2017 Mar 24
Friday, Day 83
Unha 3/Kwangmyongsong 3 Launch Failure
The Unha 3 rocket carrying Kwangmyong 3 lifted off from Sohae 2012 Apr 12 at 22:38:55 UTC. A few minutes later, it impacted the sea to the west of Seoul, South Korea.
Launch was probably monitored closely by South Korea and the USA. The two countries would have been listening in to radio traffic that would have made them aware that something was about to happen even if the were uable to monitor the content and words. The fact that the launch had happened came into the public domain about twenty minutes after the event.when the South Korean news agency, Yonhap, issued brief newsflash.
Within a few minutes the story was being built-on by other news agencies. By that time, the launch had already failed. Shortly after, the news of that came through too. Later, North Korea put out a statement confirming launch and that it had failed.
Ironically, the journalists who had accepted North Korea's invitation to observe the event appeared to have been oblivious to it having occurred it until their colleagues back home told them about the failure.
Reports on the event were initially mixed but most agreed on an explosion. That does not necessarily point to the rocket blowing itself up. Although that is a possibility, loss of thrust or steering would also lead to en explosive end because aerodynamic forces would have caused the vehicle to break up. Once propellant started to spill, contact with a hot rocket engine, or mixing of fuel and oxidiser would have caused it to ignite explosively.
The US Department of Defense issued a press release saying that preliminary analysis indicated the remains of the rocket came down in the sea 165 kilometres to the west of Seoul in South Korea. The wording pointedly referred to it as a "Taepodong-2 missile" rather than 'Unha 3 rocket.'
Separately, South Korean news sources reported descent of the rocket into a different area much further south. The Yonhap News Agency reported Major-General Shin Won-shik, a Defense Ministry spokesman, as saying that Unha 3 broke up into about 20 pieces before falling into the West Sea between 100 kilometers and 150 kilometers west of the city of Gunsan. The Korean Herald newspaper reported that it was tracked (probably using radar) by the naval destroyer "Sejong the Great", equipped with US-supplied AEGIS anti-missile armament as was used by the US to destroy its own USA 193 satellite in 2008. It first detected the rocket at 22:39:49 UTC.
Elsewhere, the Pakistan news website Dawn.com reported another part of the same press briefing. It added that the explosion occurred at 22:41:10 UTC, which was 135 seconds after lift off. Dawn described the event occurring at 70.5 kilometres altitudes when Unha 3 was travelling at Mach 5.6. Two chunks of debris continued flying upwards and southward, reaching apogee at 151.4 km. One of the two chunks further disintegrated into some 10 pieces at 22:47:42 GMT and fell over an wide area in the sea off the South’s Taean peninsula. The other chunk flew further south before breaking up into three pieces and landing in the sea off the port of Gunsan.
The DoD defined location is shown as a dot on the map at 37°.5 north, 123°.75 east. It's description is a little imprecise in that it doesn't indicate where in the Seoul area it was measured from. It could even have been measured from the international airport on the coast at Incheon. Similarly, at the very least, "west" probably means anything between WNW and WSW. It points to the rocket having come down somewhere in the rectangular area. The area includes the predicted ground track so there is nothing to indicate that the rocket was off course to either side of the track.
The detailed South Korean description puts the impacts much further south, nearer to the planned first stage impact zone but off course. The fact that fragements fell that far south indicates that the problem may have occurred near the end of the first stage operation, raising the questions of whether it was related to 1st/2nd stage separation or a failed 2nd stage ignition.
....is currently unknown but stories suggesting an interception are way off mark. There just would not have been time, and such a scenario is highly unlikely anyway. We are dependent on a combination of North Korea's investigative ability and willingness to disclose the outcome either openly or by leaking information.
The Mission in In Summary
For the sake of completeness here is Kwangmyongsong 3's entry taken from the Zarya launch list for 2012.
Page Date: 2012 December 14
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