... large surface are is sth that we all can agree on. The heat sink must

1. have large surface area
2. Be thermal resistive,
3. have high thermal conductivity
4. Have Acceptable mechanical properties
5. not produce secondary radiation and life hazard for the people inside (not relevant for satellites)

----- Nanofluidics might be helpful. There are some liquids with superior heat conductivity. They form from mixture of liquids with nanoparticles. We might enginner a system can also dissipates another wavelenght. ----

Point: The exterior side which is exposed to vacuum can be modified. It is one point. The other one is how to increase the efficiency of IR radiation. For me it divides to two tasks. Sounds good.

Eyer, what you think about i2p? And how we can really organize some work without being afraid of spy on us, i mean real set of instructions that can be used by everyone here.

Now about heat dissipation, all that we discuss earlier is just raw ideas without any numerical data that can show what is better and why. So the best way to chose the most effective method - organize some experiments (at least numerical), and again notice that mathematical model can give all necessary results.

Thermal transfer in space obviously features neither convection or conduction, lacking the physical medium in which this takes place. This is why the frequent and constant mention of various forms of radiation, like InfraRed. You may, if you'd paid attention to the topic of the thread - or not as evidence suggests, noticed it specifically mentions "in space", maybe for precisely this reason. You may of further noticed, should you of been bothered to read it in the entirety, repeated mention to systems currently deployed on ISS(like the liquid water and NH3, or Triol and PolyMethyl Siloxane that bleeds IR through radiator panels), and further their lack of efficiencies due to the ineffective methods utilsed. Which is quite why this would actually need to be a "topic". It's not enough we simply use the most effective of what exists, that's already not good enough - we need to improve upon that. A mass habitation facility will likely require to dissipate gigawatts, if not terrawatts, plus organic input which is likley to be megawatts. The ETACS system on the US side of ISS is capable of ejecting 70KW of heat(via transferring heat from the station into liquid ammonia which is then circulated through external panelling via twin indendant loops) . Honestly, the real issue is dissipating heat. Generating power is trivial, and doesn't entirely require to be generated locally. We need technologies that are more effective, and less fragile. Simply scaling existing technologies will rapidly and repeatedly generate issues.

The raw ideas are all we'd need at this stage. Magnetocaloric effect is a good one, albeit difficult in the short term, obtaining resources from the solar system will not only make building habitation facilities viable, but solve problems like "rare" materials required to leverage such effects. Actually building our own even short-term temporary habitational facilities are decades away. I couldn't road map even getting materials to begin construction on long term mass habitation facilities till closer to 2050/2060. That's a lot of time to find better ideas, better techniques. It's likely the station(s) themselves wouldn't even begin to take final designs for decades. Ofc, numbers can be useful, and after identifying "interesting" things, we have basically created lists of potential areas of research to begin experimenting with(I feel few will have access to hard vacuum, so most work will naturally be simulated).

As for i2p - and general computer usage techniques and methods, maybe another place would more suit a dedicated topic, when we have a wiki it desperately requires one, and doing it here simply dilutes it's original purpose - but as a "competitor" to the same marketplace as TOR it features equal attention to mitigation. The most "secure" method I know of tunneling data would either be VPN or IP forwarding over SSH. I lend my favour to VPN - Trust in this, like anything else extends to the trust in the operator. You'd want one that does not log. Anything, preferably(beyond debug data). Free services are unlikely to be doing so for generosity, you are the product. And they will be selling it. The only way to be assured of anything is to run these services yourself. And no, I can't fit you all on mine. Maybe if charging for access - no more than operational costs(maybe $20USD/yr per head, ballpark guess), the entire thing can be automated, pretty much, in terms of it revoking access for non-payment, obtaining/reducing hardware as useage/subscription rises/falls - I could afford to obtain the globally distributed hardware required to act as relay and effectively distribute our collective load. However, I would feel uncomfortable doing this as a personal initative, and would rather an Asgardian initative form. I would desperately seek to avoid any impression of leveraging Asgardians as a facet of a get rich quick scheme. I would not expect an entire nation to expressly place their entire faith and trust upon me simply because o my say-so - I would expect some communual agreement about what is precisely operated as much as how it is operated. I specifically use and suggest OpenVPN. Free, open source, etc. It's possible to have users validate certificates used to connect without the certificate ever leaving the machine, so implimented correctly, the connection is as secure as the user's ability to keep their key secure, and breach of that key should not impact other users security. I had made mention somewhere else of PCKS11 or X.509 to be embedded in the digital section of passports, and card readers supplied with the passport. This could be used to securely authenticate for access to services, and could potentially provide for individual access to a Citizen-Only network - a private VPN, creating a secure tunnel to Asgardian services, and providing for access to a secure area(services hosting this content only communicates from VPN, or requests from, the internet is isolated from the software) which is where sensible access to things like collaborational tools etc(when we get them) should reside. IMHO. But we've got a long way to go before even passports.

