Satellite imagery from March 28 shows the beginning of North Korean preparations at the Sohae Satellite Launching Station (more commonly known as Tongchang-dong Space Launch Center) for its planned April rocket launch. Work to prepare the launch pad for stacking the Unha-3 satellite launch vehicle (SLV) appears to be underway. The mobile launch pad is seen sitting on tracks next to the gantry tower. All the work platforms have been folded back and the crane on top is at a 45 degree angle relative to the pad, indicating that equipment is being loaded onto the gantry. At the base of the gantry there are numerous small objects on the pad and several people. There is also a plate under the mobile launch stand to cover the entrance into the flame trench that is still in place and will be removed prior to launch. A crew appears to be cutting brush away from the concrete in the brown dirt area that extends from in front of the pad up the right side. This activity has been ongoing since March 20 when previous imagery was available. The North Koreans may be concerned that a fire after the launch could spread to propellant storage buildings.
At the two largest propellant storage buildings to the right of the launch pad, containing large tanks to supply the Unha-3’s first stage, trucks can be seen delivering fuel and oxidizer to small tanks. At the fuel storage building (largest building on right), nine tanks are lined up against the building and a truck carrying a tank can be seen in the middle of the road. At the oxidizer building (second largest structure), six tanks are visible and a vehicle is parked in front of them. The two smaller propellant buildings further down the road are intended to store a different fuel and oxidizer for the Unha-3’s second and third stages. No activity appears to be taking place at these buildings as of March 29.
Launch pad preparation seems to be progressing on schedule with fuel and oxidizer being delivered to the storage buildings for the Unha-3’s first stage. The next step will be the movement of the first stage to the pad—probably on March 30 or 31—followed by the second stage a day or two later. The third stage and payload will follow probably by April 2 or 3. Several other major events will take place after the Unha-3 is completely assembled. Unless some major setback occurs, the North Koreans will be able to launch during the declared launch window starting April 12, 2012. (See the accompanying 38 North article by Nick Hansen on a timeline for the upcoming launch).