North Korea says it launches rockets for the peaceful purpose of sending scientific satellites into orbit. But Washington sees them as a cover for developing intercontinental ballistic missiles that could one day strike targets as far away as North America with nuclear warheads.
The institute first noticed that the work at Tonghae stopped at the end of 2012. In its latest update, posted on its Web site 38 North, it said on Tuesday that the construction had not resumed as of late May, although it was not clear what had caused the seven-month halt.
Even if North Korea resumes work, the lull means that the new projects might not be completed until 2017, a year longer than earlier estimates, it said.
 
“Initial speculation at the end of 2012 focused on the need for equipment and troops elsewhere to repair damage done by last summer’s typhoons and heavy rains,” it said. “That explanation now seems less plausible given the amount of time that has passed since last year’s rains.”
An alternative explanation is that the North has decided that testing conducted at the Sohae Satellite Launching Station, in northwestern North Korea, will be sufficient to support its development of larger rockets, the institute said, without citing any evidence to support its theory. North Korea conducted its December rocket launching from the Sohae station.
“Or the stoppage may reflect a decision either to slow or even halt development of larger rockets,” it said.
 
Such an analysis contradicts recent official pronouncements from Pyongyang. Despite international criticism and United Nations sanctions, North Korea has vowed to continue to build and launch more powerful rockets. Again using satellite imagery, 38 North said on July 10 that North Korea might have conducted engine tests for a more powerful rocket at the Sohae facility in late March or early April.
 
During military tensions that followed the North’s nuclear test in February and ensuing sanctions from the United Nations Security Council, North Korea claimed to have the ability to hit the continental United States with nuclear missiles. American intelligence agencies are divided over how close the North has come to attaining such an ability. Still, Washington announced plans to deploy more missile interceptors on the West Coast.