KSP Community CubeSat

[christok]

Why moss though? Moss is generally shade living, how well will it do in full sunlight? I'm not sure that is a good test of the gravity aspect since the sunlight may kill it/prevent it from growing much? What species of moss would be used?

I'm also against full sunlight but that's not something to worry about yet. The species hasn't been decided but we have asked for more info on which mosses are the commonly used model species.

[Nicholander]

Earlier someone suggested Java Moss, and anyway, it's essentially the only plant that's small enough to fit in the 0.5U pressurized area.

[Endersmens]

I started that. It's mentioned earlier in the thread but I don't blame you for not finding it

The idea was to get some sort of outline going. There isn't anything to see yet, as you may have noticed. I also need to rewrite some stuff where I guessed wrong about how it's going to work and upload what I've done. Sorry, but I had a major project at work and have been on call, so I haven't done as much as I should have. (I.e. nothing.)

Ah, okay! After you update that stuff, would you mind me using some of that information for the website? (its in one place, which makes things easier)

Also, i can put a link to there from the site, and links to the sim documents too for anyone who wants to take a look. It's up to you though, of course.

[K^2]

Earlier someone suggested Java Moss, and anyway, it's essentially the only plant that's small enough to fit in the 0.5U pressurized area.

The only trouble is that it seems to require liquid water for its medium. Which might make things a bit complicated.

I would definitely like to learn more about other options we have. Which, again, requires a good biologist/botanist. I just don't know any, other than these specializing in single cell organisms.

[Nicholander]

Which do you mean? Just Java Moss, or all moss in general?

[NERVAfan]

The only trouble is that it seems to require liquid water for its medium. Which might make things a bit complicated.

If we were going to use water as the medium anyway, duckweed (another extremely tiny plant) or algae would make more sense, I think, as they can grow in full sun.

I don't see why growing it in water would make it harder, as long as it's in a sealed container so the water can't get into any of the electronics.

[K^2]

Two main problems. First is the gas exchange. As people who have kept aquariums will tell you, simply having contact with air is not generally enough if you'll have aquarium densely populated. We'll either have to agitate the surface, or pump liquid through membranes to set up high exchange rate. Tricky.

Second is stability. Once spinning at constant rate, it's not really an issue. But during spin-up or attitude adjustments, the currents will be hard to predict, and will throw off overall moment of inertia. That can result in an axis tumble, and that's all sorts of trouble. Wouldn't be an issue with high torque reaction wheels/rockets, but magnetotorquers will not give us enough torque to counter this. I would like to avoid something that unpredictable and that likely to cause total loss.

Nicholander, Java Moss, since it is strictly aquatic. High humidity isn't an issue if needed, but anything that requires to be fully submerged is problematic.

[NERVAfan]

Earlier someone suggested Java Moss, and anyway, it's essentially the only plant that's small enough to fit in the 0.5U pressurized area.

Nah, there are also duckweeds (Lemnoideae or Lemnaceae) of various types. And tons of kinds of algae, lichens etc. if you're going to spread your definition of 'plant' wide enough.

[NERVAfan]

Two main problems. First is the gas exchange. As people who have kept aquariums will tell you, simply having contact with air is not generally enough if you'll have aquarium densely populated. We'll either have to agitate the surface, or pump liquid through membranes to set up high exchange rate. Tricky.

For fast growth, I'm sure. But wouldn't it survive anyway, just grow slower? EcoSpheres have kept algae in them (small sealed containers) for years with no pumps or anything.

If it was a 2U I'd suggest actually sending an EcoSphere, but unfortunately the smallest one is 4 inches.

Second is stability. Once spinning at constant rate, it's not really an issue. But during spin-up or attitude adjustments, the currents will be hard to predict, and will throw off overall moment of inertia. That can result in an axis tumble, and that's all sorts of trouble.

