Related Clues:

• "It's a ___" ("It's been canceled")
• Strong rebuke
• Prohibited thing
• Mission-scrapping words
• Opposite of 43-Across
• Failed NASA launch
• Answer for Nanette?
• It's out of bounds
• NASA nix
• Canceled, NASA-style
• Kiddy taboo
• Astronaut's negative
• '--, Nanette'
• Unready, in NASA-speak
• ''Don't do that!''