Korean investigators on Thursday pinned down three possible causes for last year’s failed launch of Korea’s first space rocket, saying that there might have been problems with both the upper and lower parts of the two-stage rocket.

The Ministry of Education, Science and Technology also said that the Seoul and Moscow governments would form a new 30-person civilian probe team within the month to identify the exact cause of the failure.

The state-run Korea Aerospace Research Institute and Russia’s Khrunichev State Research and Production Space Center have run the Failure Review Board to ascertain the cause since the second launch failed last June.

The FRB held four sessions, the last of which took place early this year, but failed to address their differences over the botched mission, officials said.

Naro, or Korea Space Launch Vehicle-1, was built with technological assistance from the Russian institution, which developed the liquid-fuel first-stage rocket. The solid-fuel second-stage rocket was manufactured by KARI.

After the first failure in August 2009, the second launch failed as the rocket exploded in midair some 137 seconds after it blasted off from the Naro Space Center, the country’s first space center in the southern coastal county of Goheung.

According to an interim investigation result issued by a panel consisting of Korean civilian experts not working for KARI, the KSLV-1 received a shock some 136.3 seconds after liftoff and another around one second later.

Between the two shocks, the rocket went out of contact, officials said. After the first shock, a flash appeared between the first and second stages, and then an irregular signal in the ignition device of the Flight Termination System was detected, they said.

Concerning the three possible causes of the first shock, KARI and the Russian institution have conflicting views.

Russians claim that due to the malfunction in the flight termination system in the second stage rocket, the solid fuel in the kick motor burned, which might have caused an explosion.

The Korean-made second-stage rocket, which is powered by the kick motor, carries a 100-kilogram Korean-made experimental satellite. The FTS is designed to explode the rocket if there was a problem with the flight.

KARI claims that a malfunction in the oxidation and compression systems in the first-stage rocket might have led to the failure. It also said that unverified problems with rocket separation explosives between the first and second stages could be the cause.

The civilian probe team has found it very difficult and time-consuming to verify the three possible causes as it is difficult to recreate the environment the KSLV-1 failed in.

As it would take some time for investigators to verify the cause of the failure, officials expect the third launch to take place sometime next year.

The Naro weighs 140 tons and measures 33.5 meters in length and 2.9 meters in diameter.

The second stage is to carry into orbit “the Science and Technology Satellite 2,” which was jointly developed by KAIST and the Gwangju Institute of Science and Technology. The satellite with a two-year lifespan is to gather information on the Earth’s atmosphere and measure its radiant energy and satellite orbits.

Korea has spent 502.4 billion won ($463 million) on the project, which began in August 2002. About 40 percent of that amount has been paid to the Russian organization.

By Song Sang-ho (sshluck@heraldcorp.com)