Iran's new Baby Bottle Shihab shares family looks with vintage Soviet ballistic missiles, hinting at Russian expertise behind its design.
This new Shihab has an increased range of nearly 1500 Km, and might be the long anticipated Shihab 4.
The August 11th test of Iran's latest model Shihab missile was variously described as a failure or a full success, as a live firing or as a dry exercise. This website has previously referred to the conflicting reports on this test, and analyzed some its features as could be resolved from the officially released TV footage of this event (See "Iran's New Baby Bottle Shihab", August 24 2004). A more detailed study of this footage provides further insights into the provenance and capabilities of that missile.
The most noticeable feature is the new shape of its front end. Fig 1 shows a "Nominal" Shihab 3 of the type displayed by Iran in numerous occasions since 1999. The missile sports a conical front end - presumably the reentry vehicle (RV) - followed by a cylindrical instrument section (IS) from which emerges a cable raceway that runs along the propellant storage sections.
Fig. 2 offers a good side view of the August 11 missile shortly after liftoff. Clearly, the front end of the missile has a more complex shape; the cable raceway has been elongated and is now emerging from the rear "Skirt" of the front section in what could be termed an "Over the shoulder" layout. This kind of layout used to be hallmark of Soviet ballistic missiles of the 1960's vintage. Fig 3 depicts the outlines of two versions of the Soviet SS-9 liquid fuel, silo launched ICBM. The family looks shared by the Soviet missiles and the new Shihab is remarkable. Notice the "Over the shoulder" cable raceway layout of the Soviet missile, and the "Baby Bottle" front-end geometry of the single warhead SS-9 with its rather large, spherical ablation tip.
Engineers have a tendency to copy their earlier successful design formulae and practice, or - not unlike artists - to advertise their achievements by stamping their personal style on their work. The result is often a "family look", sometimes functional, sometimes aesthetic (Like the not coincidental resemblance of the F-22 and F-35 combat aircraft). To the present writer, the family looks shared by the new Shihab and the old Soviet missiles seem to be more than a coincidence. The thumbprint of the SS-9 designers characterizes the new front end the Iranian new missile. In view of the persistent reports on missile technology transfer from Russian to Iran, this should not be too surprising. The photos of the new Shihab may be a validation of Iran 's Russian Connection.
Assuming that it was Russian missile engineering talent that provided the Iranian with the new Shihab design, it stands to reason that instrument section of the new missile is now located in the "Skirt" of the new RV rather than in the following cylindrical section. A drawing Page 97 in the Military Parade publication "Russia's Arms Catalogue, volume 4, Strategic Missile Forces" shows the instrument section of the SS- 9 as remaining attached to the RV after burnout and during reentry - a useful arrangement for precision fusing of nuclear warheads. Assuming the Russian connection, it stands to reason that the new Shihab's IS travels together with the RV, rather than being discarded after burnout, as in the previous design. The utility of the new arrangement for precise altitude fusing of prospective nuclear warheads is obvious.
In past statements, Iranian officials indicated that they intended to increase the range of the Shihab 3 missile to 1500 Km. Rough measurements taken from Fig 2 indicate that the Baby Bottle Shihab missile has indeed an increased range capability.
The length to diameter ratio in Fig 2 indicate that the new Shihab is about 1 meter longer than the "nominal" design, allowing for increased propellant tankage. In addition, the migration of the IS from its old location in the cylindrical section to the RV frees even more space for propellants. In all, our measurements indicate that the new Shihab carries about 15% more propellants than the "Nominal" version. This, (together with a modest increase in thrust by about 4%), would yield a range of about 1450 Km - close enough to the declared goal. We can therefore conclude that the Shihab missiles displayed up to now were just interim configurations, almost indistinguishable from their "No Dong" parents and "Ghauri" siblings. With the aid of Russian missile expertise, this stock design has been greatly improved. The August 11 event premiered the definitive ballistic missile - perhaps the long advertised Shihab 4? - With which Iran hopes to deter Israel and the United States in the near future, and which will serve as a basis for Iran's first ventures into space next year.