I've always wondered how well these RPi based cubesats really work in space. Really hard to find out. Also, people (naturally) aren't always eager to talk about failed projects. Maybe some people here on HN have experiences to share?
In my experience, having provided advice to a lot of academic CubeSats: the issues usually aren't related to the parts, the problems are usually lack of testing and general inexperience.
Yes, a Raspberry Pi isn't radiation hardened, but in LEO (say around 400-500 km) the radiation environment isn't that severe. Total ionizing dose is not a problem. High energy particles causing single event effects are an issue, but these can be addressed with design mitigations: a window watchdog timer to reset the Pi, multiple copies of flight software on different flash ICs to switch between if one copy is corrupted, latchup detection circuits, etc. None of these mitigations require expensive space qualified hardware to reasonably address.
The usual issues I see in academic CubeSats are mostly programmatic. These things are usually built by students, and generally speaking a CubeSat project is just a bit too long (3-4 years design and build + 1-2 years operations) to have good continuity of personnel, you usually have nobody left at the end there since the beginning except the principal investigator and maybe a couple PhD students.
And since everyone is very green (for many students, this is their first serious multidisciplinary development effort) people are bound to make mistakes. Now, that's a good thing, the whole point is learning. The problem is that extensive testing is usually neglected on academic CubeSats, either because of time pressure to meet a launch date or the team simply doesn't know how to test effectively. So, they'll launch it, and it'll be DOA on orbit since nobody did a fully integrated test campaign.
About 50% of cubesats fail, at least partially. I've worked with a dozen or so of them, supporting different people and companies trying to use them. Only one failed to work at all. But many of the others had serious problems of one kind or another that limited their usefulness.
We’ve been using Raspberry Pis in CubeSats for a while, for LEO they are good enough for a year or two. It’s the common consumer grade SD cards that are the weakest point. There are more robust industrial grade SD cards and there are RPis with flash (the compute modules) that can work great.
I've participated in the design or manufacture or launch of dozens of cubesats. The ones with RPis as their flight computers either accept that they'll get messed up by radiation with some regularity throughout their mission (and design other components accordingly, such as timeout watchdog resets), or accept that they'll have a quite limited mission lifetime.
This takes me down a memory lane! For my undergrad capstone project, we made a cubesat tracker for our university's satellite using a RPi/Arduino/Software-defined-radio to receive transmissions every time it passed over us. I cringe a little looking at the code now - but it worked!
I agree, cubsats are a wonderful way, for college students even, to tinker with space(-adjacent) tech.
I have launched raspberry pi based PicoBalloons and had one fly for over a year at 40k ft. They are remarkably resilient.
I have used CubeSats in LEO to make amateur radio contacts. AMSAT is trying to get one to MEO/HEO. New cubesats are being released frequently. Not all RPi based and usually custom PCBs. You can buy desk based CubeSats for STEM
If you want to build a "mars rover" yourself you can even simulate that at home :-)
Use LoRa in the slowest and most reliable mode as radio link. Write software to plan your tours, firmware updates over super limited bandwidth (delta updates are a must), transfer telemetry (buy a few sensors from ali) or even pictures. Autonomous driving? Yes why not.
Bonus 1: build a small PCB with a solar panel and charging circuit. That doubles the horror.
Bonus 2: Place it into your families garden that is at least 1km away.
Lots of very hard challenges to tackle for even super experienced programmers.
It's even a nice group project for an university lab. If you have to connect a real debugger to get your bot running again your team lost.
So it costs $85k to launch such cubesat. Too expensive for almost all of us. But if the cost comes down to say $5k, I'd probably be interested in this as a hobby project.
Why would it be difficult? Amateurs talk to the ISS all the time. You're only going 200 miles, and it's line-of-sight at all times while above the horizon since it's in the sky. You mostly have to just wait for a good window.
the video was long and depressingly commercialized, so I went to Wikipedia to just get the basic idea about this and im blown away how long cubesats have been around and fairly easily available.
> As of December 2023, more than 2,300 CubeSats have been launched.
