1. Natural satellite
(Science and technology/Satellite)

... dwarf galaxy orbiting a major galaxy, but it is normally synonymous with moon and used to identify non-artificial satellites of planets, dwarf planets, and minor planets. (There are no known natural satellites ...

2. Terragen
(Web Links / Space related)

Want to create a realistic planet scenary ? Terragen is free and easy enough to use for grade 8 and above. (I have not tried it with youger ones)

3. Nasa Celestia guided activity
(Web Links / Space related)