Kerbal Space Program Goes To The Movies In Stowaway

April 9, 2021 by Tom Nardi 14 Comments

Fans of the lusciously voiced space aficionado [Scott Manley] will know he often uses Kerbal Space Program (KSP) in his videos to knock together simple demonstrations of blindingly complex topics such as orbital mechanics. But as revealed in one of his recent videos, YouTube isn’t the only place where his KSP craft can be found these days. It turns out he used his virtual rocket building skills to help the creators of Netflix’s Stowaway develop a realistic portrayal of a crewed spacecraft in a Mars cycler orbit.

The Mars cycler concept was proposed in 1985 by Buzz Aldrin as a way to establish a long-term human presence on the Red Planet. Put simply, it describes an orbit that would allow a vehicle to travel continuously between Earth and Mars while needing only an occasional engine burn for course corrections. The spacecraft couldn’t actually stop at either planet, but while it made a close pass, smaller craft could rendezvous with it to hitch a ride. The concept can be thought of as a sort of interplanetary train: where passengers and cargo are picked up and dropped off at “stations” above Earth and Mars. It’s worth noting that a similar cycler orbit should be possible for Earth-Venus trips, but nobody really wants to go there.

An early KSP proof of concept for *Stowaway.*

The writers of Stowaway wanted their film to take place on a Mars cycler, and to avoid having to create the illusion of weightlessness, they wanted their fictional craft to also have some kind of artificial gravity. The only problem was, they weren’t sure what that would actually look like. So they reached out to [Scott], who in turn used KSP to throw together a rough idea of how such a ship might work in the real-world.

As you can see in the video below, the CGI spacecraft shown in the film’s recently released trailer ended up bearing a strong resemblance to its KSP prototype. While naturally some artistic license was used, [Scott] is excited by what he’s seen so far. The spinning spacecraft, which uses a spent upper stage to counterbalance its crew module and features a stationery utility node at the center, certainly looks impressive; all the more so with the knowledge that it’s based on sound principles.

While Netflix has had a hand in some surprisingly realistic science fiction in the past, they’ve also greenlit some real groan-worthy productions (if you haven’t watched Away, don’t). So until we can see the whole thing for ourselves, we can only hope that [Scott]’s sage advice will allow the crew of Stowaway to fly safe.

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Engineering The Less Boring Way

April 9, 2021 by Al Williams 6 Comments

We have to admire a YouTube channel with the name [Less Boring Lectures]. After all, he isn’t promising they won’t be boring, just less boring. Actually though, we found quite a few of the videos pretty interesting and not boring at all. The channel features videos about mechanical engineering and related subjects like statics and math. While your typical electronics project doesn’t always need that kind of knowledge, some of them do and the mental exercise is good for you regardless. A case in point: spend seven minutes and learn about 2D and 3D vectors in two short videos (see below). Or spend 11 minutes and do the whole vector video in one gulp.

These reminded us of Kahn Academy videos, although the topics are pretty hardcore. For example, if you want to know about axial loading, shear strain, or free body diagrams, this is a good place to look.

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Laser-Cut Solder Masks From Business Cards

April 9, 2021 by Bryan Cockfield 22 Comments

There are plenty of ways to make printed circuit boards at home but for some features it’s still best to go to a board shop. Those features continue to decrease in number, but not a lot of people can build things such as a four-layer board at home. Adding a solder mask might be one of those features for some, but if you happen to have a laser cutter and a few business cards sitting around then this process is within reach of the home builder too.

[Jeremy Cook] is lucky enough to have a laser cutter around, and he had an idea to use it to help improve his surface mount soldering process. By cutting the solder mask layer into a business card with the laser cutter, it can be held on top of a PCB and then used as a stencil to add the solder paste more easily than could otherwise be done. It dramatically decreases the amount of time spent on this part of the process, especially when multiple boards are involved since the stencil can be used multiple times.

While a laser cutter certainly isn’t a strict requirement, it certainly does help over something like an X-acto knife. [Jeremy] also notes that this process is sometimes done with transparency film or even Kapton, which we have seen a few times before as well.

