Iran, Missiles, and Nuclear Weapons
By
Anthony H. Cordesman
DEC 9, 2015.
In practice, Iran is revealing a fact that was inherent in the JCPOA nuclear agreement negotiations, and was openly revealed during their course. It was clear that the United States tried to put limits on Iran’s missile activities in the JCPOA and Iran refused. As a result, the United States and other members of the JCPOA chose to focus on an agreement that clearly forbade Iran from actually deploying a nuclear warhead, from getting the design and manufacturing capability to produce any nuclear weapon, and inspection provisions and controls on procurement that would prevent Iran – or at least limit it – from getting a reliable warhead.
Iran never accepted the limits placed upon its missile programs by earlier UN resolutions like UNSC 1929. Iran did make it clear in accepting the JCPOA that it would proceed with its ballistic and nuclear missile developments and deployments regardless of the UN, and other interpretations of UNSC 2231, and there has not been any meaningful prospect that it will not continue to steadily improve its missile forces and ability to strike at long ranges.
This is why the UNSC resolution passed on July 15, 2015 was less binding, and only called for Iran “not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons, including launches using such ballistic missile technology” for eight years following the JCPOA agreement and a favorable IAEA report on the possible military dimensions of Iran’s programs.
Iran’s Current Range of Tests and High Range-Payload Missiles
What does count, however, are Iran’s future actions, and Iran has recently conducted a number of missile tests that will enhance its future capability to use missiles to deliver a nuclear weapon, as well as the fact Iran already has a range of missiles that can deliver any half-way efficient fission implosion weapon.
The Ghadir-110 and Other Recent Tests
The new Iranian test of a Ghadr-110, an upgrade version of the Shahab-3 missile, seems to have been held on November 21st near Chabahar, a port near Iran’s border with Pakistan. The real-world performance capabilities of the Ghadr/Ghadir and Shahab-3 cannot be determined from unclassified data and the range is determined by the exact weight of the warhead and cannot be determined from any unclassified range report based on a nominal “guesstimate” of warhead weight.
There seems to be little doubt, however, that the Ghadir-110, however, is a liquid-fueled missile with potential nuclear nuclear delivery capability. The Ghadir-110’s maximum range is sometimes “guestimated” at around 1,700-1,950 kilometers with a nominal 800-kilogram warhead.
The Ghadir is also only one of Iran’s recent missile activities. On October 10, 2015, Iran televised the launch of another ballistic missile called the Emad, that Iran’s Minister of Defense, Hossein Dehghan, said was, “able to strike targets with a high level of precision and completely destroy them…the first long-range missile of the Islamic Republic of Iran that can be controlled until the very moment it hits the target." Other claims indicated that it had anti-missile missile countermeasures.
At the same time, Iran has also made major efforts to improve the accuracy of its shorter-range missiles, and retrofits improved guidance to older systems like its Fateh 110 and versions with built-in guidance like the Fateh 110-D1. On August 22, 2015, Iran also announced a new version of the Fateh called the Fatheh-313 which it claimed was more accurate and increased the Fateh’s range from 200 kilometers to 500 kilometers. The test of the Emad may, therefore, be more of a sign that Iran is focusing on deploying the kind of conventionally armed precision guided missiles that can be lethal against point military and infrastructure targets than that it is going nuclear.
The key problem in enforcing the JCPOA and judging this aspect of Iran’s missile programs is that only fully reliable technical intelligence on the specific payload actually deployed can reveal what the Ghadir, Emad, or any similar ballistic missile, is carrying. In most cases, the same outside warhead shape can be used for nuclear and conventional warheads, and Iran has already shown it deploys missiles with different and evolving warhead shapes. Moreover, Iran increasingly is deploying ballistic missiles with warheads that separate from the body, and this means warheads can be covertly swapped with minimum risk of detection.
Iran’s Cruise Missiles and UAVs
The same basic uncertainties apply to Iran’s cruise missiles, which have the added advantage that a low, slow flier is a far more efficient way to disseminate a biological and chemical payload than a ballistic missile, a nuclear armed cruise missile is even harder to detect and target than a mobile ballistic missile, and a combined cruise and ballistic missile nuclear threat both greatly complicates missile defense and any form of preventive/preemptive strike on Iran’s missile forces.
Iran has already shown it has cruise missiles and unmanned aerial vehicles (UAVs) that could carry a nuclear weapon moderate distances, although the data on such systems are even more uncertain than for ballistic missiles.
