In early 2020 Iran revealed a new ballistic missile, the Raad 500. Video showed a test launch as well as pictures of Iranian officials standing next to it. This enabled an accurate estimate of its length, about 13 meters (41 feet), weight of about 1.7 tons and with a claimed range of 500 kilometers. Raad 500 has a body made of lightweight carbon fiber, which accounts for its longer range than earlier models of the same size. Iran also claims Raad 500 uses a new, improved solid-fuel motor that is more efficient and reliable. Raad 500 is similar to in design to the larger solid-fuel ballistic missile, the Dezful, with a range of 1,000 kilometers. This one entered service in late 2019 and also obtained a longer range using the carbon fiber body. Iran said it was gradually replacing its older liquid-fuel missiles with carbon-body models using the new solid-fuel rocket motors. This replacement program has been pretty obvious over the last decade, the use of carbon fiber bodies less so.
The Dezful completed tests and entered service in late 2019. The Dezful appears to be an upgrade of the earlier (2016) Zolfaghar missile, which had a range of 750 kilometers. In 2018 at least one Zolfaghar was fired from Iran against ISIL (Islamic State in Iraq and the Levant) targets in Syria. This confirmed the range was 750 kilometers. Israeli and American efforts to gain more information about the use of Zolfaghar in Syria revealed that the missile was not as accurate as claimed and further investigation found that it was not very reliable either. It is unclear how many Zolfaghars Iran has, especially since this missile is difficult to manufacture. Zolfaghar is the same size as the earlier Fateh-313, which had a range of 500 kilometers. In 2017 higher resolution of Zolfaghar revealed that the body was not made of steel, like earlier models, but much lighter carbon fiber. That would account for the 40 percent increase in range claimed for this new version of an old missile.
Iran also claimed that the guidance systems for these new missiles were improved. That was probably true but it was also known that Iran had to import much of the technology for the new guidance systems that use INS (jamming proof inertial) and GPS plus optical terminal guidance. That optical terminal guidance feature is the most complex of all. This makes Iran eager to get sanctions lifted because raw materials and components for the lightweight cases, solid-fuel rockets and guidance systems depend on imports for mass production. These items can be smuggled in, but that costs a lot more and the sanctions have sharply cut Iran's oil sales which are the main source of foreign currency (dollars or euros) needed to pay for imported or smuggled goods. Iran also claimed they produce most of their missiles in underground factories that are immune to airstrikes. If Iran can import enough of the raw materials and parts for the new missile designs, these underground assembly plants will make it more difficult to disrupt the production of these missiles. With a large number of these ballistic missiles armed with non-nuclear warheads, Iran can overcome their lack of combat aircraft and smart bombs to hit an enemy (Gulf Arab states) targets defended by modern air defense systems. Those Arab defenses currently consist of more jet fighters, all of them superior to anything Iran has or is likely to have until five or ten years after arms embargoes are lifted. Iran leaders openly admit their air force is largely composed of less effective Cold War era designs that are worn out by decades of use and inadequate maintenance and few upgrades. Iranian air defenses are equally limited. The one way Iran can overcome this is with a large force of their new ballistic missiles.
Iran appears to be adopting the same ballistic missile tactics China developed for shutting down Taiwanese air defenses during the first hours of a war. This involves using a massive number of short-range ballistic missiles. Since 2009 China has maintained a force of at least 1,400 ballistic missiles aimed at Taiwan. That's up from 200 in 2000, 800 in 2004 and 1,300 in 2008. Most of these are DF-11 and DF-15 models. The DF11 (also known as the M11) has a range of 300-800 kilometer depending on warhead size plus rocket motor and flight control tech. The DF15 (M9) is basically a redesigned DF-11 that is more reliable and accurate. From the Chinese coast across the Taiwan Straits to targets in Taiwan is about 200-300 kilometers across the Taiwan Straits. The distance from Iran to key targets in Saudi Arabia or other Arab oil states is about the same.
