What happens when a North Korean ballistic missile test fails in flight and explodes in a populated area? On April 28, 2017, North Korea launched a single Hwasong-12/KN17 intermediate-range ballistic missile (IRBM) from Pukchang Airfield in South Pyongan Province (the Korean People’s Army’s Air and Anti-Air Force Unit 447 in Ryongak-dong, Sunchon City, to be more precise). That missile failed shortly after launch and crashed in the Chongsin-dong, in North Korean city of Tokchon, causing considerable damage to a complex of industrial or agricultural buildings.
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As seen in image 1, had the launch succeeded, Rodong Sinmun would likely have printed an image of Kim Jong-un standing in front of the transporter-erector-mounted IRBM in a hardened tunnel.

That would have (and now does) send a dire message to U.S. and allied military planners: North Korea’s missiles won’t be sitting ducks at known “launch pads,” contrary to much mainstream analysis. What’s more, the proliferation of newly constructed hangers, tunnels, and storage sites cannot be assumed to stop at the Pukchang Airfield. Similar facilities likely exist across the country. In 2017, not only has North Korea tested a massive variety of strategic weaponry, but it has done so from a more diverse list of launch sites — what the U.S. intelligence community calls “ballistic missile operating areas” — than ever before. Gone are the days of Kim Jong-un supervising and observing launches at a limited list of sites that’d include Sinpo, Sohae, Wonsan, and Kittaeryong.
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As North Korea’s production of now-proven IRBMs and ICBMs continues, it will have a large and diversified nuclear force spread across multiple hardened sites, leaving the preventive warfighter’s task close to impossible if the objective is a comprehensive, disarming first strike leaving Pyongyang without retaliatory options. The time is long gone to turn the clock back on North Korea’s ballistic missile program and its pre-launch basing options.

Source: When a North Korean Missile Accidentally Hit a North Korean City | The Diplomat