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– Suzanne DiMaggio
Senior Fellow, Carnegie Endowment for International Peace
April 15, 2019
Progress Seen in Iranian Missile Test

Peter Crail

Iran carried out its first successful flight test of a two-stage solid-fuel ballistic missile May 20, demonstrating increasing sophistication with its medium-range ballistic missiles (MRBMs), U.S. officials and technical experts said.

Iranian Defense Minister Mostafa Mohammad Najjar said just after the test that Iran would begin mass-producing the missile, called the Sajjil-2, that same day.

White House Coordinator for Arms Control and WMD Terrorism Gary Samore told the Arms Control Association's annual meeting May 20 that the test was "a significant step forward in terms of Iran's capability to deliver weapons." He added, "[O]bviously, this is just a test. There is much more work to be done."

Secretary of Defense Robert Gates confirmed in testimony before the House Appropriations Subcommittee on Defense May 20 that the test was successful. Tehran unsuccessfully tested nearly identical systems called the Sajjil and the Ashura in 2008 and 2007, respectively. (See ACT, January/February 2008.) Najjar said the Sajjil-2 uses a guidance system that is more advanced than ones in the previous tests.

Iran has traditionally relied on liquid-fuel technology for its ballistic missile arsenal. Solid-fuel propellants, however, offer a number of advantages over liquid fuel, including a shorter launch time, easier handling and storage, and the possibility of deploying smaller missiles.

The test "shows that Iran has a major program on solid-propellant missiles," former UN weapons inspector Geoffrey Forden said in a May 20 e-mail. The group of Iranian solid-propellant experts is perhaps as large as the one dealing with its liquid-fuel program, he said.

Uzi Rubin, former director of the Israel Missile Defense Organization, told Arms Control Today in 2007 that Iran gained experience developing solid-fuel propellant domestically from its extensive work on large-diameter solid-fuel rockets. (See ACT, January/February 2008.)

Unlike Iran's liquid-fuel programs, which depend heavily on Russian-origin technology, the Sajjil represents a significant advance in indigenous capabilities, Forden said. "As far as I can tell, only the jet vanes are probably dependent on imported Russian technology," he said.

Najjar claimed May 20 that the Sajjil is "100 percent indigenous."

The Sajjil-2 is the first multistage missile that Iran has successfully flight-tested. Staging involves the use of multiple engine systems, which are stacked on top of one another. The stages fire at different times during the missile's flight, allowing the missile to cover much longer ranges. Iran successfully launched its first multistage rocket in February, when its Safir-2 placed a small satellite in orbit. (See ACT, March 2009.)

Advances in staging technology appear to have provided Iran with a moderate increase in the reach of its missiles. Gates said May 20 that the Sajjil has a range of about 2,000 to 2,500 kilometers. Yet, "because of some of the problems they've had with their engines, we think, at least at this stage of the testing, it's probably closer to the lower end of that range," he said.

Iran is believed to have deployed an extended-range version of its Shahab-3 missile. That missile has an estimated range of about 2,000 kilometers, making it capable of reaching parts of eastern and southeastern Europe. The Sajjil extends Iran's potential reach further into those regions but remains in the category of "medium-range," under the Department of Defense's classification system. MRBMs have a range of 1,000 to 3,000 kilometers, according to the Defense Department scale.

According to an unclassified U.S. intelligence report to Congress on the proliferation of nonconventional weapons, the intelligence community judges that "Iran is currently focusing on producing more capable MRBMs." The report, released in May, said Iran views its ballistic missiles "as its primary deterrent."