Eulogy For The Satellite Phone

June 23, 2025 by Al Williams 54 Comments

We take it for granted that we almost always have cell service, no matter where you go around town. But there are places — the desert, the forest, or the ocean — where you might not have cell service. In addition, there are certain jobs where you must be able to make a call even if the cell towers are down, for example, after a hurricane. Recently, a combination of technological advancements has made it possible for your ordinary cell phone to connect to a satellite for at least some kind of service. But before that, you needed a satellite phone.

On TV and in movies, these are simple. You pull out your cell phone that has a bulkier-than-usual antenna, and you make a call. But the real-life version is quite different. While some satellite phones were connected to something like a ship, I’m going to consider a satellite phone, for the purpose of this post, to be a handheld device that can make calls.

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Earth’s Oxygen Levels And Magnetic Field Strength Show Strong Correlation

June 23, 2025 by Maya Posch 19 Comments

Time series of O2 (blue) and VGADM (red). (Credit: Weijia Kuang, Science Advances, 2025)

In an Earth-sized take on the age-old ‘correlation or causality’ question, researchers have come across a fascinating match between Earth’s magnetic field and its oxygen levels since the Cambrian explosion, about 500 million years ago. The full results by [Weijia Kuang] et al. were published in Science Advances, where the authors speculate that this high correlation between the geomagnetic dipole and oxygen levels as recorded in the Earth’s geological mineral record may be indicative of the Earth’s geological processes affecting the evolution of lifeforms in its biosphere.

As with any such correlation, one has to entertain the notion that said correlation might be spurious or indirectly related before assuming a strong causal link. Here it is for example known already that the solar winds affect the Earth’s atmosphere and with it the geomagnetic field, as more intense solar winds increase the loss of oxygen into space, but this does not affect the strength of the geomagnetic field, just its shape. The question is thus whether there is a mechanism that would affect this field strength and consequently cause the loss of oxygen to the solar winds to spike.

Here the authors suggest that the Earth’s core dynamics – critical to the geomagnetic field – may play a major role, with conceivably the core-mantle interactions over the course of millions of years affecting it. As supercontinents like Pangea formed, broke up and partially reformed again, the impact of this material solidifying and melting could have been the underlying cause of these fluctuations in oxygen and magnetic field strength levels.

Although hard to say at this point in time, it may very well be that this correlation is causal, albeit as symptoms of activity of the Earth’s core and liquid mantle.

Tiny Tellurium Orbits Atop A Pencil

June 21, 2025 by Tyler August 7 Comments

We like scale models here, but how small can you shrink the very large? If you’re [Frans], it’s pretty small indeed: his Micro Tellurium fits the orbit of the Earth on top of an ordinary pencil. While you’ll often see models of Earth, Moon and Sun’s orbital relationship called “Orrery”, that’s word should technically be reserved for models of the solar system, inclusive of at least the classical planets, like [Frans]’s Gentleman’s Orrery that recently graced these pages. When it’s just the Earth, Moon and Sun, it’s a Tellurium.

The whole thing is made out of brass, save for the ball-bearings for the Earth and Moon. Construction was done by a combination of manual milling and CNC machining, as you can see in the video below. It is a very elegant device, and almost functional: the Earth-Moon system rotates, simulating the orbit of the moon when you turn the ring to make the Earth orbit the sun. This is accomplished by carefully-constructed rods and a rubber O-ring.

Unfortunately, it seems [Franz] had to switch to a thicker axle than originally planned, so the tiny moon does not orbit Earth at the correct speed compared to the solar orbit: it’s about half what it ought to be. That’s unfortunate, but perhaps that’s the cost one pays when chasing smallness. It might be possible to fix in a future iteration, but right now [Franz] is happy with how the project turned out, and we can’t blame him; it’s a beautiful piece of machining.

It should be noted that there is likely no tellurium in this tellurium — the metal and the model share the same root, but are otherwise unrelated. We have featured hacks with that element, though.

Thanks to [Franz] for submitting this hack. Don’t forget: the tips line is always open, and we’re more than happy to hear you toot your own horn, or sing the praises of someone else’s work. Continue reading “Tiny Tellurium Orbits Atop A Pencil” →

Build Your Own Telescope The Modern Way

June 19, 2025 by Al Williams 37 Comments

When we were kids, it was a rite of passage to read the newly arrived Edmund catalog and dream of building our own telescope. One of our friends lived near a University, and they even had a summer program that would help you measure your mirrors and ensure you had a successful build. But most of us never ground mirrors from glass blanks and did all the other arcane steps required to make a working telescope. However, [La3emedimension] wants to tempt us again with a 3D-printable telescope kit.

