Hello From The NearSpace

A key challenge for any system headed up into the upper-atmosphere region sometimes called near space is communicating back down to the ground. The sensors and cameras onboard many high altitude balloons and satellites aren’t useful if the data they collect can’t be retrieved. Often times, custom antennas or beacons are added to help. Looking at the cost and difficulty of the problem, [arko] and [upaut] teamed up to try and make a turn-key solution for any near-space enthusiast by building CUBEX, a wonderful little module with sensors and clever radio that can be easily reused and repurposed.

CUBEX is meant as a payload for a high-altitude balloon with a camera, GPS, small battery, solar cell, and the accompanying power management circuits. The clever bit comes in the radio back down. By using the 434.460 Mhz band, it can broadcast around a hundred miles at 10mW. The only hardware to receive is a radio listener (a cheap RTL USB stick works nicely). Pictures and GPS coordinates stream down at 300 baud.

Their launch was quite successful and while they didn’t catch a solar eclipse, their balloon reached an impressive 33698m (110,560ft) while taking pictures. Even though it did eventually splashdown in the Pacific Ocean, they were able to enjoy a plethora of gorgeous photos thanks to their easy and cost-effective data link.

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Lessons Learned From A CubeSat Postmortem

On the 3rd of June 2019, a 1U CubeSat developed by students of the AGH University of Science and Technology in Kraków was released from the International Space Station. Within a few hours it was clear something was wrong, and by July 30th, the satellite was barely functional. A number of problems contributed to the gradual degradation of the KRAKsat spacecraft, which the team has thoroughly documented in a recently released paper.

We all know, at least in a general sense, that building and operating a spacecraft is an exceptionally difficult task on a technical level. But reading through the 20-pages of “KRAKsat Lessons Learned” gives you practical examples of just how many things can go wrong.

KRAKsat being released from the ISS

It all started with a steadily decreasing battery voltage. The voltage was dropping slowly enough that the team knew the solar panels were doing something, but unfortunately the KRAKsat didn’t have a way of reporting their output. This made it difficult to diagnose the energy deficit, but the team believes the issue may have been that the tumbling of the spacecraft meant the panels weren’t exposed to the amount of direct sunlight they had anticipated.

This slow energy drain continued until the voltage dropped to the point that the power supply shut down, and that’s were things really started going south. Once the satellite shut down the batteries were able to start charging back up, which normally would have been a good thing. But unfortunately the KRAKsat had no mechanism to remain powered down once the voltage climbed back above the shutoff threshold. This caused the satellite to enter into and loop where it would reboot itself as many as 150 times per orbit (approximately 90 minutes).

The paper then goes into a laundry list of other problems that contributed to KRAKsat’s failure. For example, the satellite had redundant radios onboard, but the software on them wasn’t identical. When they needed to switch over to the secondary radio, they found that a glitch in its software meant it was unable to access some portions of the onboard flash storage. The team also identified the lack of a filesystem on the flash storage as another stumbling block; having to pull things out using a pointer and the specific memory address was a cumbersome and time consuming task made all the more difficult by the spacecraft’s deteriorating condition.

Of course, building a satellite that was able to operate for a couple weeks is still an impressive achievement for a student team. As we’ve seen recently, even the pros can run into some serious technical issues once the spacecraft leaves the lab and is operating on its own.

[Thanks to ppkt for the tip.]

Open-Source Satellite Propulsion Hack Chat

Join us on Wednesday, December 11 at noon Pacific for the Open-Source Satellite Propulsion Hack Chat with Michael Bretti!

When you look back on the development history of any technology, it’s clear that the successful products eventually reach an inflection point, the boundary between when it was a niche product and when it seems everyone has one. Take 3D-printers, for instance; for years you needed to build one if you wanted one, but now you can buy them in the grocery store.

It seems like we might be getting closer to the day when satellites reach a similar inflection point. What was once the province of nations with deep pockets and military muscles to flex has become far more approachable to those of more modest means. While launching satellites is still prohibitive and will probably remain so for years to come,  building them has come way, way down the curve lately, such that amateur radio operators have constellations of satellites at their disposal, small companies are looking seriously at what satellites can offer, and even STEM programs are starting to get students involved in satellite engineering.

