Satellite Provides Detailed Data On Antarctic Ice

February 2, 2024 by Bryan Cockfield 19 Comments

Ever since the first satellites started imaging the Earth, scientists have been using the data gathered to learn more about our planet and improve the lives of its inhabitants. From weather forecasting to improving crop yields, satellites have been put to work in a wide array of tasks. The data they gather can go beyond imaging as well. A new Chinese satellite known as Fengyun-3E is using some novel approaches to monitor Antarctic sea ice in order to help scientists better understand the changing climate at the poles.

While it is equipped with a number of other sensors, one of the more intriguing is a piece of equipment called WindRad which uses radar to measure wind at various locations and altitudes based on how the radar waves bounce off of the atmosphere at various places. Scientists have also been able to use this sensor to monitor sea ice, and can use the data gathered to distinguish new sea ice from ice which is many years old, allowing them to better understand ice formation and loss at the poles. It’s also the first weather satellite to be placed in an early morning orbit, allowing it to use the long shadows cast by the sun on objects on Earth’s surface to gather more information than a satellite in other orbits might be able to.

With plenty of other imaging sensors on board and a polar orbit, it has other missions beyond monitoring sea ice. But the data that it gathers around Antarctica should give scientists more information to improve climate models and understand the behavior of sea ice at a deeper level. Weather data from satellites like these isn’t always confined to academia, though. Plenty of weather satellites broadcast their maps and data unencrypted on radio bands that anyone can access.

Overview of the Gwyscope SPM controller.

Low-Cost DSP For Scanning Probe Microscopy

January 31, 2024 by Maya Posch 3 Comments

A scanning probe microscope comes in a wide variety of flavors, they all produce a set of data points containing the measurements at each location. Usually these data points form a regular 2D grid, but it can be more beneficial to change the density of measurements at certain locations, or even the height, which creates a much more complex probing path and subsequent (XYZ) data set.

Yet this should not deter anyone, as [Miroslav Valtr] and colleagues demonstrate in a July 2023 article in Hardware X where they use a Red Pitaya SBC along with custom Eurocard-format PCBs to create a low-cost-ish (<1,500 USD) open hardware Digital Signal Processor (DSP) they call Gwyscope.

How the Gwyscope controller fits into an example of a scanning probe microscope setup. (Credit: Miroslav Valtr et al., 2023)

The Red Pitaya itself is used as a convenient hybrid FPGA-based module with on-board signal processing hardware, with its Xilinx Zynq ARM-FPGA chip providing both an FPGA section to implement the feedback loop module in Verilog, as well as the means to run a Linux instance with the C-based software that connects via Ethernet to a remote workstation. This communication is based around the GwyFile library, which is part of the Gwyddion project. The scanning paths are generated using libgwyscan (see this presentation for an introduction).

The resulting scan data is saved as an XYZ data file, which can be read with the Gwyddion visualization and analysis program. Although far from a quick & easy afternoon project for the casual hobbyist, it could be a boon for universities and laboratories.

Thanks to [Nicolae Irimia] for the tip.

Ingenuity May Be Grounded, But Its Legacy Will Be Grand

January 30, 2024 by Donald Papp 11 Comments

[Eric Berger] has a thoughtful and detailed article explaining why Ingenuity, NASA’s small helicopter on Mars, was probably far more revolutionary than many realize, and has a legacy to grant the future of off-world exploration that is already being felt.

Ingenuity was recently grounded due to rotor damage, having already performed far beyond the scope of its original mission. The damage, visible by way of a shadow from one of the rotors, might not look like much at first glance, but flying in the vanishingly-thin atmosphere of Mars requires the 1.18 meter (3.9 foot) carbon fiber blades to spin at very high speeds — meaning even minor rotor damage could be devastating.

Perseverance and Ingenuity pose for a selfie on Mars.

[Eric] points out a lot that is deeply interesting and influential about Ingenuity. Not only is successful powered flight on another planet a real Wright brothers moment, but how Ingenuity came to be validates a profoundly different engineering approach for NASA.

To work in the space industry is to be constrained by mass. But even so, Ingenuity‘s creators had a mere four pounds to work with. That’s for rotors, hardware, electronics, batteries, solar panel — all of it. NASA’s lightest computer module alone weighed a pound, so engineers had no choice but to depart from the usual NASA way of doing things to get it done at all. Not everyone at NASA was on board. But Ingenuity worked, and it worked wonderfully.

Powered flight opens new doors, and not just for support roles like navigation planning. There’s real science that can be done if powered flight is on the table. For example, [Eric] points out that inaccessible terrain such as the Valles Marineris canyon on Mars is doubtlessly scientifically fascinating, but at 4,000 km long and up to 7 km deep, rover-based exploration is not an option.

Harvesting Electricity From High-Voltage Transmission Lines Using Fences

January 27, 2024 by Maya Posch 373 Comments

When you have a bunch of 230 kV transmission lines running over your property, why not use them for some scientific experiments? This is where the [Double M Innovations] YouTube channel comes into play, including a recent video where the idea of harvesting electricity from HV transmission lines using regular fences is put to an initial test.

