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An Introduction to CubeSats (gereshes.com)
131 points by dyukqu 7 days ago | hide | past | web | favorite | 61 comments

For a long time now I have been very interested in sending my own satellite up as a hobbyist project. I have a good background in software, electronics and hardware (top to bottom robotics), but not a solid background in physics.

A few questions:

1. What's the cheapest you can put a satellite in space (in terms of launch) and for how long would it orbit at that cost? Size wouldn't really be too much of a problem (I can go as low as 3x3x3 cm at a push).

2. Are there strict limitations about what you are allowed to put up into space? (In terms of components and contamination). Also in terms of transforming - is it allowed to unfold?

3. Do the satellites have to undergo some formal testing to be allowed on the space craft? What's that process and how much does it cost? I imagine they can't risk it blowing up or falling apart?

4. Has anybody looked to sub-divide the cubesat 10x10x10 into 8 smaller satellites? If you could somehow keep them all attached in fixed locations, you could have a much larger sensor surface area at a low cost.

5. How do they get the satellites to the launch location and how long does it have to be there in advance?

I think using reaction wheels is good for rotation and I don't think propulsion will be as "easily" possible. Compliant communications would be the most difficult part in my opinion, trying to keep it low power and effective.

As for the actual mission of the project, I'm still not decided. It could be cool to host some kind of server from space, but just throwing some hobbyist sensors up there and seeing how they behave would also be good.

Thank you in advance for any help with those questions.

1.- As an individual, the cheapest and simplest options would be to use Nanoracks, Spaceflight, or a similar company that handles most of the launch process. Their price is ~$100k for a 1U Cubesat. I have serious doubts that they would be OK with a 3x3x3 cm satellite, as these are really hard to track and they are big enough that, if there is a collision, they can cause some serious damage. See for example https://spacenews.com/fcc-fines-swarm-900000-for-unauthorize...

2.- Yes, there are. For example, in terms of materials, you can check http://nanoracks.com/wp-content/uploads/standard-materials-a.... Yes, in satellites there are several things that normally unfold (i.e., solar panels, antennas, sensors)

3.- They normally undergo (at least) outgassing, vacuum, vibration, and thermal testing. Not sure if all of them are mandatory. I would say that outgassing is a must in most places. See http://nanoracks.com/wp-content/uploads/flammability-offgass...

4.- Yes, some people have launched things much much smaller than a Cubesat (like Chipsat), but normally you would be required to decay/deorbit quite quickly since as I mentioned, space people don't like small things flying around.

5.- If you use a launch provider, you normally do integration at their facilities. Then they handle the rest of the process for you. I would say that a normal deadline for integration is ~3 months before launch?

Thanks, especially for the links!

I worked in a lab for the US government building cubesats for a summer during college. I can't answer everything, here are a few answers.

1. Last time I heard pricing per pound to orbit was ~$10,000 per pound. This was for the shuttle though, so I don't know if this has changed. 2. I would guess this depends on the launch provider. Whoever's launch you're piggybacking off of will probably get to make this decision. I never heard of any real restrictions, but this wasn't my area of expertise. 3. You'd be right about that. I don't know about pricing, but your payload will need to go through vibration testing and the like 4. No clue on this one 5. You'd probably have to physically make the trip (and I'd think you'd want to. Seeing a launch is always cool). Timing will depend on whose launch you're piggy backing off of, but we needed to have everything done a few weeks before launch day.

Hope this helped a bit.

Would you be able to give me more details on that program? That's something I'd be really interested in pursuing!

Thanks! I did wonder whether it was costed by the weight of the craft.

Decent intro to CubeSat hardware. If you want to know about CubeSat software, let me know. The company I work for, Kubos, builds an open source OS for small satellites: https://www.kubos.com/kubos/

(I work on our web-based ground control software, Major Tom.)

(Self promotion warning!) If you find space science, CubeSat engineering, and space startup news interesting, I'm starting a short weekly newsletter that I think you will enjoy. https://goo.gl/forms/uGi2AL7ELpJK86bx2

(Say hi to Marshall!)

And if someone has any questions about the ground side of things I work at KSAT which provides a global network of ground stations (both cubes and larger).

We often find sat builders completely forgetting about the ground segment and then struggle to communicate with the cube. Often by using exotic encoding and/or modulation schemes or choosing frequency bands that are either too crowded or hard to license in some parts of the world.

Does it make sense to run a ground station as a business, renting out the bandwidth to those who need it?

Alternatively if you want to have open data and share it with the community you can set up a SatNOGS ground station. Even if you don't have a Cubesat in the works. Check out wiki.satnogs.org

Yeah, it's big business actually. Having ground stations at the right spot means a lot, but the equipment is expensive (but getting cheaper every year now). We multi-tenant our assets to provide a cost effective solution and aid in getting those licenses. From the links others posted you can see that AWS recently launched a service to compete head to head with us. It's certainly interesting to be targeted by them, to say the least.

AWS recently announced their ground station service[0] to do just this. At the time I didn't understand why they would build such a service, but reading this article and setting your comment brought it into focus for me.

[0] https://aws.amazon.com/ground-station/

> (I work on our web-based ground control software, Major Tom.)

Does it ever bug you that ground control is Major Tom?

Interesting approach to flight software. Where are you guys based? Are you hiring?

We're based in Denton, TX, but much of the team is remote. Not hiring today, but likely soon! Feel free to email me.

Cool. I sent you an email through your contact form.

How does Kubos make money and fund full time employees and future updates?

We sell Major Tom, our ground control software, and support contracts for KubOS.

Hope yall are doing well! I had no idea this industry existed until Ryan showed me one of the tiny cubesats in the office!

Curious if you receive any branding confusion over Kubos versus Kubernetes?