Michael Bretti is on the leading edge of the trend toward making satellites more DIY friendly. He formed Applied Ion Systems to address one of the main problems nano-satellites face: propulsion. He is currently working on a range of open-source plasma thrusters for PocketQube satellites, a format that’s an eighth the size of the popular CubeSat format. His solid-fuel electric thrusters are intended to help these diminutive satellites keep station and stay in orbit longer than their propulsion-less cousins. And if all goes well, someday you’ll be able to buy them off-the-shelf.

Join us for the Hack Chat as Michael discusses the design of plasma thrusters, the details of his latest testing, and the challenges of creating something that needs to work in space.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, December 11 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Hackaday Links: December 8, 2019

Now that November of 2019 has passed, it’s a shame that some of the predictions made in Blade Runner for this future haven’t yet come true. Oh sure, 109 million people living in Los Angeles would be fun and all, but until we get our flying cars, we’ll just have to console ourselves with the ability to “Enhance!” photographs. While the new service, AI Image Enlarger, can’t tease out three-dimensional information, the app is intended to sharpen enlargements of low-resolution images, improving the focus and bringing up details in the darker parts of the image. The marketing material claims that the app uses machine learning, and is looking for volunteers to upload high-resolution images to improve its training set.

We’ve been on a bit of a nano-satellite bender around here lately, with last week’s Hack Chat discussing simulators for CubeSats, and next week’s focusing on open-source thrusters for PocketQube satellites. So we appreciated the timing of a video announcing the launch of the first public LoRa relay satellite. The PocketCube-format satellite, dubbed FossaSat-1, went for a ride to space along with six other small payloads on a Rocket Lab Electron rocket launched from New Zealand. Andreas Spiess has a short video preview of the FossaSat-1 mission, which was designed to test the capabilities of a space-based IoT link that almost anyone can access with cheap and readily available parts; a ground station should only cost a couple of bucks, but you will need an amateur radio license to uplink.

We know GitHub has become the de facto standard for source control and has morphed into a collaboration and project management platform used by everybody who’s anybody in the hacking community. But have you ever wished for a collaboration platform that was a little more in tune with the needs of hardware designers? Then InventHub might be of interest to you. Currently in a limited beta – we tried to sign up for the early access program but seem to have been put on a waiting list – it seems like this will be a platform that brings versioning directly to the ECAD package of your choice. Through plugins to KiCad, Eagle, and all the major ECAD players you’ll be able to collaborate with other designers and see their changes marked up on the schematic — sort of a visual diff. It seems interesting, and we’ll be keeping an eye on developments.

Amazon is now offering a stripped-down version of their Echo smart speaker called Input, which teams up with speakers that you already own to satisfy all your privacy invasion needs on the super cheap — only $10. At that price, it’s hard to resist buying one just to pop it open, which is what Brian Dorey did with his. The teardown is pretty standard, and the innards are pretty much what you’d expect from a modern piece of surveillance apparatus, but the neat trick here involved the flash memory chip on the main board. Brian accidentally overheated it while trying to free up the metal shield over it, and the BGA chip came loose. So naturally, he looked up the pinout and soldered it to a micro-SD card adapter with fine magnet wire. He was able to slip it into a USB SD card reader and see the whole file system for the Input. It was a nice hack, and a good teardown.

AMSAT CubeSat Simulator Hack Chat

Join us on Wednesday, December 4th at noon Pacific for the AMSAT CubeSat Simulator Hack Chat with Alan Johnston!

For all the lip service the world’s governments pay to “space belonging to the people”, they did a pretty good job keeping access to it to themselves for the first 50 years of the Space Age. Oh sure, private-sector corporations could spend their investors’ money on lengthy approval processes and pay for a ride into space, but with a few exceptions, if you wanted your own satellite, you needed to have the resources of a nation-state.

All that began to change about 20 years ago when the CubeSat concept was born. Conceived as a way to get engineering students involved in the satellite industry, the 10 cm cube form factor that evolved has become the standard around which students, amateur radio operators, non-governmental organizations, and even private citizens have designed and flown satellites to do everything from relaying ham radio messages to monitoring the status of the environment.

