KSP Community CubeSat

[dharak1]

In the words of Bane: " Step forward those who would serve. For an army will be raised." Just replace army with team and there you go. I'm glad the thread has managed to stay on the front page as long as it has.

[Streetwind]

http://www.gizmodo.in/science/Australia-Is-Building-a-Pee-Powered-Ion-Thruster/articleshow/19163595.cms

possible propulsion???

No... too large, too power-hungry, too heavy for a cubesat. Remember, you're limited to 10x10x10 cm and typically 1kg in mass... An ion thruster of this class would exceed both of these measurements from just the thruster alone, nevermind propellant or the rest of the satellite. Or the power generation equipment required to drive even the smallest models. You might be able to fit a really small variant into a 3U cubesat and have enough space left for electronics and a bit of krypton, but that'll be it then. It will just be a flying thruster. And considering the smallest variant I can find a mention of still eats 50 watts, you could plaster the entire sat with solar panels and still not generate nearly enough power.

Moreover you cannot buy it yet, as they only finished building a proper ground test stand earlier this year. I have not heard (and cannot find on Google) any up-to-date mention that the purported demonstration flight is going to happen this year - there's only a handful of launches left, and the latest papers published on the HDLT don't deal with anything resembling flight hardware.

Of course I'd like to be proven wrong, but I'd say: give it another two years, then we might see a test flight... and then another two after that until you can buy it. But even then it will sadly still be oversized for the cubesat format.

Edited November 24, 2014 by Streetwind

[K^2]

Treldon, that NOAA link is in the bull's eye. Thank you.

[sgt_flyer]

Mmh - would it be possible to use DSSP's ESP thrusters (those are mini electric SRB's of various size - the solid fuel burns only when an electric current is applied, and can be shut down)

http://en.m.wikipedia.org/wiki/Digital_Solid_State_Propulsion

Those thrusters are about to be tested with Spinsat which was sent with CRS-4.

http://www.nasa.gov/mission_pages/station/research/experiments/1019.html

The first thrusters they made are meant for nanosats and cubesats.

If the spinsat experiment works, maybe they'll want to test out their technology in a cubesat

[henryrasia]

About the workshop, there will be one in London in May 2015, so maybe K^2 can attend. There's also one in Rome in February 2015, but I'm afraid we'll run into the same problem...

About propulsion: This first mission will not involve propulsion of any kind! And refrain from discussing future missions because they will simply not exist if we do not focus on this first one.

Tredlon: Nice! That's exactly the kind of help we need, action. No matter how small or "insignificant" a contribution is, any new insight, resource, calculation, or idea is what's going to drive us forwards! Thank you!

How about this for a WIP declaration of goals?

The KSP Community Cubesat Project is a project with the goal of carrying out actual, real life space missions. The team is crowdsourced, with any help being welcome, and with members of the "official" team being determined only by their continued contribution. There's no application form, no waiting list, no resume requirements, no interview, no nothing. The only requirement is enthusiasm and proactiveness. We are based on the Kerbal Space Program community for its space-savvy and space exploration loving members, but are in no way associated with SQUAD. For this reason, feel free to hop in if you're an Orbiter, Flight Simulator, Celestia, Space Engine, or just-passing-by kind of person! All are welcome!

Of course, space is hard. And sending anything up there takes more than basic orbital mechanics knowledge. For this very reason we are starting small and working our way up. There's no degree like experience! Our first mission will be a 1U cubesat, the smallest of its kind, to low Earth orbit. There will be few and simple components and no propulsion at all. To avert failure, we're setting the bar low for this one: if it gets to orbit that is confirmed with telemetry, we celebrate! If it manages to survive for multiple orbits and take pictures, we celebrate more! If it manages to conduct an experiment and yield useful data, than we will have broken some records!

But what is this mission, exactly? Well, launching something to orbit is really expensive, and so we need to make it worth it. We had to come up with an experiment that would give new data to the scientific community; useful data, that is; data that wouldn't be able to be collected on Earth; and data that the public will recognize as cool/useful. All of these requirements would give our project scientific legitimacy, public support, and maybe, just maybe, a free ride from NASA's cubesat initiative support program, cutting back the cost on a hundred thousand dollars or so.

The experiment is [...]

The cubesat will be like [...]

The funding will be done through Kickstarter, or some other crowdfunding service. This will allow for mission "tiers" to be decided by the community. The higher the "tier", the more expensive AND risky it is, but results will be better/more awesome (HD pictures! live video! All ridiculously expensive)

The project is currently in just-begun-designing phase, so if you want to help you can definitely help. We hope you will join!

