The Sejil missile is a two-stage, solid-propellant, intermediate-range ballistic missile domestically designed and built by Iran. It represents the culmination of Iranian weapons technology as it borrows heavily from the design and technology of the liquid-propelled Shahab missiles while integrating the solid-propellant technology of the Zelzal missiles.
Development of the Sejil missile likely began in the late 1990s, but the program can hardly be understood apart from other Iranian missile programs whose development began much earlier. Most importantly, Iran began development on the Zelzal missiles in 1994 or 1995. The production of the Zelzal missiles required Iran to develop the domestic ability to produce composite solid-propellant in fairly large quantities. The technology and equipment used in Zelzal fuel production has almost definitely been used for the Sejil missile project. It is believed that China aided Iran in the improvement of their solid-propellant production ability for the Zelzal missiles; it seems likely that China has also aided Iran in the production of fuel for the Sejil missile.
At the same time that Iran was developing composite solid-propellant fuel, they were working with the North Korean No Dong 1 missile design to produce the Shahab 3. The Shahab 3 design was used by Iranian engineers to produce a number of domestic missile technologies – a major advance from earlier Shahab designs, which relied almost entirely on Russian and North Korean technology. The Shahab 3 variants have provided a number of advantages over the original North Korean design and proved that Iranian engineers can domestically design and produce improved warheads and SLVs. The Sejil missile, internally quite different from the Shahab 3 missile (solid propellants require very different motors and internal design), probably borrows from a number of Shahab 3 technologies. At the very least, it is believed that the RV/nose cone design that first appeared in Shahab 3 variants has been used on the Sejil missile.
Though the missile has a similar size, weight, payload, and range to the Shahab 3 variants, the fact that it is fuelled by solid-propellants is a huge improvement over the Shahab design. Solid propellants allow for a near-immediate launch time, leaving the missile much less vulnerable during launch. Because solid-propellant missiles do not have to be fuelled immediately prior to launch, they are easily transported. On the other hand, solid propellant missiles have particular performance characteristics that make them more difficult to guide and control. How Iranian engineers have overcome these hurdles is unknown, but it seems likely that they have modified Shahab guidance systems and/or received considerable foreign assistance.
The Sejil missile has a length of 17.6 m, a diameter of 1.25 m, and an overall launch weight of 23,600 kg. It carries a payload of 500 to 1,000 kg. Presumably the missile will carry HE warheads until Iran gains nuclear warheads. The missile’s maximum range is about 2,000 km, though these figures are based upon a missile fuselage with the weight and performance characteristics of aeronautical-grade steel. Supposing that Iran had the technology to produce missiles built of maraging steel, titanium, or composite material, the missile would potentially be lighter and have an extended range upwards of 2,400 km.
The first test launch occurred in 2008 and the missile reportedly flew 800km. A second launch was conducted in May 2009 to test improved guidance and navigation systems. Four other flight tests have occurred since 2009, with the sixth test flying approximately 1,900 km into the Indian ocean. 1
The Sejil missile appears to be a unique Iranian design. Though some speculation has tied the missile to the Chinese DF-11 and DF-15, the size and specifications of the missile suggest that the Iranian missile is unique. Unlike earlier Iranian systems, the missile also does not appear to be a copy of a previously-released North Korean missile. Of course, it is highly likely that the missile project has made significant gains through foreign assistance. Because the design is new, Iran will probably have to subject it to a great deal of testing before putting the missile into regular operation. Assuming that the Sejil project moves at about the same speed as foreign missile development projects, Iran will probably not declare the missile operational until at least 2012. 2
The Sejil missile system may be operational, but regardless, Iran continues to make improvements. There may be multiple versions of the Sejil system. In 2009, Iran referred to the test launch as the Sejil 2. An unconfirmed report stated the a Sejil 3 may be in development. The Sejil 3 would reportedly have three stages, a maximum range of 4,000 km, and a launch weight of 38,000 kg. 3
- Lennox, Duncan. “Sejil (Ashoura).” Jane’s Strategic Weapon Systems (Offensive Weapons). September 7, 2012. (accessed September 12, 2012). ↩
- Iran’s Ballistic Missile Capabilities: A Net Assessment, an IISS Strategic Dossier, The International Institute for Strategic Studies, (East Sussex: Hastings Print, May 2010) 54-63; see also Jane’s Strategic Weapon Systems, Issue 50, ed. Duncan Lennox, (Surrey: Jane’s Information Group, January 2009) 71. ↩
- Lennox, “Sejil (Ashoura).” ↩