Rockets had an extremely high idiot index

Sunday, February 4th, 2024

Elon Musk by Walter Isaacson“I was pretty mad,” Elon Musk said about his failed attempt to buy Russian rockets, “and when I get mad I try to reframe the problem.” Walter Isaacson explains (in his biography of Elon) how Musk employed first-principles thinking:

This led him to develop what he called an “idiot index,” which calculated how much more costly a finished product was than the cost of its basic materials. If a product had a high idiot index, its cost could be reduced significantly by devising more efficient manufacturing techniques.

Rockets had an extremely high idiot index. Musk began calculating the cost of carbon fiber, metal, fuel, and other materials that went into them. The finished product, using the current manufacturing methods, cost at least fifty times more than that.


So on the flight home, he pulled out his computer and started making spreadsheets that detailed all of the materials and costs for building a midsize rocket.


“Hey, guys,” he said, showing them the spreadsheet, “I think we can build this rocket ourselves.” When Cantrell looked at the numbers, he said to himself, “I’ll be damned — that’s why he’s been borrowing all my books.”

Four nuclear-powered merchant ships have been built so far

Friday, February 2nd, 2024

Today, 200 nuclear reactors are operating on 160 vessels, mostly naval ships and submarines, but soon they could run on cargo ships, too:

Four nuclear-powered merchant ships have been built so far, all of them government-led projects begun mostly for developmental and testing reasons rather than purely commercial ones. The first was the American NS Savannah, built in the late 1950s at a cost of $46.9 million (an eye-popping $495 million today). It was in service from 1962 to 1972, but its pressurized light-water reactor (LWR) proved too complex and expensive for the ship to operate profitably. The Russian cargo vessel Sevmorput, commissioned in 1988, is the only nuclear-powered merchant ship still in operation as of early 2024. The other two ships, the Japanese Mutsu (1970) and the German Otto Hahn (1968), were both refitted with diesel engines partway through their service lives.

Nuclear power has been more successfully applied on submarines and ice-breaking vessels. The very first nuclear-powered vessel was the attack submarine USS Nautilus, in 1954, amid the 1950s heyday of nuclear-power research. Hundreds of nuclear reactors have since been used on ships and submarines. Russia currently operates seven nuclear-powered icebreakers.


“Engines in ordinary ships are the size of houses,” says Emblemsvåg, who is leading NuProShip. And a great deal of space is taken up by fuel: “A container vessel going from Amsterdam to Shanghai requires roughly 4,000 tonnes of fuel.”

An SMR would be much more compact and lightweight. According to Emblemsvåg, a molten-salt reactor — which uses a mixture of thorium and hot liquid salts as both fuel and coolant — would also save about $70 million over the lifetime of a ship, compared with a similar vessel powered by engines that burn diesel fuel (or, more precisely, heavy fuel oil). Another plus for nuclear-propelled ships is easy access to an endless supply of cooling water.


For ship propulsion, engineers have used pressurized-water reactors because they can produce higher power for a given mass compared with the other kind of light-water reactor, the boiling-water reactor. However, the technology comes with major challenges. They depend on complex control systems that need a technically trained operating crew, and they run on solid fuel rods that need to be replaced every 18 months. There’s also a risk, however slight, that the pressure vessel could explode.

Fourth-generation SMRs avoid all that. Emblemsvåg and the NuProShip team picked three reactor designs after analyzing 93 concepts in the International Atomic Energy Agency’s SMR handbook. One is a thorium-fueled molten-salt reactor. The second is a lead-cooled fast reactor, which replaces the water coolant of traditional reactors with molten lead. The third option, likely closest to market, is a helium gas-cooled reactor that uses a type of fuel called tristructural isotropic (TRISO), consisting of uranium particles encased in ultratough carbide and carbon layers that can handle temperatures above 2,000 °C.

