Possible Clues:

• Whiny, as a voice
• One knows the sound this makes if it comes to blows
• Of the 11 Across
• Like ens
• Part of helmet rocket launchers left behind
• One knows how to make the sound of this
• Space agency adds length in the nozzle
• One knows, by the sound of it, it's about that
• For one knows, by the sound of it, 15 across is made to follow the North
• Like the accent of a US space admin figure?