The high-powered rocket engine that North Korea carried out a ground test on over the weekend appears to be for a satellite launch vehicle rather than an intercontinental ballistic missile, a US aerospace expert said Monday.

John Schilling, known for his expertise on the North's missile program, released the assessment in a report carried by the website 38 North, saying the combination of a core engine and four vernier engines is too big to fit on any known North Korean ICBM prototypes.

"With four steering engines around a single core, the engine is probably meant to be used alone rather than clustered. Of the North Korean rocket and missile projects that we are currently aware of, the best fit for this engine would be as the second stage of the new satellite launch vehicle provisionally known as the 'Unha-9,'" Schilling said.

Unha rockets are what the North has used to put satellite into orbit. The communist nation succeeded in such a satellite launch for the first time in late 2012 and again in February last year, demonstrating strides in its long-range missile technologies.

The North has long said its rocket launches are part of its space program. But Pyongyang is banned from such launches under UN Security Council resolutions as it has been accused of using them as a cover for testing intercontinental ballistic missiles.

Schilling said there could be a "yet-unknown ICBM design" sized for the big engine, but such a possibility is not large because Pyongyang has been moving towards lighter mobile systems and solid propellants for their strategic missiles.

"They have been promising us an ambitious new space program, which will require a large new satellite launch vehicle. They have made extensive upgrades to the Sohae Satellite Launching Station to support such a vehicle," he said. "Now they have shown us an engine that would be a good fit for this vehicle." (Yonhap)