Discovering Mars Crossword Puzzle

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Across
  1. 2. someone who travels into space
  2. 4. To circle around an object
  3. 5. A tall rod of metal or wood
  4. 7. Natural waterways
  5. 9. To conquer
  6. 10. A round solid figure
Down
  1. 1. Giant holes in a planets surface
  2. 3. Gases around a star or a planet
  3. 6. A natural satellite
  4. 8. Someone who studies planets and space