Any input appreciated, I wouldn't post this as it is myself. I left the experiment and cubesat descriptions for Mazon Del and K^2, just because I don't want to write something stupid and misleading

PS: Dammit! SpinSat is taken! MossSat, anyone?

Edited November 24, 2014 by henryrasia

[MBobrik]

To MBobrick, there's nothing done until now except for the basic mission goals. That means any input will be heard! And there's no leader either, as none of us can dedicate full time into this. In a way, we all have the same level of responsibility and authority because we aren't professionals on anything, but we are kinda good at something! It's truly a community project.

Thank you very much for the answer. I've a few questions about the hardware... why to use a complete camera ( which got DSP and processor and a lot of irrelevant or redundant stuff inside ) when there will be a full on-board CPU ? What about using just a camera module, or even just hooking a sensor chip to the CPU board ? It will cut a lot of mass and power consumption.

.

And another question... It is right to get into such details here, or is there a kind of more specialized forum ?

[Nicholander]

It's right to get into details here, to answer your question MBobrik. and henryrasia, nice declaration of goals! Also, I say we name it KerbSat, though I think we should have a poll for that. Also, I think someone earlier mentioned that we should make a 3D virtual model of it, with some program which I don't remember the name of. We should really do that, does anyone having any 3D modelling experience here?

EDIT: Something like this:

EDIT 2: Found the name of the 3D modelling program, Solidworks.

Edited November 24, 2014 by Nicholander

[bounding star]

have we got any idea of what exactly we will be measuring from the moss? also, if we have an external camera for coolness, the internal camera could have some way to switch to a microscope aka moving lenses in front of it. what are we exactly going for in terms of the size/ shape/ material of the test chamber?

[MBobrik]

Found some camera modules ... not really putting effort into it, but for example

this one

or this one

or this one

[henryrasia]

Just a really quick advice to anyone new here, try to read at least from page 123 onwards. I know it's a lot of pages, but there's a lot that was discussed, and before that page we digressed a lot, so there's not much in there. Please do read all of the pages to get caught up on decisions and discussions that have already started in order to avoid repetition. Thank you!

About a dedicated subforum: I would really like that, but I'm not sure SQUAD will give their serverspace for one project in particular. Endersmen was building a site, but I don't think it's functional right now (btw where is he?). So for now everything's unorganized in this thread.

On the other hand there is this google doc I created where we're writing down the most important things. Here's a link that allows commenting : LINK. To keep things manageable full editing powers are only for a list of emails. If you'd like to be added just message me with a gmail.

About the camera, I'm hesitant to start discussing that because we're already into discussing estimated power consumption (bare minimum, excessive maximum, average, etc) to then discuss solar panel / battery / power regime of the cubesat. However K^2 is working on that, and there's not much to do until he's done (unless some of you wish to help him out with that!), so we might start talking about cameras. MBobrik, that's a very valid point on the redundant camera components, but we need to weigh in ALL consequences of different component options, so sturdiness of a dedicated action-adventure minicamera MIGHT be better, don't pay attention to me, though, because we haven't discussed this yet. However, this is a quick recap of what's been proposed for cameras (I'm excluding things written in the doc):

• Have one HD camera on board that would film the outside when a lid to the outside was moved and the experiment both through a fixed lens and directly when the lid closed. UPSIDE: only one camera DOWNSIDE: lid mechanism needed, all eggs in one basket camera, fixed lenses may not work like a microscope.
  
• Having one cheap camera outside and one good one inside. UPSIDE: less parts DOWNSIDE: The cheap camera would only be useful in the very beggining of the experiment when the craft is not spinning.
  
• Am I missing something?
  

Of course, there's a discussion on whether to have a camera/lens setup (like what you said bounding star), a dedicated microscope, or just a regular camera. This also depends, like bounding star asked, on what kind of data, exactly, we're going to be measuring. That's a question to Mazon Del, as we're basically putting into practice a thought experiment of one of his university professors, and he's done plenty of research already that we can use. Also, I may have missed some things, but this is what I can remember.

Edited November 25, 2014 by henryrasia

[Nicholander]

Hmm... I think we should go with the two camera solution, but that really depends on the reliability of the lid mechanism, and how much those solutions will cost.

Also, anyone here with any Solidworks experience?

