KSP Community CubeSat

[Nicholander]

People, we will not deploy anything outside LEO, so stop wasting time and clogging the thread with it.

It's naive and stupid to think it's possible. This is not KSP, it is real world.

Though, I'll be honest, you can't completley remove the possiblity of us getting a GTO ride, possibility being the key word.

[EpicRootHairCell]

So we are thinking of having a single kick starter campaign with stretch goals aiming for;

first mission a LEO de orbit tech demo (pretty interesting for the public and the rocket operators)

Second mission go for broke Phobos landing (amazingly spectacular and has some science value)

[K^2]

And the ground station is where? What about infrastructure? C&C? How are you going to send commands and receive your pictures from space? What's the transmission rate you can hope for? What will be your comms window? Doppler effect?

You really need to know such things, as even basic ground station is easily over 10k euro, and even then I'm not sure if you'd be able to do anything more fancy than sending some very basic commands - and you want to transfer an entire photographs from space. You have no idea how much of a challenge is that - and it becomes much, much more expensive once you think about anything further away than LEO.

And a magnetotorquer costs 600 Euro from the same people, yes. An S-band dish can be recycled from an old satellite dish for free. All you need is an actual generator and a receiver. Hell, I could build a microwave cavity for an S-band if need be, so only a transmitter really. And that's basically a microwave's magnetron that you can modulate. (Amateur S-band is actually at the same frequency as consumer microwave oven. You seriously can just turn a microwave oven into an S-band transmitter, but that's more of a fallback if we can't get funds for something better. FCC might not like us for using microwave. It's 'noisy'.) It might be a bit crude, but for sending something that's going to be a few hundred km away passing by, it will be good enough. Lets not forget that we don't need space-worthy for a ground station.

Furthermore, I'm hoping for some support from existing CubeSat users. We do need to have at least one ground station, but it'd be nice if we could rely on other people to be able to receive tracking and image data from all over the world, so we can do data pulls more frequently.

I'm going to take a closer look at available cubesat receiver/transmitter hardware before settling on protocol, but tentatively, I'd organize all of the important communications into packets of 2-byte symbols. I would chose a prime under 2^16 as a base, and have everything done in Z_p of that prime. That lets me use some theorems on polynomials over fields that can be used for error correction. I could organize the packets so that at 50% random data loss, the data is not corrupt. Missing important instructions because of noise isn't nice. Of course, the only thing worse than not receiving instruction is receiving a wrong one, so each packet will come with a CRC as well, in case signal quality causes degradation that error correction can't handle.

I'm not sure how paranoid we need to be about security, whether encryption should be used. We'll probably have to share a key with enough people to make it kind of irrelevant if we wish to get help form other users. And then it'd be just a waste of processing power. But we can talk about that.

Unlike all other data that goes up and down, image downstream does not need to be as reliable, but it needs to be both compressed and error insensitive. JPEG, for example, would be a very bad call. An error early on would junk the whole data. But sending raw images is wasteful and slow as well. I'm leaning towards something JPEG based, but using something other than Huffman codes, so that decoding can resume after a loss. Maybe just run each tile in its own packet of Huffman codes, though. That'd make it super easy for an amateur user to build a JPEG out of it. And losing a tile isn't as bad as losing the whole image. Anyways, we can work on this.

Everything else is fairly routine stuff. The Doppler factor for an LEO sat is whopping... 1.000025. I don't think we can afford a receiver/transmitter that wouldn't have a bigger window. Not even if we waste 10k Euro on a "professional" ground station.

There is a reason why I'm starting with a cubesat hardware specs first. I can work out navs and logic once I have these specs. It's not that hard. Right now, I'm going through specific hardware for LEO mission, so I can put together an "official" shopping list and a price tag for the basic mission.

Edit: Guys, deorbit is not feasible for the base mission. It's something we can try for if we have funding for much better hardware, but as it stands, I wouldn't count on being able to get closer than 10km to any given target. And that's with pretty decent off-the-shelf propulsion.

