Try making a Solar System wiki for the pupils research about the Solar System. Pupils could research key facts about the planets and moons and record their findings in the wiki. Each child could be given three key key facts to research and contribute them to the relevant area of the wiki thereby co-constructing knowledge across the class.
The wiki could be linked to a quiz that pupils use to develop their knowledge and understanding.
You could create links to activities such as BBC Bitesize, Earth, Moon and Sun.