North Korea is believed to be working on the Pukguksong-3, a suspected intercontinental ballistic missile.

During an August visit to the Academy of Defense Science, North Korean dictator Kim Jong Un ordered the Chemical Materials Institute to “produce more solid-fuel rocket engines and rocket warhead tips,” North Korean state media reported at that time. In the pictures from the visit, the designs for the Pukguksong-3 can be seen on the wall. Although it is difficult to know for certain, a mock-up of this missile may have been presented at a massive military parade in April, where two previously-unseen canisterized missiles were rolled out for the world to see.

It is unclear at this time exactly what North Korea intends to to do with its new solid-fueled engine. If it intends to load it into a solid-fueled ICBM, that is definitely cause for concern.

Unlike their liquid-fueled counterparts, solid-fueled missiles can be fueled in advance. Liquid-fueled missiles, like the Hwasong-14 ICBM North Korea tested twice in July, have to be fueled at launch. The extended preparation time, together with the larger satellite signature due to the increased size of the crew required, make these missiles vulnerable to preventative strikes. Solid-fueled missiles can be rolled out and fired with little to no warning, making them significantly more dangerous.

There is currently no indication North Korea intends to use its new solid-fueled engine to develop a new ICBM. North Korea is also developing a new ballistic missile submarine and could have plans to advance its SLBM program.