Introduction
Artillery rockets have been in use
for military purposes in various countries for hundreds of years but
their use declined towards the end of the 19th century.
Rockets of that type have many advantages: Despite the fact that a
complete rocket-powered shell is bigger and heavier than a standard
artillery shell, there is no need for a heavy, expensive-to-manufacture
barrel and with a relatively minor investment, it is possible to acquire
rockets with longer range than that of standard artillery. Most
significantly, one can achieve higher and more effective rate of fire
than possible with barrels. However, with the then current methods of
production, the rockets’ accuracy was minimal, and they were effective
primarily against extremely large and stationary, targets – cities, for
example. In the late 19th century, with the perfection of the
barrel artillery with the introduction of the rifling in the barrel,
breech loading and the use of elongated shells, rockets disappeared
almost completely from the battlefield, other than utilization for
purposes of signaling and dropping anchors and ropes.
During World War II, rockets enjoyed
a renaissance. A better understanding of aerodynamics and ballistics,
together with improved production methods, facilitated uniformity in
trajectory and minimized the inaccuracies in hitting targets of smaller
sizes. While rockets did not reach the accuracy of cannons or mortars,
they definitely reached a standard where they could be tactically used
on the battlefield. When dealing with conspicuously large targets, like
rings of fortifications and deployment areas for regiment or division-sized forces, the problem of lack of accuracy becomes negligible. The
Russians were the first ones to introduce rockets of that sort on a
massive scale. Those were the Katyushas, or as the Germans called them,
“Stalin’s organ”, because of the similarity between the launcher barrels
and the organ pipes. However, all armies used one form or another of
rocket artillery: the Americans (in order to clear the beaches before
amphibious landings), the British, the Germans and even the Japanese.
Rocket motors and the science
involved in developing and producing rockets, were for many years
considered a mysterious science whose secrets were only in the hands of
an elite few, and, truth be told, until the end of World War II, that was
more or less the case. The competition between the Soviet Union and the
United States during the Cold War and especially the race to space led
to a striking change in the area of rockets. First, research in the area
of rocket propulsion has significantly expanded and tens of thousands of
popular and technical articles and hundreds of books dealing with all
aspects of rockets and ballistics, have been published in myriad
languages. Second, the extensive occupation with the development and
production has brought about an increase in the number of people
involved in that area, ranging from low-level technicians to famous
scientists. Today, throughout the world, university courses dealing with
a variety of topics related to rockets and guided missiles are offered
at every university with a mechanical, aeronautical or chemical
engineering department and extensive professional literature is
regularly published in professional journals and presented in scientific
conferences, which for all intents and purposes are open to everyone.
All the information necessary to develop and produce rocket engines,
different types of rocket fuels and warheads is available today on the
free market to anyone with a few dollars or an Internet access.
Furthermore, in all corners of the Earth there are people with extensive
military experience in artillery and practical operational experience in
implementing those systems.
Artillery
Rockets in Palestinian Hands
Although ostensibly, the
Palestinian “intifada” is directed against the “Israeli occupation of
Palestinian territory”, the Palestinians have no qualms about attacking
civilian targets inside Israel proper. In fact, they even prefer that
type of warfare to attacking military targets in the “occupied
territories”. The method of choice in that terrorist warfare is the
suicide bomber equipped with a powerful explosive device, who serves as
a “guided missile” homing in on Israeli citizens on buses, in shopping
centers and coffee shops and even attending religious ceremonies. The
success of that tactic is guaranteed given the proximity between
Israelis and Palestinians and the absence of a physical barrier between
them, enabling the easy infiltration of terrorists into Israeli
territory.
The ability of Palestinian
terrorist organizations to initiate these attacks is extremely limited
in those areas where an effective physical barrier exists, as in the
Gaza Strip, for example. And therefore the Palestinians chose to
exchange the maneuverability of the suicide bomber with the firepower of
longer-range artillery weapons. As they lack the ability to deploy gun
artillery and from their perspective even firing mortar shells is
problematic, they sought a different measure within their technological
capabilities. The solution was found in the form of rocket fire.
Although for purely military use, significant amounts of these weapons
are required and technically they must have a high level of reliability
and accuracy, these requirements are much less severe when speaking of a
terrorist weapon aimed at population centers. Various military rockets
have already been implemented in the past in various locales as a weapon
of terrorism against population centers but the repeated Israeli
successes in frustrating Palestinian smuggling of weapons (Santorini,
Karine-A and the pressure on the tunnels in the Rafah District), along
with the propaganda defeats which ensued from those failures, prodded
the Palestinians to find another, more secure, source for those weapons.
