The rocket launch was possible not just because of outside help. North Korea has tenaciously pursued the technology. By 1990 the North Koreans had scaled up their early missiles based on the Soviet Scud B. The new powerful missile, designated as Nodong, made it to Iran and Pakistan, where it became Shahab-3 and Ghauri respectively.

After three, possibly four, previous attempts that failed, North Korea achieved its ambition of putting a satellite in orbit on December 12 and became the 10th country in the world with that capability.

The Unha-3 launch vehicle placed an imaging satellite, Kwangmyongsong-3, in orbit about 500 km above the earth. Recent media reports indicate that the satellite has stopped functioning and is tumbling as it circles overhead.

Launch vehicles are immensely complicated machines, with a large number of components and systems that must work as planned under conditions of considerable stress. Despite its poverty and relative international isolation, North Korea has shown the ability to doggedly persist in the face of failure in order to master the technology.

The dual-use nature of such technology allowed the country to draw on its experience with ballistic missiles to build satellite launchers. Now, with the progress that it has achieved in launch vehicles, the country could, if it chose, develop more powerful ballistic missiles than those it possesses.

In the early 1980s, North Korea set about reverse engineering a Soviet short-range ballistic missile, R-17E, which is better known by its western designation ‘Scud B’. The Soviet Union had exported the missile to several countries and North Korea is believed to have got a small number of those missiles from Egypt.

By early 1984, the first prototypes of the North Korean version of the missile, Hwasong 5, was ready, according to an analysis published in 1999 by Joseph S. Bermudez Jr., who was at the time with the Monterey Institute of International Studies in the U.S. It then developed an improved version of the missile, Hwasong 6, with a range of about 500 km.

North Korea then went on to make a substantially bigger missile with a longer range, which U.S. intelligence designated as ‘Nodong’. Nodong’s liquid propellant engine was a much larger and more powerful version of the one in the Hwasong missiles. The scaling up of the engine was accomplished with the assistance of Russian engineers who had earlier worked in a missile design bureau, according to Mr. Bermudez.

The Nodong prototype was ready by 1990. Subsequently, North Korea supplied the missile as well as the know-how for making it to Iran and Pakistan. In Iran, the missile became the ‘Shahab-3’ and in Pakistan the ‘Ghauri’.

Setting the stages

Nodong provided the first stage for North Korea’s first launch vehicle, Paektusan-1 (known in the West as Taepodong-1). The launcher’s second stage was thought to be based on the Hwasong missile, with what was possibly a solid propellant third stage. (Iran too used the Nodong as the first stage of their Safir launcher, which successfully put a satellite in orbit in February 2009.)

In an analysis published in 2009, Theodore Postol of the Massachusetts Institute of Technology in the U.S., however, argued that Paektusan-1’s second stage had employed a liquid-propellant engine from the Soviet SA-5 surface-to-air missile while the third stage used a solid-propellant motor from the Soviet SS-21 tactical missile.

When the Paektusan-1 was launched in August 1998, its first two stages worked well but the third stage did not ignite.

Trying again

In July 2006, North Korea made what was possibly its next attempt at launching a satellite. The rocket could have been the Unha launcher that was flown three years later, according to David Wright, an analyst with the Union of Concerned Scientists in the U.S. In any event, the rocket exploded shortly after it lifted off.

Unha-2 was then launched in April 2009. Like Paektusan-1, it had three stages but was considerably larger than its predecessor. Unha-2’s fate was sealed by the failure of its third stage.

In an examination of the Unha-2 published in the Bulletin of the Atomic Scientists in 2009, Dr. Wright and Dr. Postol took the view that the first stage of the rocket used a cluster of four Nodong engines. Its second and third stages, however, used “significantly more advanced technology” than in the past. The second stage appeared identical to the single-stage Soviet R-27 sea-launched ballistic missile.

The rocket’s third stage appeared to be “very similar, if not identical” to upper stage of the Iranian Safir launcher. In both cases, the stage used two small steering engines, running on liquid propellants, from the R-27 missile, they said.

While the Unha launcher represented a significant advance, it appeared to have been constructed using critical rocket components acquired from other countries, most notably Russia, according to Dr. Wright and Dr. Postol.

Unha-3 was launched in April this year, only to meet yet another failure. As in 2006, a problem seems to have occurred while the rocket’s first stage was firing. Eight months later, the Unha was once again on the launch pad. This time, however, the rocket’s three stages worked without a hitch and deposited the satellite it carried safely in orbit.

Capacity building

S. Chandrashekar of IIM Bangalore, who worked at the Indian Space Research Organisation for many years, believes the North Koreans have demonstrated the capacity for assimilating the many complex technological elements that go into a launch vehicle. Such challenging projects also needed an organisation framework to coordinate and oversee the effort. It was an oversimplification “to say that everything they have now was acquired from other countries,” he told this correspondent.

If the first stage of the Unha was a cluster of four Nodong engines, that was a major achievement, he said. Based on an analysis of Unha images carried out with colleagues at the National Institute of Advanced Studies in Bangalore, he was of the opinion that the Nodong also formed the second stage of the Unha launcher.

Moreover, in its latest launch, the Unha rocket had put the satellite into a near-circular 500 km orbit. The sun-synchronous orbit that had been achieved required the rocket’s third stage to be carefully reoriented before being fired. For that, the rocket needed to have good guidance and control, pointed out Prof. Chandrashekar.