Hellfire does not tidily disintegrate the target as in a video game

Tuesday, January 30th, 2024

Swarm Troopers by David HamblingCofer Black, head of the CIA’s counterterrorist Center, requested that the Predator be armed, David Hambling reports (in Swarm Troopers), and USAF General John Jumper requested a demonstration of a Predator that could “find a target, then eliminate it”:

Hellfire was chosen because it was a proven, mature missile with many years of successful service. In fact, mature is something of an understatement: Hellfire was positively middle-aged, dating back to the Nixon administration in 1974.


Hellfire has laser guidance, so the target needs to be marked with a laser designator right up until the missile hits. It is highly accurate, usually hitting within half a meter of the aim point, but it can take a while to arrive. Hellfire is faster than the speed of sound, but fired from a range of six miles, it still takes about twenty seconds to reach the target.


Hellfire is uncomfortably large to hang off a Predator but small compared to anything else available in the inventory. At the time, the Air Force’s smallest guided bomb was five hundred pounds.


The other challenge when firing a Hellfire from a Predator is the unavoidable two-second time lag caused by satellite communications. This means the laser spot effectively takes two seconds to move, so the Predator can only engage a stationary target in this mode. To hit a moving target, the operator uses targeting software to lock on to a moving vehicle; the software keeps the laser spot in place, an indirect way of engaging the target with its own risks if the system fails.


Hellfire does not tidily disintegrate the target as in a video game but leaves recognizable bodies and body parts around ground zero.


If fired in a straight line, Hellfire’s supersonic speed means the target will not hear it coming.


Hellfire may be precise, but it is not surgical. The twenty-pound high-explosive warhead can cause major “collateral damage,” killing innocent bystanders or building occupants when the target is a single terrorist.

Worse, the long time of flight means there is the risk of somebody wandering into the target area after the missile has been launched.

“Hellfire” supposedly comes from heliborne laser, fire-and-forget missile.

DJI might deplore the military use of its drones, but its new FlyCart 30 delivery drones looks perfect for delivering ordnance on target

Saturday, January 27th, 2024

DJI, based in Shenzhen, China, dominate the consumer drone industry, David Hambling notes, with an estimated 70%+ of the global market:

In particular their Mavic range of affordable drones which fold up small enough to fit in a cargo pocket are outstanding platforms for rock-steady aerial videos or swooping shots of scenery. Mavics also make great battlefield scouts, and both sides in the conflict have used the drones heavily for reconnaissance and intelligence gathering, spotting hidden targets from miles away.

Small drones also multiply the effectiveness of artillery: by precisely directing rounds on target, drones make artillery five to ten times as effective. Everything from 155mm howitzers to 30mm automatic grenade launches now uses drone guidance, and they assist tanks to score indirect-fire kills from long range in a way that was previously impossible.

And of course, small drones are used as bombers. 3D printed bombing rigs arm small quadcopters with one or two grenades (typically Russian VOG-17 or American M433 “Golden eggs”) to drop into foxholes or trenches, or through hatches to destroy abandoned vehicles.

DJI deplores the military use of their drones. The company banned sales of their products in both Ukraine and Russia in April 2022 and has issued several strongly-worded statements, but these have been ignored.

But in Ukraine, ‘Mavik’ is now a generic term for any small drone, just as ‘Hoover’ and ‘Fridge’ were applied to any product of a certain type. In October 2023, Ukrainian Prime Minister Denys Shmyhal claimed his country bought 60% of the Mavic drones produced,DJI immediately denied this claim, and it does seem unlikely as DJI produce millions of drones and Ukraine’s purchases are likely to be in the hundreds of thousands, but it gives an idea of how significant they are.

DJI might deplore the military use of its drones, but its new FlyCart 30 delivery drones looks perfect for delivering ordnance on target:

With eight rotors on four arms, the FlyCart30 can haul up to 30 kilos/66 pounds a distance of ten miles, or carry lesser payloads greater distances. The control range is given as 13 miles, but extra features allow one-button transfer to a second operator.

Top speed is 45 mph, and the drone can fly in winds of up to 27 mph.

A mass of safety features include automatic radar and visual obstacle avoidance day or night, and a parachute which deploys if the engines fail, so the drone will always make a soft landing.

