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In military terminology, a missile is a guided airborne ranged weapon capable of self-propelled flight usually by a jet engine or rocket motor. Missiles have five system components: targeting, guidance system, flight system, engine, and warhead. Missiles come in types adapted for different purposes: surface-to-surface and air-to-surface missiles (ballistic, cruise, anti-ship, anti-tank, etc.), surface-to-air missiles (and anti-ballistic), air-to-air missiles, and anti-satellite weapons.
In order to increase their range and throw weight, ballistic missiles are usually multistaged. By shedding weight as the flight progresses (that is, by burning the fuel and then discarding the pumps, flight controls, and associated equipment of the previous stage), each successive stage has less mass to accelerate. This permits a missile to fly farther and carry a larger payload.
Missiles are powered by an engine, generally either a type of rocket engine or jet engine. Rockets are generally of the solid-propellant type for ease of maintenance and fast deployment, although some larger ballistic missiles use liquid-propellant rockets. Jet engines are generally used in cruise missiles, most commonly of the turbojet type, due to its relative simplicity and low frontal area.
The function of the propulsion system is to produce thrust, which is the force that moves a rocket through air and space. Different propulsion systems generate thrust in different ways, but always through some application of Newton’s third law of motion. In any propulsion system, a working fluid is accelerated and the reaction to this acceleration produces a force on the system. A general derivation of the thrust equation shows that the amount of thrust generated depends on the mass flow through the engine and the exit velocity of the gas. The propulsion system of a rocket includes all the parts that make up the rocket engine: tanks, pumps, propellants, power head, and rocket nozzles.
In a solid rocket fuel grain, all the components required for vigorous combustion are mixed together and packed into a solid cylinder, into one substance. Once the combustion starts, it proceeds until all the propellant is exhausted. There will be an oxidizer (usually a salt such as ammonium perchlorate or potassium nitrate), a fuel (HTPB – Hydroxyl Terminated Polybutadiene) or some other solid hydrocarbon and an accelerant (sulphur, powdered aluminium, or other easily oxidized metal). When lit, the fuel grain will burn energetically, releasing a large volume of hot gases that are used to provide thrust.
“Going from rocket motor concept to full-scale production is rarely a straight path, but solving the myriad puzzles along the way always makes the process rewarding,” said Mike Fuller, manager at Northrop Grumman. According to Fuller, a solid rocket motor at its core is a relatively simple device with no moving parts. It includes an outer cylindrical casing, solid propellant with a hole — often star-shaped — down the center, called “the grain”, an igniter to light the propellant and a nozzle to exhaust the combustion gases.
Construction
A simple solid rocket motor consists of a casing, nozzle, grain (propellant charge), and igniter. Modern designs may also include a steerable nozzle for guidance, avionics, recovery hardware (parachutes), self-destruct mechanisms, APUs, controllable tactical motors, controllable divert and attitude control motors, and thermal management materials.
“We mix fuel and oxidizer in liquid form, then cast it inside the composite or steel casing,” he said. “The igniter is essentially a mini-rocket motor whose flame ignites the inner surface of the propellant. The gas created by this combustion exits the casing through the nozzle, creating the thrust that drives the rocket forward.”
Casing: The casing may be constructed from a range of materials.
Motor Case Materials: Composite ( E-glass, Aramid (Kevlar 49), Carbon fiber ), Metal ( Titanium alloy, Alloy steel, Aluminum alloy 2024 ), and combination
Titanium alloy: Heavy, Good strength to weight ratio
Alloy steel: Heavier, Strongest
Aluminum: Provides good strength to weight ratio, Lightest
Nozzles
A convergent-divergent design accelerates the exhaust gas out of the nozzle to produce thrust. The nozzle must be constructed from a material that can withstand the heat of the combustion gas flow. Often, heat-resistant carbon-based materials are used, such as amorphous graphite or carbon-carbon.
There are five types: Fixed (a), Movable (b), Submerged (c), Extendible (d) and Blast-Tube-Mounted (e)
The nozzle dimensions are calculated to maintain a design chamber pressure, while producing thrust from the exhaust gases.
Nozzles: Design and Construction
● Ablatively Cooled
● Steel or aluminum Shells
● Composite ablative liners
Aerotech L2200G-P Mojave Green and RMS 75/5120 kit comes with a nozzle
Igniters: Pyrogens and Pyrotechnic
Most frequent is Electroexplosive device (Pyrotechnic): Bridgewire
Adaptive Modeling Language(AML)
Adaptive Modeling Language(AML) is an object-oriented, knowledge-based engineering modeling framework. AML enables multidisciplinary modeling and integration of the entire product and process development cycle.
