It is no secret that North Korea plans to launch a satellite in a window between April 12-16, 2012 to coincide with the 100th birthday of Kim Il Sung, the founder of the country. It also plans to use an Unha-3 booster rocket launched from a new space port (Sohae Satellite Launching Station, a.k.a. Tongchang-dong Space Launch Center). The real secret is how North Korea plans to accomplish this task in the nearly three weeks left before the announced launch window. To provide some context on a probable timeline, this article briefly discusses the observed activities leading up to the Unha launch on July 4, 2006 and the Unha-2 launch on April 5, 2009, both from its old Tonghae Test Center.
Commercial imagery and open source reporting has shown that the launch campaigns of both 2006 and 2009 from Tonghae took about 2.25 months. Therefore, if the North Koreans are following anything like their previous schedule, the new campaign should be well underway. Imagery as of March 29, 2012, indicates that preparations have indeed begun. If a launch is really planned, it can be assumed that the Unha-3 and the satellite Kwangmyongsong-3, identified as an earth resources mission, will soon be inside the assembly building.
Previous Launch Campaigns
The first two months of the 2006 and 2009 Unha launch campaigns consisted of moving the rocket stages by train and then by road to Tonghae, which took about one week. The next six or seven weeks consisted of mainly checkout of the rocket and satellite inside the assembly building and a visit by Kim Jong Il to inspect the progress.
For the April 5, 2009 launch we can construct an accurate series of events 14 days prior to the test. For this timeline, only the launch pad and horizontal assembly building (HAB) activity is considered, although there were other visible activities.
|Start of pad activity and vehicle movement at the HAB.
|1st and 2nd stages stacked on pad and the 3rd stage and payload stacking in progress.
|3rd stage and payload related vehicles still at the pad.
|Full dress rehearsal launch in progress; Unha-2 fully seen and VIP vehicles are seen on the pad and later at the range control center.
|Gantry completely canvas covered with possible fueling activity taking place.
|Launch day: VIP pad visit 25 minutes before launch, Unha-2 fully seen; at launch, Unha-2 seen in flight and VIP vehicles seen at the control center.
Both Kim Jong Il and Kim Jong Un were at Tonghae for the launch and stayed over until April 6.
No Activity (Tonghae)
Third Stage and Payload Stacking in Progress
Full Dress Rehearsal in Progress (Tonghae)
Full Dress Rehearsal in Progress, 37 Minutes Later
Launch Day, 25 Minutes before Liftoff (Tonghae)
In contrast, there was very limited commercial imagery before the launch on July 4, 2006. Also, since this was the first test of the Unha vehicle and the first satellite launch attempt since 1998, preparations took longer.
|Work on the gantry in progress and the 1st stage seen being moved from the HAB.
|1st stage stacked and the probable 2nd stage on its trailer next to the gantry; 1st stage trailer back at the HAB.
|1st and 2nd stages stacked and the 3rd stage and payload stacking in progress; note this is the last available imagery before the July 4 launch.
The time period of pad activity was 26 days, twice as long as the 2009 launch. The one additional factor that could partially account for the longer time on the pad was the reported second Unha at Tonghae, which seems to have been removed by August 4, 2006. (It may have been present to provide a backup should there have been a problem with the primary vehicle. By having a second rocket ready, the North Koreans had a better chance for a successful on time launch. Whether it actually did replace the primary rocket and therefore extended the on pad time is unknown.)
Notional Pre-Launch Sequence of the Unha-3
Given the experiences of these previous tests, there are many indicators that can be used to identify the Unha pre-launch sequence. As the launch window gets closer, the pace of activity at the site naturally intensifies. The five day window probably means that the Unha-3 will be ready to launch on April 12, but to accommodate weather, potential technical problems and possible VIP schedules (a repeat of the 2009 visit, this time by Kim Jong Un to the launch), the North Koreans have built in another four days.
While they may start moving the rocket to the launch pad a few days earlier—since this is a new facility—based on a notional March 29 start of activities at the pad and a launch on April 12, the following is the probable sequence of events.
|Transport of the 1st stage from the assembly building by its trailer to the launch pad. Stacking the 1st stage on the mobile launch stand using the gantry overhead crane.
|March 31/April 1
|Transport of the 2nd stage to the launch pad by its trailer. Stacking it on the 1st stage using the gantry crane.
|Transport of the 3rd stage and payload to the launch pad. Stacking these on the 2nd stage using the gantry crane.
|April 4 & 5
|On pad checkout of the complete Unha-3 and its satellite payload.
|April 6 or 7
|Conducting a full launch readiness dress rehearsal. Gantry work platforms folded back with vehicles on the pad.
|Possible built in hold. Unha-3 inside the gantry work platforms that are canvas covered.
|Fueling of the rocket stages and final pad checkouts.
|Launch window. Kim Jong Un arrives for the launch. On launch day, VIP pad visits about an hour before launch and the gantry work platforms all folded back.