8 ms·

CubeSats are fascinating learning tools for space

232 points by warrenm 1y ago

vodou 1y ago
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?
- jdiez17 1y ago
  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 1y ago
    But even in LEO, there must be quite a few SEUs and resets?
    - jdiez17 1y ago
      I personally haven’t seen confirmed SEUs in the satellites I’ve designed/operated (as in, an ionized particle affecting a transistor/MOSFET in a way that creates a short circuit and can only be cleared with a power cycle). But it’s good practice to design space systems to have current monitoring and automatically power off in case of such events. Resets etc. are common, most likely caused by software bugs. This is more or less assumed as a fact of life; software for space applications is often as stateless as possible, and when it’s required you’d implement frequent state checkpoints, redundant data storage, etc. These are all common practices that you’d do anyway, it doesn’t make a huge difference if the software is running on a rad-hard microcontroller or off the shelf Linux processor - although (IMO) there are many benefits to the latter (and some downsides as well.) Assuming a base level of reliability, of course - you don’t want your OBC/PDH to overheat or reboot every 5 minutes.
- Sanzig 1y ago
  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.
  - NoiseBert69 1y ago
    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.
    - dylan604 1y ago
      That's kind of how I was thinking about it. Why does each cubesat project have to start over from scratch? Why isn't there a basic set of projects that a team can build on top of to make their own custom sensors for their purpose, but the basic operational stuff like the suggested multiple storage types with redundant code shouldn't need to be recreated each time. Just continue using what worked, and tweak what didn't. No need to constantly reinvent the wheel just because it's students learning.
- verzali 1y ago
  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 1y ago
  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 1y ago
  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.
tensorlibb 1y ago
It's beyond cool you can pretty cheaply get cube sats on Space X rockets too
hazrmard 1y ago
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. https://github.com/hazrmard/SatTrack https://github.com/hazrmard/SatTrack
firesteelrain 1y ago
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
- dylan604 1y ago
  > had one fly for over a year at 40k ft inquiring minds want to know. was this tethered? what kind of clearance did you need and what kind of equipment was necessary for safety purposes?
  - firesteelrain 1y ago
    It was connected to an Orbs 32” PicoBalloon https://balloons.online/orbs-32-clear/ https://balloons.online/orbs-32-clear/ I used 36 awg wire and fishing line. The lower half of the dipole is also 36 awg wire. No flight clearances are required If any aircraft were to hit it, then it would be obliterated. This includes Cessna’s as well
    - rogerrogerr 1y ago
      As a bugsmasher pilot, I’d be most worried about 40k ft of fishing line wrapping itself around the spinny bits on the front. What’s the tensile strength on that stuff? Doubt it’d cause an immediate issue, but doesn’t sound very fun to remove.
      - firesteelrain 1y ago
        3-6 newtons or about 0.7-1.3 pounds-force Also it’s not 40k ft of wire. Altitude is 40k ft The wire is about 16 ft for one leg of the dipole. That is the taught part. The other just floats in mid air underneath the payload The community is very small and doubtful the sky will be filled with them The balloons follow the jetstream from where they are launched. I have seen them fly over the Artic Circle, for example
NoiseBert69 1y ago
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.
- nicce 1y ago
  You can do even more than that if you want to see it moving! And without designing it completely by yourself. https://github.com/nasa-jpl/open-source-rover https://github.com/nasa-jpl/open-source-rover
  - NoiseBert69 1y ago
    Designing it is half the fun :-) Chassis aren't expensive from far east - so it's mostly the electronics.
ImJasonH 1y ago
...so how do you keep it secure? I didn't see a lot of detail at https://ethoslabs.space/ 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!
- jdiez17 1y ago
  > ...so how do you keep it secure? > 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! It is somewhat different from a security point of view, but the gap between them is getting smaller. The main "obstacle" to hackers taking over your satellite is that it is somewhat difficult to set up a UHF/VHF/S-band ground station with enough transmit power to reach the satellite. And you need knowledge of the command protocol that the satellite uses. But ground stations are getting cheaper every day, IMO you can build a fairly capable transmitting setup for ~1000€. So the remaining protection is a form of security by obscurity: "we invented this command protocol, so nobody knows how it works". But that can obviously be defeated by recording ground station signals and some dedicated reverse engineers. When those protections fall away, you'll find that a lot of satellite/CubeSat software out there is quite vulnerable (see https://jwillbold.com/paper/willbold2023spaceodyssey.pdf https://jwillbold.com/paper/willbold2023spaceodyssey.pdf). You often find things like commands