The "best" method(s) is likely the realms of personal opinion but some effective ones are to boot into a live-disc. I'd also suggested putting one on the card reader, so can boot from USB. The "live-disc" should unfold itself to RAM, so not impact any existing software or configurations. Built correctly, the livedisc would provide a known-good OS free from any unsafe user habits and all "tools" to get further, and done "right" the user wouldn't even be aware of them operating. Operating in RAM this also has the added advantage of evading digital forensics as short of freezing RAM with liquid O2 and performing a cold boot attack user activities are lost with the power. From there I'd spawn a VM(Virtual machine), and boot another(potentially the same) live-disc inside - This sectionalises "online" activities from "bare metal" hardware. Work inside the VM, most malware of modern ages detect VM and don't operate to avoid detection and observation of their operation. In the worst case senario of infection, you break the OS etc, you just reboot the VM - fixed. Same for the host OS, should that somehow fail, but as you should be really avoiding using that, it should never fail it's not doing anything.

Dear EyeR, thank you so much for your comment. I would like to share my experience with the group. I am designing a system that operates in vacuum of 1mBar.

I totally understand that the life in atmospheric pressure is much easier. My research in vacuum is very painful. I have a piezo actuator that works at 500 mBar and I have tried many types of ceramics on the planet. The thermal conductivity of piezo ceramics is usually low. Some of them include water within crystal which is necessary for their functionality and lose it in vacuum. Some even have degassing in vacuum. Others have coatings inappropriate for vacuum. Imagine that actuation itself causes local heating of piezo element and it cannot be dissipated through convection in vacuum. I have ruined many piezo actuators as a consequence of non functioning in vacuum and have asked many companies why their product fails. I have reported the result of my vacuum experiments to them. Customers like us are rare. It is only one challenge and a very clear example.

How did I think about space? My vacuum chamber is working together with a digital holographic microscope. There is the same type of microscope on the board of ISS for studying the micro-organism growth in microgravity. I already had a very strong link with space and it gave me the aspiration: how do people dissipate heat in space? How would we deal with it in future for Mars village or Larger habitable spaceships?

Think about using silicon gel to emmit heat and transfer it to a colling system.

Mars shouldn't be so much of an issue, having an atmosphere. And ground. Should open up the likes of convection and conduction - geothermal would possibly be quite effective. The problems are definitely space and IR being so inefficient. Even out past Jupiter, getting rid of excecss thermal energy is likely to be problematic. There has to be something better than 36 square miles of radiator panneling... that's a lot of fragile surface area.

I just meant I'm more interested in the uses for ceramic polymers, in general application of 3D printing, more than heat dissipation purpose. Each purpose commonly warrenting differing materials. Certainly some parts of the system would warrent use of ceramics, but that I suspect would be a few minor parts, and used for it's ability to withstand high temperatures(compared to metals, which tend to soften with temperature) whilst being light and strong more than it's ability to conduct/radiate. It might be good to construct a "parasol" to shield the radiators from Sol's input, however.

