KSP Community CubeSat

[KSat]

Hello Nicholander,

The orbiter thing I was talking about was to do what ESRO did in that youtube video, making the CubeSat in Orbiter and showing at as a thing to get more attention, as visualizing it would certainly raise interest in it.

We have a project seminar in our university where we have to write code from scratch for a spaceship in orbiter 2010. I also have a instruction how to set up visual studio and basic start code, but unfortunately it is completly in german.

Also I would not recommend making it in orbiter for visualisation /out-reach pruposes because you need to code stuff, which can consume a lot of time.

As I did

it is much easier to do stuff for KSP than for orbiter.

told me a lot of spaceprojects with low budget use KSP for visualisation. So there is no "unseriousness" attached to KSP, as long as your video does not contain some kerbals fooling around or other unphysical stuff.

Better do it in Kerbal, the community will love/have fun with it and the modders can help with every problem you stumble upon.

Cheers,

KSat

[KSat]

Hi Mazon Del,

Indeed, nothing wrong with that.

Though admittedly it would be quite fun to lob a life-in-a-jar (of my original low maintenance type) out into a solar orbit and take the world record for most distant confirmed life away from Earth. Just occasionally getting back images from the satellite as it floats around, its own little world made by us. ^^

Wouldn't that be a fun record to take from NASA?

Yes, this would be great. It might even help NASA to get more goverment funding, when they can get beaten by a bunch of space enthusiasts.

But one thing we learn from the beginning in our studies. Spaceflight is highly political, so if you go for taking a record by NASA, maybe some people by NASA might be not willing to help you. They might not want to let you take their cookies, or fear that they even get budget cuts because one record was taken by a bunch of space enthusiasts.

So just keep in mind, if at some point there are negotiations with officials, do not rub it under there nose you do better than them.

Cheers,

KSat

[KSat]

We can not use radiators or insultation if we dont have some attitude control with respect the sun.

Any good insultator would be a bad radiator and vice versa.

This is not true, but for more complex reasons. The light of the sun has a certain distribution, with a peak wavelength of 500nm.

Your spacecraft (as long as it is not as hot as the sun) radiates thermic radiation. Which can be calculated with the Stefan-Boltzman Law. So your cubesat will radiate for [0°C - 80°C] or [273K -353 K] mainly within the wavelength of [10.6 - 8.2μm]

What you mean is the Kirchhoff Law of thermal radition. But this says emission of certain wavelength = absorption of certain wavelength.

But as you see the wavelength of our body radiation and the incoming radiation from the sun is different, so a good insulator from the sun can also be a good radiator for the ship.

One example for this is a second surface mirror. Your common everday mirror with glas pane infront. The glas has the same temperature as your space craft and radiates the heat. The glas transmits the sunlight to the mirror which reflects the sunlight into space. Parts of sunlight might be absorbed, so you heat up until your thermic radiation is in equilibrium with your absorption.

If we find that in fact some components are overheating, what we can do about it?

One very easy solution is to paint your spacecraft surface white. This will reflect most of the incomming sunlight. And you will still radiate thermic radiation.

If this is not enough you might need to think about passive heat pumps that transfer core heat to the surface. It is a pipe filled with a liquid. When heat is high the liquid evaporates, as the outer surface should be cooler than the core the liquid condenses on the wall and thereby transfers heat. This heat on the outer surface is then radiated into space.

Third option is a heat sink. When you are in earth orbit, you will have shadow and sun cycles. So in worst case during a shadow phase you would even need heater not to freeze. Better is to use a heatl sink. Usual aluminium, as it is lightweight and has high heat capacity. If the surrounding is hotter than the sink it absorbs the heat, when the surrounding is cooler it gives of heat, leveling your temperature fluctuation.

So if your structure is made of aluminium fine, but maybe you need some more.

The problem is, I do not think you can not surpass the thermal calculations, because every components has certain heat capacities, absorption rates and every temperature changes influences the surroundings, so sooner or later somebody needs to tell the computer to do the math.

