Touchless Support Leaves No Mark

[Clough42] created a 3D print for a lathe tool and designed in some support to hold the piece on the bed while printing. It worked, but removing the support left unsightly blemishes on the part. A commenter mentioned that the support doesn’t have to exactly touch the part to support it. You can see the results of trying that method in the video below.

In this case [Cloug42] uses Fusion, but the idea would be the same regardless of how you design your parts. Originally, the support piece was built as a single piece along with the target object. However, he changed it to make the object separate from the support structure. That’s only the first step, though. If you import both pieces and print, the result will be the same.

Instead, he split the part into the original two objects that touch but don’t blend together. The result looks good.

We couldn’t help but notice that we do this by mistake when we use alternate materials for support (for example, PETG mixed with PLA or PLA with COPE). Turns out, maybe you don’t have to switch filament to get good results.

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hackaday.com/2026/01/22/touchl…

New Drug Hopes To Treat Sleep Apnea Without Masks

Sleep apnea is a debilitating disease that many sufferers don’t even realize they have. Those afflicted with the condition will regularly stop breathing during sleep as the muscles in their throat relax, sometimes hundreds of times a night. Breathing eventually resumes when the individual’s oxygen supply gets critically low, and the body semi-wakes to restore proper respiration. The disruption to sleep causes serious fatigue and a wide range of other deleterious health effects.

Treatment for sleep apnea has traditionally involved pressurized respiration aids, mechanical devices, or invasive surgeries. However, researchers are now attempting to develop a new drug combination that could solve the problem with pharmaceuticals alone.

Breathe Into Me

There are a variety of conditions that fall under the sleep apnea umbrella, with various causes and a range of imperfect treatments. Perhaps the most visible is obstructive sleep apnea (OSA), in which the muscles in the throat relax during sleep. Under certain conditions, and depending on anatomy, this can lead the airway to become blocked, causing a cessation of breathing that requires the sufferer to wake to a certain degree to restore proper respiration. Since the 1980s, OSA has routinely been treated with the use of Continuous Positive Airway Pressure (CPAP) machines, which supply pressurized air to the face and throat to forcibly keep the airway open. These are effective, except for one major problem—a great deal of patients hate them, and compliance with treatment is remarkably poor. Some studies have shown up to 50% of patients give up on CPAP treatment within a year due to discomfort around sleeping with a pressurized air mask.
Obstructive sleep apnea occurs when upper airway muscles relax excessively during sleep, ultimately restricting or totally blocking the airway. Credit: Apnimed
Against this backdrop, a simple pill-based treatment for sleep apnea is a remarkably attractive proposition. It would allow the treatment of the condition without the need for expensive, high-maintenance CPAP machines which a huge proportion of patients hate using in the first place. Such a treatment is now close to being a reality, under the name AD109.

The treatment aims to directly target the actual cause of obstructive sleep apnea. OSA is a neuromuscular condition, and one that only occurs during sleep—as those afflicted with the disease don’t suffer random airway blockages while awake. When sleep occurs, neurotransmitter levels like norepinephrine tend to decrease. This can can cause the upper airway muscles to excessively relax in sleep apnea sufferers, to the point that the airway blocks itself shut. AD109 tackles this issue with a combination of drugs—an antimuscarinic called aroxybutynin, and a norepinephrine reuptake inhibitor called atomoxetine. In simple terms, the aroxybutynin blocks so-called muscarinic receptors which decrease muscle tone in the upper airway. Meanwhile, the atomoxetine is believed to simultaneously improve muscle tone in the upper airway by maintaining higher activity in the hyperglossal motor neurons that control muscles in this area.
Results in phase 2 testing showed a marked decrease in AHI compared to those taking a placebo. Credit: research paper
Thus far, clinical testing has been positive, suggesting the synergistic combination of drugs may be able to improve airflow for sleep apnea patients. Phase 1 and Phase 2 clinical trials have been conducted to verify the safety of the treatment, as well as its efficacy at treating the condition. Success in the trials was measured with the Apnea-Hypopnea Index (AHI), which records the number of airway disruptions an individual has per hour. AHI events were reduced by 45% in those taking AD109 when compared to the placebo group in a phase 2 trial featuring 211 participants. It achieved this while proving generally safe in early testing without causing detectable detriments to attention or memory. However, some side effects were noted with the drug—most specifically dry mouth, urinary hesitancy, and a level of insomina. The latter being particularly of note given the drug’s intention to improve sleep.

