I was thinking about all the Qassam missles being fired at Israel, and how to shoot them down more effectively. These are a crude device, so not susceptible to some kinds of electronic hacking, jamming, decoy, etc. Just a steel tube, fuel and nozzles, payload of explosives, and a very crude ‘fuse’ consisting of a firearm cartridge and nail.
The aim of the Qassam rocket design appears to be ease and speed of manufacture, using common tools and components. To this end, the rockets are propelled by a solid mixture of sugar and potassium nitrate, a widely available fertilizer. The warhead is filled with smuggled or scavenged TNT and urea nitrate, another common fertilizer.
The rocket consists of a steel cylinder, containing a rectangular block of the propellant. A steel plate which forms and supports the nozzles is then spot-welded to the base of the cylinder. The warhead consists of a simple metal shell surrounding the explosives, and is triggered by a fuse constructed using a simple firearm cartridge, a spring and a nail.
While early designs used a single nozzle which screwed into the base, recent rockets use a seven-nozzle design, with the nozzles drilled directly into the rocket baseplate. This change both increases the tolerance of the rocket to small nozzle design defects, and eases manufacture by allowing the use of a drill rather than a lathe during manufacture due to the smaller nozzle size. However due to the cone shape of each of the 7 nozzles, each nozzle’s inside must be made with a lathe, or else the interior of the nozzle would be cylindrical rather than conical (see rocket engine nozzle). Unlike many other rockets, the nozzles are not canted, which means the rocket does not spin about its longitudinal axis during flight. While this results in a significant decrease in accuracy, it greatly simplifies rocket manufacture and the launch systems required.
The cost of the materials used for manufacturing each Qassam is up to $800 or €500 (in 2008-9) per rocket.
That ‘under $1000 each’ price point means that even if they are shot down by a high tech anti-missile missile, there is an economic disparity. Such high tech missiles will cost many thousands ( tens of thousands? hundreds of thousands?) of dollars each. You need a cheaper bullet.
Looking at the casing, it isn’t all that thick.
I’ve “played with” that sugar / potassium nitrate mixture before. It isn’t hard to ignite, but makes a mediocre substitute for real black powder in fireworks. As a rocket propellant it ought to be relatively cheap and effective. Yet a hole cut near the propellant or a ‘hot spot’ in the skin there will tend to ’cause issues’ for the rocket.
Furthermore, the ‘fuse’ will be prone to ‘cook off’ if heated enough. IMHO, that would be the preferred method of causing the rocket to fail in flight. Heat the nose.
In his book “Gunshot Wounds” Vincent Di Maio describes various experiments where ammunition was heated in ovens. He says that .22 long rifle cartridges detonate at an average of 275F, .38 Special at 290F and 12 gauge shotgun shells at 387F. The interesting thing about these furnace experiments was that in all instances the cartridge cases ruptured, but the primers did not detonate. In fact the primers were removed from some of the ruptured cases, reloaded into other brass and fired.
So we’re not talking about a really high temperature here. “Baking Bread” hot is ‘enough’.
I immediately thought of using a CO2 laser. Large industrial scale devices are available ‘off the shelf’ and “all” you need to add are laser ranging and precision aiming mirrors… The use of lasers for metal cutting is an established technology, and this needs far less heat than cutting.
Yet it happens at speed and much further away with a very hard ‘focusing’ problem…
Still, I thought, adding a bunch more power and it ought to be possible.
Then I turned up this little number from 12 years ago:
First-ever laser antimissile system hits target in field test
5 May 2000
A New York Times report
A powerful laser developed by Israel and the United States to shoot down rockets has passed its first test at the White Sands Missile Range in New Mexico, hitting a stationary target, American military officials said this week.
If it is eventually deployed, the system would apparently be the first of its kind. “To my knowledge, no nation has ever deployed an antimissile system based on a laser,” said Lt. Col. Rick Lehner, a spokesman for the Ballistic Missile Defense Organization at the Pentagon.
Designed and built by a California contractor, TRW, for Israel and the U.S. Army, the laser and its tracking system were tested last week against stationary targets, said Lt. Gen. John Costello, commander of the U.S. Army Space and Missile Defense Command. Costello said the system, the Tactical High Energy Laser, would probably be tested this month against a moving Katyusha rocket. If that test is successful, he said, the system will be shipped to Israel for further testing and deployment.
“It will be the first engagement of the Katyusha rocket by a tactical high-energy laser, something that is militarily useful,” the general said.