AML enables generative modeling, which leaps beyond the present CAD/CAM/CAE approach to integrated design and analysis processes. In a generative modeling environment, knowledge of the engineer’s tools and the intricacies associated with executing them is captured within a modeling language. This empowers the engineer to search a broader set of product design configurations, rather than being limited to simple parameter changes.
AML provides methods for automating finite element modeling and mesh generation based on either native or imported geometry, including both structured and unstructured approaches. Interfaces to pre- and post-processors and solvers including MSC Patran©, Nastran, ANSYS©, LS-DYNA©, MARC©, STAAD©, and ROBOT© are available.
A complete mathematical modeler is built into AML, providing access to logical operators, mathematical functions, matrix manipulation, and looping constructs. Pre-defined classes are provided to quickly create custom interfaces to ODBC-compliant databases utilizing SQL.
Integration to third-party applications is accommodated through a number of standard methodologies, including shared memory, pipes, TCP/IP sockets, file transfer, and foreign functions (C and Fortran).
Options are available within AML for import and export to industry-standard file formats, including IGES, STEP, STL, and DXF.
Built-in XML export capability enables a state model of the AML object hierarchy and geometry to be automatically exported to an XML file, which is viewable using TechnoSoft’s AML Viewer. The available “Net Conference” mode enables real-time collaboration among team members across local and global computer networks.
A suite of graphical user interface (GUI) classes is provided to allow developers to create customized front-ends to their AML applications. In addition, a visual GUI-builder can be used, making it easier to layout forms and controls, and assign their associated methods and properties.
Missile design software
STK
STK Missile Tool Kit comprises two applications —Missile Modeling Tool (MMT) and Missile Design Tool (MDT). MMT generates multi-stage missile trajectories, battle scenarios, and space launch trajectories that you can analyze and visualize in Systems Tool Kit (STK).
MMT can compute trajectories using its proprietary algorithms and models in its database, or it can convert trajectory data from external simulations. MDT creates complete-system-level performance models of ballistic missiles, interceptors, and space launch vehicles that you can simulate in MMT. Missile Tool Kit is developed by SAIC.
Use cases
- Create high-fidelity missile trajectories to augment STK scenarios.
- Compute guaranteed and denied footprints.
- Evaluate missile designs.
- Simulate intercept engagements.
IMD System
Developed by TechnoSoft and a major defense contractor, the IMD System is an AML-based
application that integrates multidisciplinary, system-level, missile design and analysis processes coupled with cost estimation.
The IMD system has helped missile designers win several programs enabling rapid design and
analysis of conceptual and preliminary missile models. IMD integrates primitive and arbitrary body geometry, propulsion, aerodynamics, 6 degree of-freedom simulations, structural dynamics,
lethality, aero-thermal analysis, and cost.
Additionally, the system provides the capability to conduct cost and performance tradeoffs that
are essential for Cost as an Independent Variable (CAIV) studies.
The IMD system significantly expedites the conceptual and preliminary missile design
process by a conservative factor of two (50% saving), thus favorably impacting program cycle
time, the cost of a missile system, and the overall time-to-market.
Various integrated analyses include: Missile Datcom, CAMS – trajectory/aero/propulsion
(solid and liquid), Price, Peels, Miniver, Patran, Nastran, SHABP, PANAIR, and Skin Friction
Codes
CNC Machines
CNC machines’ high precision, versatility, and compatibility with a wide range of materials make them ideal for fabricating missiles and weapons. Raytheon, one of the world’s largest producers of guided missiles, relies on multi-axis CNC machines to fabricate its 20-foot-long cruise missiles.
Needless to say, these missiles are delicate and require strict adherence to safety practices during machining. Not only is CNC technology helping Raytheon achieve precise parts, but it is also mitigating the risks of incidents or accidents caused by manual labor. And this is because CNC machines require little to no human intervention to fabricate parts.
“North Korea’s centrifuges and new missiles all depend on components made with CNC machine tools,” said Jeffrey Lewis, head of the East Asia Nonproliferation Program at the Middlebury Institute of Strategic Studies at Monterey, California. CNC machines use pre-programmed guides to produce intricate parts for everything from automobiles and mobile phones to furniture and clothes. They offer accuracy that human-machine tool operators are unable to achieve.
Digital manufacturing and 3D printing
Digital manufacturing combines desktop design software with both traditional and new manufacturing equipment including 3D printers, Computer Numerical Control (CNC) machines that use digital instructions to operate a variety of cutting and millings tools, and laser cutters. Digital manufacturing can be used to produce components for missiles that are more effective than those produced by traditional industrial processes.
