Rocket Men: The Team Building North Korea’s Nuclear Missile

When the North Korean leader Kim Jong-un celebrated the launch of a powerful new missile last month, he was surrounded by a group of top scientists and officials.
State media did not identify them, but they have all been seen with Mr. Kim before.

These men – known by nicknames such as the “nuclear duo” and the “missile quartet” – have built an intercontinental ballistic missile that appears capable of hitting any city in the United States, an extraordinary scientific achievement for the world’s most isolated country.