Edited July 15, 2014 by K^2

[dharak1]

Two separate missions would be needed because the requirements for each are so wildly different.

[Rakaydos]

Figuring out what the price tag would be for a "Magic Boulder" mission sets our "skys the limit" budget.

We are unlikely to get it in the first kickstarter, but it lets us ground our expectations.

[K^2]

The only reason I'm mentioning "ultimate mission" at this stage, is because I don't want us to end up like the potato salad guy, having no idea how to spend $50k on a potato salad.

Scratch that, I would like to see us end up exactly like that guy, but I would like us to have a backup plan.

LEO mission is more important to plan out in extreme detail. And right now, we still don't have a good objective.

[EpicRootHairCell]

In almost three years of hanging around this community, I've observed that playing KSP gives players the mistaken impression that spaceflight is easy. It isn't. When you're 16, 18 or even 22, anything can seem possible, but the sad reality is that it isn't.

I reject the idea that we think space flight is easy, i think we are some of the most grounded people on earth in that regard anyway, we understand how frustrating time consuming and irritating it is to do space flight, even when parts are like Lego, we can save and load are games, revert to VAB and have know money so we appreciate how difficult it actually is. The throws of youth should not be dismissed everything you use was once a throw of youth.

[Nicholander]

Edit: Guys, deorbit is not feasible for the base mission. It's something we can try for if we have funding for much better hardware, but as it stands, I wouldn't count on being able to get closer than 10km to any given target. And that's with pretty decent off-the-shelf propulsion.

So debris de-orbit tech demo is out of the question for the first mission. So what else can we do other then take some pictures and run a few experiments? K^2, have you found any GTO rides?

[Sky_walker]

(edit: ) oh, I just reminded myself one thing - you see the link in my signature? The one to Ariane 5 manual? I recommend you all to read it through.

It'll give you an idea about how is the commercial satellite launched and, perhaps more importantly, what tests and requirements it needs to go through before it gets a green light for launch, what are the factors involved in a launch and what your satellite might need to survive.

I think there is sufficient body of knowledge in building cube sats that the high altitude test can be dropped.

I'm yet to see any person from this CubeSat team to actually show any proof of that supposed knowledge.

K^2 at least appears to have some slight idea about how this thing works but even he is missing as essential things as the cost of ground station (which I already pointed out few pages before, and he answered just above me).

Sorry, but there's absolutely no reason to drop the high altitude test.

while i understand that having done a cube sat would give us credibility

It's not about credibility - it's about knowing what you're talking about and being able to actually pull it off.

Seeing how you talk about dropping tests and Phobos mission - I dare to say that you are one of these daydreamers with no slightest idea about scope of the project you're about to undertake.

I think that once the NASA PR dept. hears about how "inspired" we all are by the GREAT! ARM pack and their collaboration with Squad, they'll be all over us like stink on a monkey.

I'm pretty sure that people at NASA will laugh even more from nonsense that people talk in this topic than guys from my work did.

And a magnetotorquer costs 600 Euro from the same people, yes. An S-band dish can be recycled from an old satellite dish for free. All you need is an actual generator and a receiver. Hell, I could build a microwave cavity for an S-band if need be, so only a transmitter really. And that's basically a microwave's magnetron that you can modulate. (Amateur S-band is actually at the same frequency as consumer microwave oven. You seriously can just turn a microwave oven into an S-band transmitter, but that's more of a fallback if we can't get funds for something better. FCC might not like us for using microwave. It's 'noisy'.) It might be a bit crude, but for sending something that's going to be a few hundred km away passing by, it will be good enough. Lets not forget that we don't need space-worthy for a ground station.

And who exactly is going to build it? And what are you plans to test it? How about compensation for atmospheric interference, etc.? You even know what exactly are the challenges ahead of you? You ever build any antenna that receives even most basic radio signal?

Just to remind you: People here are very much for transmitting images. Not just Sputnik-style beeps.

Furthermore, I'm hoping for some support from existing CubeSat users.