The design software render a 3D model of the object for production. Designers can also take advantage of 3D scanners which can make a digital model of a physical object, saving the designer the trouble of redesigning the object from scratch and allowing the production of exceedingly exact copies. The designer can then upload their work to digital manufacturing machines that can craft a range of products.
Advanced 3D printers use lasers to harden powder or liquid in layers to create objects, and can fashion products out of a wide range of metals including steel and titanium. CNC machines can be equipped with various tools that allow them to cut or mill a block of material into a desired shape or product. Laser cutters slice sheets of metal or wood into 2-dimensional objects and components.
NASA is currently using selective laser melting, a process similar to 3D printing which uses a laser to harden layers of metallic powder into an object, to produce components for the Space Launch System(SLS). The SLS is a heavy lift rocket intended to carry robotic and manned missions to “nearby asteroids and eventually to Mars.”
As digital manufacturing allows rocket components to be produced in a single piece, rather than welding together smaller parts produced using traditional processes, the components are stronger and more resilient increasing the reliability of the launch vehicle. Digital manufacturing would likely produce similar benefits for the production of components for ballistic missiles, which share many common features with space launch vehicles.
Missile Integration Facility
The $75 million Raytheon Redstone Missile Integration Facility in Huntsville, however, is not simply a marvel of technological design. The 70,000-square-foot facility — one of the newest stars in Alabama’s aerospace constellation — produces weapons that are considered key components of the U.S. missile defense plan.
It produces the Standard Missile-6, a ship-defense interceptor used by the U.S. and Japanese Navies to defend against aircraft, drones and cruise missiles.
A key feature of the plant’s operation is the fleet of laser-guided transport vehicles that move the missiles around the factory, removing the need for workers to lift and move the weapons around the factory. The transporters can carry missile components weighing up to five tons and position the missiles within 1/10,000th of an inch. Significantly, the vehicles have eliminated all 16 of the so-called “critical lifts” involved in missile assembly, reducing the chances for an accident.
Digital manufacturing enhances the risk of missile proliferation
Digital manufacturing is disrupting traditional process and allow for the production of more effective missile components, using a wider variety of facilities and equipment, by a larger number of actors.
Digital manufacturing tools could be used to fabricate many key missile components, thereby reducing the challenge faced by a new weapons state from the manufacture of a weapon from scratch to the simpler assembly of a missile from its digitally produced parts.
Missile warheads and fuel may also be made more effective by digital manufacturing. 3D printing
could be used to produce warheads with specific geometries that would produce enhanced effects
when detonated. Similar methods could also be used to produce propellants shaped to provide
better and more efficient burn rates for rockets and ammunition.
Digital manufacturing would also allow proliferators to better leverage limited human capital. Design software requires less expertise to use than traditional design methods. Digital manufacturing systems themselves are automated, reducing the number of skilled machinists and technicians needed to produce missile components.
While the assembly and integration of components into a functioning missile system would still require a pool of experienced engineers and technicians, proliferators would still require less design and production expertise than traditional industrial production processes would demand
Digital manufacturing would also benefit non-state proliferators. Non-state actors generally lack
access to facilities to produce anything beyond crude artillery rockets and depend on support from state sponsors. As digital manufacturing capabilities become increasingly available throughout the world, non-state actors will be able to access local manufacturing capabilities to produce weapons based on designs provided by their state benefactors or to improve home built capabilities. Hamas, for instance, has made extensive use of crude artillery rockets, the accuracy and effectiveness of which would be significantly improved if engine parts and other components currently made with drills and lathes were produced with greater precision by digital manufacturing machines.
A key advantage of digital manufacturing is the ability to easily convert a design from a file directly into a physical object. It would most likely be easier for North Korea, for instance, to transfer data to allow a customer to manufacture missile components using local digital manufacturing facilities than to ship missiles or components that could be tracked and intercepted as they traveled from Northeast Asia to the Middle East or other hotspots, , writes Matthew Hallex.
Digital manufacturing is also deeply linked with the open source hardware movement which has
developed tools to allow for the easy sharing of hardware designs as well as collaboration on new
projects. This approach has been adopted for military projects in the United States; the Defense
Advanced Research Projects Agency (DARPA) currently sponsors a project to design a new
amphibious tank for the U.S. Marine Corp that uses online collaboration tools to allow far flung
networks of researchers to collaborate on designs. 14 Similar tools would facilitate collaboration
among global proliferation networks such as the Iranian-North Korean partnership for the
development of ballistic missiles, writes Matthew Hallex.