For deliveries, the FlyCart30 can carry a 70-liter cargo pod – a container the size of a suitcase – or, if there is no landing site, it can lower a payload on a winch while the drone hovers 60 feet above.

Like the Mavics, FlyCart30 folds up for easy transport. No international price has been announced, but last year the drone was advertised in China for just $17,000.


Ukraine’s heavy drones have recently taken on a new role as minelayers. Their engineers have developed a special fuse so a mine can be dropped from the air and only arm itself after it has handed. The drones can lay mines on roads or tracks from several miles away. They can also repair gaps in minefield where Russian engineers have started to clear a path.


The larger capacity also opens up the possibility of new types of attack drone. Several developers have already come up with stabilised weapon mounts for drones, such as the Baduga rifle system which comes with a high-powered rifle with 60 rounds. It can reliably hit a human-sized target with one shot from 200 meters. The Baduga system complete with a rifle and ammo weights less than 20 pounds.

In 2021, Nammo test-fired their M72 anti-armor rocket from a heavy drone. M72s weigh about eight pounds each, so FlyCart could carry a whole rack of them, benefitting from being able to attack the thin top armor.

The FlyCart could also act as a drone carrier, a mothership for multiple FPV attack drones. Both Ukraine and Russia have experimented with this concept, but an affordable heavy lift platform would make it far more feasible.

Generating Power on Earth From the Coldness of Deep Space

Thursday, January 25th, 2024

On a clear night you’ll feel your body cool; some of that cooling is heat radiating into space:

Removing heat this way can cool that object down tens of degrees below the temperature of its surroundings.

We can exploit the temperature difference by turning it into electricity through thermoelectric power generation. The working principle behind a thermoelectric generator is the Seebeck effect, which describes how a material develops a voltage difference in response to a temperature differential across it. We can manipulate the Seebeck effect in semiconductors by the controlled addition of impurities, or dopants.


With the ambient environment as a hot reservoir, we can use the coldness from deep space to create the cold reservoir. To do this, we send heat out to space using what we call an emitter, which cools itself to a lower temperature than its surroundings. That’s a phenomenon known as radiative cooling. Then, a thermoelectric generator situated between the cold emitter and the now-hotter ambient surroundings can produce electricity.

The emitter’s job is to radiate the heat out beyond Earth’s atmosphere. But the atmosphere is transparent only to photons of certain wavelengths. Within the mid-infrared range, which is where heat radiation from typical earthbound objects is concentrated, the most applicable atmospheric transmission band is in the 8- to 13-micrometer-wavelength range. Even some simple emitters send out heat radiation at these wavelengths. For example, if it’s insulated from ambient surroundings, black paint emits enough radiation within that band to cool a surface down by 10 degrees Celsius when exposed to the night sky.

In the wavelength range outside 8 to 13 mm, the atmosphere bounces back a substantial amount of radiation. During the daytime, solar radiation comes into the equation. More-advanced emitter designs aim to avoid the incoming radiation from the atmosphere and sunlight by ensuring that they absorb and emit only within the transparency window. The idea of using such a wavelength-selective emitter for radiative cooling dates back to the pioneering work of Claes-Göran Granqvist and collaborators in the 1980s. Just as an engineer designs a radio antenna with a specific shape and size to transmit over a certain wavelength in a certain direction, we can design an emitter using a library of materials, each with a specific shape and size, to adjust the wavelength band and direction for heat radiation. The better we do this, the more heat the emitter ejects into space and the colder the emitter can get.

Glass is a great material for an emitter. Its atomic vibrations couple strongly to radiation around the 10-micrometer wavelength, forcing the material to emit much of its heat radiation within the transmission window. Just touch a glass window at night and you’ll feel this cooling. Adding a metallic film to help reflect radiation skyward makes the emissions—and the cooling—even more effective. And structures can be specifically designed to strongly reflect the wavelengths of sunlight.


