Here are two suppressed inventions.

The first was Airadar. (Not "AI", "Air".)[1] I wrote about this on HN in 2016. This was a small phased-array radar for light aircraft, developed in 1973. It was suppressed by a patent secrecy order, because it was better than what the USAF had at the time. The inventor was a really good RF designer. Phased array radars existed back then, but they were huge ground-based installations. Mini phased array radars are available now, but it took decades for them to be available for light aircraft.[2]

The second was the electronic fluorescent lamp ballast. This was a replacement for those bulky magnetic ballasts found inside fluorescent light fixtures. The inventor licensed it to MagneTek, the biggest maker for magnetic ballasts, which didn't make it and didn't pay any royalties. So the inventor went to Townsend, Townsend, and Crew, the IP law firm in Palo Alto, and, after much litigation, came out with a hundred million or so. The law firm put this in their reception room brag book. Today, electronic fluorescent lamp ballasts are a commodity.

The problem with FOGBANK, the aerogel used in fusion weapons, turned out to be that the original process only worked because of some impurity in the raw materials. Attempts to replicate the process used a source for a raw material which was now better purified, and the process failed. It required tens of millions of dollars and a special appropriation to figure out the underlying problem. There was a period of over a decade during which the US could not make new H-bombs.

[1] https://books.google.com/books?id=NWzlTqj0gQ4C&pg=PA64#v=one...

[2] https://www.garmin.com/en-US/p/576890/

[3] https://news.ycombinator.com/item?id=11862911

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lostlogin 3 days ago | parent [-]

Re FOGBANK, isn’t that the opposite of what you’re arguing? It’s an invention for which the production method was lost.

It also seems it wasn’t fully understood initially.

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estimator7292 3 days ago | parent [-]

It wasn't fully understood, but at the time they understood it well enough to make it work. It was lost because it was an extremely classified material that we had no use for for decades. By the time we needed it again, most of the original records had been lost and all previous engineers were long dead.

We knew what it was and roughly how it worked, but it was very much a process of re-inventing from scratch.

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tialaramex 3 days ago | parent [-]

I think it's important to distinguish that what happened is they did not really understand why Fogbank worked, they just thought they did.

Consider fire. Or fluorescent lamps. Or radio. There's a trick, we don't really understand what's going on, yet there is clearly something here worth more investigation and gradually we get a better understanding.

A give away is often that there's perceived to be an "art" to making it work, and then once we understand properly the art dissolves, replaced by science. Making fudge without modern technology involves hard to learn judgement to get the right temperatures, but, today you can buy an accurate digital probe and use the recipe and that'll work reliably because it's just sugar chemistry, no art needed.

Cost does factor into it. They're never going to make more of those last gasp Walkmans, where the device is barely bigger than the tape and it has excellent sound quality and long battery life. Not because it's somehow lost technology but because it doesn't make economic sense any more. It's worse along so many dimensions at once than what we have today, and yet it'd be incredibly expensive, so it won't happen.

	▲	Animats 3 days ago \| parent [-]
		> Consider fire. Or fluorescent lamps. Or radio. There's a trick, we don't really understand what's going on, yet there is clearly something here worth more investigation and gradually we get a better understanding. More significantly, steel. Making steel was hit-and-miss until the capability to analyze ores was developed. Even then, it took about 10,000 tries to debug the Bessemer process. Steel has been made in small quantities for thousands of years, but quality steel only dates from the 1880s. The first steel I-beams were made in the late 1880s. (Despite what Microsoft Copilot says, steel I-beams were not made in 1849. Those were wrought-iron I-beams.)