KSP Community CubeSat

[Nicholander]

KSat: I'll probably draw something, scan it, put it on my PC, and then upload it to Imgur, for everyone to see.

Majorjim: My god, you're paranoid about that?!? The chances of that are extremely low, and CubeSats are designed to orbit for 3-5 months before burning up in the atmosphere due to orbital decay. And that article is stupid, I mean, they think we should make it harder for people to get access to space? That is stupid and astrophobic!

[megatiger78]

note to Majorjim: thisccubesat is basically going to phobos anyway

[Nicholander]

Uh... Our first one is just going to go to LEO and have some artificial sub-gravity by spinning, where we will study how moss reacts and behaves in those conditions. (Mars and Moon gravity)

[megatiger78]

Uh... Our first one is just going to go to LEO and have some artificial sub-gravity by spinning, where we will study how moss reacts and behaves in those conditions. (Mars and Moon gravity)

so when do we land on phobos or something?

[andrewas]

Realistically? We probably don't. That would be an insanely ambitious project, we'd need lots of funding and we need to do an intermediate mission to get the hang of propulsion and navigation.

But it doesn't hurt to have it as a long term goal.

[astropapi1]

so when do we land on phobos or something?

I think my head hurts from facepalming so hard at most of your comments on this thread. I'm sorry to be kinda rude, but you should consider reading (or at least skimming through) most of this thread to have any meaningful impact on the discussion.

1) Majorjim isn't a spammer. He's a fantastic builder and a good member of this community. Just because he doesn't get that this cubesat will deorbit after a short time due to the atmosphere, doesn't mean you should call him a conspiracy theorist. At least have some respect for other members of the forum.

2) Launching from a balloon isn't worth the effort. Have you ever heard of "rockoons"? They were the closest thing to what you describe, but they came nowhere near orbital velocity. TL;DR: Not worth it.

3) Our first satellite (Let's call it KerbSat-1 for the time being, that isn't an official name) will be taken to LEO as a "secondary payload" for another launch. What does that mean? That we won't build a rocket, we'll just use some other rocket with a primary payload and stick our cubesat to it. It has been done and we can certainly do it.

4) KerbSat-1 will be a "technology demonstrator". What does that mean? We'll test things like control algorythms, tracking, ground stations, thermal protection, etc. It will be used to test things and to show everyone that we can manage a spacecraft successfully. As a bonus, we'll put a biological experiment on it. The experiment will consist (roughly) of two chambers with moss in them. First, the satellite will use a counterweight to spin up to 0.16 Gs and then pour water into the first chamber, to see how well it can develop on lunar gravity. When that experiment is completed (at least a couple of weeks), it will accelerate to 0.4 Gs and pour water into the second chamber, simulating martian gravity.

5) The second satellite doesn't have a definitive destinity. If we managed to **** everything up, we'll need another satellite to replace the first one (plus another launch ), and we don't even know if getting to Phobos with a 3U is possible. There's a lot of things that could go wrong, and if one of those happens to our satellite, he ded. Like 7 ded.

[NERVAfan]

Yeah, cubesats in LEO deorbit pretty fast. Not just the lack of propulsion, but also (if I understand it correctly) there's a square-cube law thing where drag has more effect on smaller objects. The KickSat cubesat deorbited in just a couple of weeks.

[Nicholander]

Hmm... I think the 2nd CubeSat we launch should be made by the guys over on Reddit, the "Lunar Team", which will hitch a ride on Astrobotic's Griffin lander in 2015/2018 (I don't know when they'll be ready to launch). Also, K^2, how's the sim going?

[Majorjim!]

Hello Majorgim,

even though you sound like you are not willing to discuss, more like accusing people of being bad, I am going to further explain my point.

Yes there are surely many papers and articles about this topic, but if you want to discuss something specific you need to reference it.

The Kessler syndrome is a known problem, but that CubeSats are a major factor to this is in doubt. Even the article you referenced states:

"Still, other researchers say Lewis's findings may overestimate the problem. "There is always a choice of model inputs and the spin put on interpretation," says Sara Seager at MIT."

There is no clue if their simulation has considered orbital decay, if not then the article is nothing more than attention seeking.

You state that the orbit is littered for no good reason, but this is wrong.

Most, if not all, CubeSats are for science and most of them will deorbit in a relativ short amount of time. As previously stated, CubeSats with very long deorbit times are much further away and there is a lot more space before anything gehts crowded.

Please dont get me wrong. Orbit littering is a problem, but accusing CubeSats for it is, in my opinion, way over the top.

Cheers,

KSat

Hi,

I'm sorry for my harsh tone. I was super grumpy today and not really myself (for many reasons).

Yes I would like to discuss it sometime in some place and I promise to be civil.

I have seen others stating that they deorbit fairly quickly too. Seems reasonable.