Putting all these optimizations together, we calculated that the maximum achievable power density for this technology is 2.2 W/m2. This power density is a lot lower than what can be generated with solar cells under sunlight. However, when sunlight isn’t readily available, this is pretty good; it’s significantly higher compared to what can be achieved with many other ambient energy-harvesting schemes. For example, it’s orders of magnitude more than the less than 1 mW/m2 that can be harvested from ambient radio waves.

The imagery appeared to be highly addictive

Tuesday, January 16th, 2024

Swarm Troopers by David HamblingBy 2001, David Hambling notes (in Swarm Troopers), the Predator had, in the words of the Air Force, “become the commander’s real-time eye in the sky, providing real-time streaming video back to the command post”:

The imagery appeared to be highly addictive, leading to it being called “Predator crack” because it seemed that commanders right up to the White House could never get enough of it.


On the other hand, intelligence analysts were accustomed to imagery in the form of black-and-white still photographs, not color video. Initially their approach was to take stills from the video feed and print them out.


The plane can be broken down and stored in a shipping container known as a “coffin” and flown around the world on a transport aircraft. In theatre, it needs a five-thousand foot runway and a dedicated ground support team. Once it is rolled onto the runway, the drone is piloted by a local crew who get it into the air and on its way. Then it is handed over via satellite link–it has its own special twenty-foot dish and dedicated satellite systems–to a remote team. From then on the Predator is flown from Creech Air Force Base, forty minutes outside Las Vegas.

Unmanned aircraft like Predator have major support requirements, but each flight provides twenty-four hours of continuous surveillance on station with cameras, infrared, and radar sensors. By using the drones in relays, the Air Force can maintain a permanent presence over an area, known as a “combat air patrol,” “CAP” or “orbit.” Each CAP requires at least three drones. In 2010 there were fifty Predator/Reaper CAPs; by 2013 the number was up to sixty-five, with plans to replace all the Predators with Reapers by 2016.


The plane may keep going for twenty-four hours, but that requires several shifts of pilots, with replacements for those that are sick or otherwise not available.


One study suggested that ten pilots were needed for each predator CAP to keep operations going 24/7. These days less than half of drone pilots qualified on other aircraft first. Pure drone pilots may have some advantages; reports suggests that pilots have to unlearn some of their skills before they can fly the Predator effectively, as they may have become reliant on feeling the tilt of the aircraft or the change in note of the engine to tell how it was flying.


One of the biggest differences from other aircraft is the time lag of a few seconds (latency) due to the satellite communications.


The real business end of the Predator is a “sensor ball” eighteen inches in diameter. This is the AN/ AAS-52 Multi-Spectral Targeting System (3), which has a stabilized gimbal mount with two axes of rotation, keeping the cameras pointed in exactly the same direction regardless of the motion of the drone. It has normal visible-light cameras for daytime use and image-intensified night cameras, as well as infrared imaging, along with software that combines the inputs from different cameras into a single image. It features various levels of zoom, from a forty-five degree wide-angle view down to an ultra-narrow 0.2-degree view. This is equal to a x200 zoom range. On a standard 35mm camera, the equivalent lenses at the extreme ends would be a 50mm wide-angle lens and a 12,000mm telephoto.


The sensor ball also contains a laser illuminator, like an invisible searchlight indicating targets for friendly forces, a laser designator for the Hellfire missile, and a laser rangefinder to determine the exact location of the target.

Even in pitch darkness–or in the rain, which was a problem previously–the Predator can pick out objects on the ground with great accuracy. This is thanks to a radar system called Lynx developed in 1998 by Sandia National Laboratories (4) to overcome the limitations of cameras. Existing radar was too large for the Predator at some four hundred pounds. In a major feat of miniaturization, the necessary electronics were crammed into a package weighing just a hundred and twenty pounds which generates an image resembling a black and white video with an impressive level of detail.

From fifteen miles away, Lynx produces images in which features four inches across can be distinguished. It also has some other clever tricks. A process called coherent change detection shows the difference between the current scene and one recorded previously. This is accurate enough to pick up the disturbance left by a bomb buried under the road surface.


