Space travels

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Across
  1. 2. gather objects
  2. 4. modesty
  3. 14. you are not alone
  4. 15. alien
  5. 17. orbiting device
  6. 20. no limit
  7. 21. waste
  8. 22. opposed to past
Down
  1. 1. possibilities
  2. 3. images
  3. 5. advances
  4. 6. travel to unknown places
  5. 7. Einstein was one
  6. 8. tiny piece of something
  7. 9. men and women
  8. 10. expensive
  9. 11. Mars or Venus
  10. 12. hazardous
  11. 13. useful when you're lost
  12. 16. duty
  13. 18. trip
  14. 19. information