Immediately after the launch, many analysts assumed that a Hwasong-14 had been fired; subsequently, however, the North Korean government released video of the launch showing a completely different missile. North Korea claimed the missile reached an altitude of around 4,475 km and traveled 950 km downrange, flying for a total time of 53 minutes. Based on its trajectory and distance, the missile would have a range of more than 13,000 km – more than enough to reach Washington D.C. and the rest of the United States, albeit, according to the Union of Concerned Scientists, probably with a reduced payload. Several important US allies, including the United Kingdom and France, also lie within the missile's theoretical range, which covers most of Earth's land masses except South America, the Caribbean, and the majority of Antarctica. Some international weapons experts, however, believe the missile is only capable of firing a light warhead. The different densities of different casing materials and explosive mechanisms make accurately estimating warhead payload based on images alone very difficult, if not impossible. Based on the limited information available, the Union of Concerned Scientists did conclude that equipping the missile with a normal-sized payload would likely reduce the overall range. It was the first launch after a 10-week break. According to a statement by Japanese Minister of DefenceItsunori Onodera, the missile's re-entry vehicle failed to successfully re-enter the Earth's atmosphere, breaking apart and crashing into waters within Japan's exclusive economic zone. Later assessments from the Union of Concerned Scientists, however, raised questions as to whether the object Onodera described may have been the missile's detached first stage, not its re-entry vehicle.
Design
Engine
According to international weapons analysts, the Hwasong-15 first stage has a gimbaled two-chambered main engine system, as opposed to the Hwasong-12 and Hwasong-14 which have one fixed main chamber and four gimbaled steering vernier thruster chambers. Its first stage booster design is strikingly similar to the Titan II missile. According to missile specialist Norbert Brügge, the missile uses the ‘Paektusan, 백두산’, the first stage of the two stage missile uses an RD-250 clone liquid propulsion system developed by Pyongyang, comprising two combustors fed by common turbopump to increase takeoff thrust. The new propulsion is estimated to have 170 percent increase in thrust, compared to the Hwasong-14.
Warhead
On November 29, 2017, Michael Elleman wrote for 38 North that at 13,000 km, the payload would be around, based on flight data of the test and conjectured it was a reconfigured Hwasong-14 and on November 30, after release of the images and video of launch, he wrote a subsequent article on 38th North in which he stated that he first visualized the design of the missile based solely on flight data. After seeing the images and video, Elleman increased the maximum estimate of payload from 150 kg to at a range of 13,000 km. He noted major differences in the design of the actual Hwasong-15 and the missile he visualized the day before, from the dimensions to two nozzles/engine instead of one, such as on the Hwasong-14. Analysts have noted that the re-entry vehicle has a blunter nose than previous designs, which can accommodate a larger diameter warhead and reduces re-entry stress and heating at the cost of accuracy. Some analysts think it may have been designed with multiple warheads or decoys in mind.
Launch vehicle
The 9 axle Transporter erector launcher vehicle is larger compared to the 8 axle TEL vehicle of the Hwasong-14. However, just like the Hwasong-14, the launch footage indicates the missile was fired from a fixed launch pad, not from the vehicle.