Most universities have free licences for very expensive software (example ANSYS), you need somebody who knows how to use the software, provide a CAD model, have material properties and provide expected heat loads. Then you have to let the computer do its thing for hours to days and hope that you are lucky or you need to redesign.

You might be able to skip this step to get approved for launch, because your cubesat is in passive mode during launch till orbit, but you might not have fun with if for a long time if you do not check the thermal conditions.

I saw many videos where cubesats are inspected in special facilities which commonly work for the launch provider.

You have an idea or estimate of this inspection and testing cost?

I talked to a testing provider at the ILA Berlin, who told me they already did shaker tests for cubesats for 1000-2000 €. This is already pretty cheap. The test is done within hours.

Basically a shaker test is testing your spacecraft about the capability to sustain the vibrations during launch.

Our professor told me, when his ISS experiment was on the shaker he was not able to look at it, because the tests are brutal.

So turned around and hoped everything will weigth the same as before and no lose parts where to hear when the test was over.

Yes, we can keep our cubesat-tether normal to earth surface, but I am not sure yet how control the spin on that axis.

I will make a research to know if there is another passive way to achieve that.

I would go for magnetorquers.

Other stuff that might be of help, but probably have a small impact in LEO. Yarkovsky-Effect and Poynting-Robterson-Effekt , which uses radiation pressure to change angular momentum.

This altitude difference may increase the launching cost mostly due to possible lifespan as debris in case the tether system fails?

I am not sure I do understand the question 100%. What debris? Danger to the tether from debris? Or the tether becoming debris?

Cheers,

KSat

[TJPrime]

I'd vote for something else - a Uranus and/or Neptune capture orbit to study their moons and atmosphere. The only mission ever sent to these planets was voyager 2 in the 70's/80's, and that was just a fly-by.

[Rakaydos]

I'd vote for something else - a Uranus and/or Neptune capture orbit to study their moons and atmosphere. The only mission ever sent to these planets was voyager 2 in the 70's/80's, and that was just a fly-by.

There's been a lot of talk since the poll was put up... the short version is that any mission beyond earth's SoI will be a stretch goal, and the biggest point of failure is setting up the "Arianne 5 slingshot." Being able to acomplish a solar orbit to earth return proves that it is possible to reach just about any target you could care to name in the solar system, so if we get that (very expensive) stretch goal, that will be the primary mission. Aerocapture or slingshot would be secondary, at least on the first mission.

Really, practicing aerocapture at Earth is kinda a best case situation- we dont need to put the atmospheric sensors on the probe because we have other sensors in orbit already, and we can apply near-real time Command and control.

[KvickFlygarn87]

Jeez, those are some long posts. I'm just gonna drop my idea I just had here.

Setting the cubesat on a heliocentric orbit with the perihelion at earth's orbit. The aphelion will be so far out that the orbit has a period of 2 years. This way, in two years the probe will arrive at the L3 point. The probe burns to orbit the lagrange point.

Surely in my poor understanding of L-points I have made some mistake. That's my idea anyways.

[Nicholander]

Got any experience coding in machine language and/or assembly?

Unfortunately not.

EDIT: KSat, yeah. We should probably do that visualization in KSP. (I brain farted when I put Orbiter, and I only realized that now. Derp.) Also, should we name our CubeSat KSat-1? I know it's WAY to early for that, but should it be something else? Like Kerbal-1 or KerbSat-1?

Edited July 27, 2014 by Nicholander

[MBobrik]

Got any experience coding in machine language and/or assembly?

Well, I do. it's getting already a little rusty, so, I will welcome any opportunity to use it once again.

[KSat]

Unfortunately not.

EDIT: KSat, yeah. We should probably do that visualization in KSP. (I brain farted when I put Orbiter, and I only realized that now. Derp.) Also, should we name our CubeSat KSat-1? I know it's WAY to early for that, but should it be something else? Like Kerbal-1 or KerbSat-1?

Yes you should decide for a name. Its just better for propagnada err PR purposes to have a clear label for something, then always refer to it as the cubesat the ksp forums wants to build...

Open a thread to discuss the name and create a poll so most people are satisfied.