Iran has also had ample opportunity to develop long-range. Nuclear-armed missiles. Ukrainian officials revealed in 2005 that Iran had made illegal purchases of 12 Kh-55 Soviet cruise missiles in 2001, and China had bought six. These were very long-range missiles designed to carry nuclear warheads, although the missiles Iran and China acquired did not have nuclear warheads.
In March 2015, Iran displayed a cruise missile called the Soumar that appeared very similar to the KH-55. It is far from clear that Iran has the technology to achieve motors with the same ranges, even through reverse engineering, or the ability to achieve the same low warhead weights. Nevertheless, the Iranian press briefings on the missile indicate that it had a similar range of 2,500 kilometers. Iran also has a new long-range anti-ship cruise missile with the same name as the Ghadir that shows both its progress in this area and has some potential to be nuclear armed.
Iran’s Existing Nuclear Capable Missiles
Iran also has a number of missiles that are already deployed or under advanced development that can almost certainly carry nuclear weapons. Its Shahab-3 and a range of variants has a maximum range “guestimated” at around 1,300 to 2,500 kilometers with a nominal 800-1,200 kilogram warhead. Iran has a solid fuel missile under development that is usually called the Seiji, and whose maximum range is “guestimated” at around 2,000 kilometers.
Its proven and deployed shorter-range systems include the Shahab 1 (maximum range “guestimated” at around 385 kilometers with a nominal 985 kilogram warhead) and Shahab 2 (maximum range “guestimated” at around 500 kilometers with a nominal 775 kilogram warhead). It should be stressed, however, that actual range will be determined by the actual warhead, and differences of even 20-40 kilograms in warhead weight have a significant impact on actual range.
All these uncertainties aside, one thing is clear. Regardless of whether these missiles carry conventional warheads for years to come, they can be quickly adapted to carry a nuclear warhead once Iran is confident in its nuclear weapons designs. Moreover, the UN never addressed cruise missiles, and Iran is developing cruise missiles that can potentially deliver nuclear weapons over a substantial distance.
Other Trends in Longer Range Systems
Iran has other developments underway which need careful consideration. Iran is developing a space program whose boosters can potentially deliver missiles much longer ranges, and Iran is reported to be developing a Shahab 4 with maximum range that is sometimes “guestimated” at around 2,000-4,000 kilometers.
U.S. intelligence is reporting that Iran may be developing an ICBM – although James R. Clapper, the U.S. Director of National Intelligence did not repeat past statements that Iran might have such efforts underway, and gave a much more qualified assessment of Iran in his annual global threat assessment on February 26, 2015:
We continue to assess that Iran’s overarching strategic goals of enhancing its security, prestige, and regional influence have led it to pursue capabilities to meet its civilian goals and give it the ability to build missile-deliverable nuclear weapons, if it chooses to do so. We do not know whether Iran will eventually decide to build nuclear weapons
We also continue to assess that Iran does not face any insurmountable technical barriers to producing a nuclear weapon, making Iran’s political will the central issue. However, Iranian implementation of the Joint Plan of Action (JPOA) has at least temporarily inhibited further progress in its uranium enrichment and plutonium production capabilities and effectively eliminated Iran’s stockpile of 20 percent enriched uranium. The agreement has also enhanced the transparency of Iran’s nuclear activities, mainly through improved International Atomic Energy Agency (IAEA) access and earlier warning of any effort to make material for nuclear weapons using its safeguarded facilities.
We judge that Tehran would choose ballistic missiles as its preferred method of delivering nuclear weapons, if it builds them. Iran’s ballistic missiles are inherently capable of delivering WMD, and Tehran already has the largest Inventory of ballistic missiles in the Middle East. Iran’s progress on space launch vehicles — along with its desire to deter the United States and its allies, provides Tehran with the means and motivation to develop longer- range missiles, including intercontinental ballistic missiles (ICBMs).
…The Islamic Republic of Iran is an ongoing threat to US national interests because of its support to the Asad regime in Syria, promulgation of anti-Israeli policies, development of advanced military capabilities, and pursuit of its nuclear program.
President Ruhani—a longstanding member of the regime establishment—will not depart from Iran’s national security objectives of protecting the regime and enhancing Iranian influence abroad, even while attempting different approaches to achieve these goals. He requires Supreme Leader Khamenei’s support to continue engagement with the West, moderate foreign policy, and ease social restrictions within Iran.
