Asia Times June 9, 2005
Iran's missiles on a solid footing
By David Isenberg
WASHINGTON - On May 31, Iranian Defense Minister Ali Shamkhani announced that Iran had successfully tested a solid-fuel motor for its medium-range Shahab-3 ballistic missile. Further details of just what was tested remain unclear, but the test is significant because if it truly was successful, it would represent an important breakthrough for the Islamic republic's missile program.
To develop a missile with a range greater than 2,000 kilometers - in effect, a two-stage rocket that separates in mid-flight - Iran would need to master the more complex solid-fuel technology. This is because the separation is very complex, and to maintain the accuracy of the missile, it needs to be using solid fuel.
One advantage of using solid-fuel missiles is that they are more mobile and can be deployed far more quickly than liquid-fuel devices, which need to be filled on the launch site. In practice, if Iran has mastered such technology, that means the Shahab-3 missiles could spread across the country and be stored far from any refueling facilities in preparation for immediate deployment.
Also, when a missile is filled with liquid, it has to be used quickly due to the relatively short shelf life and volatility of liquid fuel. With solid fuel, however, a missile can be stored for years, far longer than liquid-fuel weapons, making mass production much more practical.
"It's a big leap in technology," said Aaron Karp, adjunct professor at Old Dominion University in Norfolk, Virginia. "The big problem with anything Scud-derived is that it is liquid fueled. You have to wear a MOPP [mission-oriented protective posture] suit around the fuel. From a handling view it's a big leap."
Karp said the Iranians have been working on solid motor fuel for a long time, but mainly in the area of smaller systems such as artillery rockets. One example is the Mushak, a short-range surface-to-surface missile Iran developed during its war with Iraq (1980-88) using mainly nitrocellulose fuel, a technology that dates to the 1940s. "Now they have made a leap to 60s technology. This gives them the ability to make bigger and better rockets. If you want to increase the range you just make a bigger fuel casting," said Karp.
Currently, the Shahab uses a fuel mixture of 20% gasoline and 80% kerosene, with an oxidizer consisting of 27% dinotrogen tetroxide and 72% nitric acid with an imodium inhibitor.
There is still some confusion about the latest test, however. While Shamkhani did speak of a "two-motor missile", a Defense ministry official said he was only referring to separate launch and flight thrusters of the single-stage Shahab-3.
Iran reportedly has six models of the Shahab (which means meteor in Persian) in its inventory or under development, the first of which, a Russian Scud derivative, dates to the mid-1980s when it was fighting Iraq. The most recent model reportedly under development, with the help of North Korea, is the Shahab-6, a 6,300 mile (10,000 km) range missile that could strike cities in the eastern United States. But whether this is actually an active project is unclear.
According to US-based Globalsecurity.org in Alexandria, Virginia, the Shahab-3 (there are also 3A and 3B models), alternatively designated Zelzal (Earthquake), is said to be a derivative of the 1,000-1,300 km range North Korean Nodong-1. The Nodong missile was developed by North Korea with Iranian financial assistance. The Shahab-3 missile is capable of carrying a 500-650 kilogram warhead. The range is believed to be 1,550-1,620km (based on performance data of the Nodong B). More specifically, it is believed that with a warhead mass of 760 kg the missile will fly 1,560 km, and with a warhead mass of 1,158 kg the missile will fly 1,350 km.
The Iranian missile program and the speed of its development would not have been possible without extensive assistance from abroad, notably from North Korea, Russia and China. In particular, China reportedly supplied help with guidance and solid-fueled rocket propulsion. In its last semi-annual report on the subject, the US Central Intelligence Agency reported that "ballistic missile-related cooperation from entities in the former Soviet Union, North Korea and China over the years has helped Iran move toward its goal of becoming self-sufficient in the production of ballistic missiles".
Beijing's help appears to have started in the 1980s, during Iran's work on the Mushak missile. In 1998, The Commission to Assess the Ballistic Missile Threat to the United States (known as the Rumsfeld Commission after its chair, Donald Rumsfeld, the current US defense secretary) reported that China had already "carried out extensive transfers to Iran's solid-fueled ballistic-missile program".
The Shahab-3, like the North Korean Nodong missile from which it is derived, is a scaled-up version of the Russian Scud B and Scud C missiles, and shares the Scud's weaknesses. Because accuracy diminishes with range for a given guidance system, the accuracy of the Shahab-3 at its range of 1,300 km has been estimated at no better than three kilometers of its target, making it of little use as a battlefield weapon. With such low accuracy, it currently could not be counted on to hit troops or even an airfield. Instead, it seems intended for use against cities and civilian populations and has no military application other than simply holding enemy populations hostage.
According to the Missile Threat Project of the Claremeont Institute in California, the Shahab-3's range is sufficient to target Israel, Turkey, the Indian sub-continent, and US forces stationed in Iraq, Afghanistan, and the Persian Gulf.
Thus far, Israel's Arrow missile defense system is said to be unable to intercept Shahab-3 systems. Prior to the recent rocket motor test, Iran last conducted a test of the Shahab-3 on October 20, 2004.
David Isenberg, a senior analyst with the Washington-based British American Security Information Council (BASIC), has a wide background in arms control and national security issues. The views expressed are his own.
© Copyright 2005, Asia Times