[dharak1]

We could name it Cubesat Kerman, like the names the kerbals get.

[Nicholander]

Yes you should decide for a name. Its just better for propagnada err PR purposes to have a clear label for something, then always refer to it as the cubesat the ksp forums wants to build...

Open a thread to discuss the name and create a poll so most people are satisfied.

Good Idea! I don't know if it's to early, but now we have a base goal for it having a pressurized module with some plants, so I think we should at least consider having that poll now or pretty soon.

[AngelLestat]

Gaseous exhausts are definitely allowed. There are plenty of propulsion systems designed specifically for cubes.

And yes, the tethered ideas are higher budget, and most likely exclusive with bio experiment. I have nothing against doing theoretical work for both until we have some sort of an idea on the budget, however.

yeah, that is why we are doing this research, so we can compare with real numbers, but if we take into account the complexity of the micro gravity biologic experiments, it does not seems cheaper than the tether.

This is not true, but for more complex reasons. The light of the sun has a certain distribution, with a peak wavelength of 500nm.

Your spacecraft (as long as it is not as hot as the sun) radiates thermic radiation. Which can be calculated with the Stefan-Boltzman Law. So your cubesat will radiate for [0°C - 80°C] or [273K -353 K] mainly within the wavelength of [10.6 - 8.2μm]

What you mean is the Kirchhoff Law of thermal radition. But this says emission of certain wavelength = absorption of certain wavelength.

But as you see the wavelength of our body radiation and the incoming radiation from the sun is different, so a good insulator from the sun can also be a good radiator for the ship.

One example for this is a second surface mirror. Your common everday mirror with glas pane infront. The glas has the same temperature as your space craft and radiates the heat. The glas transmits the sunlight to the mirror which reflects the sunlight into space. Parts of sunlight might be absorbed, so you heat up until your thermic radiation is in equilibrium with your absorption.

You are right. So many times I discuss these effects using similar words, that I can not believe I total pass over it here.

One very easy solution is to paint your spacecraft surface white. This will reflect most of the incomming sunlight. And you will still radiate thermic radiation.

If this is not enough you might need to think about passive heat pumps that transfer core heat to the surface. It is a pipe filled with a liquid. When heat is high the liquid evaporates, as the outer surface should be cooler than the core the liquid condenses on the wall and thereby transfers heat. This heat on the outer surface is then radiated into space.

Yeah, I am very familiar with the heat pipe technology. But my question was in case we measure in space that is heating up over our estimation levels, what can we do? Shutdown some systems?

Most universities have free licences for very expensive software (example ANSYS), you need somebody who knows how to use the software, provide a CAD model, have material properties and provide expected heat loads. Then you have to let the computer do its thing for hours to days and hope that you are lucky or you need to redesign.

Yeah, that would be great. This would save us from the "crossing fingers" method.

I talked to a testing provider at the ILA Berlin, who told me they already did shaker tests for cubesats for 1000-2000 €. This is already pretty cheap. The test is done within hours.

Basically a shaker test is testing your spacecraft about the capability to sustain the vibrations during launch.

Our professor told me, when his ISS experiment was on the shaker he was not able to look at it, because the tests are brutal.

this cost is more than I expected for only one of many test.

I sympathize with your professor feeling in that moment.

I would go for magnetorquers.

Other stuff that might be of help, but probably have a small impact in LEO. Yarkovsky-Effect and Poynting-Robterson-Effekt , which uses radiation pressure to change angular momentum.

I was thinking in permanent magnets (like a compass in equatorial orbit), but I dont know if this would be enoght in case the starting cubesat spin were too fast.

My other concern is how to guarantee if the tether would deploy in earth direction or towards outer space, this has implications in the thermal shielding design and to chose the camera location.

I am not sure I do understand the question 100%. What debris? Danger to the tether from debris? Or the tether becoming debris?

My question was related to the cost of the chosen altitude, what is the difference bettwenn 300 km or 700 km. The only things that I know is that at higher altitudes the lifespan as "future debris" of the cubesat (without a deorbit plan) increase exponentially, and I am not sure if that has an extra cost penalty.