The Chinese missiles use high explosive, penetrator (“bunker buster) or cluster bomb warheads and are similar to bombs delivered by aircraft. These payload delivered by missile are much more difficult to intercept. For that reason, Taiwan is investing in an anti-missile system that would negate a large number of the Chinese missiles and so are the Arab states within the range of Iranian missiles. If used, perhaps 75 percent of the Iranian missiles would actually hit their target. The others would suffer failures in propulsion or guidance systems. Each missile is the equivalent of a half-ton or one ton aircraft bomb. Initially the Chinese missiles had primitive guidance systems, meaning that the warheads will usually hit up to 500 meters from the target. The Chinese equipped their missiles with several generations of GPS tech, in response to advances in Taiwanese jamming technology. Guidance systems that are more difficult to jam are always being worked on. This technology has been much sought after by Chinese spies in the United States over the last decade. Iran has not got the Chinese level of missile guidance tech and are not likely to share any of those secrets. Corruption in Iran is pretty bad and Chinese tech secrets are lucrative items that have many eager and affluent buyers.
The Iranian advances in ballistic missile technology were not hard to track. Solid fuel rocket developments were more obvious than carbon fiber cases or guidance systems. Iran began the switch from liquid fuel motors in in 2002 with the Fateh 110. This was a copy of the 1980s era Chinese DF-11 ballistic missile (range 300 kilometers, 800 kg warhead). Subsequent versions of Fateh followed the same development pattern the Chinese DF-11/15 went through years earlier. This included the use of GPS (American or Chinese) guidance in addition to the less accurate INS as a backup. For nuclear warheads, either guidance system is accurate enough. For conventional warheads, GPS is essential to avoid missing the target and being wasted because of the smaller explosive power of a conventional warhead. More modern INS systems have much improved accuracy, approaching that achieved by GPS. But the more recent INS tech is difficult to steal and duplicate.
Solid fuel rocket motors are cheaper to maintain and enable a missile to be made ready in less than 30 minutes compared to several hours for liquid-fueled missiles like the SCUD. It was known that Iran has put a lot of effort into developing better solid-fuel rocket motors. No one was paying much attention to what they were doing with carbon fiber materials and when higher resolution photos of Zolfaghar became available it could be seen that the rocket body was not metal but the much lighter carbon-fiber. It is no wonder that the manufacture of carbon fiber cases and solid fuel rocket motors are underground because Iran apparently has limited production capability for both items. Knock out the handful of plants manufacturing these items and missile production is halted and component development is slowed down.
The Fateh 110 is an 8.86 meter (27.5 foot), 3.5 ton rocket with a half-ton warhead. The first version had a range of 200 kilometers. By 2010 there had been two improved models, with ranges of 250 and 300 kilometers plus improvements in reliability and accuracy. The Fateh 110 was developed to replace the liquid-fueled SCUD ballistic missiles Iran first obtained from North Korea in the 1980s. SCUD was developed in Russia using the German World War II era V-2 missile experience. North Korea continued to supply Iran with ballistic missile technology and that evolved into the two countries trading solid-fuel rocket motor and guidance system technology.
Israel has an active and often very effective intelligence effort to obtain details of Iranian ballistic missiles. Israel does not make public much of what it discovers in order to keep secret its sources and methods. However, there have been leaks indicating that the quality control on the more advanced ballistic missiles, like Zolfaghar and Dezful, is uneven and that these missiles are difficult to build in large quantities. Iranian press releases like to indicate otherwise and that is one thing Iran often uses press releases for. It is also telling that the hundreds of Israeli airstrikes against Iranian missile shipments to Syria and Lebanon are destroying a lot of the older Fateh 110 missiles, along with guidance system upgrade (to GPS) kits for older, and shorter-range rockets. Israel has also bombed several factories in Syria and Lebanon that Iran has built to upgrade the older rockets with guidance systems. This involves more than just fitting the front end of the rocket with the guidance system; you also have to install the control flaps which the computerized guidance system manipulates to achieve the accuracy. This is not a simple or quick update and without a facility resembling the one used to actually build these rockets and missiles, the upgrade does not get done.
For Israel keeping these new ballistic missiles out of Lebanon, Iraq and Syria is a high priority. While Israel has developed and deployed new air-defense systems that can intercept these missiles, those defenses are unable to handle a large number of ballistic missiles coming in at the same time. In the last five years, Israel has carried out hundreds of airstrikes in Syria and Lebanon to destroy Iranian missiles and guidance system upgrade kits (for older, unguided long-range rockets and ballistic missiles) needed to establish a large force of missiles capable to hitting Israeli military targets as well as the larger, sprawling, urban areas.
The Arab Gulf states are facing a similar threat but they cannot destroy Iranian stockpiles of these missiles and that is one reason the Arab Gulf states have dropped their decades-old hostility towards Israel and sought to create a military alliance strong enough to discourage Iranian plans to use its new ballistic missile force to at least intimidate the Gulf Arab states into submission.