Conquering The Earth With Cron

June 25, 2018 by Tom Nardi 15 Comments

The GOES-R series of Earth observation satellites are the latest and greatest NASA has to offer. As you might expect, part of the GOES-R job description is imaging Earth at high-resolution, but they also feature real-time lighting monitoring as well as enhanced solar flare and space weather capabilities. Four of these brand new birds will be helping us keep an eye on our planet’s condition into the 2030s. Not a bad way to spend around 11 billion bucks.

To encourage innovation, NASA is making the images collected by the GOES-R satellites available to the public through a collaboration with Google Cloud Platform. [Ben Nitkin] decided to play around with this data, and came up with an interactive website that let’s you visualize the Earth from the perspective of GOES-R. But don’t let those slick visuals fool you, the site is powered by a couple cron jobs and some static HTML. Just as Sir Tim Berners-Lee intended it.

But it’s not quite as easy as scheduling a wget command; the images GOES-R collects are separated into different wavelengths and need to be combined to create a false-color image. A cron job fires off every five minutes which downloads and merges the raw GOES-R images, and then another cron job starts a Python script that creates WebM time-lapse videos out of the images using ffmpeg. All of the Python scripts and the crontab file are available on GitHub.

Finally, with the images merged and the videos created, the static HTML website is served out to the world courtesy of a quick and dirty Python web server. The site could be served via something more conventional, but [Ben] likes to keep overhead as low as possible.

If you want to take the more direct route, we’ve covered plenty of projects focused on pulling down images from weather satellites; from using old-school “rabbit ears” to decoding the latest Russian Meteor-M N2 downlink.

Continue reading “Conquering The Earth With Cron” →

Would You Look At That Yaw Control

June 20, 2018 by Brian Benchoff 38 Comments

[Jeff Bezos] might be getting all the credit for developing a rocket that can take off and land vertically, but [Joe Barnard] is doing it the hard way. He’s doing it with Estes motors you can pick up in any hobby shop. He’s doing it with a model of a Falcon 9, and he’s on his way to launching and landing a rocket using nothing but solid propellant.

The key to these launches is, of course, the flight controller, This is the Signal flight controller, and it has everything you would expect from a small board meant to mount in the frame of a model rocket. There’s a barometer, an IMU, a buzzer (important!), Bluetooth connectivity, and a microSD card slot for data logging. What makes this flight computer different is the addition of two connectors for standard hobby servos. With the addition of a 3D printed adapter, this flight controller adds thrust vectoring control. That means a rocket will go straight up without the use of fins.

We’ve seen [Joe]’s work before, and things have improved significantly in the last year and a half. The latest update from last weekend was a scale model (1/48) of the Falcon Heavy. In a 45-second video, [Joe]’s model of the Falcon Heavy launches on the two booster rockets, lights the center core, drops the two boosters and continues on until the parachutes unfurl. This would be impressive without active guidance of the motor, and [Joe] is adding servos and launch computers to the mix. It’s awesome, and certainly unable to be exported from the US.

What Is Our Martian Quarantine Protocol?

June 19, 2018 by Al Williams 89 Comments

If you somehow haven’t read or watched War of the Worlds, here’s a spoiler alert. The Martians are brought down by the common cold. You can argue if alien biology would be susceptible to human pathogens, but if they were, it wouldn’t be surprising if aliens had little defense against our bugs. The worrisome part of that is the reverse. Could an astronaut or a space probe bring back something that would ravage the Earth with some disease? This is not science fiction, it is both a historically serious question and one we’ll face in the near future. If we send people to Mars are they going to come back with something harmful?

A Bit of News: Methane Gas Fluctuations on Mars

What got me thinking about this was the mounting evidence that there could be life on Mars. Not a little green man with a death ray, but perhaps microbe-like life forms. In a recent press release, NASA revealed that they not only found old organic material in rocks, but they also found that methane gas is present on Mars and the amount varies based on the season with more methane occurring in the summer months. There’s some dispute about possible inorganic reasons for this, but it is at least possible that the variation is due to increased biological activity during the summer.

Continue reading “What Is Our Martian Quarantine Protocol?” →

Books You Should Read: Sunburst And Luminary, An Apollo Memoir

June 15, 2018 by Gregory L. Charvat 7 Comments

The most computationally intense part of an Apollo mission was the moon landing itself, requiring both real-time control and navigation of the Lunar Module (LM) through a sequence of programs known as the P60’s. Data from radar, inertial navigation, and optical data sighted-off by the LM commander himself were fed into the computer in what we’d call today ‘data fusion.’

The guy who wrote that code is Don Eyles and the next best thing to actually hanging out with Don is to read his book. Don’s book reads as if you are at a bar sitting across the table listening to his incredible life story. Its personal, hilarious, stressful, fascinating, and more importantly for those of us who are fans of Hackaday, it’s relatable.