Did you buy or build your vacuum chamber? This is equipment I suspect few will posess. If you bought it, how much for? If you built it, open source the design? I've not looked for one, but should a design not exist as open source then I'm sure I could muddle one together. Likely just a box frame, seals applied, thick perspex bolted to frame compressing the seals, a fridge compressor and a valve from either a gas bottle or a compressor tank... Then all people should need is testing equipment, and here's where I would imagine the real costs to occur, going "professional", but an arduino(nano, $2) could hook up to a BMP180(Bosh atmospheric pressure/temperature sensor - $2) and some MLX90614(contactless IR thermometer, about $6»$8 each. Multiple can observe several spots) and graph($3 if want that on a seperate screen, potentially mounted on vacuum chamber, Something like RRDtool could run on computer(assuming you power the nano via USB) and sample data into Round Robin Database). Would be unlikely to be the "best" setup available, such cheap sensors featuring obvious limits(BMP180 only goes doesn to 300hPa, MLX90614 only goes up to 125°C etc) - My focus being low cost(more accessible to more people) more than high accuracy - but could be tweaked "good enough" to enable simple experiments in this field to establish proof of concept and gauge dissipation times from various materials/techniques for a given input value. "Sensor package" could be done for less than $30... cheaper than I'd likely be able to build a vacuum chamber. With a little calibration, cheap(10/$2) IR sensor diodes - the type commonly used in TV's to change the channel could be distributed around the chamber and if dense enough with sensors, actually "see" the IR dissipation. Even the cheapest diodes should be good enough for 8-bits of resolution, that's a range between 0»255. They might be good for 12-bit or even 16bit resolution. This would obviously increase cost, circuit complexity, and for anything greater than data collection, code complexity but still viable. Without attempts to mitigate other wavelengths, it might not be incredibly accurate - but otherwise equipment couldn't be totally described as "cheap" right now. Thanks to software like Fritzing, circuit diagrams and visual hookup examples are just as easy to provide as the code that makes it go (as well as template up a PCB, but we can get a solder free solution cheaper methinks, but that could be as low as $1/each not in bulk, if it's wanted). I'd not be attempting a vacuum chamber any time soon, my efforts most focusing on a reflow oven, then CNC, then 3D printer - and from there attempting to muddle together some seed factory. But I might be able to squeeze one in after the 3D printer. This is likely to be late 2017 at the earliest, but I wouldn't hold my breath on that. I am confident I could design one in my head and it'd work OOTB, however. I do want one, not only for testing of thermal dissipation in vacuum, but for general operations in vacuum. I also need to be able to test for "harsher" evironmental extremes, but I sense it's more sensible at this level of development to have another device(s) for this.

I have been playing with the idea of theoretically building a spacecraft out of the Falcon 9 second stage and 5.2 meter fairing. I have done some very basic math on this and have found that this craft could be no more than 111,500kg (the total mass of the fully fueled Falcon 9FT 2nd stage) I was calculating all the weight of every component to build a comfortable craft that could sustain 3 people for over 1 year and I also ran into the problem of heat management in space. I looked to the ISS radiator arrays and got to thinking: what if a stirling engine is used to convert heat energy into mechanical energy? With a properly engineered stirling engine, you could absorb your extra heat from the spacecraft using a liquid running through the skin of the craft and then run that heated liquid to the stirling engine to reduce that heat into mechanical energy. I do believe that a NASA tech has just developed a stirling engine that is between 30% and 50% efficient to run off a small RTG to boost its effectiveness. What if instead of being powered by an RTG you use heat radiators? LEO space travel puts a craft into an environment that subjects it to 200 degrees + and 200 degrees - every 90 minutes ( depends on how high your orbit is). To me a stirling engine would make since if you could get 1 light enough. Keep in mind it's primary goal is not to generate power but to dissipate heat. a by product of this would generate some power but not enough to power the whole ship, having multiple sources of power is never a bad idea in space anyways. P.S. I did come up with a mathematically feasible ship that could travel to local places in our solar system using the falcon 9 2nd stage requiring at least 2 additional launches for refueling and passenger delivery, but that's a discussion for another thread ;)

Added thought: If you take a gas at room temp and compress it, it becomes hotter and when it is decompressed it becomes cooler (most people if not all in this thread should understand this), this is how an A/C unit works. With this thought in mind if we use a gas instead of a liquid as the heat transfer medium we can take heat from the spacecraft using a gas, compress that gas many times to amplify the heat, run the hot gas around the piston of the stirling engine and you have it! The stirling engine will reduce the heat of the gas because a part of that heat is being converted into mechanical energy. once the gas is depressurized it will be cooler than when it had started. bad thing is, any power you might have gained from the stirling engine will most likely be lost due to power requirement of the compressor and gas pumps but I do think this has the potential to solve heat dissipation in space. If you want to boost the power output of the stirling engine then you can contain the engine in high pressure helium (spaceships use helium for a multitude of systems). I bet there is a gas that can be used for the stirling engine that will maximize its heat reducing characteristics and still maintain a level of effectiveness at generating power. We might want to consider this in case the stirling engine ever needs to be used as emergency power. In space EVERYTHING needs to be engineered for redundancy, interchangeability and reusability including the heat energy. I'm not a fan of just dumping the heat energy overboard, lets use it!