What's the benefit for them? How do you plan to seek them out and convince to spend their time on it?

Everything else is fairly routine stuff.

Not even if we waste 10k Euro on a "professional" ground station.

10k is an amateur low end station... if you actually manage to buy it for that price.

Edit: Guys, deorbit is not feasible for the base mission.

As long as you go to LEO - it shouldn't be necessary. Satellite will deorbit itself due to atmospheric drag (again: real life is not KSP). In theory you could try doing what students in Poland failed to - deploying a long wire to accelerate deorbit. Look for info about PW-Sat.

Edited July 15, 2014 by Sky_walker

[EpicRootHairCell]

When i said dropped i meant not down so i agree with you there.

Yes we are dreamers but is that such a bad thing?

[dharak1]

Maybe we could do a basic orbit change and take pictures before and after?

[Nicholander]

Maybe we could use an ion propulsion system to raise the orbit and study the van allen radiation belts.

[K^2]

Sky, they are talking about finding a piece of debris and deorbiting it. Deorbiting our cubesat isn't an issue, of course. Even with ISS insertion, it will be gone after a few months to a year. Our hardware probably won't even live that long, though.

Oh, and I do know all of the challenges of working with microwave transmitters/receivers, since I've done some lab work with these. Microwave interferometry in S-band, in fact. But I'll be first to admit that I know zip about how much difficulty atmosphere is going to add. I do know people in the next building over that do environmental studies that would know all about it, though. I also know the specs on TV receivers, and that we can't do worse than that if we try.

So it's all details to be worked out as we get closer to it. The only serious obstacles are costs of launch and cost of solar panels, in that order. Because these are the things we cannot wing or fake in absolutely any way. These will have to be payed for by somebody in full.

[Nicholander]

Also, K^2, in the KickStarter, what should we do about stretch goals? They could be that if we reach a ceratin one which is to go to, for example, the Moon for a fly-by, then would we change where the current mission goes or launch another mission? (Though the equipment required for going to the Moon is pretty diffrent then just sitting around in LEO)

[K^2]

Any of these ideas assume hitching a ride with a more serious launch. And some GTO-bound rockets do bring smaller payloads with them. It's just bloody expensive.

I've found companies that done more reasonably priced LEO rides in the past, but I can't seem to find any of them advertising available cubesat space in future missions. GTO or LEO. Looks like we'll have to go door-to-door with this. Fortunately, not that many doors.

Also, K^2, in the KickStarter, what should we do about stretch goals?

We'll need to have some ideas prepared in advance, but we'd add stretch goals as necessary, not dump them all in at once. We'll work it out later. I'm sure we'll need a separate KicStarter topic just for figuring out everything involved with it. Might be useful to find some people with KS experience. Or maybe some marketing types to help us out, even. I know a few people.

In this thread, we should work out a short list of challenges that we can try, and base line for how much each one would cost to try and achieve.

Edited July 15, 2014 by K^2

[Rakaydos]

Would anyone mind if I made a separate thread for the "Kerbal 2- Flight to Magic Boulder" theorycraft? That way we can start figuring out what questions we dont know without interfering with the (far more likely) "Kerbal 1- First Orbit" planning.

[PakledHostage]

I reject the idea that we think space flight is easy, i think we are some of the most grounded people on earth in that regard anyway, we understand how frustrating time consuming and irritating it is to do space flight, even when parts are like Lego, we can save and load are games, revert to VAB and have know money so we appreciate how difficult it actually is. The throws of youth should not be dismissed everything you use was once a throw of youth.

Interesting that you chose to delete the last sentence of the passage that you chose to respond to from my post... You know, the one where I said "great things are only possible with a lot of hard work, luck and talent"? Everything I use may well have once been "a throw of youth", but you're arguing with the benefit of hindsight. For every idea that seems half baked but turns out to be brilliant, there are millions more that don't amount to anything. Convince me that you're not one of the millions. So far, I am not convinced.

