In early December 1961, a United States Air Force rocket took off from Vandenberg Air Force Base in California carrying a special payload. The main payload was a Corona surveillance satellite, but tucked just aft of that spacecraft was a tiny package of homebrew electronics stuffed into something the looked like a slice of cake. What was in that package and how it came to tag along on a top-secret military mission is the story of OSCAR 1, the world’s first amateur radio satellite.
[INCO] gave this extremely informative talk on building a CubeSat. CubeSats are small satellites that piggyback on the launches of larger satellites, and although getting a 10 cm3 brick into orbit is cheap, making it functional takes an amazing attention to detail and redundant design.
[INCO] somehow talks through the entire hour-long presentation at a tremendous speed, all the while remaining intelligible. At the end of the talk, you’ve got a good appreciation for the myriad pitfalls that go along with designing a satellite, and a lot of this material is relevant, although often in a simpler form, for high altitude balloon experiments.
CubeSats must be powered down during launch, with no radio emissions or anything else that might interfere with the rocket that’s carrying them. The satellites are then packed into a box with a spring, and you never see or hear from them again until the hatch is opened and they’re pushed out into space.
[INCO] said that 50% of CubeSats fail on deployment, and to avoid being one of the statistics, you need to thoroughly test your deployment mechanisms. Test after shaking, being heated and cooled, subject to low battery levels, and in a vacuum. Communication with the satellite is of course crucial, and [INCO] suggests sending out a beacon shortly after launch to help you locate the satellite at all.
Because your satellite is floating out in space, even tiny little forces can throw it off course. Examples include radiation pressure from the sun, and anything magnetic in your satellite that will create a torque with respect to the Earth’s magnetic field. And of course, the deployment itself may leave your satellite tumbling slightly, so you’re going to need to control your satellite’s attitude.
Power is of course crucial, and in space that means solar cells. Managing solar cells, charging lithium batteries, and smoothing out the power cycles as the satellite enters the earth’s shadow or tumbles around out of control in space. Frequent charging and discharging of the battery is tough on it, so you’ll want to keep your charge/discharge cycles under 20% of the battery’s nominal capacity.
In outer space, your satellite will be bombarded by heavy ions that can short-circuit the transistors inside any IC. Sometimes, these transistors get stuck shorted, and the only way to fix the latch-up condition is to kill power for a little bit. For that reason, you’ll want to include latch-up detectors in the power supply to reset the satellite automatically when this happens. But this means that your code needs to expect occasional unscheduled resets, which in turn means that you need to think about how to save state and re-synchronize your timing, etc.
In short, there are a ridiculous amount of details that you have to attend to and think through before building your own CubeSat. We’ve just scratched the surface of [INCO]’s advice, but if we had to put the talk in a Tweet, we’d write “test everything, and have a plan B whenever possible”. This is, after all, rocket science.
Earlier this week, the US Air Force lost a few satellites a minute after launch from Barking Sands in Hawaii. This was the first launch of the three stage, solid fueled SPARK rocket, although earlier versions were used to launch nuclear warheads into space. There are some great Army videos for these nuclear explosions in space, by the way.
[Alexandre] is working on an Arduino compatible board that has an integrated GSM module and WiFi chip. It’s called the Red Dragon, and that means he needs some really good board art. The finished product looks good in Eagle, and something we can’t wait to see back from the board house.
The Chippocolypse! Or however you spell it! TI is declaring a lot of chips EOL, and although this includes a lot of op-amps and other analog ephemera (PDF), the hi-fi community is reeling and a lot of people are stocking up on their favorite amplifiers.
[Jeremy] got tired of plugging jumper wires into a breadboard when programming his ATMega8 (including the ‘168 and ‘328) microcontrollers. The solution? A breadboard backpack that fits right over the IC. All the files are available, and the PCB can be found on Upverter.
In case you haven’t heard, we’re having a Super Conference in San Francisco later this week. Adafruit was kind enough to plug our plug for the con on Ask an Engineer last week.
GPS is a global technology these days, with the Russian GLONASS system and the forthcoming European Galileo orbiting alongside the original US GPS satellites above our heads. [Florin Duroiu] decided to embrace globalism by forking the TinyGPS library for the Arduino platform to add support for these satellite constellations.
In addition to the GLONASS support, the new version of the venerable TinyGPS adds some neat new features by incorporating the NMEA 3.0 standard (warning: big-ass PDF link). Using this, you can extract interesting stuff such as the calculated position from each satellite constellation, the signal strength of each satellite and a lot more technical stuff about what the satellites are saying about you to your GPS receiver. [Florin] claims it is a drop-in replacement for TinyGPS that should require no rewriting. There is no support for Galileo just yet (as the satellites are still being launched: eight are in orbit now), but [Florin] is looking for help to add this, as well as the new Chinese BEIDOU system once it is operational.
(top image: artists’ view of a Galileo satellite in orbit, courtesy of ESA)
GoGo, the largest provider of Internet above 30,000 feet, has announced they are now testing their next generation of in-flight Internet.
Of special interest in the new 2Ku system is the antennas strapped to the top of a GoGo-equipped plane’s fuselage. These antennas form a mechanically-phased-array that are more efficient than previous antennas and can provide more bandwidth for frequent fliers demanding better and faster Internet.
