"Space Crossword": HTML5 Crossword

Across

4. The path of a planet around a star (5)
6. Some planets are made of rock and some are made (5)
8. The nationality of the first man in space (7)
9. One of the gases that is found in the Sun (8)
10. A natural satellite (4)
13. The group of planets and star that Earth is part of (11)
16. Largest planet in the Solar System (7)
17. Our planet (5)
18. No longer a planet (5)

Down

1. Planet closest to the Sun (7)
2. The hottest planet in the Solar System (5)
3. The red planet (4)
5. This was left on the moon (10)
7. These is found in between Mars and Jupiter (9)
11. Neil The first man to walk on the moon (9)
12. Vehicle to transport people into space (6)
14. The time it takes for a planet to complete an orbit (4)
15. The number of planets that have been discovered in our Solar System (5)