Launching Rockets Is Hard, Bringing Them Back Is Harder

Since the first V2 rocket sailed above the Kármán line back in 1944 and right up until the modern era, the trajectory of most space-bound rockets was more or less the same: after expending their propellants they would either crash into some desolate steppe or plunge into the ocean. In either event, the rocket was disposable. The important bit up top might go on to explore the stars or send a human crew off on their mission, but the booster rocket that lifted the spacecraft out of the atmosphere was always going to be sacrificed for the cause.

But in the 1970s NASA had a wild idea: what if we didn’t smash a brand-new rocket valued at millions of dollars into the ocean every time we wanted to put something in orbit? Instead, they would build a hybrid space vehicle that blended the vertical takeoff and raw power of a rocket with the capabilities of an airplane, allowing it and whatever it was carrying to make a gentle runway landing at the end of its mission. As such, the Space Shuttle was born.

With the benefit of hindsight, we now know the Shuttle wasn’t quite the spaceflight revolution that NASA had hoped for. The age of reusable rockets didn’t truly begin until 2015, when SpaceX landed the first stage of their Falcon 9. To date they’ve repeated the feat nearly 600 times, all the while increasing the reliability and speed of their operations. Today the Falcon 9 is the most prolific launch vehicle in history, and nearly every other rocket in active development is being designed to include some element of reusability.

Most recently, China demonstrated that they could recover their Long March 10B rocket by gently bringing it down into what amounts to a giant butterfly net. While it might seem a bit quaint compared to rockets that land on their tails like something out of a 1950s sci-fi movie, the idea offers considerable promise.

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UDP Broadcasting And The Joys Of IPv4 Subnetting

In the previous installment on UDP broadcasting and service discovery, the basics of both were explored, including an implementation in the form of NyanSD and its protocol. Contained in the comment section was a very good demonstration of why one of the most exciting aspects of software development is the opportunity to share your latest creations with other people. This being the ability to get solid feedback on all the points – including any potential boneheaded omissions – that you really should address, whether intentional or accidental.

The most pertinent point raised was definitely that of broadcast addresses and IPv4 subnets, with the latter topic especially being something that the sysadmins at the office would talk about all the time, but which us software developers were always happy to ignore as something that didn’t concern us. Turns out the joke was on me and everyone else – like our esteemed readers – who thought that they could escape the fascinating world of subnets, as today we’ll take an in-depth look at what subnets are and how they are relevant to the world of UDP network discovery.

I somewhat alluded in the first article to the topic of ‘which broadcast address to use’ as being somewhat of a rough topic to figure out, which is clearly why I just stuck to a blatantly ‘works for me’ /24 subnet that usually will work on networks, until it does not.

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The Death Of Physical Media And The Real Challenges To Software Archiving

Along with the many displays of outrage, gnashing of teeth and other displays of profound grief at the recent news that Sony will no longer manufacture physical game discs come 2028, we have also heard some voices pipe up with a variety of statements, such as that this decision makes game archiving basically impossible. Of course, the truth of the matter is that software archiving in general has become much harder already over the past decades, while game consoles are just late to the archiving-hostile party.

As an example, one merely has to contrast Sony’s PlayStation with e.g. the Valve Steam store and software by juggernauts like Adobe and Autodesk. Here the former moved after the Creative Suite (CS6) series of Photoshop and other tools fully over to the Creative Cloud (CC) subscription model, where DRM and constant rental software renewals are in order. Unlike that disc copy of CS6 Master Collection that will stay good practically forever, there’s nothing really to archive with Adobe’s CC software.

Similarly, with digital game downloads and their constant patches now put inside a heavily encrypted environment that relies on a special launcher, preserving video games has been turned into into a virtual nightmare for many years now.

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A Brief History Of The Crazy Old 7-Segment Display

How old is the seven-segment display? Surely it is a product of the 1970s. After all, calculators started showing up, and the height of junior high humor was plugging 7734 into your calculator and showing it to someone upside down. Of course, for it to go mainstream, maybe they really originated in the 1960s, but no earlier than that, right? Actually, no. Sure, the LED seven-segment display had to wait for LEDs. But the actual idea is much older than that.

The concept of building numbers from a small set of reusable segments predates LED displays by decades. In fact, the basic idea appears in patents from the early 1900s and may have roots in even older mechanical signs and printing techniques.

