Decoding The Tianwen-2 Sample Return Mission’s Telemetry Signal

May 27, 2026 by No comments

China’s Tianwen-2 asteroid sample return mission launched on 28 May of 2025 and is scheduled to arrive at its target – near-Earth asteroid 469219 Kamo’oalewa – in June 2026. This gives folk back on Earth plenty of time to listen in on the probe’s communication with its home base, such as [Daniel Estévez] who recently had a poke at this telemetry as captured by the Dwingeloo radio telescope in the Netherlands.

With not a lot of public information on its trajectory it’s a hard probe to track, but now that it’s nearing its destination there’s an obvious part of the sky to aim for. This is X-band telemetry, broadcast at 8428.19 MHz, with the same basic modulation as its predecessor Tianwen-1.

Where it differs is in the coding, with Tianwen-2 also using concatenated coding, but having a frame length that’s better suited to submitting full Reed-Solomon codewords and does not require omitting bytes to make things awkwardly fit.

After analyzing the telemetry data itself, there doesn’t seem to be anything exciting contained within this capture. This does seem to be as expected considering that the probe is still in its coast phase where it doesn’t have to do much and likely is in a low-power state most of the time. Once its orbital insertion burn begins is when this knowledge can likely be used to track the mission in fine-grained detail, which is an event that we’re definitely looking forward to.

Linux Distributions And Who Is Responsible For The Software

May 27, 2026 by 34 Comments

The topic of downstream and upstream is an important one in the Linux ecosystem, where from one base distribution you can go many layers of distros deep before even looking at all the other base distributions. Within that veritable jungle you get questions about who is responsible for packaging software, where to report bugs found with a specific application, as well as what ‘LTS’ truly means in a consumer context. These and other points are raised in a recent video by [Brodie Robertson], with many examples of things going tragically wrong.

There’s a good argument to be made that ultimately it is the distro that is responsible for the software that they provide via their repositories. As [Brodie] shows in the video, there are a few cases where an ‘LTS’ distro uses an old version of some software that contains a bug that has been fixed a while ago, so reporting it to the developer is rather pointless, while the distro maintainers should fix it with backporting of patches or updating the version.

From an end user experience this also makes the most sense, as in the end they just want to have the Windows experience of downloading a proverbial installer, clicking through whatever dialogs pop and have working software. If the software is provided via the distro, it is their responsibility, the same way that you contact the developer if you get a DEB or RPM from a GitHub project page and it doesn’t work.

This current Linux Chaos Vortex can be called a major issue when e.g. FreeBSD has no such upstream/downstream issues, with cross-platform installers being basically impossible on Linux ever since the Linux Standard Base effort died.

Perhaps Linux will get a distroless future, however, which may finally herald that Year of the Linux Desktop.

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Autopsy Of A Failed Vintage Carbon Resistor

May 27, 2026 by 5 Comments
Detail of the lead connecting to the inner carbon-filled tube. (Credit: CuriousMarc)
Detail of the lead connecting to the inner carbon-filled tube. (Credit: CuriousMarc)

Although resistors are hardly among the most exciting components, they are arguably one of the most important ones, as anyone who has done any amount of circuit design and debugging can attest to. So too with a single carbon resistor in a vintage Metrix oscilloscope that [CuriousMarc] recently repaired. After recapping the board there was still a major issue that got traced down to said resistor. After replacing it with a fresh resistor obviously this meant doing an autopsy to see why the old resistor had failed.

The 20 kOhm-rated resistor looked fine on the outside, with no obvious damage or discoloration, but it measured around 0.843 MOhm. To get to the insides [CuriousMarc] asked his friend [TubeTime] on how to proceed. The answer here was sandpaper and a lot of patience, and thus the experiment to see how much sanding it takes to get to the core of a fairly big resistor commenced.

Ultimately the insides were revealed, and they turned out to be rather interesting, with what looked like a glass tube filled with what would be the carbon-laden material between the two lead terminals. From poking around a bit at these insides it would appear that the failure mode was a degraded contact between these terminals and the carbon material. Considering that this resistor is many decades old and has gone through many thermal cycles and potentially various kinetic events some fractures are probably to be expected.

Perhaps most fascinating is the construction of this carbon resistor that looks to be a step above that of the average carbon resistor that [TubeTime] has taken apart over the years.

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A black-and-white clock face is shown. The numerals are ranged around the right edge of the clock. One pointer extends from the center of the clock, and one is on the left side of the face.

A Clock Inspired By Failed Cognitive Tests

May 27, 2026 by 54 Comments

One simple screening tool for cognitive impairment is the clock-drawing test (CDT): the patient is provided with a printed circle and asked to draw a clock face with the hands pointing to a certain time. Depending on how the clock is drawn, this could indicate a variety of different disorders, particularly dementia, with a particular deformity in the drawing sometimes pointing to a specific issue. These failed tests inspired [John Silvia] to create a clock with a unique, disordered face.

