Basics Of Remote Cellular Access: Watchdogs

October 14, 2021 by Zoe Skyforest 21 Comments

When talking about remote machines, sometimes we mean really remote, beyond the realms of wired networks that can deliver the Internet. In these cases, remote cellular access is often the way to go. Thus far, we’ve explored the hardware and software sides required to control a machine remotely over a cellular connection.

However, things can and do go wrong. When that remote machine goes offline, getting someone on location to reboot it can be prohibitively difficult and expensive. For these situations, what you want is some way to kick things back into gear, ideally automatically. What you’re looking for is a watchdog timer!

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Space Age Road Rage: Right Of Way Above The Karman Line

October 13, 2021 by Ryan Flowers 35 Comments

On a dark night in 2006 I was bicycle commuting to my office, oblivious to the countless man made objects orbiting in the sky above me at thousands of miles per hour. My attention was instead focused on a northbound car speeding through a freeway underpass at dozens of miles per hour, oblivious to my southbound headlamp. The car swerved into the left turn lane to get to the freeway on-ramp. The problem? I was only a few feet from crossing the entrance to that very on-ramp! As the car rushed through their left turn I was presented with a split second decision: slow, and possibly stop in the middle of the on-ramp, or just go for it and hope for the best.

A graphic depicting a dawdling bicycle rider about to be in the way of a speeding car driver — In Blue: Terrified cyclist. In Red: A speeding car careening around a corner without slowing down.

By law I had the right of way. But this was no time to start discussing right of way with the driver of the vehicle that threatened to turn me into a dark spot on the road. I followed my gut instinct, and my legs burned in compliance as I sped across that on-ramp entrance with all my might. The oncoming car missed my rear wheel by mere feet! What could have ended in disaster and possibly even death had resulted in a near miss.

Terrestrial vehicles generally have laws and regulations that specify and enforce proper behavior. I had every right to expect the oncoming car be observant of their surroundings or to at least slow to a normal speed before making that turn. In contrast, traffic control in Earth orbit conjures up thoughts of bargain-crazed shoppers packed into a big box store on Black Friday.

So is spacecraft traffic in orbit really a free-for-all? If there were stringent rules, how can they be enforced? Before we explore the answers to those questions, let’s examine the problem we’re here to discuss: stuff in space running into other stuff in space.

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A Tritium Story: How Afraid Should You Be Of Hydrogen’s Big Brother?

October 12, 2021 by Maya Posch 30 Comments

Despite being present in everything that contains water, tritium is not an isotope that many people were that familiar with outside of select (geeky) channels, such as DEF CON with a tritium-containing badge, the always excellent NurdRage’s assembly of a tritium-based atomic battery, or the creation of a tritium-phosphor-based glow-in-the-dark tesseract cube.

Tritium is a hydrogen isotope that shares a lot of characteristics with its two siblings: ¹H (protium) and ²H (deuterium), with the main distinction being that tritium (³H) is not a stable isotope, with a half-life of ~12.32 years that sees it decay into ³He. Most naturally occurring tritium on Earth originates from interactions between fast neutrons (>4.0 MeV) from cosmic radiation and atmospheric nitrogen.

Recently tritium has become a politically hot topic on account of the announced release of treated water at the Japanese Fukushima Daiichi nuclear plant. This has raised for many the question of just how much tritium is ‘too much’ and what we’re likely to notice from this treated — but still tritium-containing water — being released into the ocean.

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Things Are Looking Brighter! But Not The Stars

October 11, 2021 by Bob Baddeley 37 Comments

Growing up in Montana I remember looking out at night and seeing the Milky Way, reminding me of my insignificance in the universe. Now that I live in a city, such introspection is no longer easy, and like 1/2 of humanity that also lives in urban areas, I must rely on satellites to provide the imagery. Yet satellites are part of the problem. Light pollution has been getting worse for decades, and with the recent steady stream of satellite launches and billionaire joyrides we have a relatively new addition to the sources of interference. So how bad is it, and how much worse will it get?

Looking up at the night sky, you can usually tell the difference between various man-made objects. Planes go fairly slowly across the sky, and you can sometimes see them blinking green and red. Meteors are fast and difficult to see. Geostationary satellites don’t appear to move at all because they are orbiting at the same rate as earth’s rotation, while other orbit types will zip by.