The history isn’t entirely straightforward. Unlike vacuum tubes or transistors, segmented displays evolved gradually through a series of practical ideas rather than one defining invention.

Blacking out the Eight

While looking into the history of segmented displays, I was reminded of something I’d seen years ago in retail stores: reusable price tags printed with rows of eights.

Rather than printing every possible price, the clerk simply used a marker to black out portions of each figure, transforming an 8 into whatever digit was needed. Cover a few strokes, and the eight becomes a three. Remove a different set, and it becomes a zero or a five. It was, in essence, a manual segmented display.

Finding the exact origin of these price tags is akin to finding out where Romans bought sponges. They were inexpensive commercial supplies, not the sort of products that historians carefully documented. My recollection is from the middle of the twentieth century, but the underlying concept is almost certainly older.

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Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

Is Now The Time For Volumetric 3D Printing?

Of all innovations adopted by the maker community within the past couple of decades, one stands among the rest on top for anything regarding manufacturing. It goes without saying here at Hackaday how many projects have been reliant on using the technology to turn their ideas into reality. 3D printing has been a maker community invention and, in return, has expanded this hacky community into something that anyone with an imagination can get into. It also goes without saying that the layer-based tech imposes limits on what we can actually create: think overhangs and layer adhesion. However, there’s a possibility that a recent offshoot of this scrappy community has the power to eliminate some of these faults.

Volumetric additive manufacturing (VAM) is a young technology that has a similar start to many new tech toys, including the original SLA of the first 3D printers. That is expensive and completely stuck in the laboratory… Fortunately, that’s not where 3D printing as a whole stayed, as the RepRap project managed to bring the obscure technology to the hobbyists’ main stage. An entire group of people formed and spent countless hours until the useless pieces of poorly extruded plastic could form parts impossible to make with anything else. A cool quirk of history is that it likes to repeat: examples spur recreation, and this appears to be happening with the technology found within VAM printing.

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Ultra-Long Range Flights To Ease Australian Air Travel

Pity the poor Australians. Isolated on a jagged hunk of land far from everywhere else, these industrious people have to take two-legged flights (or more) to reach a great many destinations in the northern hemisphere. It’s expensive, time consuming, and makes planning a trip a complete headache when wars break out around popular hub airports.

One airline is trying to solve this problem. The nation’s flag carrier, Qantas, has been hard at work on Project Sunrise. The goal is to run some of the longest non-stop commercial passenger flights ever, with great effort going into solving the technical and economic challenges involved.

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Know Your Food: Organic Production

A few weeks ago we published the first in a new series of articles, Know Your Food. It was born out of the realisation that most people know surprisingly little about what they eat, and to apply a bit of Hackaday curiosity to received opinion on the subject. As we put it then: “To know both how common foodstuffs should be made, as well as how they are made industrially, should be an essential for everyone” We’ll continue in that vein, with a look at organic food.

If you buy your food in a supermarket it’s likely that in the vegetable aisle you’ll be presented with a choice. On one hand you will have the normal vegetable, and on the other and usually for a slightly higher price, the organic version of the same vegetable. What’s going on?

So What Is This Organic Stuff All About?

A watercolour picture of a bucolic scene with a farmhouse surrounded by trees, and some cows in the foreground.
It is unlikely that a typical organic farm in the 2020s will resemble this John Constable painting. John Constable, Public domain.

Organic production is a system of agriculture that emphasises natural fertilisers, pesticides, and farming methods over synthetic or intensive ones. It has its roots in the first half of the 20th century, and as the decades progressed it has become an important sector of agricultural industry. I grew up steeped in organic agriculture because my grandfather was an early adherent in the years following the war, so I’ve seen it from the sharpest end. There is a lot to commend organic production for and plenty of reasons to embrace it, but with that come some problematic aspects, and even dubious claims. Here I’ll try to unpick some of that.

It’s tempting to believe that all organic production is somehow a return to a 19th century rural idyl, complete with the obligatory chickens in the farmyard. Some organic producers do take a slice of this back-to-the-land approach to their craft, but the reality of organic farming is a very modern approach to managing the ecosystem. Organic farmers are not wary of progress, and neither are they reluctant to use pesticides or other chemicals. Instead they do so according to the principles of organic agriculture, so any techniques they use are designed to be beneficial to the ecosystem, and any chemicals have a natural origin. Continue reading “Know Your Food: Organic Production”