Curated

76 Articles

Hackaday’s finest original content articles curated by the Hackaday editors

SpaceX Clips Dragon’s Wings After Investigation

August 5, 2019 by 120 Comments

When the SpaceX Dragon spacecraft reached orbit for the first time in 2010, it was a historic achievement. But to qualify for NASA’s Commercial Orbital Transportation Services (COTS) program, the capsule also needed to demonstrate that it could return safely to Earth. Its predecessor, the Space Shuttle, had wings that let it glide home and land like a plane. But in returning to the classic capsule design of earlier spacecraft, SpaceX was forced to rely on a technique not used by American spacecraft since the 1970s: parachutes and an ocean splashdown.

The Dragon’s descent under parachute, splashdown, and subsequent successful recovery paved the way for SpaceX to begin a series of resupply missions to the International Space Station that continue to this day. But not everyone at SpaceX was satisfied with their 21st century spacecraft having to perform such an anachronistic landing. At a post-mission press conference, CEO Elon Musk told those in attendance that eventually the Dragon would be able to make a pinpoint touchdown using thrusters and deployable landing gear:

The architecture that you observed today is obviously similar to what was employed in the Apollo era, but the next generation Dragon, the Crew Dragon, we’re actually going to be aiming for a propulsive landing with gear. We’ll still have the parachutes as a backup, but it’s going to be a precision landing, you could literally land on something the size of a helipad propulsively with gear, refuel, and take off again.

But just shy of a decade later, the violent explosion of the first space worthy Crew Dragon has become the final nail in the coffin for Elon’s dream of manned space capsules landing like helicopters. In truth, the future of this particular capability was already looking quite dim given NASA’s preference for a more pragmatic approach to returning their astronauts from space. But Crew Dragon design changes slated to be implemented in light of findings made during the accident report will all but completely remove the possibility of Dragon ever performing a propulsive landing.

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A Trillion Trees – How Hard Can It Be?

August 5, 2019 by 167 Comments

Data from 2016 pegs it as the hottest year since recording began way back in 1880. Carbon dioxide levels continue to sit at historical highs, and last year the UN Intergovernmental Panel on Climate Change warned that humanity has just 12 years to limit warming to 1.5 C.

Reducing emissions is the gold standard, but it’s not the only way to go about solving the problem. There has been much research into the field of carbon sequestration — the practice of capturing atmospheric carbon and locking it away. Often times, this consists of grand plans of pumping old oil wells and aquifers full of captured CO2, but there’s another method of carbon capture that’s as old as nature itself.

As is taught in most primary school science courses, the trees around us are responsible for capturing carbon dioxide, in the process releasing breathable oxygen. The carbon becomes part of the biomass of the tree, no longer out in the atmosphere trapping heat on our precious Earth. It follows that planting more trees could help manage carbon levels and stave off global temperature rises. But just how many trees are we talking? The figure recently floated was 1,000,000,000,000 trees, which boggles the mind and has us wondering what it would take to succeed in such an ambitious program.

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Retrotechtacular: The OSCAR 7 Satellite Died And Was Reborn 20 Years Later

August 2, 2019 by 35 Comments

If I were to ask you what is the oldest man-made orbiting satellite still in use, I’d expect to hear a variety of answers. Space geeks might mention the passive radar calibration spheres, or possibly one of the early weather satellites. But what about the oldest communication satellite still in use?

The answer is a complicated one. Oscar 7 is an amateur radio satellite launched on November 5th 1974, carrying two transponders and four beacons, all of which operate on bands available to amateur radio operators. Nearly 45 years later it still provides radio amateurs with contacts just as it did in the 1970s. But this bird’s history is anything but ordinary. It’s the satellite that came back from the dead after being thought lost forever. And just as it was fading from view it played an unexpected role in the resistance to the communist government in Poland.

