North Korea's test of a new rocket engine this week shows the communist nation has made real strides in its rocket and missile programs to a point where it could send unmanned probes to the Moon, a US missile expert said Thursday.

The North unveiled the massive new engine Tuesday, claiming it successfully conducted a "ground jet test of a new type high-power engine of a carrier rocket for the geo-stationary satellite." It said the engine has a thrust of 80 tons, which is three times the power of the engine used in the North's previous long-range rocket launches.

John Schilling, a top aerospace engineer with expertise in the North's missile programs, said the new engine is "too big and powerful" for use in intercontinental ballistic missiles the North has been developing, such as KN-08 and KN-14 road-mobile missiles.

But it could be used for outer space missions, he said.

"North Korea recently announced it plans to launch rockets to the Moon within the next ten years, along with launching increasingly capable satellites into Earth orbit. This engine would be suitable for launching modest unmanned lunar probes," Schilling said in an article in the website 38 North.

"They still have a way to go on the necessary satellite technology, of course, but they are now one step closer to demonstrating a basic operational capability in outer space. We should start thinking about how we might live with a North Korea that has such a capability," he said.

Even though the new engine isn't right for ICBMs, the North has already demonstrated that it can build large rockets using both solid and high-energy liquid propellants, to their own requirements, Schilling said.

"Whatever missiles North Korea may roll out in coming years, we can no longer expect to be limited to what can be cobbled together from old Russian cold-war leftovers," he said.

The expert also noted that the North has upgraded its Sohae long-range rocket launch site in the country's northwest to make it possible to launch bigger rockets from there. The new engine might be for a new larger space vehicle, he said.

"Liquid-fuel space launch vehicles typically use more than one engine on the first stage, and North Korean practice so far has been to use four engines," Schilling said. "A launch vehicle using four of these new engines would be about the right size for the upgraded launch pad and gantry tower at Sohae."

The North is banned from any ballistic missile activity under UN Security Council resolutions over concern that the regime could develop nuclear missiles. Experts say long-range rockets and ICBMs are basically the same with differences only in payloads.

This week's new engine test came amid heightened worries sparked by the North's fifth nuclear test on Sept. 9 that Pyongyang is making real headway in its nuclear and missile development, and could soon perfect capabilities to threaten the mainland US with nuclear-tipped intercontinental ballistic missiles.

The Sept. 9 test was the most powerful of the five conducted by the North, with its yield estimated at 10 kilotons of TNT, compared with January's 6 kilotons. The previous four tests came in 2006, 2009, 2013 and January this year.

By comparison, the Hiroshima bomb was about 15 kilotons.

Analysts have warned that it is only a matter of time until the North develops nuclear-tipped missiles. Some experts have projected that the communist nation's nuclear arsenal could expand to as many as 100 bombs by 2020. (Yonhap)