Iran possesses a substantial inventory of theater ballistic missiles capable of reaching as far as some areas of southeastern Europe. Tehran is developing increasingly sophisticated missiles and improving the range and accuracy of its other missile systems. Iran is also acquiring advanced naval and aerospace capabilities, including naval mines, small but capable submarines, coastal defense cruise missile batteries, attack craft, anti-ship missiles, and armed unmanned aerial vehicles. (
http://www.dni.gov/files/documents/Unclassified_2015_ATA_SFR_SASC_FINAL.... .)
Moreover, U.S. Secretary of Defense, Ash Carter, testified to Congress in July 2015 that this was only a possibility and that, ““I wouldn’t rule out that in 10 years, Iran could progress to an ICBM.” Admiral William Gortney, chief of Northern Command, answered a question for the record from a
March 19 congressional hearing by saying, “Iran will not be able to deploy an operational ICBM until later this decade at the earliest.” (see Greg Thielman, “It’s Official: There Will Be No Iranian ICBM in 2015, ”The National Interest, November 25, 2015,
http://nationalinterest.org/feature/its-official-there-will-be-no-irania... .)
What Kind of Missile Does it Take to Deliver a Nuclear Warhead?
There is no clear basis for assessing the size and weight of a warhead with a nuclear weapon, but it takes roughly 300 kilograms of high explosive warhead to have moderate effectiveness against a point targets in a missile with excellent accuracy and reliability. It takes closer to 1,000 kilograms of high explosive to produce a significant effect as more than a terror weapon against even an area target given the limited reliability and accuracy of most of Iran’s current ballistic missiles.
As is discussed shortly, there is no current way to predict how small a nuclear warhead Iran could develop or take the risk of deploying – particularly without an actual fissile test of the nuclear weapon it carried and extensive tests of the warhead capability. Nuclear missile warheads have been under development for a long, long time, however, it seems likely that Iran will have picked up a considerable amount of design data from other countries.
The unclassified history of U.S. nuclear weapons designs shows that modern designs can be very light –although Iran would probably want a much more robust and reliable design than the most advanced warheads. A summary chronology is available at
List of All U.S. Nuclear Weapons. This chronology does have significant uncertainty in terms of the precise numbers involved, but the broad patterns it reveals are almost certainly accurate and make it clear that virtually all Iranian ballistic missiles – as well as many of the cruise missile and UAV designs it clams to have under development, have the range-payload to carry a nuclear weapon.
It indicates that the United States first experimented with early fission missile warhead designs weighing as much as 2,700 kilograms. However, this was in the late 1940s and the first years of the 1950s.
The earliest functional U.S. tactical nuclear warheads – for systems like the Regulus and Matador in the early 1950s – only weighed around 1,200 kilograms and this was back in the early 1950s. By the mid-1950s, warhead designs -- for Talos -- were down to around 420 kilograms, the United States was deploying nuclear artillery shells with “warhead” weights of around 390 kilograms. Thermonuclear warheads remained much heavier, but even two-megaton warheads were down to around 1,270 kilograms by the 1960s.
By the early to mid-1960s, even variable yield boosted fission warheads were down to 200-225 kilograms, and the United States was experimenting with a nuclear warhead for the Hawk and GAR-8 air defense missiles with weights of only 34 to 40 kilograms. The United States was deploying variable warheads for MADM and Little John of 69 to 160 kilograms. The Honest John warhead weighed around 428 kilograms and the Pershing only 185 kilograms. By the late 1960s, even MRV 200 kiloton weapons were down to 120 kilograms each, and 1 megaton Minuteman RVs were down to 250 kilograms.
By the late 1980s and early 1990s – when U.S. tactical missile programs ended – warhead weights were down to 175 kilograms for the GLCM and 400 kilograms for the complex Pershing II. Artillery shell designs were down to 43 kilograms.
Even allowing for all of the uncertainties in both these U.S. numbers and the complete lack of any specifics on how far Iran has gotten in weapons design and its access to the designs of other countries, it seems likely that Iran could covertly get to the 300 kilogram level of warhead design over the next five to eight years, and have reasonable confidence in a 1,000 kilogram design. Any actual underground test would probably allow Iran to have reasonable confidence in a significantly lower weight design.
It should be stressed, however, that these estimates are not based on any knowledge of how well Iran has done in reducing the overall weight of reentry vehicles, the additional weight of guidance packages, ensuring warhead stability and reliability, adding any safety or fail-safe design features, issues with warhead separation, and a host of other real-world issues.
Iran, Missiles, and Nuclear Weapons | Center for Strategic and International Studies
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