> Academia accounted for the majority of CubeSat launches until 2013, when more than half of launches were for non-academic purposes, and by 2014 most newly deployed CubeSats were for commercial or amateur projects.[3]
2013?!?! Regular academics have been putting little cubes into space with whatever they want since 1998! amateurs have been doing it for more than eleven years?? There's 2300 of them! this is all blowing my mind that space is even this accessible to people who don't work for NASA, ESA or SpaceX.
My first thought was, even before reading the article, that these cubesats would be perfect for practicing satellite tracking.
Lo and behold the article mentions one of my favorite youtubers, Gabe from saveitforparts! I love that channel.
It's so much fun to see someone tinkering with old hardware to connect to these flying devices. He is a genuinely wholesome guy. It's really fun to watch his videos.
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[ 1.9 ms ] story [ 47.4 ms ] threadYes, a Raspberry Pi isn't radiation hardened, but in LEO (say around 400-500 km) the radiation environment isn't that severe. Total ionizing dose is not a problem. High energy particles causing single event effects are an issue, but these can be addressed with design mitigations: a window watchdog timer to reset the Pi, multiple copies of flight software on different flash ICs to switch between if one copy is corrupted, latchup detection circuits, etc. None of these mitigations require expensive space qualified hardware to reasonably address.
The usual issues I see in academic CubeSats are mostly programmatic. These things are usually built by students, and generally speaking a CubeSat project is just a bit too long (3-4 years design and build + 1-2 years operations) to have good continuity of personnel, you usually have nobody left at the end there since the beginning except the principal investigator and maybe a couple PhD students.
And since everyone is very green (for many students, this is their first serious multidisciplinary development effort) people are bound to make mistakes. Now, that's a good thing, the whole point is learning. The problem is that extensive testing is usually neglected on academic CubeSats, either because of time pressure to meet a launch date or the team simply doesn't know how to test effectively. So, they'll launch it, and it'll be DOA on orbit since nobody did a fully integrated test campaign.
I agree, cubsats are a wonderful way, for college students even, to tinker with space(-adjacent) tech.
https://github.com/hazrmard/SatTrack
I have used CubeSats in LEO to make amateur radio contacts. AMSAT is trying to get one to MEO/HEO. New cubesats are being released frequently. Not all RPi based and usually custom PCBs. You can buy desk based CubeSats for STEM
Use LoRa in the slowest and most reliable mode as radio link. Write software to plan your tours, firmware updates over super limited bandwidth (delta updates are a must), transfer telemetry (buy a few sensors from ali) or even pictures. Autonomous driving? Yes why not.
Bonus 1: build a small PCB with a solar panel and charging circuit. That doubles the horror.
Bonus 2: Place it into your families garden that is at least 1km away.
Lots of very hard challenges to tackle for even super experienced programmers.
It's even a nice group project for an university lab. If you have to connect a real debugger to get your bot running again your team lost.
I didn't see a lot of detail at https://ethoslabs.space/ besides a Contact Us form, but it sounds like a fascinating problem.
Is hosting a RPi in space different from hosting one on the ground, reachable over the public internet? I assume it is, but tell me more!
I’ve got some cool ideas for atmospheric Reentry but I’d imagine there are all kinds of permits needed?
https://en.wikipedia.org/wiki/CubeSat
> As of December 2023, more than 2,300 CubeSats have been launched. > Academia accounted for the majority of CubeSat launches until 2013, when more than half of launches were for non-academic purposes, and by 2014 most newly deployed CubeSats were for commercial or amateur projects.[3]
2013?!?! Regular academics have been putting little cubes into space with whatever they want since 1998! amateurs have been doing it for more than eleven years?? There's 2300 of them! this is all blowing my mind that space is even this accessible to people who don't work for NASA, ESA or SpaceX.
Lo and behold the article mentions one of my favorite youtubers, Gabe from saveitforparts! I love that channel.
It's so much fun to see someone tinkering with old hardware to connect to these flying devices. He is a genuinely wholesome guy. It's really fun to watch his videos.