North Korea’s Taepodong and Unha Missiles

Overview

The Taepodongs are not production missiles and have never been successfully tested. The Taepodong-1 has been used as a space launcher and analysts are fairly confident about its performance. The one launch attempt of the Taepodong-2 ended after 40 seconds of flight when the missile disintegrated. There is, therefore, much greater uncertainty about what its performance could be or even precisely what the missile is. Developing, designing, and producing a missile is a complex, challenging, and expensive task. As a result, once a missile component has been developed, it will often be reused in several applications or, looking at it from the missile-designers’ perspective, a “new” missile can sometimes be assembled largely from existing components. When making a multi-stage missile from existing components, the missile may not be optimized, but better to accept that performance loss than incur the high costs of developing an entirely new missile. This works to the advantage of outside analysts in the case of North Korea because, while the North Koreans are extremely secretive about new missile developments, analysts can make intelligent guesses based on existing tested hardware. Even so, one should be aware that all existing descriptions, especially of the Taepodong-2, include some speculation and guesses.

History Return to Top

An extremely condensed history of the North Korean long-range missile program begins with the reverse engineering of Egyptian-supplied Soviet SCUD missiles, which themselves were a straightforward extension of German V-2 technology. The models built by the Koreans they called Hwasong-5. These missiles were sold to Iran during the Iran-Iraq War and were used in the War of the Cities to bombard Baghdad and other cities. Use during that war and other access to the missiles has allowed outside analysts to collect detailed information about the missile. Evolutionary improvements in the missile were incorporated in a new version, known in North Korea as Hwasong-6, with improved range and payload. This missile was also sold to Iran and there called the Shehab-2. For the next increment in range and payload, the North Koreans simply scaled up the Hwasong-6 by 50%; this missile is known in the West as the Nodong (named after the county, or “dong,” where it was first observed). The Nodong has been produced in number and is considered a deployed weapon. Some missiles, or perhaps components, have been sold to Pakistan, where the missile is known as the Ghauri and can reach deep into Indian territory, and sold to Iran, where it is known as the Shehab-3. The missile has been tested in both Pakistan and Iran and there are press reports that the North Koreans were involved in the tests so these flights should be considered part of the overall test program. The test program has not been entirely successful; in Iran’s first test of its Shehab-3, the missile exploded in flight.

The Taepodongs Return to Top

The next steps in North Korean missile development are the Taepodong-1 and Taepodong-2 (known as Paektusan in North Korea, named after the highest mountain in Korea, which is important in the Korean national origin mythology and the alleged birthplace of Kim Jung Il—he was in fact born in the Soviet Union). The characteristics of neither missile are perfectly well known. The Taepodong-1 is a two stage missile. Based on satellite photographs, the first stage appears to be a Nodong missile and the second stage a Hwasong-6. The Taepodong-1 has been test flown only once on 31 August 1998 as a space launcher; instead of a normal ballistic missile payload, the missile carried a third stage, probably solid fuel, that was meant to inject a small satellite into low Earth orbit. The first two stages appear to have worked but, based on radar tracking data, the third stage seems to have exploded and no satellite entered orbit. (The North Koreans ignore this and officially claim that the satellite is up there.) This one flight test was followed on radar so the United States and Japanese governments probably have good data on its performance. In addition, because the performance of both the Nodong and the Hwasong-6 are well-known, Western open-source analysts believe that they can calculate the performance of the two-stage Taepodong-1, indicating a 25 meter long missile with an initial weight of 21 tons and able to deliver a one ton payload to a range of 2500 kilometers. It is possible that the Taepodong-1 was always meant as a space launcher and it was never intended to be used as a intermediate range military missile.

Estimates of the performance of the Taepodong-2 are much more speculative. This missile has also been tested only once, in the early morning of 5 July 2006 (still 4 July in the United States) but the missile flew only 40 seconds before exploding. Analysts have speculated on the cause but the timing suggests structural failure due to aerodynamic forces. The aerodynamic force on a missile increases as the speed increases but decreases as the air density gets lower as it rises to higher altitudes. Thus, the aerodynamic force is zero at the beginning of the flight when the speed is zero and it is again zero when it enters orbit and the air density is zero. There is a point in between in the missile’s flight where the combination of speed and density produce a maximum aerodynamic force and that would occur at about the time of failure.

