A short thread on the shipping container that showed up at an engine test stand in North Korea -- and what it means.
First, a clarification: Rocket engineers conduct static tests (the engine fires on the ground) and flight tests (the missile, er, flies.) We are talking about facility to do static tests on the ground. We are not talking about a missile launch.
The shipping container showed up at a place the North Koreans call Sohae Satellite Launching Station (Sohae means "West Coast"). The the US and South Korea called Tongch'ang-ri after the nearest populated place, although sometimes you might hear it called Yunsŏng (윤성) . 
The name Yunsŏng is used rarely, but it illustrates that the site contains *two* key facilities -- a launch pad for space launches and a test stand for static tests of rocket engines on the ground. The test stand is closer to Yunsŏng than Tongch'ang-ni. Here it is in operation:
The engine test stand is important because it is one of a small number of places where North Korean can test large liquid propellant rocket engines. As part of the agreement in Singapore, Donald Trump bragged that North Korea had agreed to dismantle the engine test stand.
For its part, North Korea presented the dismantlement of the engine test stand as a "physical verification of the suspension of ICBM production." Tests can be used to develop new engine designs or verify that the ones North Korea makes now work properly.
uriminzokkiri.com/index.php?lang…
uriminzokkiri.com/index.php?lang…
North Korea did dismantle the test stand after Singapore, but then started putting it back together in the days *before* talks collapsed in Hanoi -- judging by @planetlabs optical imagery and @Airbus SAR imagery.)
Still, we had not seen any activity at the test stand -- until yesterday. @planetlabs imaged it twice on on December 5: at 11:23 am and 2:27 pm local time. A large shipping container -- a decent indicator of an impending engine test -- arrived sometime in that three hour window.
One challenge in interpreting these images is that North Korea constructed an environmental shelter at the test stand to keep the engineers free from the elements and hidden from satellites. So we can't see what's going on underneath it until they pull it back to do the test.
It is clear that this is one more sign that North Korea is conducting more missile-related activities as Kim Jong Un's end-of-year deadline for sanctions relief approaches. This isn't the "Christmas gift" that Kim promised Trump, but it is another lump of coal in his stocking.
