[wordup] The Low Cost Cruise Missile

[Adam Shand]

Via: Brett Shand <bretts at earthlight.co.nz>
From: http://www.aardvark.co.nz/pjet/cruise.shtml

The Low Cost Cruise Missile: A looming threat?
Last Updated: 25 May, 2002

You Can Already Buy All The Bits

Cruise Missile Cruise missiles such as the Raytheon Tomahawk have proven
themselves as an extremely cost-effective method of delivering a wide
range of ordinance with pin-point accuracy against targets that may be
up to 1,000 miles from the launch point.

By using mil-spec GPS, highly sophisticated terrain recognition systems
and a raft of other previously top-secret technologies, the cruise
missile allows its owner to deliver a powerful offensive strike against
an enemy with no risk to its own troops or vehicles.

However, during the past decade, huge strides have been made in
commercializing much of the technology on which the cruise missile is
based and it is my firm belief that building a low-cost, autonomous,
self-guided, air-breathing missile with a significant payload capability
is now well within the reach of almost any person or small group of
persons with the necessary knowledge and skills.

Targeting/Guidance

As mentioned above, one of the key components of a cruise missile's
guidance system is a mil-spec satellite-based GPS system.

Today, compact, high quality, high accuracy GPS receivers are readily
available for just a few hundred dollars. The inclusion of an easily
used computer interface in many of these units makes them well suited
for use in a low-cost cruise missile (LCCM).

While the GPS provides information necessary for tracking waypoints and
identifying the final destination, smaller course corrections (for
stability) can be provided by the solid-state gyro systems now readily
available for use in model helicopters and aircraft.

Instantaneous measurement of altitude and groundspeed can be provided by
a semi-forward looking radar and doppler radar units (possibly built
around components such as these and these. This allows a the LCCM to fly
lower than would be possible if relying solely on GPS and offers a
degree of contour-hugging even when the exact nature of the terrain is
not available.

The gyroscopic and radar-based systems could also provide an inertial
backup guidance facility in the event that the GPS system was lost,
blocked or simply turned off when an attack by such LCCMs was imminent
or underway.

Onboard Computing

As Moore's law continues to produce a rapid rise in the speed and fall
in the cost of computer chips, we've already reached the point where
obtaining sufficient number crunching capability is no longer difficult
or expensive.

Single-board computer systems are another readily available off the
shelf component that can be recruited for use in an LCCM. Even the
sophisticated realitime operating systems necessary for supporting the
type of software needed to interface the guidance/targeting systems to
the control servos are just a download away.

Airframe

Since an LCCM would be designed to fly at subsonic speeds (probably
around 450-500 mph) the aerodynamic design of such a craft is relatively
simple and there is plenty of resource material available to assist in
such an undertaking.

Indeed, the fact that so many very successful radio-controlled model
aircraft have been designed and built from scratch by talented amateurs
testifies to the viability of such an option.

LCCM-specific factors that need to be taken into account when designing
and constructing the airframe include the need for a low heat signature
and low radar profile.

The use of materials such as fiberglass and kevlar composites would go a
long way towards reducing the radar profile of such a craft, as would
the insight gained from a close inspection of the masking techniques
used on the existing generation of stealth craft.

Experimentation with coatings containing finely ground ferrites may even
offer some degree of radar absorbsion. The heat signature of a suitable
engine could be significantly reduced by judicious entraining of
slipstream air to dilute and cool the jet exhaust prior to ejection
behind the craft. At the cost of some thrust, the jet efflux could also
be channeled so that the engine itself is not visible even from a rear
view.

Powerplant

The realization of just how practical an LCCM has become came to me when
I was doing development on my pulsejet engines -- since they would make
an ideal low-cost powerplant for such a vehicle.

V1 Buzz Bomb The fact that the German V1 "flying bomb", perhaps the
first practical implementation of the cruise missile concept, was also
powered by a pulsejet speaks volumes for the practicality of using such
a powerplant today.

Traditional pulsejets would not be the best choice for an LCCM however
as their very hot exhaust would make them an easy target for even the
most primitive heat-seeking missile and their astonishingly poor
fuel-efficiency plus limited reliability would reduce the LCCM's
practical range.

A small turbojet (or the XJet) engine with 100lb-500lb of thrust
however, would be the perfect powerplant -- offering a high level of
reliability and longer ranges without the need for an excessive
fuel-load.

Launch Facilities

Most existing hi-tech cruise missiles are designed for launch by way of
a solid-rocket booster to get them up to flying speed, or they're
dropped from an aircraft already flying at speed and altitude.

The V1s of WW2 were launched using a catapult system powered by a mix of
nitric acid and hydrogen peroxide.

None of these systems would be required for an LCCM. A simple launch
attachment could be fitted to the roof of an SUV or truck that would
allow the takeoff speed of around 70mph to be achieved. At that point
the engine could be ignited and the craft released.

Using this method, a reasonable sized LCCM could be transported by road
to a position within range of the desired target, unpacked, prep'd and
then launched from a deserted stretch of roadway within a few minutes.

Payload

Cruise missiles can carry just about any payload required in the theater
of war.

High explosives are the most common payload but probably the least
attractive to a terrorist group -- since, to be effective, these
explosives do require very accurate targeting and represent a higher
level of risk during the transport and launch phase.