[EpicRootHairCell]

GTO to LIO is a small amount of delta-v that would enabled, with a earth slingshot, to visit a lot of the solar system.

[Kryten]

I agree, it is possible, but unlikely. Only if some company that launches a satellite into GEO is willing to release something before circularization burn, and that's just highly unlikely. Launching a rocket with the exact purpose of having such orbit for the CubeSat would be insanely expensive. Hitching a ride is the only way.

It would be cool, though. Molniya orbit would be even cooler.

Making a microsatellite and then launching it together with some Soyuz to ISS mission, and then releasing them from ISS, would be among the easiest ways. Deploying from a commercial satellite would probably be more expensive as modifications to the satellite would have to be made.

Secondary payloads are deployed from stages, not primary payloads. Most cubesats are released from stages after insertion of commercial payloads into earth orbit and quite a few are released into GTO in the same manner (for a good bit more money). Launch from the ISS after delivery with cargo is possible (and allows checks to be made before deployment), but is going to be one of the most expensive options.

[Sky_walker]

Sky, they are talking about finding a piece of debris and deorbiting it.

Really? Hahahahaha, oh man, this topic is really awesome.

Oh, and I do know all of the challenges of working with microwave transmitters/receivers, since I've done some lab work with these.

Awesome That's a great start! Try building something that can transmit over 1km range and automatically find a target - that will definitely be a good 1st stage of testing if you don't want to buy an off-the-self station. And beware that the further you go the worse it becomes. And more expensive.

The only serious obstacles are costs of launch and cost of solar panels, in that order. Because these are the things we cannot wing or fake in absolutely any way. These will have to be payed for by somebody in full.

Transceiver and an on-board computer are not? And that's just a beginning, I'm afraid.

I reject the idea that we think space flight is easy, i think we are some of the most grounded people on earth in that regard anyway, we understand how frustrating time consuming and irritating it is to do space flight, even when parts are like Lego, we can save and load are games, revert to VAB and have know money so we appreciate how difficult it actually is

You're just one small step above Star Wars fans. Only Star Wars fans realize that their world is full of misconceptions - meanwhile many of KSP fans are truly convinced that this game got a lot to deal with a real space flight. This whole topic is an ideal illustration of that.

Edited July 15, 2014 by Sky_walker

[EpicRootHairCell]

Interesting that you chose to delete the last sentence of the passage that you chose to respond to from my post.

I deleted that last sentence as i thought it was axillary to the point i was making. I agree with that point but also view that if any community has the talent or the ability for hard work it is ours.

[Nicholander]

Would anyone mind if I made a separate thread for the "Kerbal 2- Flight to Magic Boulder" theorycraft? That way we can start figuring out what questions we dont know without interfering with the (far more likely) "Kerbal 1- First Orbit" planning.

So you want to make a thread where future missions are discused? Yes, I know the future is fascinating, but those things are only ideas that will fly in many years. Those ideas should be developed later, and we haven't even decided what our first mission will do in LEO.

[lajoswinkler]

Secondary payloads are deployed from stages, not primary payloads. Most cubesats are released from stages after insertion of commercial payloads into earth orbit and quite a few are released into GTO in the same manner (for a good bit more money). Launch from the ISS after delivery with cargo is possible (and allows checks to be made before deployment), but is going to be one of the most expensive options.

Why would it be more expensive? They just have to account for approx. 1 kg more mass. The cube is stuffed together with toothpaste and toiler paper.

Deploying from unmanned rockets carrying satellites requires structural modifications and tests. That looks a lot more serious.

[Rakaydos]

Transceiver and an on-board computer are not? And that's just a beginning, I'm afraid.

I've got a obsolite cell phone... that's got more processing than apollo did, right?

[PakledHostage]

I deleted that last sentence as i thought it was axillary to the point i was making. I agree with that point but also view that if any community has the talent or the ability for hard work it is ours.

It was relevant because it puts the passage you were quoting in proper context. Quoting someone out of context is poor form. Just because politicians and journalists do it doesn't make it acceptable.