Bladerunners And The Mother Of Invention

August 13, 2026 by Al Williams No comments

There are plenty of stories about inventors who see a problem and decide they can do better. But Van Phillips had a little more motivation than most. The problem was his own leg. In 1976, Phillips was a 21-year-old college student when a water-skiing accident cost him his left leg below the knee. If that wasn’t bad enough, the prosthetic leg he received afterward wasn’t exactly a technological marvel. Prosthetic limbs of the era were generally designed to look and act something like a biological leg and foot, but “act” might be giving them too much credit. They were passive structures that provided something to stand on and roll over while walking.

Phillips wanted to do more than walk. There was just one problem: he wasn’t an engineer. Before the accident, he had been studying business. So, if he was going to build a better leg, first he was going to have to learn how.

Back To School

Traditional prosthetic feet (public domain)

Phillips became fascinated with prosthetics and eventually studied prosthetic design at Northwestern University’s Prosthetic-Orthotic Center. He also worked at the University of Utah’s prosthetics laboratory, where he had access to both the people and equipment he needed to experiment.

The conventional wisdom was that a prosthetic foot should imitate a human foot. That seems perfectly reasonable — evolution has had quite a long time to work on the design. But there’s a problem with simply copying the shape. A real foot isn’t just a foot-shaped object attached to the bottom of your leg. Muscles, tendons, and ligaments store and release energy as you walk or run. Your Achilles tendon, in particular, acts very much like a spring. A conventional prosthetic foot might look right, but it didn’t have anything corresponding to that spring.

Phillips eventually stopped worrying so much about making something that looked like a foot. Instead, he decided to make something that worked like one.

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The Chernobyl NPP And Forty Years Of Robots For High Radiation Environments

August 13, 2026 by Maya Posch 3 Comments

With the massive steam explosion that shredded the #4 RBMK reactor at the Chernobyl Nuclear Power Plant in 1986 it suddenly made robots that could survive a high ionizing radiation environment into the hottest item on the planet. Over the course of forty years many generations of such robots were developed, tested, improved upon or discarded, all to explore and handle hazardous waste throughout the depths of the #4 reactor’s remains.

Researchers of the ISP NPP next to one of the TR robots. (Credit: ISP NPP)

Even if the entire development and decisions here would easily fit a couple of feature length movies, the recent documentary by the [Chornobyl Family] provides a solid overview of the engineering challenges, the issues encountered along the way and the forced evolution of initially very basic designs into the robotics that today trundle and wriggle around inside reactor #4, as well as their cousins over at the couple of stricken reactors at Japan’s Fukushima Daiichi power station.

Unlike the other robots developed from 1986 onwards to provide general clean-up of scattered core material outside of the core, these robots had to venture deep inside, where radiation levels were the highest and correspondingly the challenges much more severe. This was such a problem that initially it were humans who did the exploration, as robots proved to be too fragile and too prone to getting stuck.

Until the 1990s exploration of the ruined core was quite limited, also because of a lack of urgency. While the outside clean-up and construction of the sarcophagus had to be done as quickly as possible, the core exploration was more slow and methodical, based around trying to establish its condition, what core material remained inside and try to take samples of interesting objects like the well-known ‘elephant’s foot’.

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PC-1: The 1954 Computer With No Tubes, Relays, Or Transistors

August 11, 2026 by Al Williams 29 Comments

However you make a digital computer, you need something to represent a binary digit. Usually this is some form of switch: a relay, a tube, or a transistor, although there have been other ways to represent state. In 1954, [Eiichi Goto] of Japan invented the parametron, a resonant circuit using a ferrite core and a capacitor that could be moved between two phases.

According to [Goto’s] 1959 paper, the device is effectively a parametric oscillator, similar to some used at UHF frequencies by hams. The idea is that a tuned circuit is set to some frequency and driven with twice that frequency.

A What?

A parametron is essentially a resonant circuit made with inductors or capacitors whose reactance is varied at twice its resonant frequency. That “pumping” causes the circuit to oscillate at half the pump frequency. The neat trick is that there are two equally stable oscillation states at half the pump frequency, separated from each other by 180° of phase. Those two phases become binary 0 and 1. Depending on the incoming signals, one phase will win over the others.

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Chernobyl’s Robots, Or The Hackathon From Hell

August 7, 2026 by Maya Posch 21 Comments

When the Chernobyl Nuclear Power Plant’s #4 reactor experienced an extreme criticality event on that infamous day in 1986, the resulting steam explosion and lack of any kind of containment building meant that parts of the core were scattered throughout the site. In an extensive update to the original 2023 video, the [Chornobyl Family] covers the mad scramble to design robots to perform on-the-ground measurements, and ultimately remove all this debris for safe disposal.

The TR-1A, an early debris removal robot. (Source: Chornobyl Family, YouTube)

This essentially took the form of a hackathon, involving teams from all over the USSR and allied nations, creating the most diverse range of robots that 1980s Soviet technology and later Western technology could muster.

Many of these robots didn’t perform very well, or at all, mostly due to the bypassing of any kind of testing before deployment. Especially at the beginning of the clean-up the robots were being pushed into the high-radiation zones as soon as they were finished, with not only mechanical issues being a problem, but also with e.g. inaccurate radiation measurements by the RR-1 robot, that overstated measurements by more than a factor of ten. Meanwhile the RR-2 and RR-3 were too top-heavy and after deployment by helicopter simply tipped over. Eventually manual measurements proved to be faster and safer.

Early debris removal robots like the TR-1A were rather simplistic, with successive generations of robots over the next weeks and months improving on it. The use of a combustion engine instead of batteries provided to be a boon, as combustion engines are far less affected by radiation.