But before any of that can happen, CubeSat builders need to know that their little chunk of hardware is going to do its job. That’s where Alan Johnston, a teaching professor in electrical and computer engineering at Villanova University, comes in. As a member of AMSAT, the Radio Amateur Satellite Corporation, he has built a CubeSat simulator. Built for about $300 using mostly off-the-shelf and 3D-printed parts, the simulator lets satellite builders work the bugs out of their designs before committing them to the Final Frontier.

Dr. Johnston will stop by the Hack Chat to discuss his CubeSat simulator and all things nanosatellite. Come along to learn what it takes to make sure a satellite is up to snuff, find out his motivations for getting involved in AMSAT and CubeSat testing, and what alternative uses people are finding the platform. Hint: think high-altitude ballooning.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, December 4 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Plasma-Powered Thrusters For Your Homebrew Satellite Needs

It seems as though every week we see something that clearly shows we’re living in the future. The components we routinely incorporate into our projects would have seemed like science fiction only a few short years ago, but now we buy them online and have them shipped to us for pennies. And what can say we’ve arrived in the future more than off-the-shelf plasma thrusters for the DIY microsatellite market?

Although [Michael Bretti] does tell us that he plans to sell these thrusters eventually, they’re not quite ready for the market yet. The AIS-gPPT3-1C series that’s currently under testing is designed for the micro-est of satellites, the PocketQube, a format with a unit size only 5 cm on a side – an eighth the size of a 1U CubeSat. The thrusters are solid-fueled, with blocks of Teflon, PEEK, or Ultem that are ablated by a stream of plasma. The gaseous exhaust is accelerated and shaped by a magnetic nozzle that’s integrated right into the thruster. The thruster is mounted directly to a PCB containing the high-voltage supplies and control electronics to interface with the PocketQube’s systems. The 34-gram thrusters have enough fuel for perhaps 500 firings, although that and the specifics of performance are yet to be tested.

If you have any interest at all in space engineering or propulsion systems, [Michael]’s site is worth a look. There’s a wealth of data there, and reading it will give you a great appreciation for plasma physics. We’ve been down that road a lot lately, with cold plasma, thin-film plasma deposition, and even explaining the mystery of plasmatic grapes.

Thanks to [miguekf] for the tip.

Spain’s First Open Source Satellite

[Fossa Systems], a non-profit youth association based out of Madrid, is developing an open-source satellite set to launch in October 2019. The FossaSat-1 is sized at 5x5x5 cm, weighs 250g, and will provide free IoT connectivity by communicating LoRa RTTY signals through low-power RF-based LoRa modules. The satellite is powered by 28% efficient gallium arsenide TrisolX triple junction solar cells.

The satellite’s development and launch cost under EUR 30000, which is pretty remarkable for a cubesat — or a picosatellite, as the project is being dubbed. It has been working in the UHF Amateur Satellite band (435-438 MHz) and recently received an IARU frequency spectrum allocation for LoRa of 125kHz.

The satellite’s specs are almost as remarkable as the acronyms used to describe them. The design includes an onboard computer (OBC) based on an ATmega328P-AU microcontroller, an SX1278 transceiver for telecommunications, and an electric power system (EPS) based on three SPV1040 MPPT chips and the TC1262 LDO. The satellite also uses a TMP100 temperature sensor, an INA226 current and voltage sensor, a MAX6369 watchdog for single-event upset (SEU) protection, a TPS2553 for single-event latch-up (SEL) protection and various MOSFETs for the deployment of solar panels and antennas.

Up until this point the group has been tracking adoption of LoRa through the use of weather balloons. The cubesat project plans to test the new LoRa spread spectrum modulation using less than $5 worth of receivers. Ultimately with the goal of democratizing telecommunications worldwide.

The satellite is being built in a cleanroom at Rey Juan Carlos University and has undergone thermovacuum and vibration testing at the facility. The group has since developed an educational satellite development kit, which offers three main 40×40 mm boards that allow the addition of modifications. As their mission states, the group is looking to develop an open source project, so the code for the satellite is freely available on their GitHub.

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