Related Clues:

• Spoken thumbs-up
• NASA fine?
• Perfect for NASA
• Totally good
• "Perfect!" NASA-style
• Perfectly fine
• Jolly good
• "All systems go!"
• Perfect, NASA-style
• NASA's 'all systems gO'
• Perfectly fine, informally
• Fine, to astronauts
• 'K3wl'
• Project Mercury affirmative
• Astronaut's affirmative