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Abraham Wald’s Problem Solving Lesson Is To Seek What’s Not There

August 1, 2019 by 26 Comments

You may not know the name Abraham Wald, but he has a very valuable lesson you can apply to problem solving, engineering, and many other parts of life. Wald worked for the Statistical Research Group (SRG) during World War II. This was part of a top secret organization in the United States that applied elite mathematical talent to help the allies win the war. Near Columbia University, mathematicians and computers — the human kind — worked on problems ranging from how to keep an enemy plane under fire longer to optimal bombing patterns.

One of Wald’s ways to approach problem was to look beyond the data in front of him. He was looking for things that weren’t there, using their absence as an additional data point. It is easy to critique things that are present but incorrect. It is harder to see things that are missing. But the end results of this technique were profound and present an object lesson we can still draw from today.

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Automate The Freight: When The Freight Is People

August 1, 2019 by 35 Comments

Before I got a license and a car, getting to and from high school was an ordeal. The hour-long bus ride was awful, as one would expect when sixty adolescents are crammed together with minimal supervision. Avoiding the realities going on around me was a constant chore, aided by frequent mental excursions. One such wandering led me to the conclusion that we high schoolers were nothing but cargo on a delivery truck designed for people. That was a cheery fact to face at the beginning of a school day.

What’s true for a bus full of students is equally true for every city bus, trolley, subway, or long-haul motorcoach you see. People can be freight just as much as pallets of groceries in a semi or a bunch of smiling boxes and envelopes in a brown panel truck. And the same economic factors that we’ve been insisting will make it far more likely that autonomous vehicles will penetrate the freight delivery market before we see self-driving passenger vehicles are at work with people moving. This time on Automate the Freight: what happens when the freight is people?

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Machinist Tools: Edge Finding

July 31, 2019 by 35 Comments

Machinists like to live on the edge, but they always want to know precisely where it is. If you’ve watched any machining videos (*cough*) then you’ve seen heavy use of digital readouts on machines. A “DRO” (as the cool kids call them) is a little computer that knows where the slides are, and thus where your cutter is on the piece. However, there’s a catch. DROs don’t know the absolute position of the spindle, they know the relative position of it. The bottom line is that a DRO is just a fancier version of the graduated scales on the hand wheels. The key difference is that the DRO doesn’t suffer from backlash, because it is measuring the slides directly (via glass scales similar to your digital caliper) rather than inferring position from rotations of the leadscrews. With traditional hand wheels, you have to compensate for backlash every time you change direction, and a DRO saves you from that (among other convenience features).

The point is that, whether old school or new, you still only get a relative coordinate system on your part. You need to establish an origin somehow. A useful way to do this is to set an origin at one corner of the part, based on its physical edges. How do you tell the DRO (or hand wheels) where the edges are? Enter the edge finder.

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C++20 Is Feature Complete; Here’s What Changes Are Coming

July 30, 2019 by 105 Comments

If you have an opinion about C++, chances are you either love it for its extensiveness and versatility, or you hate it for its bloated complexity and would rather stick to alternative languages on both sides of the spectrum. Either way, here’s your chance to form a new opinion about the language. The C++ standard committee has recently gathered to work on finalizing the language standard’s newest revision, C++20, deciding on all the new features that will come to C++’s next major release.

After C++17, this will be the sixth revision of the C++ standard, and the language has come a long way from its “being a superset of C” times. Frankly, when it comes to loving or hating the language, I haven’t fully made up my own mind about it yet. My biggest issue with it is that “programming in C++” can just mean so many different things nowadays, from a trivial “C with classes” style to writing code that will make Perl look like prose. C++ has become such a feature-rich and downright overwhelming language over all these years, and with all the additions coming with C++20, things won’t get easier. Although, they also won’t get harder. Well, at least not necessarily. I guess? Well, it’s complex, but that’s simply the nature of the language.

Anyway, the list of new features is long, combining all the specification proposals is even longer, and each and every one of these additions could fill its own, full-blown article. But to get a rough idea about what’s going to come to C++ next year, let’s have a condensed look at some of these major new features, changes, and additions that will await us in C++20. From better type checking and compiler errors messages to Python-like string handling and plans to replace the #include system, there’s a lot at play here!

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