that are literally "arbitrary memory read/write". While they are a nightmare from a security point of view, they are extremely useful for operators of experimental satellites, e.g. to patch software in memory to fix bugs or read variables that are not exposed as telemetry. I have written a few of these patches myself, and my friend PistonMiner used them brilliantly to hack in a software update capability and revived a 15 year old CubeSat that was assumed to be dead - see their 38C3 talk: https://www.youtube.com/watch?v=KdTcd94pVlY https://www.youtube.com/watch?v=KdTcd94pVlY If you ask me, the way to keep satellites secure is to basically apply the lessons that we have learned in terrestrial computing to space applications. Things like using encryption/authentication, process isolation backed by a MMU, memory safe languages, etc. That's what we're trying to do with RACCOON OS btw. You can take at the flight software of CyBEEsat, a 1U CubeSat that is launching soon(tm): https://gitlab.com/rccn/missions/cybeesat https://gitlab.com/rccn/missions/cybeesat
kadushka 1y ago
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.
- abirch 1y ago
  The question is how to deal with all of the space debris. It seems like they should factor in the total cost (retrieving anything that goes up) and not only the cost to launch it.
  - treyd 1y ago
    Sattelites in LEO without the ability to boost their orbits back up will fall out of orbit in a few years due to natural atmospheric resistance. Exactly how long it takes depends on the shape and mass of the sattelite. It's of very very low Kessler syndrome risk.
  - kulahan 1y ago
    It all falls back down eventually. Anything too small will stay up for some time, but even the half-billion copper needles put in space by the US have almost all come down. Wikipedia says there are <50 clumps of needles left.
  - junon 1y ago
    Cubesats in most cases must have documented materials that are burnt up in the atmosphere upon reentry, for this exact reason. They don't stay up there forever.
  - mbonnet 1y ago
    FCC (or FAA, can't remember, that's systems engineering's job) mandates that all satellites, including cubesats, be able to deorbit within 5 years of the end of their mission with some confidence rate (90%, iirc). Almost all cubesats are launched at about a 550km x 550km orbit or lower circular orbit. Cubesats (most satellites, in fact) will deorbit naturally within a few years (almost definitely <= 5Y) at that altitude due to orbit decay, mostly from drag. Now, some cubesats will have onboard propulsion, which they'll use to extend their mission by burning back into higher orbits, allowing them to still naturally decay at the end of their mission. Indeed, they can even use remaining propellant to speed their orbit's decay.
7373737373 1y ago
it would be awesome for this to become popular enough to see teams of people race each other out of the solar system
- warrenm 1y ago
  how much of a propulsion system could you feasibly pack in a cubesat?
  - geerlingguy 1y ago
    Very very little, but not nothing. I've seen a few tiny deployable solar sails and a few tiny electric motors in my brief research for my video. They seem mostly experimental, to test out theories and miniaturization.
  - notahacker 1y ago
    Enough to maintain your CubeSat's orbit and do a bit of pointing, but you'd need something bigger to have the propellant and power to get out of the solar system
- abirch 1y ago
  I frequently wonder if alien didn't send RNA to Earth to start life here. It seems like that could be the payload for anyone shooting satellites out to the universe.
bilsbie 1y ago
I’m really confused how you communicate with it? That seems like the most (expensive?) and technically difficult part. I’ve got some cool ideas for atmospheric Reentry but I’d imagine there are all kinds of permits needed?
- bragr 1y ago
  >I’m really confused how you communicate with it? That seems like the most (expensive?) and technically difficult part. Not really. They typically use standard amatuer radio frequencies and protocols. Making space to ground contacts is doable with a handheld radio and directional antenna. Main limitation is low data rates (dialup or worse) and low coverage (you'll probably only get 1-2 passes a day from a single ground station). A decent semi-permament ground station can be built from off the shelf parts at a fraction of the cost of the overall satellite.
- throwup238 1y ago
  A combination of amateur radio operators, university ground station cooperatives (most universities with a cubesat program set up their own and join something like UniCOGS), open source ground station networks like SatNOGS, and commercial services like AWS Ground Station. On the satellite it’s just an off the shelf UHF/VHF transmitter or SDR.
- rzimmerman 1y ago
  If you're interested in building something, Planet released an open source hardware/software satellite radio that works over amateur radio bands for ~$50: https://github.com/OpenLST/openlst https://github.com/OpenLST/openlst
- zanderwohl 1y ago
  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.
zzzeek 1y ago
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. https://en.wikipedia.org/wiki/CubeSat 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.
- kanwisher 1y ago
  commercialized? He just talks to people building open source cubesats
rester324 1y ago
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.
deleted 1y ago
[deleted]

