Related Clues:

• 38-Across, to us
• It precedes 'Blastoff!'
• A person
• Sole
• Self starter?
• Microphone tester's word
• More than zero
• See 32-Across
• Count start
• Low digit
• Dirty rat
• Formal pronoun
• Good-for-nothing
• Top-of-the-chart number
• Telephone button that lacks letters