Sil-li Ballistic Missile Support Facility
- A new facility is nearing completion near Pyongyang International Airport that is almost certainly related to North Korea’s expanding ballistic missile program.
- A high-bay building within the facility is large enough to accommodate an elevated Hwasong-15 intercontinental ballistic missile and, therefore, the entirety of North Korea’s known ballistic missile variants.
- The facility has been constructed next to an underground facility whose likely size is also large enough to easily accommodate all known North Korean ballistic missiles and their associated launchers and support vehicles.
In a joint baseline analysis with Jane’s Intelligence Review, the Center for Strategic and International Studies surveys a previously undisclosed facility near Pyongyang International Airport in North Korea that is likely related to its expanding ballistic missile development program.
Since mid-2016, North Korea has undertaken the construction of a uniquely configured facility on the southwest corner of Pyongyang International Airport and approximately 17 kilometers northwest of the capital city of Pyongyang.1 Among the unique characteristics of this new facility are:
- Layout, configuration, and large size of the buildings
- Interconnected buildings designed for drive-through access
- Raised center section (i.e., a high-bay) on the largest building
- Large underground facility (UGF) adjacent to the facility
- Wide-radius road network connecting all the buildings and the UGF
- Unusually large covered rail terminal and new rail spur line
- Location relatively close to ballistic missile component manufacturing plants in the Pyongyang area
Taken as a whole, these characteristics suggest that this facility is likely designed to support ballistic missile operations and for the interim is identified as the Sil-li (신리) Ballistic Missile Support Facility. As such, it is another component of the North Korean ballistic missile infrastructure that has been undergoing both modernization and expansion during the past 10 years. While the precise function of the facility is unclear, its configuration and the size of its buildings and UGF indicate that it can be used for, the assembly of ballistic missiles from components delivered by rail from nearby ballistic missile component factories (e.g., Tae-sung Machine Factory, Mangyongdae Light Electric Factory), accommodate all known and anticipated North Korean ballistic missiles and their transporter-erector-launchers (TEL), mobile-erector-launchers (MEL) or transporter-erectors (TE) for depot-level maintenance, storage of ballistic missiles and their transporters, or any combination of these functions.
Given the unfinished perimeter security wall, the continued presence of temporary construction buildings and storage units within the facility, the upcoming completion of nearby worker housing units, and the incomplete railroad spur line, the facility is undoubtedly not yet complete. If construction continues at its current pace, and barring unforeseen delays, it could be complete and ready for operations sometime during late-2020 or early-2021.
Excluding the new housing units in the village of Sil-li, the facility encompasses approximately 442,300 square meters, including three large drive-through structures, a large adjacent drive-through UGF, and a covered rail terminal—all connected by a 9- to 10-meter-wide surfaced road network with wide radius turns suitable for the movement of large trucks and ballistic missile launchers.2
The most visually distinctive features of the Sil-li facility are its three large interconnected drive-through buildings. The construction of which was begun around June 2017 with the leveling of the land and excavations in preparation for foundations. The pouring of the concrete foundations would begin the following month and was slowly followed by the erection of walls. By June 2018, all three buildings were externally complete and closed in. By August of 2018, the roads around connecting the buildings, and the UGF were paved and competed. Since that time, work likely has focused upon completion of the interior of the buildings.
The largest drive-through building measures approximately 122-meters-by-43-meters with an approximately 6-meter-wide bay door at either end. This building is connected to the two smaller buildings by two approximately 12-meter-wide passageways—one at each end. The few publicly available satellite images of the buildings during construction shows a predominantly wide-open floorplan with some workshop or office space along some of the longest sides. Although they will likely be installed, no bridge cranes were visible within the interior of the building during construction. Significantly, the building has a 37-meter-by-30-meter elevated center section (i.e., a high-bay) that is high enough to allow for a Hwasong-14 or Hwasong-15 intercontinental ballistic missiles (ICBM) on a TEL to be easily elevated into the firing position to allow for testing of both, as well as the training of maintenance and ground crews.
The two smaller drive-through structures measure approximately 84-meters-by-42.5-meters each with an approximately 6-meter-wide bay door at either end. They are connected to each other by an 8-meter-wide passageway and, as noted above, are connected to the larger building by two large passageways. No bridge cranes were visible within the interior of either of the buildings during construction, although it is likely they will be installed.
All the bay doors and passageways on the three buildings are wide enough to accommodate all known North Korean ballistic missiles and their associated TELs, MELs, or TEs. By comparison, the two smaller buildings by themselves and the larger building by itself are larger than the horizontal processing building either at the Sohae Satellite Launch Facility or Tonghae Satellite Launch Facility.
As construction of the main buildings commenced, several existing small support buildings directly to the northeast were appropriated and incorporated into the facility. There are no indications as to whether these will remain or be razed when construction is finished. Additionally, as the three main buildings were being closed in, an approximately 33-meter-by-76-meter parking apron was poured immediately to their west, along the main access road.