The Predator can also carry various electronic warfare packages that allow it to detect, locate, and intercept radio signals. The simplest of these was a radio receiver bought from Radio Shack; the most advanced are highly classified and cost millions. These could, for example, pick up walkie-talkie or cell phone transmissions and pinpoint the users. Predators can reportedly track individual cell phones when they are on by their SIM cards.

Their arms and legs get sheared off clean, as if God himself lowered a big rotary saw

Monday, January 15th, 2024

I haven’t heard any complaints about dense inert metal explosives recently:

A DIME weapon consists of a carbon fiber casing filled with a mixture of explosive and very dense microshrapnel, consisting of very small particles (1–2 mm) or powder of a heavy metal. To date, tungsten alloy (heavy metal tungsten alloy, or HMTA) composed of tungsten and other metals such as cobalt and nickel or iron has been the preferred material for the dense microshrapnel or powder.


The HMTA powder acts like micro-shrapnel which is very lethal at close range (about 4 m or 13 ft), but loses momentum very quickly due to air resistance, coming to a halt within approximately 40 times the diameter of the charge. This increases the probability of killing people within a few meters of the explosion while reducing the probability of causing death and injuries or damage farther away. Survivors close to the lethal zone may still have their limbs amputated by the HMTA microshrapnel, which can slice through soft tissue and bone.


In July and August 2006, doctors in the Gaza Strip reported unusual wounds caused by Israel Defense Forces attacks against Palestinians, claiming that they were from previously unknown weapons. A lab analysis of the metals found in the victims’ bodies was reportedly “compatible with the hypothesis” that DIME weapons were involved. Israel denied possessing or using such weapons, and an Israeli military expert said that the wounds were consistent with ordinary explosives.

Gary Brecher, the War Nerd, reported on their use against Hamas a few years ago:

There’ve been reports out of Gaza that when the Israelis blast one of these Hamas guys outside a coffee house or his home, there’ve been weird injuries to the people standing next to the target — their arms and legs get sheared off clean, as if God himself lowered a big rotary saw over him and lifted him up into the sky like a core sample from an oil rig, along with the odd arm or leg of other people who happened to be inside the magic 4 meters. The wounds have supposedly stopped clean at that point, cauterized by the blast.

Naturally, such precise munitions are considered a crime against humanity — because tungsten powder can cause cancer.

This radical shift in thinking allows for large-scale defensive launches at extraordinarily low cost

Friday, January 12th, 2024

Anduril Industries announced its Roadrunner and Roadrunner-Munition (Roadrunner-M) last December:

Roadrunner is a modular, twin-jet powered autonomous air vehicle with extraordinary performance at low cost. Vertical takeoff and landing capability gives Roadrunner the flexibility to rapidly launch from and return to any location, pairing high subsonic speed with exceptional agility and stability.


Similar to traditional approaches to deter and defeat incoming aerial threats like scrambling expensive and airfield-dependent jets, Roadrunner-M can take off, follow, and intercept distant targets at the first hint of danger, giving operators more information and time to assess the target and rules of engagement. If there is no need to destroy the target, Roadrunner-M can simply return to base and land at a pre-designated location for immediate refueling and reuse. If the target does need to be destroyed, Roadrunner-M will swiftly do so. Unlike legacy missile systems, you can reuse all craft that are launched but not consumed. This radical shift in thinking allows for large-scale defensive launches at extraordinarily low cost, increasing redundancy for higher probability of lethality and enhancing the ability to simultaneously engage many targets.


A single operator can launch and supervise multiple Roadrunner or Roadrunner-M squadrons. Roadrunner-M can be controlled by Lattice, Anduril’s AI-powered software suite for command and control, or be fully integrated into existing air defense radars, sensors, and architectures to provide immediately deployable capability.