Stirling engines are heavy, but so are gyroscopes. Both of which require mass to function and gyros are a must have on any spacecraft if you hope to turn it. (gyros are used for reaction control systems and navigation systems) What if we placed the stirling on a pivot and it doubled as a secondary reaction control system? This would justify the weight penalty and seeing as it is also generating a small amount of secondary power, gives it a 3 fold usefulness. I know gyros require a very fast spin but I imagine that a stirling could be geared to accommodate the required RPMs to make an effective reaction control system. This would not be the only gyros on the spacecraft, but a well built spacecraft requires several gyros located in different parts of the craft to function correctly. This would also lower the required energy needed to power said gyros and make the craft more efficient.

3 people isn't going to cut the mustard. There's not enough Falcon 9 upper stages to consider even 10% of the population, and one year really isn't long enough, we need to be thinking generations. Multiple. There's no sense starting until can deal with everybody. Use the resources up in LEO to make that happen, instead of wasting them on small scale, unsustainable ventures.

Stirling engines as a dissipation method isn't overly clever from the introduction of extra mechanical actions - this is simply something else to break, something else with mechanical wear - however, it could be possible to add resistance(possibly by using it's output) making it eat more energy. Even adding this alongside traditional radiatior panelling, it's still not going to be enough - but it could cut a few square miles of radiator down, maybe.

We have a problem dissipating heat, we do not require techniques to magnify... Even @ "50% efficiency" that's only halved the problem, and I'd question hitting that high. RTG's are not applicable for IR, I don't think, the effectiveness being boosted in that principle being the RTG, not the stirling engine, by way of the stirling engine harvesting energy from the RTG that wasn't converted to electricity.

The seerback effect would potentially be a better principle to leverage, having less moving parts.

@Dear Yousef, I will try your idea. Thanks for the comment.

@Dear EyeR, I have designed my chamber with the help of an electric engineer and a mechanics engineer. The commercial chambers are up to 45000 Euro. We have made it much cheaper. My goal is to measure thermo-optical properties of Silicon. So it is very relevant. The idea of ceramics is very good but they are very poor disspators. I guess it is a goof idea to work on this topic or discuss it in more detail. Please take a look at this paper (http://www.nextbigfuture.com/2016/12/imperial-college-of-london-makes-worlds.html?m=1) its not the heatshield material withstanding the heat thats the issue, its preventing the heat being transferred to the shuttle proper. The TPS is essentially insulation. So heat resisting high temperatures alone is not enough at all.

@WoefulZeus: I also agree with EyeR comment on yours. The idea of using the thermodynamics and phase change together works perfectly between two solid surfaces. Please take a look at: https://en.wikipedia.org/wiki/Heat_pipe

I am very happy that we are discussing one major issue of aerospace technology in space. Also Thanks for explaining the difference between Mars and space heat-dissipation techniques.

My proposal writing took a bit longer since we are heavily discussing it and I got new ideas. I also think exposing it for a little bit longer with help us. The document is ready on Sunday for sure. EyeR and Artem, should I talk directly with the admins? I will request for a place for uploading our first proposal.

@Marjan: I think we should try to talk directly with admins, why not, at least, we will made one more step to the our goal.

Returning to the topic that we discuss here, there many interesting ideas, and I think they can be useful until other will be proved. Recently I read a little bit about protection of satellites from huge changes in temperature and find that now, most commonly, used a multilayer materials. In which different layers designed for different purposes, some of them just reflect infrared radiation, some works like insulators. Such system is good but very vulnerable.

Using sillicon gel to pick up thermal energy from the heatsink in order to carry it to the exchange loop, and that carry it to the radiators, isn't likely to impact the (in)efficencies of bleeding the temperature into space via IR. Using the gel in the external loop isn't likely to impact the (in)efficencies of bleeding the temperature into space via IR. Pumping the gel itself into space might work, but that's going to be causing problems sooner rather than later.

If there was any issues with picking up the heat in the first place I'd of been suggesting use of high W/m.K materials, like diamond particles suspended in a lubricant. Silloxanes traditionally being famous for their low thermal conductivity, low electrical condictivity - and hence their common use as insulators as opposed to conductors.

Yes, I did think it'd be cheaper to construct a vacuum chamber than a commercial alternate. Would you be willing to share/open source the design? or at least a few pictures so I may begin to reverse engineer it and leverage any principles that potentially solve any facet I may of neglected when constructing on casually in my head. For this and many other subjects, I predict a few citizens would quite like themselves a vacuum chamber.