More attractive would probably be some form of biological agent
(anthrax, nerve gas, poison, etc) or even some type of nuclear material.
the LCCM could be programmed to disperse its payload over a large area
of high population with massive potential for death and injury in a
manner that would be very difficult to defend against.

At What Cost

The electronics (guidance/targeting, control systems, etc) could be
purchased for less than $2,000. An airframe, built using the type of
foam-composite construction found in a number of home-built light
aircraft would cost between $1,000 and $5,000 depending on the size of
the craft. The engine would cost between $500 and $150,000 depending on
the type and size. Turbojets/turbofans are significantly more expensive
than pulsejets and would be far more likely to ring "warning bells" if
they were purchased in quantity by someone without an established track
record or presence in the aviation marketplace so a simple pulsejet
would be the most prudent option for a terrorist group.

The total component costs for an LCCM (less payload) could be as little
as $6,000 for the smallest, simplest version, with a larger, more
sophisticated design still requiring little more than $10,000 worth of
parts and materials.

The real costs would come from the integration of all these components
and the development of the software required to link the
guidance/targeting systems to the aircraft's control systems. However,
suitable resources are available in many eastern-bloc countries and
doubtless could be purchased on a "no questions asked basis." This
development cost is also a one-off expense that would be effectively
amortized across the number of individual units constructed.

There is even a very good chance that the development costs could be
quickly recouped by selling the resulting design to other parties
interested in constructing similar LCCMs.

The cost of the payload carried by the LCCM would depend entirely on
nature of that material -- but it would appear that those bent on
terrorism have little difficulty in obtaining explosives or biological
warfare agents.

Why Worry?

Personally, I'm more than a little worried at the prospect of terror
groups or others constructing and launching their own LCCMs.

To date, the most effective method terrorist groups have had at striking
against military or civilian targets has been the suicide bombing.

With the massively increased levels of security and surveillance that
have been implemented in the September 11 attacks, the viability of such
attacks are now in question.

The very fact that so many people with known anti-USA affiliations were
turning up to have flying lessons and simulator time was enough to ring
alarm bells at the FBI -- when it comes to the LCCM we might not be
quite so lucky.

An LCCM can be built with items that are so readily available that, even
if a group decided to build hundreds of them, there would be no way of
easily detecting their activities. Although purchasing a number of
turbojet or turbofan jet engines might pose a problem, pulsejets (even a
sophisticated design such as the X-Jet) could be easily built from
stainless steel using readily available tooling and machinery.

As someone with over 20 years experience in the design and construction
of electronic control systems, realtime systems software, large model
aircraft, and most recently, high efficiency pulsejet engines, I
consider the design and construction of a simple yet surprisingly
effective LCCM to be well within my own capabilities. If I could do it
then you can bet that there are many others who have the ability to do
the same -- and not all will be friends of the West.

In fact, if I had the time and the money, I'd love to build such a
vehicle (albeit without the lethal payload) simply as a proof of
concept.

If the LCCM concept was implemented by a terrorist group, they would
likely carry out the design, development and testing work in a
relatively safe, secure location within the borders of a friendly nation
and then send the plans electronically (probably using something as
simple as encrypted email) to agents operating in relatively close
proximity to the intended target.

>From there it would be a very simple task to purchase the required
components and materials then fabricate and assemble the actual LCCM.
The completed units would be loaded onboard trucks hired or purchased
for the purpose and transported to within striking distance (100-300
miles) of a major city or military target. From any number of widely
dispersed locations within the launch radius, the LCCMs could be
launched simultaneously so as to stretch the defense capabilities of the
party being attacked.

Imagine the effect of just one such LCCM reaching central NYC on a warm
summer's afternoon, and dispensing a hundred pounds or more of highly
radioactive material or anthrax spores in a fine dust across an area of
(say) a square mile.

What Can Be Done About This Threat?

Unfortunately there's probably very little that can be done to reduce
the magnitude of this potential threat.

Doubtless a country such as the USA has the technology to shoot down an
LCCM -- but there's a very good chance that multiple launches from
dispersed points relatively close (say 100 miles -- representing a
flight time of just 12 minutes) to the intended target would likely make
it impossible for a defending force to deal with all the LCCMs launched.

A small (say 5-foot long) target travelling at 500 mph, less than 200
feet above the ground while following an unknown and deliberately
erratic course becomes an extremely difficult target to hit -- even if
you're ready and waiting for it.

Given that, with a radioactive or biological payload, it would only
require a single LCCM to reach its intended target in order to inflict a
damaging blow, the capability of defending against such a strike must be
considered just modest at best.

While one could argue that driving a large truck to the intended target
and then detonating whatever device was onboard remains a far simpler
option for terrorists -- it must also be acknowledged that this is not a
particularly effective way of dispersing a bio or nuclear agent. Such a
blast, especially in an area containing many high-rise buildings, would
only provide minimal dispersal. A air-drop could cover a much wider area
with resultantly greater effect.

The fact that the September 11 terrorists were obviously considering
just such an aerial dispersal through the use of crop-spraying aircraft
is clear indication that they are very much aware of this.

In the 21st century, technology plays no favorites -- it is the slave of
anyone who chooses to master it.