The Predator was expendable

Tuesday, January 9th, 2024

Swarm Troopers by David HamblingEarly Predator losses were high, David Hambling notes (in Swarm Troopers), but acceptable:

By 2001, twenty of the sixty Predators had been lost to a mixture of pilot error, bad weather, accidents, and enemy fire. “Situational awareness” in unmanned aircraft is notoriously poor because of the limited view and the lack of feedback from other senses. You cannot hear the engine or feel vibration. The extreme case occurred when a pilot crashed during landing because she did not realize that her Predator had been flipped over and was flying upside down. Lesser mishaps are common. The accident rate peaked at one crash per 2,500 hours flown, far higher than any manned aircraft–but not unusual for a drone.


At less than $3 million an airframe, compared to over $200 million for some manned jets, and with no pilot casualties to worry about, the Predator was expendable. Improvements in training and additional safety features brought the accident rate down to one per 20,000 hours in 2010. By 2013, large drones had a lower accident rate than many manned aircraft.

This is exactly what Makarenko means by a failure of detonation control

Monday, January 8th, 2024

Russian tactical radars are designed to pick up jets, not small, slow-moving targets:

“The results of field tests showed that the target detection radar of the Tor air defense system provides detection of small UAVs at ranges of only 3-4 km,” writes Makarenko.

This explains why drones are able to get so close and take video of these systems: the Russians are unable to spot a drone unless it is practically on top of them. When the drones are spotted, Makarenko says Tor has trouble shooting them down.

“The practical experience of experimental firing at small targets [with Tor] … indicates the low efficiency of their destruction. The main reasons for this are the imperfection of the SAM warhead detonation control system, as well as large errors in target tracking and SAM guidance on small-sized UAVs.“

This has been borne out in Ukraine, for example by this video of a Tor missile hurtling past a Ukrainian quadcopter without exploding. This is exactly what Makarenko means by a failure of detonation control.

Spent coffee grounds could make concrete stronger

Sunday, January 7th, 2024

Concrete is made of four basic ingredients: water, gravel, sand and cement.

Roychand and his team partially replaced sand with biochar — a material similar to charcoal — derived from coffee waste; they obtained their best result when they replaced 15% of the sand and baked the grounds at 350 degrees Celsius (662 degrees Fahrenheit). The resulting concrete was 30% stronger than regular concrete by compressive strength — the ability of the material to withstand a load.

In regular concrete, water, its second-largest ingredient by volume, is absorbed by the cement over time, reducing the amount of moisture that’s still inside the concrete, Roychand says. This drying effect, known as desiccation, causes shrinkage and cracking at a microscale, weakening the concrete.

Biochar from coffee waste can reduce this natural process. When the biochar is mixed with concrete, Roychand says, its particles act like tiny water reservoirs, distributed throughout the concrete. As the concrete sets and begins to harden, the biochar slowly releases the water, essentially rehydrating the surrounding material and reducing the impact of shrinkage and cracking.

Few would call the Predator a design classic

Tuesday, January 2nd, 2024

Swarm Troopers by David HamblingFew would call the Predator a design classic, David Hambling notes (in Swarm Troopers):

It is more a technological kludge of different components tacked together, with an engine derived from a snowmobile at the back, an outsize satellite communications pod stuck on top, and missiles so heavy it can barely carry them slung underneath. According to one estimate, it takes seventeen people just to fly this “unmanned” aircraft. And yet the General Atomics MQ-1 Predator has been immeasurably more successful than any previous drone.


DARPA, the Pentagon’s Defense Advanced Research Projects Agency, identified the need for a long-endurance drone and had carried out a classified study under the codename Teal Rain in the 1970s. This led to the construction of an aircraft called Amber with a wooden propeller and a distinctive upside-down-V tail.

Amber was designed by Abraham Karem, an expert on gliders and other soaring aircraft.


Leading Systems’ most important asset was a cheap export version of the Amber called the GNAT-750. The Turkish government had expressed an interest in the GNAT-750, a larger version of Amber, with a wingspan of thirty-six feet and an empty weight of five hundred pounds. Being an export model, it had less expensive electronics. The engine was a German Rotax 914 used in sailplanes and light aircraft (a smaller version is used in snowmobiles).