Testing on AD109 continues, with randomized Phase 3 trials measuring its performance in treating mild, moderate, and severe obstructive sleep apnea. For now, commercialization remains a ways down the road. And yet, for the first time, it appears promising that modern medicine will develop a simple drug-based treatment for a disease that leaves millions fatigued and exhausted every day. If it proves viable, expect it to become a major pharmaceutical success story and the hottest new drug on the market.

hackaday.com/2026/01/22/new-dr…

STL Editing with FreeCAD

[Kevin] admits that FreeCAD may not be the ideal tool for editing STL files. But it is possible, and he shares some practical advice in the video below. If you want to get the most out of your 3D printer, it pays to be able to create new parts, and FreeCAD is a fine option for that. However, sometimes you download an STL from the Internet, and it just isn’t quite what you need.

Unlike native CAD formats, STLs are meshes of triangles, so you get very large numbers of items, which can be unwieldy. The first trick is to get the object exactly centered. That’s easy if you know how, but not easy if you are just eyeballing it.

If you use the correct workbench, FreeCAD can analyze and fix mesh problems like non-manifold parts, flipped normals, and other issues. The example is a wheel with just over 6,000 faces, which is manageable. But complex objects may make FreeCAD slow. [Kevin] says you should be fine until the number of faces goes above 100,000. In that case, you can decimate the number of faces with, of course, a corresponding loss in resolution.

Once you are satisfied with the mesh, you can create a real FreeCAD shape from the mesh. The resulting object will be hollow, so the next step will be to convert the shape to a solid.

That still leaves many triangles when you really want flat surfaces to be, well, flat. The trick is to make a copy and use the “refine shape” option for the copy. Once you have a FreeCAD solid, you can do anything you can do in FreeCAD.

We’ve run our share of FreeCAD tips if you want more. There are other ways to tweak STLs, too.

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hackaday.com/2026/01/22/stl-ed…

Skimming Satellites: On the Edge of the Atmosphere

There’s little about building spacecraft that anyone would call simple. But there’s at least one element of designing a vehicle that will operate outside the Earth’s atmosphere that’s fairly easier to handle: aerodynamics. That’s because, at the altitude that most satellites operate at, drag can essentially be ignored. Which is why most satellites look like refrigerators with solar panels and high-gain antennas attached jutting out at odd angles.

But for all the advantages that the lack of meaningful drag on a vehicle has, there’s at least one big potential downside. If a spacecraft is orbiting high enough over the Earth that the impact of atmospheric drag is negligible, then the only way that vehicle is coming back down in a reasonable amount of time is if it has the means to reduce its own velocity. Otherwise, it could be stuck in orbit for decades. At a high enough orbit, it could essentially stay up forever.
Launched in 1958, Vanguard 1 is expected to remain in orbit until at least 2198
There was a time when that kind of thing wasn’t a problem. It was just enough to get into space in the first place, and little thought was given to what was going to happen in five or ten years down the road. But today, low Earth orbit is getting crowded. As the cost of launching something into space continues to drop, multiple companies are either planning or actively building their own satellite constellations comprised of thousands of individual spacecraft.

Fortunately, there may be a simple solution to this problem. By putting a satellite into what’s known as a very low Earth orbit (VLEO), a spacecraft will experience enough drag that maintaining its velocity requires constantly firing its thrusters. Naturally this presents its own technical challenges, but the upside is that such an orbit is essentially self-cleaning — should the craft’s propulsion fail, it would fall out of orbit and burn up in months or even weeks. As an added bonus, operating at a lower altitude has other practical advantages, such as allowing for lower latency communication.

