Pukguksong-4 [Pukguksong-3 mod]

The most probable step North Korea may take as a way to bolster nuclear capabilities would be launching a new submarine and submarine-launched ballistic missile (SLBM). Compared to liquid fuel, solid fuel rockets do not have to be fueled before launch and the fuel can be stored for a long period of time in the missile. When this type of missile is attached to a mobile launch pad, North Korea could launch it at any time and from any place, making it harder for Seoul and Washington to detect the missile before launch. Solid fuel engines are more combat proficient and it would be hard for Seoul to use the Kill Chain system to launch a pre-emptive strike on a solid fuel missile.

South Korean intelligence authorities said they have been closely monitoring the North's activities regarding preparations for the launching of a new submarine it first unveiled in July 2019. The submarine, believed to be a 3,000-ton one, is capable of carrying three SLBMs and to have been under construction at its naval base in Sinpo on its east coast.

In August 2016, North Korea launched the Pukguksong-1 from a submarine and it flew over 500 kilometers. Experts say it could carry a payload of about 650 kilograms with a maximum range of 2,000 kilometers, putting all U.S. bases stationed in Japan in reach. And athe mid-range missile North Korea fired in February 2017, the Pukguksong-2, appeared to be an upgraded version of its submarine-launched ballistic missile. North Korea conducted the first test of its newest SLBM, the Pukguksong-3, on 03 October 2019 off the east coast near Wonsan. Classified as a medium-range missile, it is believed to be an upgraded version of the Pukguksong-1 missile. During the October test, the missile flew around 450 kilometers at a maximum altitude of about 910 km.

"It would pose threats not only to the regional but the global security, as the missiles launched from underwater are hard to detect. It is likely designed to be launched from canisters so that it can be easily transported," said Shin Jong-woo, a senior analyst at the Korea Defense Security Forum in Seoul.

A group led by Dr. Victor Cha of the Center for Strategic and International Studies “Beyond Parallel” website, posted new and unusually clear satellite images taken 04 September 2020 that showed North Korea may be preparing its first submarine-launched ballistic missile test, potentially a major new development for the North. The experts said the pictures show a submersible test stand barge at the Sinpo South Shipyard. Cha said “A sea-launched missile test would definitely cross all of President Trump’s red lines because it would involve a major ballistic missile... It would be difficult for President Trump to ignore this.”

A North Korean military parade was held 10 October 2020 for the first time in about two years to celebrate the 75th anniversary of the Workers' Party of Korea. Chairman Kim Jong Un said "We will continue to show off our war deterrence as a means of self-defense." The military parade was held against the backdrop of the night view of Pyongyang, and honorary cavalry and walking companies entered in sequence. Korean Central Television emphasized that "the generation who participated in today's military parade has changed so much that no one can imagine it and show it to the world."

On display was a weapon that seems to be a new type of SLBM (submarine-launched ballistic missile), which is said to reach Japan. The letters "Pole Star 4" were on the missile.

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