SpaceX has committed to reducing satellite brightness, and some observations have confirmed that new models are a full magnitude darker, right at the threshold of naked-eye observation. Unfortunately, it’s only a step in the right direction, and not enough to satisfy astronomers, who aren’t looking up at the night sky with their naked eyes, naturally.

The satellites aren’t giving off the light themselves. They are merely reflecting the light from the sun back to the earth, exactly the same way the moon is. Thus something that is directly in the shadow of the Earth will not reflect any light, but near the horizon the reflection from the satellites can be significant. It’s not practical to only focus our observatories in the narrow area that is the Earth’s shadow during the night, so we must look closer to the horizon and capture the reflections of the satellites. Continue reading “Things Are Looking Brighter! But Not The Stars” →

Can We Repurpose Old Wind Turbine Blades?

October 8, 2021 by Zoe Skyforest 92 Comments

Wind turbines are a fantastic, cheap, renewable source of energy. However, nothing lasts forever, and over time, the blades of wind turbines fatigue and must be replaced. This then raises the question of what to do with these giant waste blades. Thankfully, a variety of projects are exploring just those possibilities.

A Difficult Recycling Problem

Around 85% of a modern wind turbine is recyclable. The problem is that wind turbine blades currently aren’t. The blades last around 20 to 25 years, and are typically made of fiberglass or carbon fiber. Consisting of high-strength fibers set in a resin matrix, these composite materials are incredibly difficult to recycle, as we’ve discussed previously. Unlike metals or plastics, they can’t just be melted down to be recast as fresh material. Couple this with the fact that wind turbine blades are huge, often spanning up to 300 feet long, and the problem gets harder. They’re difficult and expensive to transport and tough to chop up as well.

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Creating Methane From Captured Carbon Dioxide And The Future Of Carbon Capture

October 7, 2021 by Maya Posch 125 Comments

There’s something intrinsically simple about the concept of carbon (CO₂) capture: you simply have the CO₂ molecules absorbed or adsorbed by something, after which you separate the thus captured CO₂ and put it somewhere safe. Unfortunately, in physics and chemistry what seems easy and straightforward tends to be anything but simple, let alone energy efficient. While methods for carbon capture have been around for decades, making it economically viable has always been a struggle.

This is true both for carbon capture and storage/sequestration (CCS) as well as carbon capture and utilization (CCU). Whereas the former seeks to store and ideally permanently remove (sequester) carbon from the atmosphere, the latter captures carbon dioxide for use in e.g. industrial processes.

Recently, Pacific Northwest National Laboratory (PNNL) has announced a breakthrough CCU concept, involving using a new amine-based solvent (2-EEMPA) that is supposed to be not only more efficient than e.g. the previously commonly used MEA, but also compatible with directly creating methane in the same process.

Since methane forms the major component in natural gas, might this be a way for CCU to create a carbon-neutral source of synthetic natural gas (SNG)? Continue reading “Creating Methane From Captured Carbon Dioxide And The Future Of Carbon Capture” →

Decoding SMD Part Markings

October 6, 2021 by Chris Lott 29 Comments

You’ve probably encountered this before — you have a circuit board that is poorly documented, and want to know the part number of a tiny SMD chip. Retro computer enthusiast [JohnK] recently tweeted about one such database that he recently found, entitled The Ultimate SMD Marking Codes Database. This data base is only a couple of years old judging from the Wayback Machine, but seems to be fairly exhaustive and can be found referenced in quite a few electronics forums.

Unlike their larger SMD siblings, these chips in question are so small that there is no room to print the entire part number on the device. Instead, the standard practice is for manufacturers use an abbreviated code of just a few characters. These codes are only unique to each part or package, and aren’t necessarily unique across an entire product line. And just because it is standard practice does not imply the marking codes themselves follow any standard whatsoever. This seemingly hodgepodge system works just fine for the development, procurement and manufacturing phases of a product’s lifecycle. It’s during the repair, refurbishment, or just hacking for fun phases where these codes can leave you scratching your head.

Several sites like the one [JohnK] found have been around for years, and adding yet another database to your toolbox is a good thing. But none of them will ever be exhaustive. There’s a good reason for that — maintaining such a database would be a herculean task. Just finding the part marking information for a known chip can be difficult. Some manufacturers put it clearly in the data sheet, and some refer you to other documentation which may or may not be readily available. And some manufacturers ask you to contact them for this information — presumably because it is dynamic changes from time to time. Continue reading “Decoding SMD Part Markings” →