christok

Incorrect. That acceleration is quite typical of gun-launched rockets for military applications.

Totally agree on splitting the UI/engine. I'm not overly familiar with suitable libraries for the interface but I guess it's always a good time to learn. I'd pick OpenGL over DirectX for portability reasons (not that I actually know either). A web interface may be best of all, since it's something that can come in handy during crowdfunding. I can help out a little with physics programming (I'm not completely ignorant) but I'll need to brush up on some things first. I understand Hamiltonian mechanics is what's normally used? From your previous post I think I that you want to assume a Keplerian orbit and simulate mainly the attitude control system as the satellite moves through the varying magnetic field, or did I misunderstand?

I mean modelling systems, as in simulation. My academic background is in statistics and I do some work with chemical/physical models in the real world (but that isn't the main focus of my job).

Oh I read it, I just plain don't remember it because this thread is too long. I'll start thinking about it the requirements. K^2, what's your language/library preference for this? Anyone else have an opinion?

Programming? Yes. Modelling? Yes. Physics? Not nearly as much. If K^2 can specify in more detail what he(?) has planned, I could perhaps look into getting it started.

Here's an interesting article on crowdfunding (of 3D printers) I found via Hacker News: http://3dprototypesandmodels.com.au/blog-2/. Much of it is irrelevant to this project but the potential pitfalls of stretch goals are worth keeping in mind.

Mazon Del, good work. I think you should ask the Prof. about the following: - If we chose to go with moss, which species are the most common model species in the field? - Which introductory text or texts would he recommend? - Which journals are well-respected in the field? (We should try to read at least some related articles.) - Are there any good well-known effects of gravity on them (such as size or reproduction rate) that we can try to observe with just a webcam instead of a microscope? Beyond that, I wouldn't want to add pathogens to the experiment. The size is too small and bacteria are known to grow extremely fast in microgravity, so we are likely to kill the plants. Let's keep in mind that our experiment should test one variable only.

Highly relevant Economist article on successful crowdfunding: http://www.economist.com/blogs/prospero/2014/08/spike-lee-and-kickstarter When we're ready to start the crowdfunding campaign I think we should take a page out of Mr Lee's book and also ask Kickstarter (or whatever other place we use) if our funding goals are realistic and if they have any other comments before we publish it. That article doesn't seem to be about garden variety 3D-printed plastics. Given that consumer grade 3D printers use volatile thermoplastics, I can't imagine the stuff being of any use in a satellite.

New Pu-238 production was approved in 2009 but there have been some budgetary delays. NASA had a bit of a disagreement with the congressional subcommittee overseeing the DOE budget recently, because the DOE subcommittee wants NASA to pay every single cost related to restarting Pu-238 production for spacecraft (it used to piggy-back off nuclear weapons production) while the military routinely gets to order whatever they want whenever they want and only pays production costs. It ended in "NASA will pay". (http://www.planetary.org/explore/the-planetary-report/tpr-2013-3-polygons-on-mars.html) Under these circumstances, I don't think it's fair to say that RTG manufacturing capability is "lost". There's just not enough Pu-238 to go around and there will probably be some amount of maintenance deferred.

