Iranian Missile launch tests.
In tandem with its efforts to expand its nuclear capabilities, the Islamic Republic of Iran is making robust strides in developing ballistic missiles. The two programmes appear to be connected, with the aim of giving Iran the capability to deliver nuclear warheads well beyond its borders, though Iran steadfastly denies any interest in nuclear weapons and claims that its missiles are strictly defensive in nature.
Iran’s modifications of the North Korean No-dong missile, resulting in the longer range Ghadr-1, and its recent success in testing locally produced space-launch vehicles and two-stage solid-propellant missiles have heightened concerns. Yet the worst-case scenario projected at the end of the twentieth century about Iran being able to develop an intercontinental ballistic missile capable of striking the United States within five years has not materialised.
The IISS Strategic Dossier on Iran’s Ballistic Missile Capabilities: A net assessment aims to contribute to the policy debate about Iran’s strategic challenges by establishing a shared understanding of the missile programmes. Produced by an international team of experts, the dossier offers the most detailed information available in the public domain about Iran’s liquid- and solid-fuelled missiles and its indigenous production capabilities. The dossier also analyses the military and strategic effectiveness of Iran’s potential arsenal, including both conventional and non-conventional warheads. By comparing Iran’s progress with that of missile-development programmes elsewhere, the dossier assesses the types of missiles Iran might try to develop in future, how long it could take, and what observable trends and indicators will allow other nations to monitor Iranian progress and to plan appropriate responses.
Ballistic Missile Arsenal
Iran’s acquisition of ballistic-missile technologies began in the mid-1980s, when it purchased a limited number of liquid-fuelled, Scud-Bs from several foreign sources to satisfy an immediate wartime need. The perceived success of Scud-B missile attacks during its war with Iraq led Iran to purchase additional 300km-range Scud-Bs (Shahab-1), 500km-range Scud-Cs (Shahab-2), and longer-range Nodong (Shahab-3) missiles from North Korea, beginning in the late 1980s and extending to the mid-1990s. Based on the number of imports, it is estimated that Iran today has approximately 200–300 Shahab-1 and -2 missiles capable of reaching targets in neighbouring countries. Iran can also hit targets about 900 km from its borders using the Shahab-3, which has a nominal payload of 1,000kg and was commissioned in mid-2003. A modified version of the Shahab-3, the Ghadr-1, which began flight tests in 2004, theoretically extends Iran’s reach to about 1,600km, but with a smaller, 750kg warhead. Information available within the public domain suggests that Iran has approximately six Shahab-3/Ghadr-1 transporter-erector-launcher (TEL) vehicles and between 12 and 18 Shahab-1/-2 TELs, although this number may be growing.
Iran is also developing a new medium-range, solid-propellant missile, the Sajjil-2, potentially capable of delivering a 750kg warhead to a range of about 2,200km. Iran is the only country to have developed a missile of this reach without first having developed nuclear weapons. The solid-fuelled system offers many strategic advantages, including being less vulnerable to pre-emption thanks to its shorter launch-preparation time. The Sajjil-2, which was successfully flight-tested for the first time in November 2008, is still two to three years of flight testing away from becoming an operational system that can be deployed to military units. Iran has yet to demonstrate that the missile’s individual stages perform consistently and reliably under a variety of operational conditions. If deemed necessary, this new missile could conceivably be used for combat in late 2010 or early 2011. However, the history of solid-propellant missile programmes elsewhere suggests an initial deployment of the Sajjil-2 in 2012 or later is more likely.
Utility of Iran’s current missile arsenal
Iran’s ballistic missiles could be used as a political weapon to wage a terror campaign against adversary cities. While such attacks might trigger fear, the expected casualties would be low – probably less than a few hundred, even assuming that Iran unleashed its entire ballistic-missile arsenal and that a majority of the warheads penetrated missile defences. The military utility of Iran’s ballistic missiles is severely limited because of their very poor accuracy. The confident destruction of a single, fixed-point military target, for example, would require Iran to allocate a very significant percentage, if not all, of its missile inventory to one specific mission. Against large-area military targets, such as an airfield or seaport, Iran could conduct harassment attacks aimed at disrupting operations or causing damage at fuel-storage depots, but the missiles would probably be incapable of shutting down critical military activities. The number of TELs available and the delays necessary to reload would also be limiting factors to any massive attack.
The possibility of chemical or biological warhead use cannot be excluded, although Iran is not known to possess such weapons and has forsworn them by treaty. Even if armed with chemical or biological warheads, however, the missiles could not reliably and predictably deliver enough warfare agent over a wide enough area to stop an adversary’s military operations. Moreover, Iran has too few missiles, TELs and trained launch crews to sustain the delivery of chemical agent to the battlefield for more than a few hours. Civil-defence measures can be effective in minimising potential casualties in urban areas.
