Recent activity at a North Korean rocket production facility suggests that North Korea may be preparing a space launch, based on new evidence.
The Second Academy of Natural Sciences (SANS), located near Sanum-dong, outside of Pyongyang, is North Korea’s primary developer of ballistic missiles and space launch vehicles. SANS has its own production facilities in this area. (SANS appears to be responsible for experimental production of missiles before they enter into mass production using other facilities.)
A North Korean space launcher inside the main production hall in February 2016. 
Kim Jong inspecting a Hwasong-14 ICBM in the same location in 2017.
In 2012, SANS constructed a new production facility where long-range missiles and space launch vehicles are constructed. Although North Korea has never released images of the exterior of this building, there are at least two images showing Kim Jong Uninside the new facility — once prior to the February 2016 space launch and again prior to the July 2017 launch of the Hwasong-14 ICBMs.This was also, according to the Washington Post, the site of reported ICBM production in the summer of 2018.
According to press reports this week, “National Intelligence Service director Suh Hoon said his agency had monitored increased vehicle movement at the Sanum-dong facility.”
Satellite images taken by Digital Globe on February 22 show that there has been vehicle activity at both the production facility at Sanum-dong and at the nearby rail transfer point that serves the facility. This activity began prior to the summit in Hanoi. Activity at the Sohae Satellite Launching Station resumed in the same time period.
It is possible this activity at Sanum Dong and Sohae, in advance of the Hanoi summit, indicates a coming space launch. (An image taken by Planet Labs on March 8 shows that activity at the main production facility and at the rail transfer point has returned to normal.)
Prior to the thaw in North Korea’s relations with Seoul and Washington that followed the Olympics, North Korea appeared headed toward conducting at least one space launch. Kim Jong Un reportedly visited the Sanum-dong Research Center in late 2017 in preparation for a launch that was reportedly planned for September 2018. Moreover, North Korean officials told a visiting Russian official in November 2017 that they intended to launch two satellites, including”a communication satellite which works on a geostationary Earth orbit and weighs over 1000 kg.”
These plans appear to have been paused while US-DPRK negotiations were under way. North Korea partially dismantled both an engine test stand at Sohae, as well as the mobile gantry building used in the 2016 space launch. These steps were widely understood at the time to have been a conciliatory North Korean gesture following the Summit in Singapore.”I said, ‘Do me a favor. You’ve got this missile-engine testing site. We know where it is because of the heat.'” President Trump told reporters, “It’s incredible, the equipment we have, to be honest with you. I said, ‘Can you close it up?’ He’s going to close it up.”
Beginning in mid-February, however, North Korea began reconstituting those facilities. With the inconclusive result in Hanoi, North Korea now appears to be moving again toward a space launch. If North Korea does conduct a space launch,it is not clear what kind of rocket will be used. One possibility is that North Korea will use another rocket in the Unha/Kwangmyongsong series used in 2009, twice in 2012, and 2016. If North Korea wants to place a satellite in geostationary orbit, however, it will require a larger launch vehicle. North Korea might instead debut a new rocket, possibly using a variant of the March 18 Revolution engine that powers its new generation of strategic missiles including the Hwasong-15.
