Across
- 2. First satellite
- 4. Governs air, ocean, and space
- 6. Time it takes a planet to orbit the Sun
- 8. Long-distance satellite that has entered interstellar space
- 9. Space Shuttle and SpaceX rocket were first of this kind
- 10. First in flight
- 12. Planet first explored by humankind
- 14. Name of Pluto's moon
- 18. Orbits the Earth 16 times a day
- 19. First living thing in outer space
- 20. Closest Dwarf planet
- 21. First rockets created
- 22. Missions to the Moon
- 23. Has the most moons
Down
- 1. Energy needed to leave Earth
- 3. Theory that all the planets orbit the Sun
- 5. Solar winds making the Northern lights
- 7. Smallest inner planet
- 11. First country to outer space
- 13. Competition between US and USSR
- 15. Used first rockets for long-distance warfare
- 16. One small step for man, one giant leap for mankind
- 17. Essential for all life on Earth