The numerals in this clock face are placed exclusively along the right half of the clock (in the test, this can be a sign of damage to the right parietal lobe, or of executive dysfunction caused by dementia), and out of order. The hour hand is controlled by a servo motor, and the minute hand is mounted on a separate, commercially-purchased clock mechanism on the left-hand side of the face.

The frame for the clock and the face are 3D-printed, and the servo motor is controlled by an ESP32-C3 with an RTC module. To minimize power draw, a MOSFET disconnects the servo motor from power except for the once-per-hour position update. Once per month, the ESP32 connects to Wi-Fi to synchronize to NTP time, otherwise remaining in a low-power state – even its indicator LEDs are disconnected to save power. These efforts paid off: when the servo isn’t active, it draws only about 160 µA, and a set of three AA NiMH cells lasts about a year.

Since the servo motor draws most of the power budget, it wouldn’t make much difference, but the ESP32’s co-processor can also be used for ultra-low-power projects. For a happier take on a drawing-related clock, check out one of these projects.

Inside Dyson’s Over-Engineered ₤1000 Hand Dryer

May 27, 2026 by 44 Comments

It seems fair to say that Dyson sits at the intersection of impressive engineering and borderline ridiculous products. The Dyson Airblade 9KJ hand dryer that [ElectrArc240] recently took to bits would definitely seem to fall under the latter, combining an incredible amount of engineering all for the simple task of drying wet hands.

These hand dryers are rated for a cool 900 Watts, with an 0.5 W standby power consumption, though you can also switch it to a 650 W ‘eco mode’ when installing it. The air that gets sucked into the dryer first passes through a HEPA filter before it hits the heating element and then gets blown out of the handles onto one’s hands.

Both of these handles come with a presence sensor in the form of an ST VL53L3CX time-of-flight sensor, along with a path for the heated air towards the thin slits. Returning to the section just past the HEPA filter is the compressor, with a rather fancy airflow path that involves various stacked meshes. As can be seen in the video, where you’d expect basically a simple blower motor or so, there is a truly astounding amount of parts as the teardown progresses.

The motor disassembly is the first part where some desoldering and breaking of glue bonds is really necessary, but it gives full access to the driver board. The circuit used here is your typical IGBT-based gate driver, though with a mystery PIC MCU to do things. Following this the tear-down turns fully destructive, giving access to the motor internals.

Following an analysis of these internals we marvel at the carbon-fiber rotor that keeps the single magnet in one piece. This is another engineering choice that serves to justify the 1,000 quid price tag. All so that rest room visitors do not have to suffer the humility of using paper towels.

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AMOC And The Planet-Wide Impact Of Ocean Currents

May 27, 2026 by 11 Comments

Although it can be hard to tell from looking at the often placid waters of the Earth’s oceans, their currents carry immense amounts of water around the globe on a daily basis, underlying a dynamic system that – much like the Earth’s atmosphere – plays a major role in everything from weather systems to local climates and ecosystems.

Of all these ocean currents the Atlantic meridional overturning circulation (AMOC) is perhaps the most famous, as it is basically the sole reason why Europe has the mild climate that it does today, courtesy of it carrying thermal energy from the equator all the way to the coast off Scandinavia.

Although collapsing an ocean current seems as improbable as stopping the jet streams in the upper atmosphere, it’s actually significantly easier due to how much ocean currents rely on factors that we can fairly easily influence. Over the past decades we have seen worrying signs that the AMOC is indeed weakening, with the million-dollar question being what scenario we’ll be looking at.

While collapsing the AMOC within a decade may be theoretically possible, current models seem to point towards a weakening by about half by the end of this century, with a recent research article by Valentin Portmann et al. in Science Advances going over the various statistical models to come to this conclusion.

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Three Arduinos Team Up To Make 80s-Style Computer

May 27, 2026 by 27 Comments

Back in the 80s, buying a home computer could easily mean an inflation-adjusted cost of thousands of dollars (or your equivalent currency unit of choice), and all for an 8-bit machine that might not have a hard drive and almost certainly didn’t connect to a network. Here in the future it’s easy to get spoiled by all the computing power and inexpensive devices practically falling into our laps, but using some modern low-cost microcontrollers can connect us to our early computing roots like [Joe]’s latest Arduino-based computer.

Taking design an engineering cues from computers like the Timex Sinclair 1000, Commodore PET, and TRS-80 MC-10, this computer uses a trio of Arduinos to accomplish what the best computer manufacturers once did with tons of integrated circuits. An Arduino Due handles all of the processing and traditional computing tasks, including a somewhat customized BASIC implementation, while an Uno performs audio processing duties. Taking care of the video processing is the much more capable Arduino Mega, outputting 40×25 monochrome NTSC composite video at 8×8 character resolution. There’s even WiFi courtesy of an ESP32 — certainly an upgrade compared to the source material.

After booting it up, the user gets a Commodore-like experience that replicates the 80s computing era quite well, and is even built inside its own keyboard case just like that era of computers usually were. [Joe] plans to release all three firmware images and the Python script used to get files onto the faux-retro machine, so keep an eye out for that.

In the event that you used rubles instead of dollars to pay for your expensive 8-bit machines back in the 80s, this computer might be more up your alley instead.