Despite the basic sophistication
involved in the design of a rocket motor, world-wide proliferation of
rocket propulsion technology solved this problem for the Palestinians.
They were thus encouraged them to attempt to produce rockets of that
type in home workshops operated by the various terrorist organizations
and ultimately they developed an independent production capability in
this area. Short-range rockets, called “Qasam”, are fired from
Palestinian territory and serve as a substitute for the suicide bomber,
to carry out the same mission – increasing the number of casualties
among the Israeli population.
There is no reliable information
regarding the number of rockets which were produced, the number of
accidents in production and deployment and not even regarding the number
which were fired but did not explode. The present assessment is that
more than three hundred homemade rockets were fired, and that number is
sufficient to cause headaches to the Israeli decision makers. As
mentioned above, their primary advantage lies in the fact that they do
not require a heavy barrel to serve as a launcher, and two connected
metal rods or angled steel can fill that role
(see illustration no. 1).
Fig.
1: Qasam rocket (apparently model 2) during launch
A launcher of that sort is simple
to produce, easy to transport and conceal, and if the need arises, it can
be left behind after the launch. The limited range of these rockets also
does not constitute a real limitation, as appropriate targets are
located within their range. And despite that fact, the terrorist
organizations are unceasingly taking steps to increase their range.
First, it will allow them greater flexibility in choosing targets or
launching sites. Second, a longer range, resulting from a more powerful
motor, can be traded-off to a shorter-range rocket with a heavier
warhead.
The Palestinian terrorist
organizations incessantly make an effort to upgrade the Qasam rockets’
payload capabilities. The first model, the Qasam-1, had a short range, a
few kilometers. Later, the Palestinians began producing the rockets on
the West Bank as well. However, Operation “Defensive Shield”, for all
intents and purposes, liquidated the Palestinian effort to expand the
circle of terrorism. The development and production continue in the Gaza
Strip, and two models of the more sophisticated rockets are now in use:
|
|
Qasam-2 |
Qasam-3 |
|
Diameter
(mm.) |
115 |
170 |
|
Length
(mm.) |
1,800 |
2,000 |
|
Range (km.) |
7 - 10 |
10 |
|
Warhead
weight – total/explosive (kg.) |
8/5 |
20/10 |
Note: Some of the
above figures are educated assessments based on a variety of factors.
Technical Data of the Qasam Rockets
Design of the Rocket Engine:
An interesting facet of the
Palestinian effort in this area is the technical aspect, which to a
certain degree reveals the thought processes and the problems of the
rocket designers.
Short-range missiles and rockets
are exclusively based on motors propelled by solid fuel. The solid fuel,
known as the grain, is entered into a casing made of metal or aluminum.
At the rear end, an exhaust nozzle or a system of exhaust nozzles is
affixed, the purpose of which is to transform the pressure created in
the motor casing into thrust. Conventional (standard) solid fuels are
produced through complex chemical processes replete with safety
mechanisms, as each one of their component materials, and most certainly
the final product, are volatile or explosive and careless handling is
likely to cause a large-scale disaster. As the semi-underground
terrorist organizations are incapable of creating these fuels, they
chose a simpler composition, produced from readily available and less
dangerous materials. The standard fuel in their possession is composed
of 60% potassium nitrate and 40% sugar. Potassium nitrate can be freely
purchased on the civilian market, as it is a type of widely used
chemical fertilizer. The final product is a square fuel grain whose
diagonal fits into the inside diameter of the motor casing. (The inner
space of the motor casing is not insulated against the flame. Since the
motor burns for only a short time, about one second, no damage will be
caused to the metal casing.) The aft bulkhead, containing the nozzles,
is then screwed on and a few spot welds are applied to prevent
unscrewing. Welding, even a careful one, while the motor is loaded with
fuel, is a dangerous action, which would not be allowed in any proper
manufacturing plant. The Palestinians use this method and, as mentioned
above, we have no information regarding the number of mishaps, which
occurred during production.
Fig. 2: A grain of solid fuel for a Qasam rocket.
Fig. 3: A seven-nozzle configuration on a Qasam rocket.
Fig. 4: The rear end of a Qasam rocket after one nozzle was torn off.
The early rockets had a single
exhaust nozzle but all later rockets were equipped with seven nozzles
(see Fig.3). This arrangement is less effective in terms of the thrust
of the rocket motor but it is possible that the Palestinians chose this
configuration for two reasons. First, the number of nozzles will
minimize the effects of production inaccuracies on the trajectory of the
rocket. Second, it was apparently easier to produce smaller nozzles,
either by means of turning (on a lathe) or direct drilling of the aft
bulkhead, and it is certainly more economical in terms of use of
materials than turning a single relatively large nozzle. It is
interesting to note that these nozzles are not canted, like the nozzles
of the “Katyusha” rockets and thus no roll is imparted to these rockets.
