Related Clues:

• Unable to proceed
• NASA scrub
• Unrealistic
• NASA failure
• Futile
• Off-limits
• Q: Are you an idealist? A: No. ___
• Scrapped, at NASA
• 'Ixnay'
• Canceled, slangily
• Impossible
• Scrubbed, as a mission
• 'Fuggedaboudit'
• Scratch, at NASA
• Unable to launch