Related Clues:

• Word separator
• Hole
• Type of heater
• Place to park
• Dentist's find
• "Final frontier" related to this puzzle's theme
• Comet's place
• Room to move
• Part of 65 Across
• Room
• Elbow-room
• NASA workshop?
• Almost every written sentence has at least one
• Text separator
• Astronauts' realm