Continue reading “Books You Should Read: Sunburst And Luminary, An Apollo Memoir” →

The Flight Of The Seagull: Valentina Tereshkova, Cosmonaut

June 12, 2018 by Dan Maloney 47 Comments

That the Cold War was a tense and perilous time in history cannot be denied, and is perhaps a bit of an understatement. The world stood on the edge of Armageddon for most of it, occasionally stepping slightly over the line, and thankfully stepping back before any damage was done.

As nerve-wracking as the Cold War was, it had one redeeming quality: it turned us into a spacefaring species. Propelled by national pride and the need to appear to be the biggest kid on the block, the United States and the Soviet Union consistently ratcheted up their programs, trying to be the first to make the next major milestone. The Soviets made most of the firsts, making Sputnik and Gagarin household names all over the world. But in 1962, they laid down a marker for a first of epic proportions, and one that would sadly stand alone for the next 19 years: they put the first woman, Valentina Tereshkova, into space.

Continue reading “The Flight Of The Seagull: Valentina Tereshkova, Cosmonaut” →

Stars Looking A Bit Dim? Throw Some Math At Them.

June 6, 2018 by Tom Nardi 16 Comments

As the cost of high-resolution images sensors gets lower, and the availability of small and cheap single board computers skyrockets, we are starting to see more astrophotography projects than ever before. When you can put a $5 Raspberry Pi Zero and a decent webcam outside in a box to take autonomous pictures of the sky all night, why not give it a shot? But in doing so, many hackers are recognizing a fact well-known to traditional telescope jockeys: seeing a few stars is easy, seeing a lot of stars is another story entirely.

The problem is that stars are fairly dim; a problem compounded by the light pollution you get unless you’re out in a rural area. You can’t just brighten up the images either, as that only increases the noise in the image. A programmer always in search of a challenge, [Benedikt Bitterli] decided to take a shot at using software to improve astrophotography images. He documented the entire process, failures and all, on his blog for anyone else who might be curious about what it really takes to create the incredible images of the night sky we see in textbooks.

In principle it’s simple: just take a lot of pictures of the sky, stack them on top of each other, and identify which points of light are stars and which ones are noise artifacts. But of course the execution is considerably more difficult. For one thing, unless the camera was on a mount that was automatically tracking the sky, the stars will have slightly moved in each image. To help with this process, [Benedikt] used a navigational trick that humanity has relied on for millennia: mapping constellations. By comparing groupings of stars in each image, his software is able to accurately overlay each image.

But that’s only one part of the equation. In his post, [Benedikt] goes over the incredible amount of math that goes into identifying individual stars in the sea of noise you get when a digital image sensor looks into the black. You certainly don’t need to understand all the math to appreciate the final results, but it’s a fascinating read for those with an interest in computer vision concepts.

This kind of software is precisely what you want to pair with your 3D printed star tracker, or even better a Raspberry Pi sky monitoring station.

[Thanks to Helio Machado for the tip.]

3D Printed Clockwork Star Tracker

June 3, 2018 by Tom Nardi 8 Comments

Astrophotography is one of those things you naturally assume must be pretty difficult; surely something so awesome requires years of practice and specialized equipment which costs as much as your car. You shake your fist at the sky (since you have given up on taking pictures of it), and move on with your life. Another experience you’ll miss out on.

But in reality, dramatic results don’t necessarily require sticker shock. We’ve covered cheap DIY star trackers before on Hackaday, but this design posted on Thingiverse by [Tinfoil_Haberdashery] is perhaps the easiest we’ve ever seen. It keeps things simple by using a cheap 24 hour clock movement to rotate a GoPro as the Earth spins. The result is a time-lapse where the stars appear to be stationary while the horizon rotates.

Using a 24 hour clock movement is an absolutely brilliant way to synchronize the camera with the Earth’s rotation without the hoops one usually has to jump through. Sure you could do with a microcontroller, a stepper motor, and some math. But a clock is a device that’s essentially been designed from the ground up for keeping track of the planet’s rotation, so why not use it?

If there’s a downside to the clock movement, it’s the fact that it doesn’t have much torque. It was intended to move an hour hand, not your camera, so it doesn’t take much to stall out. The GoPro (and other “action” cameras) should be light enough that it’s not a big deal; but don’t expect to mount your DSLR up to one. Even in the video after the break, it looks like the clock may skip a few steps on the way down as the weight of the camera starts pushing on the gears.

If you want something with a bit more muscle, we’ve recently covered a very slick Arduino powered “barn door” star tracker. But there’re simpler options if you’re looking to get some shots tonight.

Continue reading “3D Printed Clockwork Star Tracker” →