Nuclear warheads have a much stronger strategic logic and all of Tehran’s ballistic missiles are inherently capable of a nuclear payload, if Iran is able to make a small enough bomb. The most likely delivery platforms for a notional Iranian nuclear weapon would be the Ghadr-1, and possibly the Shahab-3, although the solid-propellant Sajjil-2, once it becomes operational, may supplant its liquid-fuelled counterparts because it offers greater operational flexibility and possesses a superior range–payload capacity. The Sajjil was possibly designed with the knowledge that the first nuclear warhead could weigh one tonne or more, and thus the Ghadr-1 would be inadequate. The re-entry body configuration for either the Sajjil or the Ghadr, however, imposes difficult technical challenges for Iran, primarily because such a notional nuclear device would have to be small enough to fit within the existing 600mm payload bay.
While Iran is capable of designing a new warhead section for the Ghadr and Sajjil missiles, the overall mass of the new re-entry vehicle loaded with a notional nuclear weapon would likely exceed 1,200kg. In this case, the Ghadr-1 may not be capable of reaching targets in Israel without being fired from points very close to the Iran–Iraq border, making the launcher and missile vulnerable to pre-emptive strikes. If this is indeed the case, development of the Sajjil-2 would assume greater priority, as this missile, once fully developed, would be capable of delivering payloads of up to 1,500kg to about 1,500km, and would thus be suitable for threatening Israel, Turkey and most of the Arabian Peninsula.
Iran’s ballistic-missile industries
Iran has invested heavily in programmes to develop an indigenous liquid-propellant missile industry. These efforts began with the purchase of Scud-B and -C missile maintenance and assembly facilities from North Korea in the early 1990s. Tehran’s decision to procure the Nodong missile (Shahab-3) from North Korea in the early to mid-1990s, rather than design, develop, test and produce a more capable missile based on a cluster of four-Scud engines suggests that its technical wherewithal and indigenous missile capabilities were at that time limited. However, shortly after the turn of the century, Iranian engineers began asserting greater independence from foreign supply, starting with the major, foreign assisted re-design of the Shahab-3, which resulted in the longer-range Ghadr-1. Iran’s technical prowess has continued to improve over the past decade, and by 2009, the Islamic Republic had successfully integrated a second stage on to a modified Ghadr-1 airframe to create the Safir space launch vehicle, which put a small satellite into low-earth orbit. The February 2010 unveiling of a mock-up of the two-stage, Simorgh launch vehicle, based on a cluster of four Nodong engines, suggests that Iran plans to develop and use more powerful satellite carriers in the coming years.
Iran’s accomplishments over the past five to seven years are impressive. The Islamic Republic is deemed to have the capacity to modify existing missiles, to produce indigenously a large percentage of the necessary components to go into a missile, including the airframe and propellant tanks, create new systems by integrating available sub-systems and components, test new configurations, and fix the design or manufacturing flaws discovered during the development of new systems. These capabilities demonstrate unambiguously that Iran has created and applied a disciplined, structured engineering and programme-management process to its missile and space-launcher development programmes. Equally importantly, these endeavours have strong political support, judging from the financial resources they have been allocated. Iran’s growing and increasingly capable engineering and management infrastructure may, over the long term, be the greatest strategic legacy to emerge from its missile-development programmes during the past decade. However, it is important to recognise that future progress may still depend on significant foreign support and the supply of key materials, equipment and components.
Some of Iran’s future advances, especially in the field of space launch vehicles, will be governed by its ability to produce liquid-propellant engines indigenously. The absence of the necessary number of flight tests to validate engine performance and reliability, the nearly identical performance of the Shahab-1 and the Scud-Bs built in the Soviet Union (similarly the Shahab-2 and the Scud-C), and the uncanny similarities in the exterior features of the engines shown on Iranian television and those known to be of Soviet origin, point convincingly to a reliance to date on imported Scud and Nodong engines. However, speculation that foreign specialists may have helped Tehran to create a production line, combined with television images of Iranians fabricating engine components and Iran’s demonstrated modifications to the steering engines of the Soviet R-27 system for use on the Safir second stage suggest that the Islamic Republic may soon establish a liquid-propellant engine production line of its own, if it has not done so already.
In the field of solid fuel, over the past 25 years Iran has procured a series of licensed solid-propellant production lines. This has facilitated the development of an indigenous industrial infrastructure that is robust and capable, and the accumulation of the learned knowledge needed to support future endeavours. The solid-propellant missile production facilities and equipment in Iran today have a demonstrated capacity to manufacture rocket motors weighing up to 13 tonnes. It seems reasonable to conclude that the current production infrastructure was established to support the manufacture of the Sajjil-2 missile, though the facilities may have been procured with growth potential in mind. Regardless, the production of larger motors will impose significant challenges.