And K^2, could you put this logo Lunniy Korabl made in the first post?

[Nicholander]

Also, K^2 and henryrasia, maybe we should set up a Chatzy chat room, so we can have a sort of Skype meeting. (Without needing to create a Skype account, getting and setting up a webcam, etc.) Maybe we can have a "Chatzy meeting" every once in a while, if everyone is able to be there at the same time. I could set one up, it's easy. Link to Chatzy

[technicalfool]

Also, K^2 and henryrasia, maybe we should set up a Chatzy chat room, so we can have a sort of Skype meeting. (Without needing to create a Skype account, getting and setting up a webcam, etc.) Maybe we can have a "Chatzy meeting" every once in a while, if everyone is able to be there at the same time. I could set one up, it's easy. Link to Chatzy

Note that the same IRC servers that run the official chat (available on that link at the top of the page here) can be used to make any channel you like (so long as it doesn't contravene Espernet's rules). Just "/join #aChannelThatDoesn'tExistYet", and it's yours to register with Chanserv and claim.

[K^2]

Main reason to go with more than a simple sensor for the camera is because we want to compress images, and rad-hard CPUs with enough power to do compression will a) eat through a lot of power even when idle, and be very expensive.

I would rather have a camera capable of on-board compression as a stand-alone unit. If we can find the funds to upgrade to a rad-hard camera, great. If not, we are risking only to lose the camera. Not the whole mission.

That said, the camera doesn't have to be anything fancy. The earlier suggestions about something like Go Pro are total overkill. We can't handle data rates for the quality where we'd need this, and it has a whole bunch of stuff we don't need, including its own battery. I have a tiny robotics camera that does VGA stills and handles JPEG compression on board. I can use that for early testing. We can later get something slightly fancier, so as to get better quality images.

Microscope is a separate story. I think our best bet is buying a cheap microscope and cannibalizing its optics for a custom solution. Though, I'm not entirely sure what exactly we are looking, and how we are going to get what we are interested in in the focal plane, without anything else getting in the way. But again, worst case scenario, we won't get microscope data. So long as we are getting clean readings from all of the sensors, we should still be able to estimate biomass growth pretty reliably.

I think, key word in almost everything we do is reliability and redundancy.

[dharak1]

I think a moving lens system is out of the question. Too many moving parts and it would take up too much space. A failure on one lens or all of them would leave us with an unusable or unfavorable camera. I say we either go with a microscope if it doesn't take up too much space or go with just a regular camera with no microscope. An external camera is an option if we have enough space and power for it. if the craft is spinning at 30 RPM that gives us a fairly slow spin speed and it would be possible to take pictures out of the sides.

[K^2]

I don't think there's a problem having a microscope camera, a basic experiment camera, and an exterman camera. These things are small, light, and only need to take up power when taking picture, which isn't much even then.

You have a point on moving optics. But I think we might be able to use a head from an optical drive for it. The lens in it has enough travel for our needs. If it gets stuck, we will simply be limited to a fixed focal plane, which is hardly worse than starting with fixed optics to begin with. It's worth experimenting with, at least.

Edit: Just to clarify. Ideally, you want multiple moving lenses, so that optics still properly compensates for aberrations. But if you just need tiny adjustments, you can get away with a single moving lens in the middle of the assembly without loss of quality.

[Treldon]

About cameras: the only way to go is to use two (or more) smaller ones. Using one that rotates around would take too much space, would not have correct zoom for both types of pictures we need. Plus the rotating mechanism would break down.

Furthermore, as we are spinning the sat, we don't want any moving parts, because unless they move long the spin axis they could unbalance the craft

As for the optics, I did study some back in uni so when we have a basic setup of what goes where I could try and calculate what we would need in terms of lens

Finally, I have some experience with SolidWorks and SolidEdge, so I can help with the models

P.S: anything else that needs to be (re)searched?

[Ravenchant]

@Ravenchant. How far along are you in your studies? I can probably use another set of eyes to look over the equations of motion. But I don't want to scare you with graduate level mechanics if you haven't had a classical mechanics course yet. Though, theory isn't critical here, it's mostly just Diff Eqs. If you'd like to take a crack at a few checks, I can write out what you'd need.

Classical mechanics is fine. Are you using Lagrangian/Hamiltonian formalism? Because those aren't exactly my cup of tea, but I could try.

[K^2]

I want to compare precision of doing orbits in Newtonian vs Hamiltonian. Newtonian is trivial integration of all forces along the trajectory. I should probably refocus on that so that we get some basic functionality sooner.

