South Korea tests hypersonic missile: A new threat to North Korea's underground bunkers?

South Korea has successfully tested a domestically developed hypersonic boost-glide vehicle, with footage showing the vehicle impacting the water at the end of its flight. The missile has been tested by South Korea's Agency for Defense Development (ADD). The weapon would give Seoul a significant new way to hold targets in North Korea at risk as the arms race on the peninsula deepens. It follows the Hyunmoo-5, whose massive unitary warhead already lets South Korea threaten deeply buried and hardened targets, and fits the country's Korea Massive Punishment and Retaliation policy.At the very high speeds reached in the terminal phase, boost-glide vehicles also offer bunker-busting benefits. South Korea is also developing an air-breathing hypersonic cruise missile and new air- and sea-launched ballistic missiles for its warships and submarines. It remains to be seen when an operational capability will be fielded.