232 points by warrenm 1y ago

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?

jdiez17 1y ago
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 1y ago
  But even in LEO, there must be quite a few SEUs and resets?
  - jdiez17 1y ago
    I personally haven’t seen confirmed SEUs in the satellites I’ve designed/operated (as in, an ionized particle affecting a transistor/MOSFET in a way that creates a short circuit and can only be cleared with a power cycle). But it’s good practice to design space systems to have current monitoring and automatically power off in case of such events. Resets etc. are common, most likely caused by software bugs. This is more or less assumed as a fact of life; software for space applications is often as stateless as possible, and when it’s required you’d implement frequent state checkpoints, redundant data storage, etc. These are all common practices that you’d do anyway, it doesn’t make a huge difference if the software is running on a rad-hard microcontroller or off the shelf Linux processor - although (IMO) there are many benefits to the latter (and some downsides as well.) Assuming a base level of reliability, of course - you don’t want your OBC/PDH to overheat or reboot every 5 minutes.
Sanzig 1y ago
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.
- NoiseBert69 1y ago
  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.
  - dylan604 1y ago
    That's kind of how I was thinking about it. Why does each cubesat project have to start over from scratch? Why isn't there a basic set of projects that a team can build on top of to make their own custom sensors for their purpose, but the basic operational stuff like the suggested multiple storage types with redundant code shouldn't need to be recreated each time. Just continue using what worked, and tweak what didn't. No need to constantly reinvent the wheel just because it's students learning.
verzali 1y ago
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 1y ago
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 1y ago
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.

tensorlibb 1y ago

It's beyond cool you can pretty cheaply get cube sats on Space X rockets too

hazrmard 1y ago

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. https://github.com/hazrmard/SatTrack https://github.com/hazrmard/SatTrack

firesteelrain 1y ago

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

dylan604 1y ago
> had one fly for over a year at 40k ft inquiring minds want to know. was this tethered? what kind of clearance did you need and what kind of equipment was necessary for safety purposes?
- firesteelrain 1y ago
  It was connected to an Orbs 32” PicoBalloon https://balloons.online/orbs-32-clear/ https://balloons.online/orbs-32-clear/ I used 36 awg wire and fishing line. The lower half of the dipole is also 36 awg wire. No flight clearances are required If any aircraft were to hit it, then it would be obliterated. This includes Cessna’s as well
  - rogerrogerr 1y ago
    As a bugsmasher pilot, I’d be most worried about 40k ft of fishing line wrapping itself around the spinny bits on the front. What’s the tensile strength on that stuff? Doubt it’d cause an immediate issue, but doesn’t sound very fun to remove.
    - firesteelrain 1y ago
      3-6 newtons or about 0.7-1.3 pounds-force Also it’s not 40k ft of wire. Altitude is 40k ft The wire is about 16 ft for one leg of the dipole. That is the taught part. The other just floats in mid air underneath the payload The community is very small and doubtful the sky will be filled with them The balloons follow the jetstream from where they are launched. I have seen them fly over the Artic Circle, for example

NoiseBert69 1y ago

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.

nicce 1y ago
You can do even more than that if you want to see it moving! And without designing it completely by yourself. https://github.com/nasa-jpl/open-source-rover https://github.com/nasa-jpl/open-source-rover
- NoiseBert69 1y ago
  Designing it is half the fun :-) Chassis aren't expensive from far east - so it's mostly the electronics.

ImJasonH 1y ago

...so how do you keep it secure? I didn't see a lot of detail at https://ethoslabs.space/ 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!

jdiez17 1y ago
> ...so how do you keep it secure? > 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! It is somewhat different from a security point of view, but the gap between them is getting smaller. The main "obstacle" to hackers taking over your satellite is that it is somewhat difficult to set up a UHF/VHF/S-band ground station with enough transmit power to reach the satellite. And you need knowledge of the command protocol that the satellite uses. But ground stations are getting cheaper every day, IMO you can build a fairly capable transmitting setup for ~1000€. So the remaining protection is a form of security by obscurity: "we invented this command protocol, so nobody knows how it works". But that can obviously be defeated by recording ground station signals and some dedicated reverse engineers. When those protections fall away, you'll find that a lot of satellite/CubeSat software out there is quite vulnerable (see https://jwillbold.com/paper/willbold2023spaceodyssey.pdf https://jwillbold.com/paper/willbold2023spaceodyssey.pdf). You often find things like commands that are literally "arbitrary memory read/write". While they are a nightmare from a security point of view, they are extremely useful for operators of experimental satellites, e.g. to patch software in memory to fix bugs or read variables that are not exposed as telemetry. I have written a few of these patches myself, and my friend PistonMiner used them brilliantly to hack in a software update capability and revived a 15 year old CubeSat that was assumed to be dead - see their 38C3 talk: https://www.youtube.com/watch?v=KdTcd94pVlY https://www.youtube.com/watch?v=KdTcd94pVlY If you ask me, the way to keep satellites secure is to basically apply the lessons that we have learned in terrestrial computing to space applications. Things like using encryption/authentication, process isolation backed by a MMU, memory safe languages, etc. That's what we're trying to do with RACCOON OS btw. You can take at the flight software of CyBEEsat, a 1U CubeSat that is launching soon(tm): https://gitlab.com/rccn/missions/cybeesat https://gitlab.com/rccn/missions/cybeesat

