Should we colonise space?

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Across
  1. 3. a person who receives or entertains other people as guests
  2. 4. suitable enough to live in
  3. 6. to be equivalent to
  4. 9. to come into possession of; get, acquire
  5. 10. closely compacted in substance
  6. 12. to speed up
  7. 14. appropriate, fitting
  8. 15. to set up
  9. 16. not adapted for use or action
  10. 18. to continue to exist, endure
  11. 20. resemblance
Down
  1. 1. a result or effect
  2. 2. the carrying of people or things from one place to another
  3. 5. deep
  4. 7. the outside/ upper layer of something
  5. 8. able to continue in a healthy state without outside assistance.
  6. 11. respect and admiration
  7. 13. a person who has been shipwrecked and stranded in an isolated place.
  8. 17. the process of decomposing
  9. 19. point or direct at a target