But the more interesting case is Hamiltonian. The reason for that is that thanks to Canonical Transformations, it's possible to treat forces as perturbations on central potential, a lot like analogous procedure in Quantum. Unfortunately, in Classical, it's way more algebra.

Basic idea is that we write the central potential problem: H₀ = p²/(2m) - μ/r. Then we add in other forces, including these due to gravity not being perfectly spherical, as local potential. H = H₀ + U(r). The real trick is that instead of using original coordinates, we choose a set of generalized coordinates and momenta Q_i, P_i, such that ∂H₀/∂Q_i = 0 = ∂H₀/∂P_i. In other words, Q_i and P_i are constants in unperturbed Hamiltonian. These are the constants of motion for a particular orbit. Starting in spherical coordinates, these work out to be (via Hamilton-Jacobi Equation) time of periapsis passage (T), argument of periapsis (É), longitude of ascending node (Ω), energy (E), angular momentum (L), and z-component of angular momentum (L_z). These are easily related to standard Orbital Elements.

But the super nifty part is that in perturbed Hamiltonian, these are no longer constants. And they are governed, as one would expect from Hamilton's Equations, by dQ_i/dt = ∂U/∂P_i and dP_i/dt = - ∂U/∂Q_i.

Naturally, we don't know exact shape of U, but we do know forces. In other words, ∂U/∂r = - F_r, ∂U/∂θ = - r F_θ, ∂U/∂Æ = - r sinθ F_Æ. Chain rule insanity ensues. I've been able to verify that dP_i/dt equations do work out to be work and torques as appropriate. What I need some sanity checks on are the equations for the Q_i elements.

Ok, so why all of this? The disadvantage, clearly, is complexity. Both in derivation and in computation. That's going to contribute to errors. However, by far the largest force that has to be integrated over in Newtonian formalism is gravity. And by far the strongest component of that is the spherically symmetric part. And perturbations approach takes that out completely. So while computations are heavier, we are integrating over much, much smaller corrections. So I expect overall precision to be dramatically improved.

I'll make a write-up of all of this with detains in the near future. I'd be happy if people to whom it isn't all Greek would take a look and see if there are any obvious gremlins in my math.

[Aethon]

Sounds like we've got our top men/women on it.

Well I'm half Greek, and my math skills say that if you understood the above, half as much as I did, then you understood it twice as much as I did.

NASA's CubeQuest challenge. Launching Moon CubeSats on the SLS.

http://www.nasa.gov/cubequest/#.VHSslYvF-Ye

[MBobrik]

Just a really quick advice to anyone new here, try to read at least from page 123 onwards. I know it's a lot of pages, but there's a lot that was discussed, and before that page we digressed a lot, so there's not much in there. Please do read all of the pages to get caught up on decisions and discussions that have already started in order to avoid repetition. Thank you!

I admit, I didn't read all up. But I think that shouting at me because of that was unnecessary. Now, after I read through pages 123 - current, I found that the cam was indeed discussed a few times, but all suggestions were stand-alone cameras.

No one mentioned camera modules or using raw chips. And thus I would like to present this little gem.

Just a quick comparison with the suggested GoPro:

I would rather have a camera capable of on-board compression as a stand-alone unit.

While not stand-alone, the module can send both raw and h264 compressed stream. No processing on CPU necessary, but sending it over to the transmitter.

[henryrasia]

Mbobrik, sorry if it sounded like I was shouting, I just made it into a bigger font to attract the attention of anyone passing by, especially because this thread seems like text walls for newcomers.

So, K^2 seems to be in some serious physics right there! So until you're done with calculating, we're going to be discussing cameras. Mbobrik, that camera is very nice! I wouldn't expect so much out of a Raspberry Pi component, the more you know . I think 30 FPS and 5 MPx is absolutely fine for our purposes. Is it going to survive space, though? For 3-4 weeks?

[MBobrik]

Is it going to survive space, though? For 3-4 weeks?

No clue about that. But I suppose it is not less durable than the raspberry pi itself...

[K^2]

Video compression is useless. We won't have the bit rate for it. And we need a rad-hard option. I don't think there is one for Pi. There are plenty of camera options that will not require a specific CPU.

[Nicholander]

I really don't think we should use a Raspberry Pi as the CPU, can't we just modify the Raspberry Pi camera module to work with a CPU designed for CubeSats?