----------------------------------------------------------------------------------------

I was making some research:

The TetherSim software cost is: 5000 U$S

http://www.tethers.com/tethersim.html

Robert Hoyt told me that he provided some licenses to a few universities in the past. But for ITAR rules he can not give license to outsiders (that was for my case).

So is still not sure yet if we can reach an agreement to avoid part of the cost. But he was very polite with all the info that he give to me.

I read a paper which compare the lifespan of a single tether (in different diameters and long) vs a double tether in space.

A single tether lifespan can round (in our case) between 15 days to 3 month. That is not enoght, a double tether on the other hand may last several years.

Other concern is the chosen orbit, the EDT effect is higher in equatorial orbits, for example an orbit of 75 degress with respect equatorial would have an efficiency 70% lower. But the chosen orbit has effects in the power transmission needed to comunicate with the probe.

If I find time, I would try to complete the budget for all components on the electrodynamic tether case.

Edited July 28, 2014 by AngelLestat

[Mr_Brain]

I think it should be named Tony Probe.

[AngelLestat]

yeah... this topic needs more serious people or it would not go anywhere.

[Nicholander]

Okay, but I think that the name of the CubeSat can wait until later. Also, will we need (Or really should have) more then 1 communications center, or will one be sufficient? (Though we can only communicate with the CubeSat when it's over the communications center)

[KASASpace]

What about landing on Europa? Perhaps with airbags? It hasn't really been done has it? Maybe Enceladus? I say this because it's bold and very KSP. Problem with this is mainly radiation, but I don't know about Delta-v requirements to Europa.

I would go with a 2U because it seems like a better plan than a 1U, 2Us have up to four times the volume, unless it's just two 1Us attached at one side.

Edited July 29, 2014 by KASASpace

[KASASpace]

Perhaps, if we only get LEO, we could launch a 1U that can separate. It then flies away a bit, rendezvous with the detatched piece and dock. We could use this to test out in-space refueling, with multiple consumables transferred (electric charge, fuel for propulsion, etc.)

[KASASpace]

We need to start small. Maybe a 2U in LEO to start with and figure things out. People would be more likely to back future projects if we have some experience. The U.S. is probably the best place to construct as that's where the most users are and probably has the cheapest shipping because that's where the parts are already.

Actually, 10x10x5 cm kits are available, and if we do a PR mission first I would say that is the size to go with.

[Nicholander]

One: Sup KASASpace!

Two: How do you guys think we could get this more "Formal and organized?" Also, I though one of the mods would have stickied this by now!

[Aethon]

Hmmm. The group now using the ISEE-3 spacecraft got their funding from RocketHub and not Kickstarter.

http://www.rockethub.com/

[Nicholander]

So? And none of the successful crowd funded CubeSats where funded on Indiegogo. It doesn't matter which crowd sourcing website we get the money from, though I will awlays prefer KickStarter.

[Aethon]

Just checking in, and making an observation.

[Nicholander]

Okay, that's perfectly fine. Also, do you have any ideas on how we could get our CubeSat project more formal and organized?

[DasValdez]

what about landing on europa?

All These Worlds

Are Yours Except

Europa

Attempt No

Landing There

[christok]

What about landing on Europa? Perhaps with airbags? It hasn't really been done has it? Maybe Enceladus? I say this because it's bold and very KSP. Problem with this is mainly radiation, but I don't know about Delta-v requirements to Europa.

Out of the question for several reasons:

1) This team does not have a spacecraft to its name. We could not be realistically expected to build such a thing without substantial experience.

2) We could not expect to raise that kind of money by any means without demonstrated ability. A LEO orbit cubesat will not cut it.

3) The delta-v requirement is high. Very high.

4) The travel time is very long and the environment less forgiving than LEO. We're no longer talking about cheap COTS parts.

5) It's forbidden. You're not allowed to even risk crashing into either Europa or Enceladus, let alone land there without meeting the highest standards of sterility. The same rules apply to any place where Earth organisms could conceivably survive, as we won't otherwise be able to tell whether a new discovery is really native.