Pukguksong-4

Pukguksong-4 made its public debut in a military parade commemorating the 75th anniversary of the founding of the Workers' Party of Korea on 10 October 2020. According to German expert Norbert Brügge, it was seen with a Korean People's Army Ground Force escort. Four Pukguksong-4 missiles were seen, and these missiles were placed on trucks. North Korea introduced Pukguksong-4 missiles as "underwater strategic ballistic missiles". These missiles appear to have different lengths. According to South Korean Chief of Naval Operations Boo Suk-jong, the name written in these missiles is Pukguksong-4S, not Pukguksong-4A, and the letter "ㅅ" (S) may stand for "sujung" (수중; lit. 'underwater') or "susang" (수상; lit. 'water surface'). A further development of Pukguksong-4, called Pukguksong-5, was displayed on 14 January 2021 during a military parade. Pukguksong-5, believed to be similar to Pukguksong-4, appears to be larger than its predecessor. There have been no known test for Pukguksong-4 so far. However, an alleged flight test occurred on 19 October 2021. Initially, the missile used for the test-fire was supposed to be some types of SLBMs, including Pukguksong-4. Later, the missile used in the 19 October 2021 launch was judged to be Hwasong-11S, an underwater-launched variant of Hwasong-11A (KN-23).

Pukguksong-4 is a two-stage, solid-fueled ballistic missile. As a further development from Pukguksong-3, it is significantly increased in size compared to the predecessor, with an estimated length and diameter of about 10 m (33 ft) and about 2 m (6.6 ft), respectively. Other sources claimed Pukguksong-4 to be shorter than Pukguksong-3. It is likely designed to be fitted with Sinpo-C class submarine, which was being built in 2020, capable of carrying 3–4 SLBMs. As portions of the Pukguksong-4's engine appear to be filament-wound, the missile has a heavier payload, a better range and is lighter compared to the previous missiles. The maximum range of Pukguksong-4 is estimated from 3,500 km (2,200 mi) with a 1,300 kg (2,900 lb) payload to 5,400 km (3,400 mi) with a 650 kg (1,430 lb) payload. It is alleged to be MIRV-capable, but it remains unconfirmed. According to Daily NK, Pukguksong-4 is capable of carrying four warheads, but it can be increased to eight. The missile is also claimed to be a silo-based missile and missing the second stage or stage separation mechanism. Pukguksong-4 appears to have two versions, with different lengths for different launch tubes. Daily NK's sources state that the two versions of Pukguksong-4 are: a shorter version, whose diameter is larger than Pukguksong-3, and a slightly longer version.