Construction of the covered rail terminal began during January 2018 and was externally complete by October 2019. The covered rail terminal itself measures approximately 180-meters-by-33-meters and consists of a loading/unloading track, engine runaround track, and 188-meter-by-12-meter platform.3 (The ramp extends out of the covered terminal.) It allows for the concealed loading and unloading of outsized loads. It is unknown whether a bridge crane has been, or will be, installed within the terminal to facilitate loading or unloading operations. This covered rail terminal is similar to those previously constructed at missile-related facilities such as the Sohae Satellite Launch Facility during 2015 and more recently at the Sinpo South Shipyard during 2017.4 Similarly, these terminals were also built to conceal loading and unloading operations for outsized loads. By November 2019, much of the roadbed for the 3.5-kilometer-long railroad spur line connecting to the Sunan Rail Station had been built, and the laying of ballast had begun. As of imagery acquired on March 21, 2020, approximately 2.3 kilometers of the new railroad spur line has had ballast and railroad ties (i.e., sleepers) laid, although no track has been placed.
Sometime during late-2019 and early-2020, a small building was erected west of the covered rail terminal. Its size and location suggest that it may serve as offices for a small facility guard force.
Another unique feature of the Sil-li facility is its construction adjacent to an existing UGF to which it is connected by its road network. This facility was built during the 1980s, perhaps earlier, to provide wartime protection for the aircraft and equipment of a fighter air regiment based at the Pyongyang International Airport tasked with the defense of Pyongyang. As the nationwide network of air facilities developed over the years, the air regiment was moved elsewhere, and the UGF was then used for general equipment and vehicle storage. It was then apparently abandoned until reactivated as part of the Sil-li facility. Although specific internal construction details of this UGF are unknown, using the little available information about North Korean UGFs, the topography in which it is located, and the layout of the Sil-li UGF’s entrances, it is likely that the primary tunnel is approximately 750-meters-long and 40-meters-wide, with 30-meter-wide entrances at both ends. Once again, large enough to easily accommodate all known North Korean ballistic missiles and their associated launchers and support vehicles.
An April 28, 2017 image of Kim Jong-un standing at the entrance of a UGF at the Pukchang-ni Airbase prior to the test launch of a Hwasong-12 ICBM provides some perspective of how large these aircraft UGFs are and how a TEL fits within them.
During 2018, the construction of a security wall around the facility was begun. This wall not only encompassed the new buildings but, when finished, will run along the ridgeline above the UGF.5 As this wall was being erected, construction of a new road running along its outside perimeter was begun to allow for movement around the new facility. As of imagery acquired on March 21, 2020, this road was still under construction.
It was in the small village of Sil-li, during August 2016, that the first indications of the construction of the facility were identified. At this time, much of the eastern section of the village was razed, and construction began on what would become a new housing facility for staff, engineers, and workers at the Sil-li facility. Approximately six months later, an additional section on the south side of the village was razed, and the construction of a second housing facility was begun. As construction of these housing facilities progressed, additional sections of the original village were razed. As of imagery acquired on March 21, 2020, much of the original village has been razed, and a total of 31 new multi-story housing units have been completed or are under construction in the two housing areas.
At a macro level, the Sil-li Ballistic Missile Support Facility is served by both paved roads and the national railroad system—through the dedicated rail spur line that connects to the Sunan-up rail station. Aside from the Pyongyang International Airport, the nearest operational military air facility is Sunchon Airbase, 32 kilometers to the northeast. There are at least 17 air defense artillery bases and numerous military and paramilitary barracks within a 5-kilometer radius of the plant. Additionally, the plant is covered by 17 S-75 (SA-2 Guideline), 6 S-125 Pechora (SA-3 Goa), and at least one S-200 (SA-5 Gammon) surface-to-air missile bases.
This report, as are the others in this series, is based upon an ongoing study of the Korean People’s Army ballistic missile infrastructure by the Korea Chair at the Center for Strategic and International Studies.
- The airport is also known as Sunan International Airport or Pyongyang Sunan International Airport. ↩
- It should be noted that if only the area encircled by the perimeter security fence is counted, this figure would be reduced to 267,000 square meters. ↩
- An engine runaround track is a second parallel track that allows an engine (i.e., locomotive) to pull a line of rail cars into a dead-end terminal, uncouple from the rail cars and then switch to the second track to “run around” the parked rail cars. This way, it is not “trapped” while the rail cars are loaded/unloaded. ↩
- Similar, but smaller, covered rail terminals have been long constructed at VIP rail stations and strategic facilities around the nation. ↩
- It is important to note that the security wall along the ridgeline above the UGF does not define the extent of the tunnels within the UGF. ↩