mars book and astronaut Paolo Nespoli in the Earth one. My only problem with the series is that the photo selection is not particularly good, including lots of outdated visualizations. But the text makes up for that, and this is one series I'm keeping on my daughters' bookshelf.
For ages 9-13: The American Space Missions—Astronauts, Exploration, and Discovery series includes six 48-page books by three authors. They concern space history, with narratives about Gemini 4, Apollo 11, Apollo 13, the Challenger disaster, the Hubble Space Telescope, and the International Space Station. (The last title is an odd duck in the series, more focused on facts than story.) Although I think the series focuses rather too heavily on failures, the stories are good, and every two-page spread has an excellent photo printed across at least half a page. This might be a good series to present to reluctant readers, because the drama and the beautiful photos encourage page-turning.