This week, the day after the EastWest Institute released a report concluding that Iran could develop a nuclear warhead for ballistic missiles in six to eight years but would "not be able, for at least 10 to 15 years, to independently master the technologies necessary for advanced intermediate-range ballistic missiles or intercontinental ballistic missiles," Iran test-fired a two-stage, solid-fueled ballistic missile with a possible 1,200-mile (2,000-kilometer) range.
Missile Defense Agency Director Lt. Gen. Patrick O'Reilly today was asked at a House Armed Services strategic forces subcommittee hearing whether he agreed with the report's conclusions. He did not:
A lot of the assumptions they use in these types of assessments are not accurate, and they don't reflect our true capability, our specifications, what we've demonstrated, also what we know of the threat for what I have access to in intelligence, it does not correlate to the basic assumptions that they use in that study and others I've seen like that.
We asked MIT Professor Ted Postol, one of the co-authors of the report and a missile defense critic, whether the Iranian test changes any of the report's conclusions. Here's his response:
The short answer to your question is that the recent launch of a two-stage solid propellant missile does not change any of our conclusions. However, it does raise questions that were not addressed in the current report that will have to be dealt with in our continuing work at MIT and Stanford on this and related questions.
There is very little data on the Sejjil missile and very rough estimates I have done this evening suggest that it is likely to be able to carry a 1000 kg payload to 2000 km range. I will need to do further analysis on this missile, but it cannot be ruled out that it could eventually achieve a range of 2500 km. I caution you these are very preliminary numbers and I am not yet ready to stand by them.
Our current study estimates that if Iran moved ahead with a nuclear program it could take Iran 1 to 3 years to test a first nuclear weapon and an additional 5 to 6 years or more to develop a nuclear warhead compact and light enough to fly on a ballistic missile. This estimate was arrived at by the experts in our study who have built nuclear weapons. Our estimates in the study for the time it would take Iran to be able to deliver a nuclear weapon to a range of 2000 km was for a modified version of the Safir satellite launch vehicle (SLV) where the second stage was redesigned to carry a payload of about 1000 kg. The development of this modified version of the Safir SLV would probably take no more than several years, but the long pole in having a nuclear-armed delivery system would be obtaining the warhead. This situation is also true if the solid propellant Sejjil missile is successfully refined into an operating system within the next several years. So in short, there is essentially no substantial change in our findings.
However, the fact that the Sejjil is a solid propellant missile introduces a new set of questions that we did not deal with in our report. This set of questions has to do with longer-term advances in ballistic missile capabilities that are based on solid propellant missiles. In the case of the Sejjil, increasing its range substantially would require building essentially a different and much larger solid propellant missile. This would be a gigantic enterprise, since scaling up the size of solid rocket motors is a gigantic technical and engineering task.
Problems that occur in constructing much larger rocket motors result from the sheer size of the motor and the casing. Early solid rocket motor casings were made of steel, and as the technology advanced the casings were fabricated from glass, Kevlar, and finally carbon epoxy materials. Winding these much larger casings, maintaining the strength and integrity of these much larger casings, mixing the propellant so that they are extremely uniform, and getting more energy out of the propellants, require major industrial and scientific efforts. You may recall, that when the US was rushing to deploy Pershing's in Europe, the development program was plagued with failures of that solid rocket motor. So the introduction of the Sejjil does not necessarily foretell the rapid development of larger longer-range solid propellant missiles. It does, however, introduce a potentially new class of systems. Since solid rocket propellant systems have relatively short burn times compared with similar classes of liquid propellants, they can potentially pose more demanding challenges to boost-phase and ascent-phase missile defense systems.
With regard to the boost-phase system discussed in the appendix of the report, this new technology will not be available for much larger and longer range rocket systems for quite a while, and even if it were available, the rockets would be very large and subject to the same vulnerabilities that were described for large liquid propellant missiles.