The GNAT-750 flew at barely a hundred miles an hour, but resembling a glider it required minimal power to stay in the air. A flight endurance of around forty-eight hours meant the GNAT-750 could maintain constant watch over a given area for longer than any manned aircraft.


When the 1993 conflict in Bosnia flared up, the US had no suitable reconnaissance drones on hand. Satellites were unable to see beneath the cloud cover. Existing spy planes were designed to operate in hostile skies, flying at extreme altitude like the U-2 or at extreme speed like the Mach-3 SR-71 Blackbird. The requirement was for a drone that could fly at low speed and low altitude, carry an off-the-shelf camera system, and beam back real-time video via a relay aircraft.


The GNAT-750 looked like the ideal solution. It provided a stable platform with long endurance and, because it was “export technology,” there was nothing sensitive that would cause problems if one was shot down and the remains analyzed.

All the GNAT-750 needed was the communications link to a relay aircraft.


One of the modifications overseen by the CIA was a security feature that shut down everything if the speed dropped too low, as it was assumed the aircraft must be on the ground. A gust of wind from behind caused the flight speed indicator to drop below the vital figure. The GNAT-750 duly switched itself off and dropped like a stone.

That sort of accident could kill a manned program along with the pilot, but the loss of a drone is not such a serious matter.


The CIA operated the GNAT-750 from Albania, flying missions to Bosnia with considerable success. Video was sent back via the manned relay aircraft — like the earlier TDR-1, DASH, and Firebee, radio range was the limitation — and missions only lasted as long as the relay plane was in place.


The resolution on the ground was eighteen inches — as good as many satellites, with the advantage that it could be sent when and where needed, whereas satellites only appear every ninety minutes as their orbit allows.


The drone turned out to be stealthy, not from design but because it was largely made of composite material and there was not much metal to give a radar return.


The Pentagon was not content to let the CIA have a monopoly on drones. As it was apparent that there might be further limited conflicts where such drones could be useful, they funded their own development of the GNAT-750. This was an Advanced Concept Technology Demonstration or ACTD for a version known as the 750-45 or 750-TE Predator. The Predator name was chosen after a competition among General Atomics employees.

The result was a larger aircraft; the empty weight almost doubled to a thousand pounds. It could stay in position five hundred miles from its base for twenty-four hours. Most important, it had extra communication equipment, including a large and unwieldy but effective Ku-band satellite communications setup with a gimbaled antenna that swivels around under its cover to keep pointing at a satellite. Sudden maneuvers tended to break the link and contact could be lost for a minute; the autopilot kicked in while the drone found its satellite again. While it was not be entirely reliable, armed with this capability, the new drone could beam back video from anywhere in the world without a relay plane. And it could fly anywhere, watching for as long as fuel lasted. It entered service in 1995 as the RQ-1 Predator.


At ten thousand feet it was inaudible, and rarely noticed by those on the ground unless they actually craned their head back to look at it. Skilled operators learned to use the cover of the sun to shield their aircraft from those they were watching.

In former Yugoslavia the Predator was of little use in directing air strikes due to a lack of training and poor communication between different units. One officer complained it took about forty-five minutes to get a strike aircraft into the same area as the drone, while the drone operators sometimes provided poor descriptions of the target — “the house with orange tiles” was not enough in a village with twenty of them. This experience prompted the addition of a laser illuminator to the Predator so the operator could highlight an aim point by shining the laser light on it, “sparkling” it, in in Air Force slang.


In a later addition, originally known as Wartime Integrated Laser Designator (WILD), Predators were fitted with lasers to mark targets so laser-guided weapons could home in on them — “lasing” rather than just “sparkling.”

Contested Logistics System, 300 Nautical Miles

Tuesday, December 26th, 2023

Silent Arrow has been selected by the USAF’s accelerator, AFWERX, for an SBIR contract focused on its CLS-300 (“Contested Logistics System, 300 Nautical Miles”) long-range attritable cargo drone — which sounds suspiciously like it’s not for cargo:

The CLS-300 is based on the commercially successful Silent Arrow GD-2000, which according to the company, is the world’s first heavy payload, autonomous and attritable cargo delivery aircraft designed to carry 1,500 lbs. of cargo over 35 nautical miles when deployed from cargo aircraft such as the Lockheed Martin C-130, Boeing C-17, and Airbus A400M.

