Members of a conservative civic group burn missile mockups carrying an effigy of North Korean leader Kim Jong-un near the U.S. Embassy in downtown Seoul, Friday. / Yonhap

By Philip Iglauer

What caused North Korea’s rocket to blow up soon after being launched? One expert says that the location of North Korea makes such a launch tricky and obviously the Stalinist country has not reached the technical level to overcome it.

“Even highly developed nations do not have successful launches 100 percent of the time,” said Shin In-kyun, founder and president popular military website Korea Defense Network.

“North Korea’s location makes it extremely difficult because it is so far from the equator and because it launched the rocket with a polar trajectory and not eastward in line with the Earth’s rotation.”

The launch vehicle gets a boost from the Earth which, at the equator, moves at a speed of 1,675 kilometers per hour. Thus the rocket can do its job with less rocket fuel. North Korea’s Tongchang-ri site is located at 39 degrees latitude. Spaceport Cape Canaveral is, for example, at 28 degrees latitude.

Being so far from the equator — about 4,300 kilometers away, compared with about 3,100 kilometers away in the case of Cape Canaveral — can make it difficult to reach the more-traveled orbits used by other nations.

“Three-stage rockets are very complicated. The scientists have to calculate when to separate the stages at just the right altitude and speed to achieve orbital velocity and place the satellite at just the right place.”

“The usual practice is to launch a satellite rocket in the direction of the Earth’s rotation, to save fuel by taking advantage of the plant’s spin.” This is why the previous attempts were from launch stations on North Korea’s east coast, he said.

North Korea had to select a difficult flight path also because it is sandwiched between so many countries and their air space. It selected a narrow launch window along a polar trajectory over the East Sea and the Pacific Ocean.

“Rockets usually launch from as close to the equator as possible to give the launch vehicle a free boost. The strength of this boost depends on the rotational velocity of Earth at the launch location. The boost is greatest at the equator, where the distance around the Earth is greatest and so rotation is fastest.”

Another big technical hurdle North Korea’s rocket scientists faced was the rocket’s payload.

The North claimed it was a weather satellite. Iran’s Safir rocket launched on Feb. 3 carried the Navid satellite which weighed 50 kilograms. Some estimates put the Unha-3’s refrigerator-sized payload, the Kwangmyongsong-3 weather satellite, at twice that at over 100 kilograms.