The strength of Iran’s tacit knowledge today is sufficient to design and produce larger solid-propellant motors, if the manufacturing equipment to support production is available. However, because Iran’s propellant specialists acquired most of their experience and know-how from Chinese tutors, the depth of their tacit knowledge is assessed to be too limited to design, develop, test and validate a new, more powerful rocket motor for an intermediate-range missile in less than the two- to three-year timeline experienced by the United States, USSR/Russia, China, France or India.
There exists no evidence to date to suggest that Iran can, on its own, develop or produce the individual components of a strap-down navigation and guidance system for ballistic missiles. Historic parallels suggest that Iran very likely must instead import complete guidance units. Nonetheless, Iran does appear to have some capability to assemble basic components for an inertial and guidance system, and the capacity to incorporate imported, factory-assembled guidance packages into its current fleet of missiles, a capability that seems adequate for the foreseeable future. Iranian engineers might seek to import better inertial navigation units or incorporate GPS receivers to enhance missile accuracy. However, without including precise thrust-termination capabilities or post-boost control systems, such improvements would be moderate at best. Therefore, Iran’s missiles armed with conventional warheads will very likely remain too inaccurate to be militarily effective.
Future missile prospects
Iran’s ability to produce new liquid-propellant missiles will be constrained by a continuing inability to design and develop a new liquid-propellant engine. Moreover, the primary sources of such engines – Russia and Ukraine – are now closely adhering to Missile Technology Control Regime guidelines. Consequently, Iran will almost certainly have to rely on the engine technology in its possession today for all future liquid-propellant missiles and space launch vehicles it may consider developing.
If Iran were to seek to develop a missile with a significantly longer range, it would have to build a much larger missile. Other alternatives, such as putting the Safir satellite launcher to military use or incorporating into a new airframe the R-27 main engines that may have ended up in Iran, would not extend the performance envelope already achieved with the Sajjil-2.
A multi-stage missile, powered by engine clusters is the most logical and probable configuration for a hypothetical future long-range, liquid-propellant missile or space launch vehicle with substantially increased performance. Iran has adequate industries to design and build larger airframes. It has already demonstrated an ability to build a two-stage missile with the staging technologies developed for the Safir and Sajjil-2. In addition, there are no apparent technical barriers to prevent Iranian engineers from creating an engine cluster using either Scud or Nodong liquid-propellant engines, as was indeed exhibited in February 2010.
Given the state of Iran’s liquid-propellant missile industries and its reliance on Scud and Nodong engines, the performance of future systems would likely correspond to that of the Soviet missiles built in the late 1950s and early 1960s, or possibly the Chinese DF-3. Assuming an approximately one-tonne warhead, a liquid-propellant missile capable of flying 4,000km – the approximate distance to the UK – would weigh in the order of 70–80 tonnes, and have a first-stage diameter in excess of 2.0 metres. The notional missile might resemble a two-stage version of the North Korean Unha-2 vehicle and rely on a first stage similar to that posited in the mock-up of the Simorgh space launcher. If Iran sought to build an intercontinental ballistic missile (ICBM) using available technology, it would likely weigh in the order of 120 tonnes, and have a diameter of about 2.5m.
It is clear that if Tehran sought to build the capacity to threaten targets in Western Europe or the continental US with liquid-propellant missiles, the resulting systems would be very large and cumbersome. The projected size of the longer-range missiles would force Tehran to base and launch the missiles from fixed sites, most likely silos, as an above-ground launch pad would be too vulnerable to pre-emptive attack. Systems for launching missiles weighing 70 tonnes or more from an underground silo would require considerable time and investment to develop, and would necessarily involve multiple test launches.
If Iran were to decide to develop more survivable long-range missiles, it would logically follow the solid-propellant path. Although the Sajjil-2 is still in development, the sub-systems and basic technologies included in the medium-range missile could be leveraged to create a new missile with significantly longer-range potential. Test flights to date of the Sajjil-2 have shown that Iran can build a multi-stage, aerodynamically stable, guided, solid-propellant missile. Hypothetically then, Iran could combine and reconfigure existing Sajjil rocket motors to create a new three-stage missile. Two configurations seem reasonable: a three-stage version of the Sajjil, consisting of one first stage and two motors similar to the second stage stacked on top of one another, or a three-stage missile built with two first-stage motors, and a single second-stage motor. The thrust output of the Sajjil’s first-stage motor is more than sufficient to accommodate these two configurations, whose notional range–payload characteristics are, for a one-tonne warhead, 2,700km and 3,500km respectively. However, there are important caveats. Experimenting with a new configuration using unproven rocket motors would be a risky endeavour and would not contribute to Iran’s overall goal of mastering solid-propellant missile technologies. Moreover, despite the Sajjil-2 development efforts to date, it would still be necessary to conduct a series of flight tests to demonstrate the operational viability of a three-stage configuration, and develop the necessary firing tables, incorporate improvements and prove reliability.