Whereas the GD-2000 is a glider, the new CLS-300 can travel nearly 10 times as far by utilizing an innovative propulsion unit and propeller system that are inexpensive enough to allow the entire cargo drone to be attritable. In addition to being air droppable, it will also be capable of taking off from the ground including from unimproved surfaces, naval vessels and other launch points.

It maintained height and stayed in the jet stream for the three-day journey across the Pacific

Monday, December 25th, 2023

Swarm Troopers by David HamblingIn December 1944, David Hambling explains (in Swarm Troopers), US military observers on the West Coast reported a wave of unidentified flying objects:

On investigation, these were found to be paper balloons thirty feet across.


The balloons were filled with hydrogen and had a complex mechanical gondola. At first, they were thought to be weather balloons, but after reports of unexplained explosions, one was captured intact and found to be carrying incendiary bombs. This was the Japanese Fu-Go or “windship weapon.”


It was months before intelligence revealed they had flown all the way from Japan. The Japanese were taking advantage of a newly discovered natural phenomenon, the jet stream, a narrow ribbon of fast-moving air at high altitudes.


A clockwork mechanism controlled the release of a set of small sandbags around the rim of the gondola. Whenever the balloon fell too low, it dropped another sandbag. If it rose too high, which might cause it to burst, a valve vented a small amount of hydrogen. This control system meant it maintained height and stayed in the jet stream for the three-day journey across the Pacific.


The aim was to start forest fires in the heavily wooded regions of the Pacific Northwest. This would spread panic and divert resources from the war effort. The target was big enough that even this rough method of aiming had a chance of success.


US analysts estimated the Fu-Go cost $ 200 each, at a time when a P-51 Mustang was $ 50,000. The little balloons were hard to intercept. There was not enough metal on them to show up on radar, and they were surprisingly fast at high altitude, making them difficult to catch. Only around twenty were shot down.


At least four hundred Fu-Go made it to America, scattered from Mexico to Canada. The number would have been greater but for a problem with antifreeze in the altitude control system. This was too weak and the altitude controls were apt to freeze up, leaving Fu-Go to slowly descend into the waters of the Pacific.

After the war, the US considered balloons:

The E77 balloon bomb was similar to the Fu-Go, but delivered an anti-crop agent in the form of feathers dipped in a bacterial or fungal culture. Like the Fu-Go it was an imprecise way of hitting a large target, but 1954 tests suggested that balloon bombs would be effective.


The US also tested long-distance balloons for photographing enemy territory, but again balloons were edged out by manned aircraft. As always, the US military took more interest in high-performance manned aircraft than small, unmanned alternatives.

The remains were put on display, but there was no media interest

Monday, December 18th, 2023

Swarm Troopers by David HamblingIf the Pentagon hates drones, David Hambling notes (in Swarm Troopers), the CIA seems to love them:

Drones have a unique capability to carry out deniable operations, which are important to the CIA. The Agency learned the hard way just how disastrous it can be when a spy plane mission goes wrong.


Four years after the U-2 incident, the Chinese shot down a number of Fire Fly drones in their airspace. The remains were put on display and, like the Russians before them, the Chinese denounced American imperialist aggression. But there was no media interest. The Chinese might well claim that the peculiar wreckage was from American unmanned spy planes, but where was the proof? There was none of the international outcry that had accompanied the Gary Powers incident and no embarrassment for the politicians or the CIA. Equally, there was no risk that the pilot would be interrogated and give away information. (The main long-term consequence was that the Chinese reverse-engineered the drones. They ended up with a clone called WuZhen, which kick-started their own unmanned aircraft effort).

When drones did eventually find a place in the US military, thanks to the success of the Predator, it was only with considerable assistance from the CIA.