One activity for younger students that combines reading, writing and learning about space is to create a model of the solar system for the classroom. In addition to creating models for each planet around the Sun, split the students into groups and assign each a planet. Each group will then be responsible for researching its respective planet, then producing a summary of the most important information about the planet. This summary should be at least a paragraph long, but you can assign older students to write longer summaries.
Long before humans began to understand the Sun, Moon, and stars through scientific inquiry, people created myths and legends to explain them. Many of these focus on how the Sun and Moon came to be, why the Earth has day and night and explanations for what those bright stars are. Reading these myths in class can serve as an interesting prelude to learning the actual science behind the Earth, Moon and stars. Additionally, it broadens a student's awareness of the mythology of other cultures.
Give your students an assignment to seek out, and write a summary for, a recent news article covering some new development in astronomy. This could be about astronomers finding a previously unknown planet in a solar system, the discovery of new characteristics about extraterrestrial bodies or the launch of a new telescope. This will not only give students practice reading and writing, but helps expand students' awareness of what space exploration currently looks like.
Not all science fiction is juvenile entertainment. Authors, such as Isaac Asimov and Tom Goodwin, used futuristic visions of space and technology as a setting against which to tell stories that posed the deep questions that characterize high literature. Giving stories, such as Goodwin's "The Cold Equations" or Asimov's "The Last Question," to your students as reading assignments will expand their reading abilities and appreciation of literature, but will also teach them bits of science and astronomy in the process.