Before you fire up the 3D printer, be aware that PLA is not recommended, and, of course, you are going to need some extra parts. There is supposed to be a README with a bill of parts, but we didn’t see it. However, there is a support page in French and a Discord server, so we have no doubt it can be found.

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Space-Based Datacenters Take The Cloud Into Orbit

June 19, 2025 by Tyler August 41 Comments

Where’s the best place for a datacenter? It’s an increasing problem as the AI buildup continues seemingly without pause. It’s not just a problem of NIMBYism; earthly power grids are having trouble coping, to say nothing of the demand for cooling water. Regulators and environmental groups alike are raising alarms about the impact that powering and cooling these massive AI datacenters will have on our planet.

While Sam Altman fantasizes about fusion power, one obvious response to those who say “think about the planet!” is to ask, “Well, what if we don’t put them on the planet?” Just as Gerard O’Neill asked over 50 years ago when our technology was merely industrial, the question remains:

“Is the surface of a planet really the right place for expanding technological civilization?”

O’Neill’s answer was a resounding “No.” The answer has not changed, even though our technology has. Generative AI is the latest and greatest technology on offer, but it turns out it may be the first one to make the productive jump to Earth Orbit. Indeed, it already has, but more on that later, because you’re probably scoffing at such a pie-in-the-sky idea.

There are three things needed for a datacenter: power, cooling, and connectivity. The people at companies like Starcloud, Inc, formally Lumen Orbit, make a good, solid case that all of these can be more easily met in orbit– one that includes hard numbers.

Sure, there’s also more radiation on orbit than here on earth, but our electronics turn out to be a lot more resilient than was once thought, as all the cell-phone cubesats have proven. Starcloud budgets only 1 kg of sheilding per kW of compute power in their whitepaper, as an example. If we can provide power, cooling, and connectivity, the radiation environment won’t be a showstopper.

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History Of Forgotten Moon Bases

June 16, 2025 by Al Williams 37 Comments

If you were alive when 2001: A Space Odyssey was in theaters, you might have thought it didn’t really go far enough. After all, in 1958, the US launched its first satellite. The first US astronaut went up in 1961. Eight years later, Armstrong put a boot on the moon’s surface. That was a lot of progress for 11 years. The movie came out in 1968, so what would happen in 33 years? Turns out, not as much as you would have guessed back then. [The History Guy] takes us through a trip of what could have been if progress had marched on after those first few moon landings. You can watch the video below.

The story picks up way before NASA. Each of the US military branches felt like it should take the lead on space technology. Sputnik changed everything and spawned both ARPA and NASA. The Air Force, though, had an entire space program in development, and many of the astronauts for that program became NASA astronauts.

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End Of An Era: NOAA’s Polar Sats Wind Down Operations

June 12, 2025 by Tom Nardi 16 Comments

Since October 1978, the National Oceanic and Atmospheric Administration (NOAA) has operated its fleet of Polar-orbiting Operational Environmental Satellites (POES) — the data from which has been used for a wide array of environmental monitoring applications, from weather forecasting to the detection of forest fires and volcanic eruptions. But technology marches on, and considering that even the youngest member of the fleet has been in orbit for 16 years, NOAA has decided to retire the remaining operational POES satellites on June 16th.

NOAA Polar-orbiting Operational Environmental Satellite (POES)

Under normal circumstances, the retirement of weather satellites wouldn’t have a great impact on our community. But in this case, the satellites in question utilize the Automatic Picture Transmission (APT), Low-Rate Picture Transmission (LRPT), and High Resolution Picture Transmission (HRPT) protocols, all of which can be received by affordable software defined radios (SDRs) such as the RTL-SDR and easily decoded using free and open source software.

As such, many a radio hobbyist has pointed their DIY antennas at these particular satellites and pulled down stunning pictures of the Earth. It’s the kind of thing that’s impressive enough to get new folks interested in experimenting with radio, and losing it would be a big blow to the hobby.

Luckily, it’s not all bad news. While one of the NOAA satellites slated for retirement is already down for good, at least two remaining birds should be broadcasting publicly accessible imagery for the foreseeable future.

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