[vodou]

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?

[Sanzig]

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.

[minetest2048]

As someone that have successfully flown a RPi CM4 based payload on a cubesat, I fully agree with this. There's not enough funding in my research group to hire a dedicated test engineer so I need to both design and test my payload. It was a long lonely road

It does work at the end, but shortly after we got our first data from space, I decided to quit the space industry and become a test engineer at a terrestrial embedded company instead

[NoiseBert69]

It's a bit like balloon projects that have a transmitter. I think now the 20th group found out that standard GPS receivers stop reporting data of at a specific height because of the COCOM limit implementation (They 'or' speed and height). Well.. there are quite a few modules around that 'and' this rule and so work perfectly fine in great heights.

It's all about the learning experience and evolution of these projects. Mistakes must happen.. but learning from them should take place too.

[mannyv]

I wondered about the radiation hardening aspect.

At one altitude does that make a difference?

[jdiez17]

There are many Raspberry Pis on the International Space Station (AstroPis). They're subject to a similar amount of space radiation as CubeSats in LEO, and they work just fine. There's also an increasing trend of building CubeSat On-Board Computers (OBCs) as some form of Linux System-on-Module (these would traditionally be microcontrollers). I think Raspberry Pis (especially the Compute Modules) are quite suitable for Payload Data Handling (PDH) systems, although I've personally not had a chance to launch a RPi chip yet.

[vodou]

But even in LEO, there must be quite a few SEUs and resets?

[verzali]

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.

[jwrallie]

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.

[mbonnet]

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.