The nearly final measurement by [Double M Innovations]. — The nearly final voltage measurement by [Double M Innovations].

A rather hefty 88 µF, 1200 V capacitor, a full bridge rectifier, and 73 meters (240 feet) of coax cable to a spot underneath the aforementioned HV transmission lines. The cable was then put up at a height consistent with that of fencing at about 1.2 m (4 ft), making sure that no contact with the ground occurred anywhere. One end of the copper shield of the coax was connected to the full bridge rectifier, with the opposite AC side connected to a metal stake driven into the ground. From this the capacitor was being charged.

As for the results, they were rather concerning and flashy, with the 1000 VAC-rated multimeter going out of range on the AC side of the bridge rectifier, and the capacitor slowly charging up to 1000 V before the experiment was stopped.

Based on the capacity of the capacitor and the final measured voltage of 907 VDC, roughly 36.2 Joule would have been collected, giving some idea of the power one could collect from a few kilometers of fencing wire underneath such HV lines, and why you probably want to ground them if energy collecting is not your focus.

As for whether storing the power inductively coupled on fence wire can be legally used is probably something best discussed with your local energy company.

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Could Moon Mining Spoil Its Untouched Grandeur And Science Value?

January 25, 2024 by Lewin Day 89 Comments

It’s 2024. NASA’s Artemis program is in full swing, and we’re hoping to get back to the surface of the Moon real soon. Astronauts haven’t walked on the beloved sky rock since 1972! A human landing was scheduled for 2025, which has now been pushed back to 2026, and we’re all getting a bit antsy about it. Last time we wanted to go, it only took 8 years!

Now, somehow, it’s harder, but NASA also has its sights set higher. It no longer wants to just toddle about the Moon for a bit to wave at the TV cameras. This time, there’s talk of establishing permanent bases on the Moon, and actually doing useful work, like mining. It’s a tantalizing thought, but what does this mean for the sanctity of one of the last pieces of real estate yet to be spoilt by humans? Researchers are already arguing that we need to move to protect this precious, unique environment.

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Human-Written Or Machine-Generated: Finding Intelligence In Language Models

January 24, 2024 by Maya Posch 45 Comments

What is the essential element which separates a text written by a human being from a text which has been generated by an algorithm, when said algorithm uses a massive database of human-written texts as its input? This would seem to be the fundamental struggle which society currently deals with, as the prospect of a future looms in which students can have essays auto-generated from large language models (LLMs) and authors can churn out books by the dozen without doing more than asking said algorithm to write it for them, using nothing more than a query containing the desired contents as the human inputs.

Due to the immense amount of human-generated text in such an LLM, in its output there’s a definite overlap between machine-generated text and the average prose by a human author. Statistical methods of detecting the former are also increasingly hamstrung by the human developers and other human workers behind these text-generating algorithms, creating just enough human-like randomness in the algorithm’s predictive vocabulary to convince the casual reader that it was written by a fellow human.

Perhaps the best way to detect machine-generated text may just be found in that one quality that these algorithms are often advertised with, yet which they in reality are completely devoid of: intelligence.

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X-Ray CT Scanners From EBay, Brought Back To Life

January 22, 2024 by Donald Papp 13 Comments

If you have ever wondered what goes into repairing and refurbishing an X-ray Computed Tomography (CT) scanner, then don’t miss [Ahron Wayne]’s comprehensive project page on doing exactly that. He has two small GE Explore Locus SP machines, and it’s a fantastic look into just what goes into these machines.

CT scan of papyrus roll in a bamboo sheath.

These devices use a combination of X-rays and computer software to reconstruct an internal view of an object. To bring these machines back into service means not only getting the hardware to work correctly, but the software end (including calibration and error correcting) is just as important.

That means a lot of research, testing, and making do. For example, instead of an expensive calibration grid made from an array of tiny tungsten carbide beads, [Ahron] made do with a PCB laden with a grid of copper pads. The fab house might have scratched their heads a little on that one, but it worked just fine for his purposes and price was certainly right.

Tools like these enable all kinds of weird and wonderful projects of their own. So what can one do with such a machine? CT scanning can spot fake AirPods or enable deeper reverse engineering than a regular workshop is normally able to do.

What else? Shown here is an old foil Pokémon card ~~from an unopened package!~~ (Update: the scan is not from a card in a sealed package, it is just a scanned foil card. Thanks to Ahron for clarifying.) [Ahron] coyly denies having a pet project of building a large enough dataset to try to identify cards without opening the packs. (Incidentally, if you just happen to have experience with supervised convolutional neural networks for pix2pix, he asks that you please reach out to him.)

The real power of CT scanning becomes more apparent if you take a look at the videos embedded below the page break. One is a scan of an acorn, [Ahron]’s first successful scan. Another is an interesting scan of a papyrus roll in a bamboo sheath. Both of the videos are embedded below.

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