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Uplink System For High-Altitude Balloons

April 9, 2021 by Maya Posch 10 Comments

Most uses of high-altitude balloons are fairly simple: send balloon up, have it beam down measurements and images. While this is indeed straightforward, it is also very limiting. This is why [Dave Akerman] has been working on adding to the HAB balloons he regularly flies. This builds on the work [Dave] did back in 2015 with adding LoRa transceiver RF communication.

Since LoRa transceivers are by definition capable of bidirectional communication, this was very useful for adding simple but essential features such as retransmission of data in case e.g. part of some image or telemetry data is missing. Other interesting things one can do with bidirectional transmission include controlling individual balloons, and having them transmit or relay information between balloons.

A tricky thing which [Dave] describes in the blog post is making sure that both ends of the connection are actually listening using timing settings. The use of encryption is also strongly recommended, unless you want to risk someone hijacking your balloons. This has now all been implemented in the HAB Explora app for Android, as well as the application for Windows.

Header image: Antonino Vara, CC BY 4.0.

Hamster Goes On Virtual Journey

April 9, 2021 by Bryan Cockfield 19 Comments

Hamsters are great pets, especially for those with limited space or other resources. They are fun playful animals that are fairly easy to keep, and are entertaining to boot. [Kim]’s hamster, [Mr. Fluffbutt], certainly fits this mold as well but [Kim] wanted something a little beyond the confines of the habitat and exercise wheel and decided to send him on a virtual journey every time he goes for a run.

The virtual hamster journey is built on an ESP32 microcontroller which monitors the revolutions of the hamster wheel via a hall effect sensor and magnet. It then extrapolates the distance the hamster has run and sends the data to a Raspberry Pi which hosts a MQTT and Node.js server. From there, it maps out an equivalent route according to a predefined GPX route and updates that information live. The hamster follows the route, in effect, every time it runs on the wheel. [Mr Fluffbutt] has made it from the Netherlands to southeastern Germany so far, well on his way to his ancestral home of Syria.

This project is a great way to add a sort of augmented reality to a pet hamster, in a similar way that we’ve seen self-driving fish tanks. Adding a Google Streetview monitor to the hamster habitat would be an interesting addition as well, but for now we’re satisfied seeing the incredible journey that [Mr Fluffbutt] has been on so far.

Linux Fu: Shell Script File Embedding

April 9, 2021 by Al Williams 25 Comments

You need to package up a bunch of files, send them somewhere, and do something with them at the destination. It isn’t an uncommon scenario. The obvious answer is to create an archive — a zip or tar file, maybe — and include a shell script that you have to tell the user to run after unpacking.

That may be obvious, but it assumes a lot on the part of the remote user. They need to know how to unpack the file and they also need to know to run your magic script of commands after the unpack. However, you can easily create a shell script that contains a file — even an archive of many files — and then retrieve the file and act on it at run time. This is much simpler from the remote user’s point of view. You get one file, you execute it, and you are done.

In theory, this isn’t that hard to do, but there are a lot of details. Shell scripts are not compiled — at least, not typically — so the shell only reads what it needs to do the work. That means if your script is careful to exit, you can add as much “garbage” to the end of it as you like. The shell will never look at it, so it’s possible to store the payload there.

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Hackaday Podcast 113: Python Switching To Match, A Magnetic Dyno, A Flying Dino, And A Spinning Sequencer

April 9, 2021 by Mike Szczys 2 Comments

Hackaday editors Mike Szczys and Elliot Williams recap a week of great hacks. You won’t want to miss the dynamometer Leo Fernekes built to measure the power output of his Sterling engine, which is also DIY. In this age of lithium-powered multirotors, it’s nice to step back and appreciate a hand-built rubberband-powered ornithopter.

We have a surprising amount to say about Python’s addition of the match statement (not be be confused with switch statements). And when it comes to electromechanical synth gear, it’s hard to beat a spinning tape-head sequencer.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (~60 MB)