The North Koreans are making good progress to be able to launch the Unha-3 on April 12, 2012, the start of their announced launch window. Analysis on the most recent available imagery from April 9 shows activity at the propellant storage buildings adjacent to the pad, indicating fueling the rocket is about to start. In addition, the needed instrumentation equipment is being readied at the new site on a ridge south of the launch pad. The gantry work platforms have been closed around the Unha-3 so it cannot be seen on the image. The following discusses these and other activities at the Sohae Satellite Launching Station (Tongchang-ri).
The launch pad has been closed down since the media tour visited it on April 8. Figure 1 shows the pad and the adjacent propellant storage buildings. Note the activity at the four propellant storage buildings includes tank trucks, empty tanks, and people. In addition, there are three possible security vehicles parked on the pad. This activity is in contrast to the April 8 image where they were preparing for the media visit.
Figure 1. April 9, 2012 image of the Sohae (Tongchang-ri) Launch Pad.
The new instrumentation site built on a ridge midway between the launch pad and rocket engine test stand also showed new activity (figure 2). The mobile radar-tracking antenna was out of the stowed position and a white bus/van was parked next to it. Two possible antennas have been mounted on the roof of the building at the end of the road and a mobile possible optical instrument is set up on the road in front of the building. Two communications masts are also observed. This site fills a very important function during the rocket launch as it tracks and collects telemetry from the rocket, which it then passes to the launch control center where it is analyzed to determine the performance of the rocket.
Figure 2. Activity seen at the instrumentation site on April 9, 2012.
Another important indicator of when the rocket stages were moved to the pad is the presence of the first and second stage trailers. These trailers were seen at the Tonghae (Musudan-ri) test center for both the 2006 and 2009 Unha launches, parked in a dirt area and canvas covered after the rocket was erected on the pad. They now have been identified at Sohae in the support area associated with the horizontal assembly building. Figures 3 and 4 show the parked trailer on April 8 and 9. These trailers were not at this parking area on April 4 or 6, indicating the rocket may not have been completely stacked on the pad.
Figure 3: Support area on April 8, 2012.
Figure 4. Support Area on April 9, 2012.
On April 8, the train bringing media representatives to Sohae for their tour was seen on the siding, two vehicles blocked the road to the support area and a probable check point had been set up on the concrete road leading to the assembly building. The image was collected at 14:21 local time and the tour group was probably in the building at that time. This is where they were shown the Kwangmyongsong-3 satellite (figure 5). On April 9, there was little activity around this building.
Figure 5. The horizontal assembly building during the media tour on April 8, 2012.