Highlights this week: Specific Aperture Radar from space 📡 Astro Mechanica deep dive 🚀 and thoughts on a PCB Act 🔖
📝 Featured Article: From Partsbox - The 10 Most Popular Hobbyist Electronic Components (2024).
🎙️Featured interview: This week we spoke with Nick McCleery of Anneal.
Interesting Links 🏭
How the Lockheed SR-71 Blackbird Works. Incredibly detailed video that goes every nearly every engineering detail and function in the SR-71, from fuel chemistry to engine design. For weight reduction, the SR-71 doesn’t have a built-in starter. Instead, ‘start-carts’ with two muscle-car engines (and no mufflers) were hooked up on the ground and used at full blast. The video also covers the reconnaissance equipment aboard the SR-71, including the astral navigation system (ANS) which would track three groups of stars to determine the jet’s position to within 300ft anywhere on the globe, well before GPS was available in the 1960’s.
Packy McCormick of Not Boring explains the science and engineering behind the Astro Mechanica Turboelectric Adaptive Jet Engine. This engine is ‘efficient at every speed’, which is critical as we push faster and faster past mach-5 flight. One of the core design insights is separating the compressor from the actual jet engine. Air flows in through the turbogenerator (which Astro Mechanica buys off the shelf) to produce electrical power. That electrical power is used to power an electric motor. The electric motor can be used to adaptively control the propulsion unit (which Astro Mechanica makes in-house) on the left with precision, making it behave like a turbofan, turbojet, or ramjet depending on the speed. AM built their prototype with just $200k and are now in YC’s W24 batch after a $3M seed raise from A16Z.
A window into Amphenol’s PCB fab, one of just 150 remaining domestic US PCB manufacturers. The US now makes only 13 percent of the world supply of semiconductors, 4 percent of the PCB’s, and a fraction of a percent of IC substrates. This piece from The Lexington Institute discusses a recently proposed PCB’s act which, similar to the CHIPS act, would rebuild US domestic PCB manufacturing capabilities.
50 million metric tons of e-waste are generated globally in 2018. Despite the $60B of value in the materials it contains, only 20% of them are currently recycled. PCB’s represent on average 8% of this electronic waste, yet only about 10 out of the 60-plus chemical elements that they contain are routinely recovered and recycled. This complete breakdown covers every effective method to disassemble a PCB and then recycle to recover raw materials from components and the PCB. One of the most important aspects of PCB recycling is whether components are able to be sorted, or if bulk crushing methods have to be used.
A thread explaining Spruce Pine high-purity quartz, which is an essential semiconductor raw material. This mine in North Carolina supplies 80-90% of the global high-purity quartz demand, and it would be incredibly expensive to purify other types of quartz to this level with modern techniques. Effectively, one of the world’s most important natural resources resides in a near-single-source in North Carolina.
How the analog filters inside the iPhone have changed over the years. In just ten years, from the first iPhone to the iPhone 7, the device went from receiving a single cellular band to more than twenty. Two technologies, specific acoustic wave (SAW) and bulk acoustic wave (BAW) are used to filter out the relevant bands. As the number of frequency bands rises the IC dies of these SAW and BAW filters increasingly look like mineral deposits. Check out these examples from Yole Group.
A very interesting piece from COMSOL explaining the ideal capacitor paradox. Essentially if you draw a circuit with two ideal capacitors connected by ideal wires and provide an initial charge to one of them, circuit analysis will appear to violate the conservation of energy, with half the energy disappearing. In reality the ideal wire needs to be represented by an ideal inductor and this is where the other half of the energy goes.
Startup News 🚀💰:
Picogrid has raised a $12M Seed round to further develop its cloud defense connector platform Legion, which provides a secure way to exchange defense data between systems even if they were not designed to be interoperable. Led by Initialized Capital with participation by Starburst Ventures, Credo Ventures, Giant Step Capital, Domino Ventures, and Alumni Ventures.
iSpace has raised $53.5M to fund its third spacecraft when a major investor exercised warrants to purchase more shares following a failure of its second spacecraft on the lunar surface earlier this year.
Vista, a startup developing structural batteries for space applications, has launched recently. Publicly announced fundraising is just a $500k YC convertible note at this time.
Evari raised a $7.5M Seed round to develop a turbomachinery powered heat pump that can work across a much wider range of temperatures than is currently possible. Drawing upon a background in EV technology the oil-free pump is up to 50% more efficient. Led by Clean Energy Ventures, with participation from Clean Energy Venture Group (CEVG) angel investors and Farvatn Venture
DiamFab raised a $9.4M funding round to set up a pilot production line and ‘pre-industrialize’ the company’s diamond semiconductor power conversion products. Able to withstand high voltage, temperature, and radiation levels, diamond semiconductors could offer higher efficiencies than is currently possible.
This bistatic specific aperture radar image captured by Umbra.