I wish this endeavor good luck as it would indeed be awesome.

MJ

[astropapi1]

Hi,

I'm sorry for my harsh tone. I was super grumpy today and not really myself (for many reasons).

Yes I would like to discuss it sometime in some place and I promise to be civil.

I have seen others stating that they deorbit fairly quickly too. Seems reasonable.

I wish this endeavor good luck as it would indeed be awesome.

MJ

By the power given to me by the forum gods, I here pardon your life before the rest of the people. May our land rest in peace once again.

Now that we're back on track, has anyone given any thought to the thermal control system? So far, it looks like we'll endure temperatures of 100°C to -130°C. We have to mantain an average internal temperature of 36° C with passive systems, which should be able to mantain a +/- 5 degree variation.

I'm thinking about some multi-layer insulation with a reflective surface. That way, it would reflect some heat away while working as a "blanket" on the night period of the orbit, preventing heat losses. However, I'm not a rocket scientist an engineer yet..., so it would be great to have an educated word on the topic.

[NERVAfan]

Samples of the moss can be obtained cheaply (maybe a couple dollars for the full loadout of moss) or free from my contact Professor Vidali, as can the sample container dishes and whatnot. One thing he is excited about is that in order to fit as many samplse in as possible, he is going to have to design a new smaller sample dish, which he is just going to do in his own time.

The current plan is that once we have an idea for the volume and such of the sample container area, and we have built a mockup with working sensors (need not be the actual ones we use) then he can get NASA funding for additional research to help us out.

OK, so is this the general concept? (Excuse the MS Paint...)

I guess there should be some oxygen/CO2/humidity sensors in there somewhere too?

EDIT: this is meant to be just the plant part of the cubesat, not including reaction wheels, communication equipment, solar panel etc. - I know we need those things too.

But it would be nice to have the plant-part designed early so some of us can try out a similar design for growing stuff on Earth.

[NERVAfan]

BWe have to mantain an average internal temperature of 36° C with passive systems, which should be able to mantain a +/- 5 degree variation.

Where does the 36 C number come from? A range of 31 C - 41 C sounds rather too hot from the (admittedly limited) information I have been able to find.

"Even tropical bryophytes seem to do poorly above 25°C (Frahm 1990), where their net assimilation rate decreases drastically, respiration rates are high, and they fail to reach their compensation point"

"Indeed, for most bryophytes, the optimum is near 20° C and for many it is much lower."

"Physcomitrella patens developed capsules best at 15-19ºC, "

Hohe et al. (2002) found that the highest number of sporophytes in Physcomitrella patens were produced at 15ºC, with numbers dropping greatly at 25ºC. Vegetative growth, on the other hand, was best at 25ºC. "

Glime, Janice M., 2007 Bryophyte Ecology http://www.bryoecol.mtu.edu/ .

"the lethal cold temperature for 50% mortality (LT50) for P. patens protonemal tissue is around -2 C"

Annual Plant Reviews, The Moss Physcomitrella patens

[Protonema = the shoot that sprouts from a moss spore]

So maybe we should be shooting for more like a 15-25 C range. But we should talk to someone who actually has experience growing this species. Growing conditions information doesn't seem to be easily available online.

[astropapi1]

Where does the 36 C number come from? A range of 31 C - 41 C sounds rather too hot from the (admittedly limited) information I have been able to find.

IIRC, someone on this thread posted earlier (before the reddit thing) that Spirulina showed optimal growth between 35° and 37°. I have no idea about that, and what you researched seems to contradict it abruptly. Yeah, we're gonna need an expert.

Growing conditions information doesn't seem to be easily available online.

I feel you. Most of the time when I'm reading about this kind of stuff, I end up digging up old university reports and even files from the 60s/70s. I wish more people did this kind of stuff so information on these subjects would be more easily available.

Edited September 29, 2014 by astropapi1

[Nicholander]

NERVAfan, yeah, 15C-25C sounds good.

[KSat]

How many CubeSat Units does the current baseline assume? 1U/2U/3U??

[henryrasia]

What is the expected lifetime of the experiment? Because we should have as many mosses tested growing at moon and mars gravity, but it'd be nice to test 0 g and earth gravity to compare it to ground experiments (control group, if you will). Also, I'm not a biologist, but can moss be killed and wiped from a petri dish and then grow from scratch again? Like bacteria? Cause that would allow for 1 petri dish to do all of the tests.

On a related note, if this is a serious project, we should at least set up some kind of website or forums (subreddit?) so people can brainstorm/share concrete ideas in a academic environment (read: detached from KSP the game). Also, how is mission control going to be handled? It should be very open to qualify as an educational project, perhaps even relaying all data to whoever wants it.

And the satellite itslef. Who's gpong to build it? Should it be stress tested? How?

