A large cargo ship has appeared in front of the construction hall of North Korea’s nuclear-powered missile submarine for the first time, according to NK Pro analysis of satellite imagery, a possible sign the project is entering a new stage.

Planet Labs and Maxar imagery shows that a bulk cargo ship measuring 98 to 100 meters long and 16 meters wide arrived outside the Pongdae Submarine Factory in Sinpho between the mornings of Feb. 13 and 14. 

High-resolution Maxar images taken on Feb. 15 and 18 show the vessel docked at the slipway directly in front of the building housing the