North Korea is barred under UN Security Council resolutions from launching rockets as that technology can also be used to launch ballistic missiles. Kim, however, declared this month that its space program "can never be abandoned."
North Korea has been upgrading the Sohae launch site on its west coast since mid-2013 after it blasted its first rocket into space in December 2012. It says the space program is peaceful.
The institute likens it to facilities in China but says there's no publicly available evidence to suggest Beijing is providing help.
The most recent image is from May 16.
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"The Sohae facility upgrade program represents a significant investment of financial, material and personnel resources and is another indicator, along with its public statements, that North Korea is determined to pursue its space program," read the analysis provided to The Associated Press ahead of publication on the institute's website, 38 North.
Concern is rising over North Korea's weapons development. The North recently claimed it tested a new type of missile from a submarine and reiterated that it had built a nuclear warhead small enough to be mounted on a long-range missile.
Outside analysts are skeptical about both claims, but they believe the North has built a small but growing nuclear bomb arsenal and advanced its missile program since international nuclear disarmament talks stalled in early 2009.