Related Clues:
- 15-Across, once
- Pantera cover "___ Caravan"
- Mars, for example
- Craft needs a little time to become orbiter
- Alien after map to find Earth, perhaps?
- Earth perhaps flat — first of theories
- Way to load part-emptied revolver?
- Krypton or Vulcan, in sci-fi
- Aggressive character to travel with protection of body of guards
- Pluto, before a 2006 downgrade
- Many a "Star Trek" stopover
- Mercury, for instance, showing temperature with level
- Earth, say, where flower perhaps stores energy
- Theme of this puzzle, repeated in some clues
- Earth or Mars