The Israeli Defense Ministry said it planned to deploy the system along its northern border to shoot down guerrilla rockets after Israel withdraws from Lebanon in the summer. A spokesman for the ministry, Dan Weinreich, said the weapon was in the final stages of testing in the United States and Israel.
Marco Morales, a spokesman for the Space and Missile Defense Command, said the cost to develop the system through the first attempted shoot-down was $190 million.
At a briefing this week in Huntsville, Ala., on missile defense, Costello said developing the system over five years “could in fact revolutionize warfare” by protecting troops from rockets, mortars and other artillery. But he said use of lasers in rain and fog will require special experiments.
The possible deployment of the laser, though its geographic range is modest, represents a striking turnaround for an antimissile technology that was criticized as unworkable in the Strategic Defense Initiative of the 1980s. Since then, most American antimissile systems have turned to “hit-to-kill” technology. That means that a rocket-propelled vehicle maneuvers toward an incoming missile to collide with it and destroy it. But the U.S. military has also continued long-term research and development on laser-based systems.
Those include the Israeli-American program for intercepting short-range missiles; an Air Force program to shoot ballistic missiles, such as Iraqi Scuds, using a laser on a Boeing 747 jumbo jet; and a joint venture by the Air Force and the Ballistic Missile Defense Organization at the Pentagon to develop lasers that could be fired from space to destroy intercontinental ballistic missiles.
All those lasers would derive their energy from powerful chemical reactions and destroy the missiles by heating them to high temperatures. Although the Israeli- American laser, if successful, would intercept rockets in the middle or end of their flights, the others would try to destroy missiles earlier, as their boosters fired.
The laser’s exact power, range and repetition rate for firing are classified. But at the briefing in Huntsville, Richard Bradshaw Jr., a project manager at the Space and Missile Defense Command, said the laser fired fast enough that it was “capable of engaging multiple targets coming in.”
Costello suggested that the laser would have an initial range of four miles. “Frankly,” he added, “we´ve designed it with the Israelis because of the threat to northern Israel.”
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So they had a development program over a decade ago that was reaching the ‘field test’ stage.
At this point, I can’t add much to what they were already doing. But I’m left with a pondering. Did this system just get dropped? Is it developed, but deployed at the ‘wrong end’ of Israel for the present problems? Is it part of “Iron Dome”, just not talked about much (for obvious reasons)?
Given that ‘low tech’ fuse, I’ve got to think that you don’t need a really big precise focus laser cutter so much as you need a broader focus ‘heater’. Perhaps even MASERs or x-Ray lasers would heat better. A bit of ‘think time’ about heating that ‘fuse’ would likely lead to a cheaper and easier to focus missile defeating ‘directed energy weapon’. Though a big old CO2 IR laser can pump out a lot of heat for cheap… For urban environment ‘city fixed defense’ installations, it can be the size of a small warehouse and ‘grid connected’, so a whole lot of technical issues in packaging and powering a mobile system ‘go away’.
Things that make you go ‘Hmmmmm…..’
But at least they are thinking about lower priced ‘bullets’ to shoot down cheap missiles.
This newer article (but only a little newer) has some information about the type of laser:
Nautilus Tactical High Energy Laser
The cooperative Tactical High Energy Laser (THEL) Demonstrator ACTD was initiated by a memorandum of agreement between the United States and the Government of Israel on 18 July 1996. The THEL is a high- energy laser weapon system that uses proven laser beam generation technologies, proven beam- pointing technologies, and existing sensors and communication networks to provide a new active defense capability in counterair missions. The THEL can provide an innovative solution not offered by other systems or technologies for the acquisition and close-in engagement problems associated with short- to medium-range threats, thereby significantly enhancing coverage of combat forces and theater-level assets. The THEL low-cost per kill (about $3,000 per kill) will also provide a cost-effective defense against low-cost air threats. It features up to 60 shots without reloading and a P(k) near 1 at ranges of some 5 km.
A joint U.S.-Israeli program was initiated to develop a THEL demonstrator using deuterium fluoride chemical laser technologies. THEL uses a Deuterium-Fluoride (DF) laser. NF3 and C2H4 are first reacted in multiple, side-by-side, high-pressure combustion chambers using an oxidizer (NF3) rich mixture that generates free F atoms. After ignition the combustion-generated F atoms, mixed with combustion by-products and a He diluent, flow into the laser cavity. A mixture of He and deuterium is also injected into the laser cavity, and DF is generated in an excited state as deuterium reacts with the free F atoms. The laser cavity is now ready to produce a laser beam.
