While the US Department of Defense (DoD) has been reportedly alarmed by the recent apparent single very low orbital test of a Fractional Orbital Bombardment System (FOBS)-style hypersonic Glide missile by China during July, there was a worse surprise: during October North Korea made a successful second test launch of its Pukguksong 3 fully functional Submarine Launched Ballistic Missile (SLBM) . This launch took place from the Port of Sinpo – presumably from a submerged submarine – and flew on a high altitude arc to its target point in the Sea of Japan. While the range of this test was, like the first test in October 2019, a paltry 450 km, if a normal ballistic trajectory had been used experts estimate that 1,900 km range could have been achieved. This puts the weapon close to being equivalent to the early A1 versions of USA’s first nuclear armed submarine launched ballistic missile system, Polaris, the longer ranged A3 version of which was also used by the Royal Navy.
The significance of these recent tests by China and North Korea is that while Intercontinental Ballistic Missiles (ICBMs) have much longer ranges, these missiles and launch sites relatively easy to track and target. China already has SLBMs to provide a measure of invulnerability to its nuclear deterrent: SLBMs have shorter flight times while their submarines are very hard to detect. To add to this, it is also apparently also going for hypersonic weapons flying in from low orbits which gives a target nation very little warning time, wile their cross range manoeuvrability makes them very difficult to track and intercept.
Meanwhile, North Korea finally gets itself a notable nuclear deterrent or even surprise strike weapon. That is North Korea is now capable of mounting a successful nuclear attack on the United States if its submarines can get within range in the Pacific or Atlantic.
Update on 22 October 2021: The US Navy reportedly made a successful test of its own hypersonic glide weapon on 20 October 2021, via a missile launch from Wallops Island, Virginia. A second test flight was a reported failure.
Comment by David Todd: Past US Administrations run by George W. Bush, Obama, Trump, and now Biden seemed to be more worried about Iran or Iraq gaining nuclear weaponry, or worse, not wanting to do anything provocative to where true nuclear threat lay: North Korea. And now it is too late. By the way, the US and allied invasions and military interventions in Iraq, Libya and Afghanistan have given succour to the idea within certain countries that if a nation has invulnerable nuclear weapons, their deterrent effect will prevent attacks by USA. They have a point. And so sadly, and dangerously, nuclear proliferation with its increased risk of causing nuclear war, is bound to go on.