Currently, GoGo in-flight wireless uses terrestrial radio to bring the Internet up to 35,000 feet. Anyone who has flown recently will tell you this is okay, but you won’t be binging on Nexflix for your next cross country flight. The new system promises speeds up to 70Mbps, more than enough for a cabin full of passengers to be pacified by electronic toys. The 2Ku band does this with a satellite connection – much faster, but it does have a few drawbacks.
Because the 2Ku system provides Internet over a satellite connection, ping times will significantly increase. The satellites GoGo is using orbit at 22,000 miles above Earth, or about 0.1 light seconds away from the plane. Double that, and your ping times will increase by at least 200ms compared to a terrestrial radio connection.
While this is just fine for email and streaming, it does highlight the weaknesses and strengths of mobile Internet.
Satellite television is prevalent in Europe and Northern Africa. This is delivered through a Set Top Box (STB) which uses a card reader to decode the scrambled satellite signals. You need to buy a card if you want to watch. But you know how people like to get something for nothing. This is being exploited by hackers and the result is millions of these Set Top Boxes just waiting to form into botnets.
This was the topic of [Sofiane Talmat’s] talk at DEF CON 23. He also gave this talk earlier in the week at BlackHat and has published his slides (PDF).
The Hardware in Satellite receivers is running Linux. They use a card reader to pull in a Code Word (CW) which decodes the signal coming in through the satellite radio.
An entire black market has grown up around these Code Words. Instead of purchasing a valid card, people are installing plugins from the Internet which cause the system to phone into a server which will supply valid Code Words. This is known as “card sharing”.
On the user side of things this just works; the user watches TV for free. It might cause more crashes than normal, but the stock software is buggy anyway so this isn’t a major regression. The problem is that now these people have exposed a network-connected Linux box to the Internet and installed non-verified code from unreputable sources to run on the thing.
[Sofiane] demonstrated how little you need to know about this system to create a botnet:
- Build a plugin in C/C++
- Host a card-sharing server
- Botnet victims come to you (profit)
It is literally that easy. The toolchain to compile the STLinux binaries (gcc) is available in the Linux repos. The STB will look for a “bin” directory on a USB thumb drive at boot time, the binary in that folder will be automatically installed. Since the user is getting free TV they voluntarily install this malware.
Click through for more on the STB Hacks.
Space. The final frontier. Every tinkerer, hacker, and maker has dreamed of flying out of Earth’s atmosphere and into the heavens. Last year one hard-working team got a chance to fly a member to space by winning the Hackaday prize. For the rest of us, we can still experience some of that excitement by contacting satellites in orbit, or even sending a bit of our own hardware into space. This week’s Hacklet focuses on the best satellite projects on Hackaday.io!
We start with [movax] and Your satellite devkit and launch. Chipsat is a tiny satellite which runs BASIC code. Yes, BASIC in space! Chipsats will be stacked into a launcher and sent off into space in groups. The idea is to eventually have them launched from the International Space Station. Power is provided by a small solar cell which charges up a pair of super capacitors. When the capacitors are charged, the satellite will run for a few seconds. Connectivity with the ground is via a 433 MHz link. Chipsat doesn’t just float in space, three coils give it the ability to control its attitude and rotation. Chipsat will sense the space around it with a magnetometer and a light sensor.
No satellite-themed Hacklet would be complete without [Pierros Papadeas] and his team’s work on SatNOGS – Global Network of Ground Stations. SatNOGS aims to create a global network of connected satellite ground stations. Think of it as a grass-roots version of NASA’s deep space network for satellites in earth orbit. This is more than just a great idea, as SatNOGS won the 2014 Hackaday Prize. You can check out our coverage of the project back in November, 2014. Since then, the SatNOGS team has been busy! They’ve just deployed the first SatNOGS V2 system above their hackerspace in Athens, Greece.
Next up is TRSI PocketQub Satellite, another project by [movax]. TRSI is a satellite that sends data via images which can be viewed with a simple RTL-SDR stick using Hellschreiber mode. Hell mode means that images can be directly viewed in the waterfall display of whichever SDR application is running the receiver. Numbers or entire images snapped with TRSI’s cell phone style camera module can be encoded and displayed. Power is of course provided by solar cells, and the communications link will be on the coordinated 433 MHz band. The original TRSI hardware has actually morphed into a deployment machine for ChipSat, [morvax’s] other satellite project. He’s put the main TRSI program on hold until after the ChipSat campaign is complete.
Rounding out our satellite special is [OzQube] with his project QubeCast Max. QubeCast is the first Australian version of the PocketQube PQ60 satellite form factor. After watching the success of $50Sat project, [OzQube] wanted to design a satellite of his own. Since he wanted to add sensors and send more data back to Earth than previous efforts, he needed a higher data rate than the current crop of satellites. This meant going to a high-powered radio. To achieve this, he’s using a NiceRF RF4463F30 radio module. The module is based upon a Silicon Labs Si4463 RF ISM band chip, coupled with a power amplifier. The module outputs 1 watt, which is quite a bit of power for a tiny satellite!
Want more satellite goodness? Check out Hackaday.io’s freshly minted Satellite List.
The countdown is almost at 0, so that’s just about all the time we have for this episode of the Hacklet. See you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!