The BAER Beloyarets used an airport cart as the basis, with its electronics relying on vacuum tube technology and relays, with an internal combustion engine. This proved to be one of the most reliable designs and it’s been largely preserved on display in the Chornobyl Exclusion Zone, with many others of these robots also being on display around the nuclear plant or in the city of Chornobyl.

Overall an absolutely dizzying number of robotic designs were invented on the spot, adapted from existing designs or repurposed for operation in a high-radiation zone. Eventually bulldozer designs like the STR-1 helped to push radioactive debris off the roofs into containers, massively reducing the radioactive contamination of the area.

The fact that following #4’s RUD the other three RBMK units were able to keep operating safely without risks to its operators, and with the zone now safe for tourists, is a real testament to the success of the worst hackathon imaginable. Many of the lessons learned are relevant today, including during the decommissioning of Fukushima Daiichi’s melted-down cores.

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FitzRoy’s Glass: Victorian Weather Marvel Or Glorified Thermometer?

August 6, 2026 by Al Williams 22 Comments

Everyone talks about the weather. This is doubly true for sailors, where bad weather could mean a very bad day. So it isn’t surprising that navies around the world have had a keen interest in weather forecasting. But how did you predict the weather before modern instruments, radar, and satellite images? Vice Admiral Robert FitzRoy had great faith in “storm glasses,” a glass chamber containing some chemicals that he didn’t invent, but did document and promote heavily during the 1860s.

Did it work? Apparently not, but the device is still interesting in its own right. FitzRoy was a pioneer of meteorology, replacing folklore with actual observations and attempts at scientific rigor. While he did arm observation stations with conventional things like thermometers and barometers, he was also a proponent of the weather glass. Continue reading “FitzRoy’s Glass: Victorian Weather Marvel Or Glorified Thermometer?” →

Re-Testing An Apollo Guidance Computer Module That Failed Certification Testing

July 27, 2026 by Maya Posch 5 Comments

After getting his hands on a rope driver module from the Apollo project era that had a big ‘Scrapped Module’ stamped on it, [Mike Stewart] was naturally left curious as to what exactly had failed in this module. Originally destined for the Apollo Guidance Computer, these Raytheon-manufactured modules were the pinnacle of space-grade high-tech of the 1960s, with requisite acceptance testing so as to not endanger a very expensive space mission.

The cool part here is that the acceptance documents for the module in question (B16-B17) have been scanned in and can be found on the Internet Archive. With the part itself being potted and very much inaccessible, this document helpfully lays out the expected measurements on the module’s pins, as well as schematics and mechanical drawings. Unfortunately the reasons for the rejection were not recorded, so replicating the failing test results is required to understand the reason.

NASA Rope Driver Module with suspicious exploration marks. (Credit: Mike Stewart, YouTube)

A slight complication here is that the testing procedure doesn’t just involve hooking up a multimeter for some voltage and capacitance measurements. There are also temperature and voltage extremes, and vibration tolerance involved, which would be somewhat complex to test, but most of all risk damaging a historical artefact. Thus a somewhat conservative testing procedure was chosen, even if this may not reveal the actual fault.

As noted in the video, sometimes modules were also rejected because someone simply dropped it on the floor along the way. However, generally if a module was found to be faulty they would open it to diagnose said fault, with a closer look at this module indeed revealing suspicious marks in the potting compound where it was apparently opened and conceivably repaired. This also might explain why they also put the ‘For engineering use only’ on it.

With multiple of such locations visible in the potting compound, these locations were mapped to the schematics for the module, to get some idea of what may have been accessed. After this, basic testing was performed on the module, as per the acceptance testing document.

Along the way an error was detected in said document, in the form of the wrong pin number. In table 4-2 the input pin 269 was mistakenly listed as having output pin number 169 when it should have been pin 168. Pin 169 is chassis ground, so this was presumably fixed in a later version of the document.

After all the testing with just stationary, room-temperature conditions, everything appeared to check out. This means that likely this was indeed a repaired module that got subsequently used for engineering purposes rather than installed in flight-ready hardware. The only issue found was that channels were out of calibration, but whether this was an original flaw or due to the module being half a century old is hard to tell in the absence of repair logs.

Overall it’s an exciting opportunity to document another part of history, since so many of the details pertaining to these original modules and related technologies got lost or muddled over the decades.

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Encryption In The 1790s

July 23, 2026 by Al Williams 12 Comments

For as long as humans have had writing, there’s been a need to send secret messages. It is easy to think that Enigma machines and their immediate predecessors are old tech, but they are much more recent than ancient systems used by the Greeks and Romans. Even Thomas Jefferson, one of the founding fathers of the United States, was interested in encryption and is often said to have invented the Jefferson Disk machine for encryption. The truth is, the device is probably older than Jefferson, but he certainly thought about using it for secret communications.

Simple but Effective

Thomas Jefferson was, apparently, a fan of secret messages

The idea is simple. We make a series of disks. Each disk has a number on it and, around the edge, all the letters of the alphabet. The placement of each wheel with the same number is the same, but, overall, the arrangement is random. That is, all disks marked #5 might start with XCBYG, but all disks marked with #10 could start with FAYQL. You take one set of disks, and I keep the other set.

When we want to send secret messages, we agree to arrange our disks on an axle in the same order. Jefferson used a 36-disk system, so we might agree to go left to right with the odd numbers first and then the even numbers, or any other setup that we could agree on.

Encryption

Once the wheels are in place, encryption is simple. There’s a bar across the device, and you line up your message using a wheel for each letter: ENEMYCOMESBYSEA, for example. Then you look at any different row, which will now read something crazy like: FSRSSXQCGAEEFOR (plus the random letters on the rest of the disks). That’s the message you send.

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