Such roll significantly enhances the accuracy of the rocket’s trajectory
but on the other hand requires considerable beefing-up of the launcher,
and in any case, complicates production. One gets the sense that
simplicity of production is a dominant consideration for the
Palestinians.
It seems that the earlier rockets
were equipped with nozzles screwed onto the rear wall (see Fig. 4, in
which one of the nozzles was detached when the rocket hit the ground).
Now apparently in an attempt to simplify production, the nozzles are
directly drilled in the rear bulkhead. The material is plain steel but
here too, because of the short burn time, nozzle throat erosion, which
is usually the most vulnerable area in rockets with longer burn times,
is insignificant.
In terms of classical rocketry, the
whole design is very inefficient. It is doubtful if this motor is
capable of producing an Isp of more than 130 seconds. (Isp
– in seconds – represents the efficiency of a rocket motor as a producer
of thrust, and it is a function of the quality of the fuel, the motor's
overall design and the pressure of combustion inside the motor.) In
comparison, the simplest standard rocket motor delivers an Isp of
approximately 200 seconds and in a sophisticated design can reach
approximately 300 seconds. However, in the conditions of the current
arena, even a motor of this sort serves its purpose.
The Warhead Design
The warhead is composed of a simple
metal shell with a conical configuration. The explosive is a mixture of
urea nitrate and TNT in various ratios, depending mostly on the current
availability of TNT, smuggled into the Gaza Strip or extracted from
standard military ammunition. While again the urea nitrate is not an
ideal explosive, like the potassium nitrate mentioned above, it is a
standard chemical fertilizer that can be obtained on the free market.
The fuse is a simple device consisting of an empty small arms casing
filled with an explosive booster material and the firing cap is aligned
opposite a spring-loaded nail. When hitting the ground, the nail moves
forward, hits the firing cap, activates the booster, which then
detonates the explosive. No safety catches or "safe & arm" mechanisms
to prevent premature detonation are employed – but with sufficiently
careful handling, it can work. Furthermore, there were efforts to
improve the lethality of the warheads by equipping them with a nose
probe that will enable them to explode a foot or so above ground.
There are no technical barriers
(within limits) to a moderate scaling-up of both the size and the range
of these devices. On the other hand, the real performance of these
rockets (range and accuracy) is probable a mystery to the Palestinians
themselves since the only firing range they do have is towards the sea.
Thus the exact descriptions of fall of shot locations, provided in the
Israeli news media, probably help the Palestinians quite a lot, by
providing range and deviation information. It can be safely assumed that
it is only a question of time before such rockets with increased range,
and possibly with better accuracy, will materialize.
While artillery rockets are not the
only terrorist weapons used by the Palestinians, from their point of
view, these devices do have some advantages, when compared with other
weapons. They are simpler to operate than mortars, by definition have a
longer range than mines, and after firing, their simple launchers can in
fact be abandoned. Compared with the complications involved in
recruiting and use of suicidal volunteers, these are ideal weapons.
What's more, there is no problem of information derived from
investigating the incident and, obviously, no security guards can stop
them.
The primary
terrorist organization involved in manufacturing and firing the Qasam
family of rockets is the Hamas. The strategic role that the Hamas plans
for its rockets is not unlike that of the Hizbullah rockets along the
Israeli-Lebanese border. The Hizbullah brandish its Iranian supplied
rockets, which can hit Israeli metropolitan areas like Haifa, as a sort
of strategic deterrence, allowing it the freedom to harass Israeli
targets near the border, with impunity. There is little doubt that the
Hamas would like to see its own rocket force fulfilling the same role
along the perimeter of the Gaza Strip, and in the future, along the
borders of the promised Palestinian state.
One ray of hope lies in the fact
that while these can be very effective terrorist weapons with definite
potential to become a genuine threat, they are as yet too primitive to be
of more than a nuisance value. To be a real threat will require better
performance, greater numbers, better equipped production facilities, a
significant investment of capital, and a serious testing system. However,
increasing the scope of the activity to that extent increases the chance
that the entire project will be more easily detected and destroyed. For
this to be successful would require constant monitoring of Palestinian
expansion efforts, along with a quick introduction of appropriate
quick-response capabilities and countermeasures, which could nip this
threat in the bud.
The