kadushka 1y ago

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.

abirch 1y ago
The question is how to deal with all of the space debris. It seems like they should factor in the total cost (retrieving anything that goes up) and not only the cost to launch it.
- treyd 1y ago
  Sattelites in LEO without the ability to boost their orbits back up will fall out of orbit in a few years due to natural atmospheric resistance. Exactly how long it takes depends on the shape and mass of the sattelite. It's of very very low Kessler syndrome risk.
- kulahan 1y ago
  It all falls back down eventually. Anything too small will stay up for some time, but even the half-billion copper needles put in space by the US have almost all come down. Wikipedia says there are <50 clumps of needles left.
- junon 1y ago
  Cubesats in most cases must have documented materials that are burnt up in the atmosphere upon reentry, for this exact reason. They don't stay up there forever.
- mbonnet 1y ago
  FCC (or FAA, can't remember, that's systems engineering's job) mandates that all satellites, including cubesats, be able to deorbit within 5 years of the end of their mission with some confidence rate (90%, iirc). Almost all cubesats are launched at about a 550km x 550km orbit or lower circular orbit. Cubesats (most satellites, in fact) will deorbit naturally within a few years (almost definitely <= 5Y) at that altitude due to orbit decay, mostly from drag. Now, some cubesats will have onboard propulsion, which they'll use to extend their mission by burning back into higher orbits, allowing them to still naturally decay at the end of their mission. Indeed, they can even use remaining propellant to speed their orbit's decay.

7373737373 1y ago

it would be awesome for this to become popular enough to see teams of people race each other out of the solar system

warrenm 1y ago
how much of a propulsion system could you feasibly pack in a cubesat?
- geerlingguy 1y ago
  Very very little, but not nothing. I've seen a few tiny deployable solar sails and a few tiny electric motors in my brief research for my video. They seem mostly experimental, to test out theories and miniaturization.
- notahacker 1y ago
  Enough to maintain your CubeSat's orbit and do a bit of pointing, but you'd need something bigger to have the propellant and power to get out of the solar system
abirch 1y ago
I frequently wonder if alien didn't send RNA to Earth to start life here. It seems like that could be the payload for anyone shooting satellites out to the universe.

bilsbie 1y ago

I’m really confused how you communicate with it? That seems like the most (expensive?) and technically difficult part. I’ve got some cool ideas for atmospheric Reentry but I’d imagine there are all kinds of permits needed?

bragr 1y ago
>I’m really confused how you communicate with it? That seems like the most (expensive?) and technically difficult part. Not really. They typically use standard amatuer radio frequencies and protocols. Making space to ground contacts is doable with a handheld radio and directional antenna. Main limitation is low data rates (dialup or worse) and low coverage (you'll probably only get 1-2 passes a day from a single ground station). A decent semi-permament ground station can be built from off the shelf parts at a fraction of the cost of the overall satellite.
throwup238 1y ago
A combination of amateur radio operators, university ground station cooperatives (most universities with a cubesat program set up their own and join something like UniCOGS), open source ground station networks like SatNOGS, and commercial services like AWS Ground Station. On the satellite it’s just an off the shelf UHF/VHF transmitter or SDR.
rzimmerman 1y ago
If you're interested in building something, Planet released an open source hardware/software satellite radio that works over amateur radio bands for ~$50: https://github.com/OpenLST/openlst https://github.com/OpenLST/openlst
zanderwohl 1y ago
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.

zzzeek 1y ago

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. https://en.wikipedia.org/wiki/CubeSat 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.

kanwisher 1y ago
commercialized? He just talks to people building open source cubesats

rester324 1y ago

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.

deleted 1y ago

[deleted]