OK, maybe I'm missing something obvious, but if you have plants floating in a sealed container, why would tumbling it be a problem at all? It'll just travel with the water. As long as it's sealed on all sides so that the water doesn't spill out...

I can go put algae or duckweed or whatever in a container and spin it around, juggle it etc. to see if anything happens, but I really doubt anything will.

I think submerged might turn out to be easier.

[CjStaal]

For fast growth, I'm sure. But wouldn't it survive anyway, just grow slower? EcoSpheres have kept algae in them (small sealed containers) for years with no pumps or anything.

If it was a 2U I'd suggest actually sending an EcoSphere, but unfortunately the smallest one is 4 inches.

OK, maybe I'm missing something obvious, but if you have plants floating in a sealed container, why would tumbling it be a problem at all? It'll just travel with the water. As long as it's sealed on all sides so that the water doesn't spill out...

I can go put algae or duckweed or whatever in a container and spin it around, juggle it etc. to see if anything happens, but I really doubt anything will.

I think submerged might turn out to be easier.

He doesn't mean spillage, he means movement of mass. In a vacuum the water sloshing around after attitude adjustments will give it *puts on shades* a bad attitude.

[CptRichardson]

If we were going to use water as the medium anyway, duckweed (another extremely tiny plant) or algae would make more sense, I think, as they can grow in full sun.

I don't see why growing it in water would make it harder, as long as it's in a sealed container so the water can't get into any of the electronics.

The water could freeze.

[mr_yogurt]

If you can find 13,150 people with CubeSats that weigh one kilogram on average, they all can send a CubeSat to space (LEO) at around $5,000 per CubeSat. The only issue is that they are all riding the same rocket to space (a falcon 9) and will be all really close when they get there. (also you could do 4,850 people at around $13,000 a cubesat to GTO)

But finding that many people who have CubeSats and would also pay the price would be difficult.

[christok]

Ah, okay! After you update that stuff, would you mind me using some of that information for the website? (its in one place, which makes things easier)

Also, i can put a link to there from the site, and links to the sim documents too for anyone who wants to take a look. It's up to you though, of course.

Of course I won't mind f you use it. But if you put up a link you should probably say that it hasn't really started yet. Otherwise you'd get people excited and they would not come back to the project after the initial letdown.

[Nicholander]

NERVAfan, I think that having a water based plant is not a good idea, as I said earlier, the point of our CubeSat is to study the effects of plants in different gravities to study how they behave and react. And you just simply can't do that with water based plants, because in the future, people will NOT be growing these water based plants that you speak of, they will be growing ground based plants/crops, and moss is small enough to fit in the 0.5U pressurized area, AND is ground based.

[Endersmens]

Of course I won't mind f you use it. But if you put up a link you should probably say that it hasn't really started yet. Otherwise you'd get people excited and they would not come back to the project after the initial letdown.

Yeah, I will. I want to use some of the information in the description, and in other various places. And there will be links to the documents on there, and when you start it, a link to the simulation.

[NERVAfan]

NERVAfan, I think that having a water based plant is not a good idea, as I said earlier, the point of our CubeSat is to study the effects of plants in different gravities to study how they behave and react. And you just simply can't do that with water based plants, because in the future, people will NOT be growing these water based plants that you speak of,

Why not? Algae is great for oxygen production, as are some water plants like Azolla - they would be great for space life support systems being very fast growing/photosynthesizing. I think these would be ideal.

Water is heavy, yes, but it doesn't need to be very deep at all.

The water could freeze.

True, but a frost might kill a land-based plant too, and water is slower to change temperature than air.

[astropapi1]

We need to put some heavy consideration on what type of plant we choose, because the whole purpose of the first mission is to show everyone we can handle this stuff while doing useful scientific studies. What are we trying to simulate here? From what has already been discussed, I think we should use a plant that:

- Grows fast.

- Can endure harsh conditions.

- Is edible.

- Produces considerable quantities of Oxygen.

