Low-cost, intelligent and inspired by swarms of insects, drone squadrons could revolutionize future conflicts, experts say.

Case in point — the damaging “Pearl-Harbor-like” surprise attack on Saudi Arabia’s Abqaiq and Khurais oil facilities on Sept. 14. If ever the world needed a reality check for the threat posed by drone swarms and low-altitude cruise missiles, this was it.

According to the Saudi Defense Ministry, 18 drones and seven cruise missiles were fired at the kingdom in the early hours the day in mid-September, Defense News reported.

While several cruise missiles fell short and did not hit the facility, four cruise missiles struck Khurais. Saudi and US officials have blamed Iran, but the government there denies involvement.

What is clear is the failure of existing air defense systems to stop the attack.

The Abqaiq facility’s air defenses reportedly included the US-made Patriot system, Oerlikon GDF 35mm cannons equipped with the Skyguard radar and a version of France’s Crotale called Shahine, the report said.

Impeded by radar ranges and the facility itself, as well as the speed and angle of the drones and missiles, Saudi air defense apparently did not engage the drones. It also appears that homing by the drones was optical, not GPS-guided — a stealthy advantage for the attackers.

“If US-supplied air defenses were not oriented to defend against an attack from Iran, that’s incomprehensible. If they were, but they were not engaged, that’s incompetent. If they simply weren’t up to the task of preventing such precision attacks, that’s concerning,” said Daniel Shapiro, a former U.S. ambassador to Israel and a visiting fellow at the Institute for National Security Studies.

“And it would seem to validate Israeli concerns that even effective air and missile defense systems, as Israel has, could be overwhelmed by a sufficient quantity of precision-guidance missiles.”

Brig. Gen. Pini Yungman, a former air defense commander with the Israeli Air Force and current head of Rafael’s air defense systems division, contrasts the drone swarm with a cruise missile with a range of 1,000 kilometers and equipped with a large warhead.

The American-made Patriot missile defense system failed to engage the cruise missiles and drones that attacked Saudi Arabian oil facilities. Courtesy, US Dept. of Defense.

“Drones, even drone swarms, are not a strategic threat, even if you take dozens to attack. They carry a very low weight of bomb or ammunition,” Yungman said.

True enough — but what if the drones carried small amounts of chemical or biological weapons? Again … the threat is very real and rather frightening.

According to Breaking Defense, as a test, Switzerland’s security agency, the DDPS, combined an off-the-shelf quadcopter with simple gaming AI and Facebook-equivalent facial recognition technology, creating a weapon that could flying into a building, find an individual and kill them — essentially, an assassin drone. The test, apparently, worked.

Now imagine 1,000 assassin drones.

Armed Forces have surprisingly few effective anti-drone tools, and none — that are declassified — to target multiple unmanned aerial vehicles (UAVs), or swarms, Popular Mechanics reported.

Shotgun shells that fire nets to snare the propellers work only at close range. Missiles, like the US$38,000 Stinger, aren’t cost-efficient for taking out US$500 drones.

And high-powered lasers and signal jammers are effective, but must be fixed on a target for precious seconds before they disable a UAV.

This spring, however, Raytheon released details on a new type of drone defense using high-power microwaves — now called the Tactical High Power Microwave Operational Responder, or THOR.

The same electromagnetic energy you use to reheat chili can knock out drones in less than a second, the report said. An HPM beam works on the atomic level, passing through a drone’s exterior and distorting the fragile semiconductors that keep the drone aloft.

Once the target is in sight, a microsecond’s worth of silent, invisible microwaves moves at the speed of light, frying the circuit.

Officials at the Air Force Research Laboratory at Kirtland Air Force Base unveiled the weapon in a live demonstration in July with local reporters, who watched the system effortlessly knock a hovering drone out of the sky with invisible and inaudible electromagnetic waves.

The National Academy of Sciences notes that most of the counterstrategies that the Army has developed are “based on jamming radio frequency and GPS signals.”

The thinking was: Drones needed those information flows to navigate effectively. Cut them off and you neutralize the attack. But, as more decision-making intelligence gets baked into groups of these systems, those techniques will become less effective.

Uzi Rubin, former director of the state-run Israel Missile Defense Organization, doesn’t think what happened in Saudi Arabia could happen in Israel. “We have a smaller area, and that has an advantage in many respects because it is an advantage in controlling our airspace.”

The $15 million system, called the Tactical High Power Microwave Operational Responder, or THOR, can disable drones in an instant. Credit: The Drive.

He said the primary challenge in stopping an attack like that in Saudi Arabia is not the ability to shoot down the threats, but rather to detect “things that can sneak in near the ground.” The key, then, is to close the low-level gap.

Rubin said shooting down drone swarms can be accomplished with anti-aircraft guns, noting that Iraq downed several Tomahawk cruise missiles in 1991 after discovering their flight path.

“You don’t need anything fancy,” he said — the Russian SA-22 or Pantsir system, with 30mm cannons, missiles and infrared direction finders would do.”

However, Thomas Karako, a senior fellow at the CSIS think tank, told Defense News that the attack suggests a dramatic escalation. “More broadly speaking, it is what I’ve been talking about: The specter of complex, integrated air and missile attack is not theoretical — it has arrived.

“It’s not a technological problem, it’s an engineering problem,” he said. “You need to look beyond the horizon and look in every direction.”

Instead of being individually directed by a human controller, the basic idea of a drone swarm is that its machines are able to make decisions among themselves. So far the technology has been at an experimental stage, but it is edging closer to becoming a reality, the BBC reported.

Quoting Paul Scharre from the Center for a New American Security think tank: “Swarming allows you to build large numbers of low-cost expendable agents that can be used to overwhelm an adversary. This reverses the long trend of rising aircraft costs and reducing quantities.

“And unlike having a large number of soldiers, robotic agents can coordinate on a scale that would be impossible for humans,” Scharre told the BBC.