As mentioned previously, the use of ceramics wasn't intended with direct refernce to the heat exchange mechanism, just a tangent that had managed to dilute the topic. Again, Beyond a few "minor" parts that are required to retain strength whilst heated to temperatures unsuitable for metals, the only potential use defined would be to a "parasol" - specifically the solar facing "skin" of - a seperately deployed array that positions itself in between the output of Sol and the radiatior, in order that it may provide shade to the radiator and increase it's effectiveness. This could possibly be deployed kilometers away, there's nothing to say it needs to be somewhere it will interere with the IR output of the radiators, and if deployed close enough to be impacted by IR output, could be angled to reflect the greater amount of energy away from the radiator array.

I'm not sure as to the "features" of your "proposal" so am unable to advise as to the "best" thing to do with / place to send/put. Is there some method of directly communicating with admin(s)? 'cause I've a size eleven what'll fit in their backside regarding a few subjects.

EyeR, thanks for your reply. I'm thinking of this craft in regards to asteroid mining. I believe that if any space colony is ever going to take place then mining ships will have to be built and that's not going to happen unless someone starts thinking about it and designing them. There is no feasible way that massive ships can be built on the ground and lifted to space, they will have to be built off earth. A 3 person crew is small and 1 year of supplies is not a lot but if it's used for mining or asteroid redirection then it's acceptable. There are 100s of near earth objects that can supply thousands if not millions of kilos of resource to start building larger ships, stations and beyond. The reason I was thinking about the Falcon9 upper stage is because it has been designed from the ground up for reusability, it has a very powerful engine (even more so if they equip it with the new raptor), but this is just an idea and I only brought it up to explain why I was thinking about heat dissipation. The idea may be dumb and may never work but heat management in space is a real problem and that is what this discussion is about. Space mining will generate a lot of extra heat that will need to be dealt with. I was thinking about redesigning the stirling with a toroidal heat transfer unit, that way you can reduce the moving parts and the displacer that absorbs the heat can keep moving in 1 direction constantly. I will build a model of this for testing but I guess it will be kinda like a rotary engine instead of a piston driven engine. I do think that using the stirling as a gyro is also advantageous because it eliminates the possibility of it interfering with the stability and navigation gyros used for reaction control, It just becomes part of the gyro system instead of having to fight against it.

Mining is certianly the first thing to be considering, IMHO, needing to acquire resources from "up there" to make further projects feasible. However, this can be almost entirely automated - kind of critical to early start on the belt between Mars and Jupiter that is our nearest source, the near-earth objects "best" used to get that far, and production facilities to handle the mass thrown back - from the point of attaching a seed factory to ISS onwards, but that's another topic. The idea itself might not be dumb, but I do question if you approach it with the "best" methodology. Some presence of small crews might be "productive" - but if at all possible should be avoided in order to mitigate the massive and mulitple risks involved with simply being that far away from any form of support, let alone anything else.

I don't see how a toroidial transfer unit will be more effective at dissipating heat - but that could be a defect on my part. If my memory the Wankle engine serves, that still uses "pistons", just a different shape, commonly forming three compression actions per rotation. Mechanical actions where possible should be avoided, giving rise to simply something else to break. Other principles like the seerback effect - which doesn't utilise mechanical princples - could be a more "efficent" and long-term resilient method, converitng that energy to electricity with higher efficency than a stirling engine. I'm not sure why stirling engines should offset reaction control systems, or interfere with stability - built and operated in pairs the stirling engines could oppose themselves...

"Mining" itself wouldn't generate that much extra heat - processing and purification facilities(just as essential to long term operations) are likely to generate lots. However, they are likely to require lots in (some of) the processes themselves, and the "problem" of dissipating heat can be used productively here - removing of much need to add heat we can't get rid of. The matter processed will also contain great amounts of that thermal energy, the act of removing this for transport should help maintain the system. That's not to say this isn't something to be addressed. In the case of mining, the kinetic energy the stirlings convert into could potentially be utilsed in part of processes, but I still maintain finding non-mechanical means to achieve the same goals will result in a much more resilient and reliable system. Just like concentrating on non-exhaust propulsion systems will maximise feasibility... Small "tugs" could be fitted with "Q-Thrusters" for towing mass to facilities for processing, larger distances(like getting to the belt, and the resources back) can be achieved via centrafugal launchers(or a series of - mechanical, I'm aware, but find a "cheaper" reusable option).

I believe these types of Stirling engines may solve this problem: https://www.youtube.com/watch?v=P1FwrDZKfKk

I believe these types of Stirling engines may solve this problem: https://www.youtube.com/watch?v=P1FwrDZKfKk