THEL uses both Hydrogen Peroxide and Nitrogen Trifluoride. Nitrogen Triflouride (NF3) NF3 is used as a fluorine source in high-energy chemical lasers. Two applications are THEL and MIRACL (Mid-Infrared Advanced Chemical Laser) at White Sands Missile Range. Type 70 Hydrogen Peroxide is a critical element in the Anti-Ballistic Laser (ABL) and THEL Programs. Chemical lasers are the only class of HEL able to achieve megawatt power levels at century’s turn. The MIRACL is a deuterium fluoride (DF) laser operating at a wavelength of 3.8 microns that has been in operation at the megawatt level since the mid 1980s at the White Sands HEL Systems Test Facility. It suffered from inherent propagation losses at full power in the operational wavelengths. DF technology found a home in the US Army/Israeli THEL, where propagation losses were mitigated by lower power levels and a crossing target.
THEL was transferred to the US Army’s Program Executive Office for Air, Space and Missile Defense (PEO-ASMD) in 2003 for further development. The demonstrated effectiveness of the fixed site THEL demonstrator led to the initiation of a system engineering trade study in FY01 to evaluate mobile THEL variants that meet both Israeli and US Army mission needs. At that time, the Tactical High-Energy Laser (THEL) represented the low-risk, low-cost approach to field a high-energy laser system with operational capability of value in defending against air and missile attacks on forces, urban areas, or critical infrastructure. The DF laser demonstrated, in tests, effectiveness in destroying Katyusha rockets and airborne targets, including simultaneous engagements of both airborne and rocketlaunched targets. THEL was the first laser weapon system developed by the United States.
That brings it up to 2003, then this one says they ‘dropped out’ in 2006:
The day before, Aug 15, StrategyPage.com reported that Israel was already working with the U.S. government to see if it could revive its participation in the laser anti-missile system, previously called THEL, or “Tactical High Energy Laser.”
Israel dropped out of the project at the beginning of this year, the report said, because of the expense of developing the system. “But after seeing Hezbollah fire over 2,000 rockets into northern Israel, and having the Palestinians fire a few dozen a month into southern Israel, the Israelis want to reconsider the new version of THEL,” StraegyPage.com said.
Northrop Grumman, the U.S. partner in THEL development, is now offering a smaller version of THEL, Skyguard, for protecting commercial aircraft from portable anti-aircraft missiles, StrategyPage.com noted. But Northrop Grumman originally developed THEL for combat situations. And tests last year had highly promising results. They “showed THEL was able to knock down barrages of incoming mortar shells,” StrategyPage.com said.
It then goes on to suggest that the whole system was scrapped due to political influence issues.
According to the StrategyPage.com report, the THEL system is remarkably cheap — at least by the astronomical standards of BMD program development. “Northrop Grumman now says that it can have an anti-rocket system ready in 18 months, at a development cost of $400 million. Each anti-rocket system would cost about $50 million, and eight or nine would be required to cover the Lebanese border. One or two could cover Gaza. Thus the total bill for just developing, building and installing the systems is about a billion dollars,” the report said.
Why then, was THEL effectively scrapped at the beginning of this year?
“It died (as) a casualty of the Iraq war and homeland security and national missile defense ideologies and bureaucratic politics,” William M. Arkin, one of the most respected and influential U.S. reporters on national security issues, wrote in his “Early Warning” column in the Washington Post Aug 9.
Arkin noted that a test laser showed its ability to shoot down a short-range Katyusha rocket in flight as early as February 1996 in a New Mexico test. As a result of that test, TRW was awarded $89 million to develop that test laser capability into THEL, he wrote. A joint program was started with Israel. In May 1996, President Bill Clinton’s Defense Secretary William Perry called THEL “an urgent matter for both governments and one to which I assign the utmost importance.”
But as early as 1997, Perry’s Department of Defense requested no further funds to develop THEL. “The big boys at missile defense didn’t want anything short-range threatening their space-based, mega-long-range systems,” Arkin wrote.
On the ‘negative space’ analysis, I’ve not found anything newer. That can mean the program was dropped, but often means “something interesting happened” and the program went black. Yes, it could just mean I’ve not done much of a ‘search’; so others are welcome to “dig here!” and find newer stuff.
To me, it looks like an effective and working technology is sitting on the shelf, just waiting to be built around the cities of Israel.