The sleuths suspected that the satellite images showed the launching site of North Korea’s most powerful missile, but they were baffled by a mysterious bustle of construction there.

Closer scrutiny, astronomy and a smart hunch about North Korea propaganda confirmed it. They were witnessing the construction of a shrine to the missile, the Hwasong-15, the first built by North Korea that could hit anywhere in the United States.

Routinely, the image sleuths try to examine sites where the North launches its mobile missiles in a hunt for deployment clues and terrain suitability. North Korea, a mountainous nation, has relatively few locations flat and accessible enough for the firing of missiles from heavy mobile launchers, and analysts of late have carefully tracked the rise in launching-site diversity.