Finally, if Iran were to seek to develop a ballistic missile with a significantly longer range, disregarding the propulsion mode adopted, two outstanding issues must be addressed. Iran would have to acquire tracking and telemetry systems that could be deployed on sea-based platforms to monitor future test flights that travel beyond the country’s borders. And Tehran would have to develop and implement technologies for protecting the warhead during high-speed re-entry into the earth’s atmosphere. While these are conquerable challenges, both would require time, money and sustained effort.
Indicators and timelines
The average time needed to develop a new design and begin manufacturing prototypes for testing is typically between two and three years for liquid-fuelled missiles, and in some instances as long as five years. The development time for a new solid-propellant rocket motor is two years or more. With determined effort, most missile design and development activities can be hidden from public view or initially concealed within a commercial, space-launcher development programme. However, it is impossible to hide flight tests, which must be undertaken to verify and document a missile’s performance and reliability, uncover design and construction flaws, validate system performance under a variety of operational conditions, and train the military forces responsible for operating the missile. Rarely are fewer than a dozen flights performed before a missile system is deployed. Additional tests are required to identify and fix any flight failures during the test programme. The number of test flights can be minimised, by design or necessity. However, in such cases the time between tests almost invariably grows in order to ensure that each test yields maximum results. Consequently, the more interesting feature of a flight-test programme centres on the time needed to validate the missile’s design, performance and reliability, not the total number of tests.
Development timelines elsewhere and Iran’s own experience with the Shahab-3 and Ghadr-1 suggest that future Iranian missile-development programmes based on liquid-propellant engines will include a flight-testing effort that extends over at least two years, and most likely three to five years, and involve at least half a dozen test launches. Flight-test programmes for solid-propellant missiles historically take on average more than four years. To achieve a reasonable measure of reliability and confidence, a dozen or more tests should be conducted. Therefore, Iran is not likely to field a liquid-fuelled missile capable of targeting Western Europe before 2014 or 2015. A three-stage version of the solid-propellant Sajjil capable of delivering a one-tonne warhead 3,700km similarly is at least four or five years away from possible deployment.
The recent presentation of the Simorgh and the four-Nodong engine cluster that Iran claims is intended for future satellite carriers does not appreciably alter these projections because the time estimate accounts for the flight-test programme and not the easily hidden research-and-development phase. Iran’s space-programme activities will certainly provide valuable experience, but these efforts appear for now to be aimed at civilian applications. To date, Iran’s space programme launches have been proof-of-principle demonstrations, offering no immediate strategic value beyond symbolism.
The modifications needed to convert the notional space launchers into a ballistic missile will require time and flight testing in the military configuration along trajectories beyond Iran’s borders. Nonetheless, testing engine clusters will endow Iran with a potential propulsion system for intermediate and possibly longer-range, liquid-propellant missiles. Iran’s space-programme activities must, therefore, be closely monitored.
The experience of other missile-development programmes suggests that Iran is many years away from developing a ‘second-generation’ 4,000–5,000km intermediate-range solid-propellant missile, if it should so decide. The French and Chinese experiences suggest that second-generation systems lag behind the first generation by more than a decade, although India’s history suggests the timeframe could be shortened to six or seven years. Based on Iran’s missile-development history relative to the experiences of other countries, there is little reason to believe that the Islamic Republic can shorten the timelines significantly. It would still have to rely on imported technologies, components and technical assistance, and carry out a lengthy flight-test programme.
Logic and the history of Iran’s evolutionary missile and space-launcher development efforts suggest that Tehran would develop and field an intermediate-range missile before embarking on a programme to develop an intercontinental ballistic missile capable of reaching the American East Coast, 9,000km away. It is thus reasonable to conclude that a notional Iranian ICBM, based on Nodong and Scud technologies, is more than a decade away from development.
Final word
In projecting Iran’s potential future missile capabilities, this dossier has adopted a ‘most likely outcome’ approach, based on the available facts about Iran’s progress to date and the historical experience of other countries. It is possible to put forward more alarming scenarios based on assumptions about massive foreign assistance and development decisions that compromise the performance and reliability of future missiles. We have not promoted such speculation, except where there is evidence that lends it credence.
(The purhcase form for the IISS dosier "Iran’s Ballistic Missile Capabilities: A net assessment" as well as additional information can be found at http://www.iiss.org)