Looks like algae is a pretty safe bet.

I think this mission's investigation could be used for a future lunar base, where in-situ Oxygen/Food production will be a must, so a 1/6g acceleration would be ideal. It doesn't make much sense to simulate the martian gravity because:

1) Most of a Mars Mission's time would be spent in 0g, and we've got a 450 ton spaceship in LEO to simulate that.

2) Unless Obama's crazy plans of swinging it and going straight for a Mars mission become true, a lunar base will have to come first.

Now, what kind of active/passive thermal control system can we install on the cubesat to keep the plants from freezing/burning?

[NERVAfan]

We need to put some heavy consideration on what type of plant we choose, because the whole purpose of the first mission is to show everyone we can handle this stuff while doing useful scientific studies. What are we trying to simulate here? From what has already been discussed, I think we should use a plant that:

- Grows fast.

- Can endure harsh conditions.

- Is edible.

- Produces considerable quantities of Oxygen.

Looks like algae is a pretty safe bet.

Yeah, the growth thing is one of the tricky bits. There are quite a few options that would be great (endures sunlight, dryness etc.; fits in a tiny space) except for being slow growing (lichens, living stones...)

2) Unless Obama's crazy plans of swinging it and going straight for a Mars mission become true, a lunar base will have to come first.

Well, SpaceX plans Mars first too...

Now, what kind of active/passive thermal control system can we install on the cubesat to keep the plants from freezing/burning?

That's a good question. What do other cubesats use? What's the temperature tolerance of the electronics in, say, a PhoneSat smartphone?

Edited September 8, 2014 by NERVAfan
quote tag/added thermal response

[astropapi1]

That's a good question. What do other cubesats use? What's the temperature tolerance of the electronics in, say, a PhoneSat smartphone?

From THIS article, it seems like our cubesat will have to endure temperatures from 100 ºC to -130 ºC, and the sudden changes of temperature that occur in LEO.

Also, it looks like we'll have to use a passive system, given that the pressurized area and the systems bay will take up a huge part of the cubesat.

EDIT: They also have this nice little graphic:

Edited September 8, 2014 by astropapi1

[Nicholander]

astropapi1, though what you said is true, we should still do Mars gravity anyway, because we need a magneto torquer to get it spinning in the first place, you might as well switch to Mars gravity after you've done some Lunar stuff.

[astropapi1]

astropapi1, though what you said is true, we should still do Mars gravity anyway, because we need a magneto torquer to get it spinning in the first place, you might as well switch to Mars gravity after you've done some Lunar stuff.

Oh, of course we should! What I meant is that our focus should be on lunar gravity, and martian gravity would be like a secondary objective.

[dharak1]

We have to decide on a certain gravity and stick with it no matter what we do. If you start with lunar and then go with martian you leave a blank spot on what happens at the beginning of the plants life for martian gravity and a blank for what happens at the end of life for lunar gravity. Lunar would be far better because the moon is a much more likely candidate for a base and it would require less power to spin up to speed for.

[K^2]

Good points. I would vote for that.

[NERVAfan]

Good points. I would vote for that.

Makes sense.

So can we get good gravity results with plants/algae suspended in water?

[Nicholander]

dharak1, even a "short term" manned Mars expedition would almost certainly grow food of some kind on the surface, we might as well just do that too. Also, we should have it that first none of the seeds are growing, and then we water/make them start growing half of them for the amount of time we have for Lunar gravity. And then, after half through our CubeSat's mission lifetime, we spin it up to Mars gravity and water/make them start growing the other half of seeds, to study how those react in Martian gravity.

You see, with that plan, the Lunar experiment is not interrupted while after it's started (Because with the previous plan all of the seeds would start at Lunar gravity, and we would not be able to study how the plants react when they start growing at Martian gravity), and we get to study both gravities.

And NERVAfan, I'm still convinced that we should grow a soil based plant, like Moss.