Related Clues:

• Approvals
• Space-age affirmatives
• Affirmative responses
• Astronauts' responses
• Astronaut affirmatives
• Astronauts' affirmatives
• NASA affirmatives
• NASA responses
• NASA approvals
• Thumbs-up responses
• Thumbs-up replies
• 'Thumbs-up' responses
• NASA go-aheads
• 'All systems go' signals
• Astronaut's thumbs-ups