SEOUL:North Korea’s test of a new medium-range missile could help the nuclear-armed state develop an operational intercontinental ballistic missile (ICBM) capable of striking the US mainland by 2020, a US think-tank said Friday. The US-Korea Institute at Johns Hopkins University said Wednesday’s test of a so-called Musudan missile was a “partial success” that demonstrated the full performance of the weapon’s propulsion system, and “at least a minimally functional” guidance system. The Musudan has a theoretical range of anywhere between 2,500 and 4,000 kilometres (1,550 to 2,500 miles), with the upper estimate covering US military bases as far away as Guam. After a string of four failed launches in previous months, North Korea tested two Musudans just hours apart on Wednesday. The first was seen as a failure, but the second was hailed by leader Kim Jong-Un as a complete success and proof of the North’s ability to strike US bases across the Pacific. The second missile was fired at an unusually elevated angle to attain a maximum height of between 1,000 and 1,500 kilometres – restricting its horizontal range to just 400 kilometres. Experts said the unusual trajectory was chosen to give the engine a full workout while avoiding any provocative overflight of a neighbouring country like Japan. Writing on the US-Korea Institute’s website 38 North, aerospace engineer John Schilling said testing six Musudans in quick succession until one of them finally worked suggested the North’s main target was a propaganda victory. “This isn’t so much an engineering programme, so much as an exercise in tossing a coin or rolling a die until it comes up with the result they like,” he said.