Because of limited flight test information, analysts must make more guesses about the performance of the Taepodong-2. Based on satellite photography, the second stages appears to be a Nodong missile, that is, the same as the first stage of the Taepodong-1, slightly modified, and the first stage appears very similar to the Chinese CSS-2. Estimates of the performance of the missile are based on the performance of these two components, not on flight tests. If the assumptions about the two stages are wrong, the performance estimates could be considerably in error. As of this writing (March 2009), the North Koreans appear to be preparing a test of the Taepodong-2 under the guise of another satellite launch attempt. If the Taepodong-2 flight is a space launch, then the missile will presumably be a three stage configuration, with a small third stage to insert a small satellite into orbit. To emphasize that this is a peaceful space launch, not a test of a military missile, the North Koreans refer to the space launcher version as Unha, which is Korean for Milky Way.

David Wright at the Union of Concerned Scientists has done an excellent analysis of the Taepodong-2 based on the CSS/Nodong configuration. He calculates that the Taepodong-2, used as a ballistic missile, could deliver a one ton payload to a range of 6,000 kilometers, which would allow it to reach Anchorage, Alaska, and, with a 500 kg payload, the missile would have a range of 9,000 kilometers, putting San Francisco within range and all U.S. cities along the Pacific coast north of there.

The Threat Return to Top

The Taepodongs are large liquid-fueled missiles. As currently configured, they are operated like space launchers, with long assembly times, and launched from fixed, above-ground launch pads. The missiles are expensive for a country as impoverished as North Korea so unlikely to ever be produced in large numbers. These missiles only make strategic sense if they are intended for a limited number of high leverage targets. Almost nothing is known about the accuracy of either of the Taepodongs. Even with a one ton payload, if the payload is a conventional explosive, accuracy of at least several tens of meters is needed before the weapon becomes useful in a direct military role. A conventional warhead could be used to target cities and kill civilians to terrorize a population.

A one ton payload of chemical or biological agent could have a much broader effect and the accuracy of the missile is far less critical. North Korea is known to have the ability to produce both chemical and biological agents. South Korean and U.S. military forces are well protected against chemical and biological attack so, again, the direct military effect would be limited while civilians would remain vulnerable.

The North Koreans have tested a nuclear explosive. The yield of their single test was equivalent to 400 tons of TNT, or 0.4 kilotons. This is less than a tenth the explosive power of most first nuclear tests, yet still a large explosion by conventional standards. Nothing is known publicly about the extent to which the explosive has been weaponized, for example, the size and weight of a potential nuclear warhead. Some have speculated that the small yield indicates a failed test, especially given that North Koreans previously alerted some Chinese officials of a test and predicted a much higher yield. Others have suggest that the explosion might not have been so much of a test as an experiment; The North Koreans might have approached the problem from the perspective of fitting a warhead on an available missile, they made due by designing a warhead as large as would fit on the missile, and then tested it to measure the yield. If this is the case, then their weaponization process could be far advanced. Building a heat shield for the warhead that can survive reentry is a technical challenge and the Koreans would almost certainly want to test that with a missile flight test. Even with an explosive force of 400 tons of TNT, the Taepodongs would have limited direct military application, especially in the very limited numbers and with the accuracy they are likely to have. But a 400 ton warhead would be a frightening weapon if used against civilians in a city, likely to destroy many city blocks and create a lethal cloud of radioactive fallout.

References Return to Top

A recent Congressional Research Service report is available on the FAS website:

North Korean Ballistic Missile Threat to the United States, Stephen A. Hildreth, Specialist in Missile Defense and Non-Proliferation, Foreign Affairs, Defense, and Trade Division, Updated February 24, 2008.

Two good histories of the North Korean missile program and current capabilities are:

Joseph S. Bermudez, “A History of Ballistic Missile Development in the DPRK, Occasional Paper No. 2,” Monterey Institute of International Studies Center for Nonproliferation Studies, 1999.

Daniel A. Pinkston, The North Korean Ballistic Missile Program (Carlisle, PA: Strategic Studies Institute, U.S. Army War College, 2008), p. vii.

This document contains useful information but is particularly noteworthy because of the many photographs of missiles:

Ballistic and Cruise Missile Threat , National Air and Space Intelligence Center, Wright-Patterson Air Force Base, Ohio. NASIC-1031-0985-06, March 2006.

David Wright of the Union of Concerned Scientists has an excellent analysis of the performance of the Taepodong-2: An Analysis of North Korea’s Unha-2 Launch Vehicle, David Wright, March 18, 2009.