Quite regularly there are news items in the press about new missile developments in Iran. In fact, some of the listings of these weapons enumerate myriads of projects but with scant information about their characteristics, capabilities and performance. Furthermore, the exotic names and numbers tend only to confuse the reader, particularly as some are probably only different names to the same project.
It was thus refreshing, so to speak, to actually see an Iranian TV program which in fact did show the experimental launching of one such weapon - claimed to be the Fateh-110, and preceded by views of the missile on the launcher.
In itself this test launching is not an earth shaking event. The Iranian effort to develop solid fuel technology started during its war with Iraq and is well documented. This effort strives to replace the ubiquitous liquid propellant technology (to be found in many third world countries and which is a legacy of the Soviet Union's largess in handing down old SCUD missiles to just about anybody) with a more convenient and flexible technology. Also well documented are the origins of this switch in technology, prompted mostly by the PRC.
What was interesting in these photos was the missile's configuration itself and some potential capabilities this configuration will provide. This missile is purported to be a surface to surface tactical missile with "exceptional accuracy", according to the Iranian commentators. However, a close scrutiny of the three sets of fins on the missile shows that only the front ones are movable. The two rear sets, adjacent to each other, are in fact solidly bolted down to the missile's body. Another interesting feature surfaces upon closer examination of the rear end and the nozzle of this single staged missile. The nozzle has no visible thrust vector controls such as jet vanes, control jets or other means. While in theory secondary injection could be employed (and not be visible) it is most unlikely to be employed in this product of a fledgling missile effort. In other words the initial stage of the flight, possibly all the way to motor burnout is unguided, requiring passive aerodynamic stability. This is possible since in the Iranian movie the missile fairly leaps out of the launcher, which is set at about 70 degrees to the horizontal.
Here however comes the interesting part. With fuel burnout the CG (center of gravity) of the missile will move forward. Coupled with the initial (during launch) required margin of stability, the missile will become exceptionally aerodynamically stable during its free flight phase, a characteristic which will militate against adequate trajectory control (necessary to achieve that "exceptional accuracy") by those puny fins on the front. A reduction of the aerodynamic static stability could solve this problem and apparently the designers of this missile, whoever exactly they were, chose an original solution, to best of our knowledge never exercised in that particular way, before. A close examination of the rear of the missile shows that apparently the rearward set of fins is attached to the rest of the missile by a single set of four bolts (one for each fin) and that there is a space between the cylindrical envelope (that serves as the seat of the rear fins) and the rocket nozzle exit. It is quite possible that at motor burnout this section, rear fins and all, is separated (probably by the actuation of explosive bolts) from the rest of the missile and slides back to fall off. This scenario is supported by the existence of a cable conduit, clearly visible running along the missile body and ending right where are the bolts holding the rear fins.
The resulting new aerodynamic configuration will suffice to give the missile a much better trajectory control, with terminal accuracy limited only by the quality of the guidance inputs - inertial or GPS - which may justify the claims of the Iranians. Furthermore, this could be achieved by the usage of the fairly small fins on the nose with the attendant advantages of smaller actuators and lesser power requirements.
However, the better trajectory control has several other advantages. When flying a pure ballistic trajectory, the range of the FATEH-110 missile is generally given (In the literature) as approximately 170 kms, which also gives an apogee of more than 60 kms. If however at some point after burnout (but most probably after coming back down to an altitude of about 8 kms) the missile is flown in an aerodynamic gliding (coasting) mode, exchanging its excess velocity and altitude to aerodynamic lift, some 50 kms can be added to the range. Furthermore, the aerodynamic trajectory will complicate prediction of missile's target and flight path and make interception more difficult. Finally, for a small price in range, such a missile could maneuver in the lower atmosphere, further complicating the problem of interception.
One problem which the Iranians apparently are not worried about is the MTCR (Missile Technology Control Regime). While the range and (probably) the warhead weight do not run afoul of the MTCR guidelines, achieving the claimed accuracy probably does. In any case, converting the missile's flight path from a purely ballistic one to an aerodynamic one, even for part of the trajectory, will play havoc with its initial accuracy and CEP, whatever they were. This will require quite sophisticated instrumentation either for maintaining a desired pre-set trajectory (by inertial means) or for real-time updated information about the missile's location (GPS or terrain mapping). It is doubtful if at this stage the Iranian missile industry is capable of developing these technologies on its own, and thus the inescapable conclusion is that they are being helped by somebody, in direct contravention of the MTCR guidelines.