Again, very cool idea! I hope I can take part in it! (aspiring aerospace engineer in 11th grade, I'm clueless but I can learn!)

[astropapi1]

What is the expected lifetime of the experiment?

Couple of weeks per sample? I don't really know.

...but it'd be nice to test 0 g and earth gravity to compare it to ground experiments (control group, if you will).

earth gravity will be done by one of us down here, and 0g can be done at the ISS. There's not much space in a 1U cubesat for so many experiments. :/

Also, I'm not a biologist, but can moss be killed and wiped from a petri dish and then grow from scratch again? Like bacteria? Cause that would allow for 1 petri dish to do all of the tests.

I think it wouldn't be worth the effort. We'd have to bring along stuff to eradicate all life on the dish and some kind of mechanism to drop the new Spirulina into it. It seems like a good idea to simply use another one.

On a related note, if this is a serious project, we should at least set up some kind of website or forums (subreddit?) so people can brainstorm/share concrete ideas in a academic environment (read: detached from KSP the game). Also, how is mission control going to be handled? It should be very open to qualify as an educational project, perhaps even relaying all data to whoever wants it.

Well, the reddit one already has a subreddit going on, but I think the forum is the best medium for us to communicate for the time being. Here we can even get new guys to join the project!

And the satellite itself. Who's going to build it? Should it be stress tested? How?

We'd have to get a (real) team of guys who live closely and have enough experience. I remember one of you guys posting about maybe being able to get a NASA engineer to collaborate.

Again, very cool idea! I hope I can take part in it! (aspiring aerospace engineer in 11th grade, I'm clueless but I can learn!)

Aspiring clueless aerospace engineers FTW!

Edited September 29, 2014 by astropapi1

[Nicholander]

How many CubeSat Units does the current baseline assume? 1U/2U/3U??

Yeah, we've all agreed that the first one will be 1U.

[tajampi]

Hey there!

If nobody have suggested this yet, would it not be a good idea to use a CAT (http://pepl.engin.umich.edu/thrusters/CAT.html) to get the Delta-V required? The main problem will be that we will require a bigger Cubesat...

Pros, cons?

Cheers!

Edited September 29, 2014 by tajampi

[Rakaydos]

Cons, lacks an active attitude control system, (it relyes on passive attitude control from permanant magnets in earth's magnetic field)

At 2 mN of thrust, a 4.5 KG cubesat (they say 5KG, so perhaps there's some leeway), it is an order of magnatude too weak to be a phobos landing thruster.

[samstarman5]

How about, instead of adding more useless and dangerous debris in orbit, we send up some KSP figurines to the ISS? Would probably be cheaper and the folks up there would get a kick out of it.

[NERVAfan]

IIRC, someone on this thread posted earlier (before the reddit thing) that Spirulina showed optimal growth between 35° and 37°. I have no idea about that, and what you researched seems to contradict it abruptly.

Ah!

Well, that's because we're taking about two totally different things. Spirulina is a cyanobacterium ("blue-green alga") not a moss. The lower numbers (15-25 C) I just posted apply to the moss Physcomitrella patens.

How about, instead of adding more useless and dangerous debris in orbit

CubeSat LEO orbits tend to decay fast enough not to present a debris hazard. The recent KickSat cubesat (deployed from the ISS) burned up in a few weeks.

On a related note, if this is a serious project, we should at least set up some kind of website or forums (subreddit?) so people can brainstorm/share concrete ideas in a academic environment (read: detached from KSP the game).

Endersmens started to set up a website: https://sites.google.com/site/kspcommunitycubesat/home

[NERVAfan]

What is the expected lifetime of the experiment?

Probably somewhere in the ballpark of two or three weeks, limited both by orbital decay and moss survival...

One of the issues we had all been worried about was of the moss eating away the atmosphere and starving/poisoning itself to death. However, with the samples in question (they are quite small) with the volume that he showed me in the enclosed petri dishes (think maybe 1.5-2.0 times as long as a quarter and 5-10 mm thick) the sample has enough air to live and grow for 2-3 weeks.

[NERVAfan]

The current plan is that once we have an idea for the volume and such of the sample container area, and we have built a mockup with working sensors (need not be the actual ones we use) then he can get NASA funding for additional research to help us out.

OK, so maybe figuring out the volume and so on the next thing we need to do/decide on.

A 1U cubesat is 10cm on a side (1 liter volume). K^2 (or anyone else who knows), how much of that space will the electronics and structure and so on take?

It may not be an issue though... if we simply grow the moss in a petri dish, that should be easy to fit in. It'll probably be the microscope/camera etc that will be trickier.

[Nicholander]

A 1U cubesat is 10cm on a side (1 liter volume). K^2 (or anyone else who knows), how much of that space will the electronics and structure and so on take?

I think about half of the space.