Hello! I'm not aware of anyone confusing the two.

Cool. I think I've met you guys at the DEC.

I'm part of the same University at Buffalo group as the author. If this interests you, we've open-sourced some of our stuff, including a VHF/UHF communications radio and star-tracker software.

Radio: http://lfradio.space

GitHub: https://github.com/UBNanosatLab

That's too awesome. I'm tearing up here. We will be using this for sure on our project. Thanks!!

And if possible would like to get in touch for possible collaboration. I have a nanosatellite project in brazil.

As an amateur astrophotographer I’ve been following the development of cubesats closely. It seems more and more likely that a small group or an individual would be able to launch a space based telescope within my life time. Right now it’s a bit tricky still, and not really sure if you’re allowed to have a camera in space yet (might be considered espionage). But still, extremely cool ... maybe someday soon a crowd funded mini Hubble might be an option!

If you're in the U.S., and are interested in the licensing issue, this is probably the page you want: https://www.nesdis.noaa.gov/CRSRA/licenseHome.html

It is indeed an issue, but a surmountable one.

Check out Spacefab: https://wefunder.com/spacefab

I apologize if this is a silly question but given that this "democratizes" satellites, is anybody allowed to launch satellites into orbit? Or is there some formal application or protocol that people and companies need to adhere to in doing so?

Yeah, launch providers (“rockets”) need to be certified by bouth their country of incorporation and the country they launch the rocket from. But law between countries doesn’t need to be synchronised.

Planet Money did a series about going to space. https://www.npr.org/sections/money/2017/12/01/567267573/plan...

They went over the history and changing economics of CubeSats.

The recent Mars lander mission included a pair of 6U cubesats used to relay communications. They worked great: https://en.wikipedia.org/wiki/Mars_Cube_One

I worked on the software for the attitude determination and control system (ADCS) for the MarCO spacecraft.

Well congratulations! Was it fun? Is working on a cubesat radically different than other types of satellites, or do the control systems end up working more or less the same?

Not radically different. The company that did this work was staffed with engineers who had experience on larger spacecraft. The fundamental algorithms are the same. The difference is that everything is much smaller - less momentum, so less large reaction wheels, etc. The nice part is that you can use commercial parts, so you get access to much more modern electronics than old rad hard parts.

Hi. If you are into open hardware and free software don't hesitate to check https://libre.space a non profit developing open source space technologies

We've built SatNOGS a global ground station network https://network.satnogs.org with more than 100 stations online globally and 50 more in testing build by volunteers

We've also built the first Cubesat under CERNs OHL license. https://upsat.gr

It seriously impresses me everytime I read about CubeSats. I still remember the first couple times there was a Kickstarter for the CubeSat when the idea came out. Admittedly, I scoffed at the idea because I didn't think it was feasible. I'm pretty happy to be proven wrong.

To impress you even further, cubesats were a thing long before Kickstarter existed.

I wrote my masters thesis on one back in 2003, and it was launched in 2004. Even back then this was such an established concepts there were niche conferences for it.

The question I ask when small satellites are promoted is, how do we avoid Kessler syndrome?


CubeSats are low mass and tend to be in low orbits that decay in time periods between a few weeks and 10 years. Also, all modern satellites have to be launched with a deorbit plan.

I'm not sure the de-orbit plan thing is successfully being enforced by any launcher.

That being said kessler's syndrome impact are usually over-exaggerated by "big space" as a reaction the disruption going on in the business.

Cube says are in rather low orbits and have a high surface area to mass ratio so they decay rather rapidly. Not really a big deal as far as space junk goes.

Well it says there are 600,000 pieces of space junk.

But that's spread out over a large area.

The area of the earth is 510million km2, so worst case (all on the same plane, at ground level) that's 850km2 for every item of 'junk'. I don't see that being sufficient density for a domino effect. I suppose it depends on how uniform the cloud density is.

It's not uniform at all. Most objects are in high inclination orbits, which means many intersect near the poles.

"To answer that, let’s first define a U. A U is 10x10x10 cm cube of space from which cubesats derive their name"

So, what's a U? Is it a mathematical constant, or just arbitrary?

A "U" is a Unit, which was arbitrarily defined as a 10x10x10 cm cube.

Kind of funny that they didn't just call it a liter, which is exactly that volume.

Well it isn’t just about the volume, since the form factor matters too. (Maybe you were just joking and I’m staying what you already know. If so, carry on)

I cant tell if you're being facetious. Does U just literally stand for unit then?

Yes, it stands for units.

"CubeSats are built to standard dimensions (Units or “U”)"


You'll see this in server hardware as well...

1U servers, 2U servers..

different size, however. in servers and equipment racks, 1U = 1.75 inches.

Height wise. Width is 19”

Depth varies dramatically - from maybe 1” to 1m

I believe so, yes.

Ok thanks ?!

Why do you need to send up atoms when you can beam up bits?

To beam bits down.

I am saying rent cubesat software like AWS. Why send more hardware?

Because you need certain sensors over a certain location on Earth? I don't think we're at the point yet where such needs can be covered by renting.

We have enough cubesats to make that happen. You can rent time slices for software.

That’s like saying you need to access certain sectors of a hard disk.

There are two important reasons for creating and launching cubesats:

1) Learning opportunity - that's how people get experience with space technologies.

2) Equipment testbeds - companies that would like to sell technology for use in space need to prove it actually works in space. If you can get a CubeSat project to use your component (by e.g. donating it + some money) as a part of their satellite, you can test it in space for much cheaper than it would take to build an entire satellite on your own. It meshes nicely with 1), as people who want to learn space technologies tend to not have money to build and launch satellites on their own.

As for your original question: we're far from the point of having all necessary sensors in orbit. There's not much to rent out yet.

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