VLEO satellites hold considerable promise, but successfully operating in this unique environment requires certain design considerations. The result are vehicles that look less like the flying refrigerators we’re used to, with a hybrid design that features the sort of aerodynamic considerations more commonly found on aircraft.

ESA’s Pioneering Work

This might sound like science fiction, but such craft have already been developed and successfully operated in VLEO. The best example so far is the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE), launched by the European Space Agency (ESA) back in 2009.

To make its observations, GOCE operated at an altitude of 255 kilometers (158 miles), and dropped as low as just 229 km (142 mi) in the final phases of the mission. For reference the International Space Station flies at around 400 km (250 mi), and the innermost “shell” of SpaceX’s Starlink satellites are currently being moved to 480 km (298 mi).

Given the considerable drag experienced by GOCE at these altitudes, the spacecraft bore little resemblance to a traditional satellite. Rather than putting the solar panels on outstretched “wings”, they were mounted to the surface of the dart-like vehicle. To keep its orientation relative to the Earth’s surface stable, the craft featured stubby tail fins that made it look like a futuristic torpedo.

Even with its streamlined design, maintaining such a low orbit required GOCE to continually fire its high-efficiency ion engine for the duration of its mission, which ended up being four and a half years.

In the case of GOCE, the end of the mission was dictated by how much propellant it carried. Once it had burned through the 40 kg (88 lb) of xenon onboard, the vehicle would begin to rapidly decelerate, and ground controllers estimated it would re-enter the atmosphere in a matter of weeks. Ultimately the engine officially shutdown on October 21st, and by November 9th, it’s orbit had already decayed to 155 km (96 mi). Two days later, the craft burned up in the atmosphere.

JAXA Lowers the Bar

While GOCE may be the most significant VLEO mission so far from a scientific and engineering standpoint, the current record for the spacecraft with the lowest operational orbit is actually held by the Japan Aerospace Exploration Agency (JAXA).

In December 2017 JAXA launched the Super Low Altitude Test Satellite (SLATS) into an initial orbit of 630 km (390 mi), which was steadily lowered in phases over the next several weeks until it reached 167.4 km (104 mi). Like GOCE, SLATS used a continuously operating ion engine to maintain velocity, although at the lowest altitudes, it also used chemical reaction control system (RCS) thrusters to counteract the higher drag.

SLATS was a much smaller vehicle than GOCE, coming in at roughly half the mass. It also carried just 12 kg (26 lb) of xenon propellant, which limited its operational life. It also utilized a far more conventional design than GOCE, although its rectangular shape was somewhat streamlined when compared to a traditional satellite. Its solar arrays were also mounted in parallel to the main body of the craft, giving it an airplane-like appearance.

The combination of lower altitude and higher frontal drag meant that SLATS had an even harder time maintaining velocity than GOCE. Once its propulsion system was finally switched off in October 2019, the craft re-entered the atmosphere and burned up within 24 hours. The mission has since been recognized by Guinness World Records for the lowest altitude maintained by an Earth observation satellite.

A New Breed of Satellite

As impressive as GOCE and SLATS were, their success was based more on careful planning than any particular technological breakthrough. After all, ion propulsion for satellites is not new, nor is the field of aerodynamics. The concepts were simply applied in a novel way.

But there exists the potential for a totally new type of vehicle that operates exclusively in VLEO. Such a craft would be a true hybrid, in the sense that its primarily a spacecraft, but uses an air-breathing electric propulsion (ABEP) system akin to an aircraft’s jet engine. Such a vehicle could, at least in theory, maintain an altitude as low as 90 km (56 mi) indefinitely — so long as its solar panels can produce enough power.

Both the Defense Advanced Research Projects Agency (DARPA) in the United States and the ESA are currently funding several studies of ABEP vehicles, such as Redwire’s SabreSat, which have numerous military and civilian applications. Test flights are still years away, but should VLEO satellites powered by ABEP become common platforms for constellation applications, they may help alleviate orbital congestion before it becomes a serious enough problem to impact our utilization of space.

hackaday.com/2026/01/22/skimmi…