I may be wrong, but I suspect we would do best if we start with a list of things to research in the literature, and people who will do them. I'd also like to see more than one person per item. Knowing who has practical experience in these would help. This list would include: - A comparison of successful and failed cubesat missions. One component manufacturer's website I checked out claimed a 50% failure rate for university cubesats, not counting launch failure. We need to do better, and understanding why they fail is the only way. Correspondence with some of the creators would be a good idea and should be documented. - Any and all available literature on partial-gravity biology, if we indeed decide to go that route. We also need to read up on Earth-normal botany and plants in microgravity. The latter two are slightly less important, as our experiment would not be quite as result-driven but rather demonstrate a method that has not been tried. - We need to start looking at attitude control. K^2, I know you're looking into this and seem to have some electronics & software experience. We need to get this right because the design we have been discussing implies it. It will also be critical for future missions, if we get that far. - Legal matters. ITAR probably doesn't apply to this project, but we need to do everything in a clear and organised manner so that we don't have problems. Especially true considering the international nature of the community. - Materials. I know that teflon and anodised aluminium are both used in spacecraft because they resist outgassing and cold-welding. For the components we wish to build, which materials are flight-tested, and which are out of the question? Will we need to test any ourselves? Spacecraft electronics are sometimes given a coating to protect them against outgassing. There are some problems associated with this (especially w.r.t. fixing problems discovered during testing). Will it be a good idea in our case? - Thermal design. Most cubesats tumble freely, which helps to control the temperature. As ours will point one side to the sun, and as cubesats have high surface:volume ratios, we need to make sure that we don't cook or freeze the experiment or critical components. - Budgeting. We should try to gather information from the AMSAT/cubesat communities as well as consider what can be learned from traditional spaceflight. - Crowdfunding. We should study the available literature on failed/successful crowdfunding efforts so that we know if, for example, a silly name would benefit or undermine a scientific project on Kickstarter et al. Giving out goodies such as mission patches seems to be required. But how much, and what? How many backer levels should there be for a Kickstarter project? How far apart should they be, monetarily? What percentage of the pledge should the rewards cost? How often should updates be posted? How big should the stretch goals be? How early or late in the funding process should they be added? Would it be an advantage to loudly associate the project with KSP players, or would it be better to put it in a footnote? (I.e., would we be taken more seriously if we emphasise ourselves as a community of spaceflight enthusiasts who happen to like KSP, or as a community of KSP players who want to reach out and teach/learn aerospace engineering in a practical manner as the game has done for many? Will something like "JebSat" lure backers, or scare them off?) If necessary, we should do our own comparative studies. This could make or break the project, especially if we're planning more missions. - Power. Who has a ham licence or intends to get one? It's not critical right now but we will need to set up ground stations. Doing some sort of educational outreach (even if it's just talking to schoolkids afterwards and showing off pictures of the satellite) would be a nice bonus. Would some people on the project be interested in that? We can also do education directly, by allowing kids on the forums to assist with some easier aspects of the design process and sharing information as the project progresses. This would however take a little extra work. Would you be interested? Not a literature study, but we should start brainstorming ideas for artwork, names and related things. I recommend that we designate different levels of seriousness. When we see everything together, and when we have more data on the crowdfunding requirements, we would be better able to judge how serious we should sound and pick the best in each category. Here's what I have in mind. Let's say we divide the names into completely silly, in-joke and completely serious. - MysteryGooSat is silly. - Making up some backronym to fit an appropriate KSP part, such as ASAS or SC-9001 Jr, would be an in-joke not obvious to the casual observer. - PEGES (Partial Earth-Gravity Experiment Satellite) woudl be a serious example. I can probably think of some more things.

It is a sufficient but not neccessary condition. Wikipedia has the definition if you're interested. Sake is normally a fermented rice beer. The question is whether it is normal to distill sake, and whether the Japanese still call the resulting drink sake. Furthermore, beers which have been freeze-distilled are usually still refered to as beers. Your pedantry is kinda unneccessary. But then again I guess I did start it. I wouldn't call the question stupid. Posting on gaming forums at work, however...

You don't need the acid to make water. There's more H2O than H2SO4 in the atmosphere of Venus. (30ppm vs. 1-2.5ppm, though only 0.8ppm H2O in the mesosphere, high up.) It also has some traces of HCl and HF. The confusion comes about because the clouds are made of H2SO4.

This is true but the matter is a little more complicated. The water on our own planet also acts as a carbon sink, by dissolving CO2 and binding it into rocks.Without water, the Earth would look a lot more like Venus.

(You mean protons. Alpha particles are helium nuclei.) Similar things already occur naturally, for example on the moon where a small amount of water is continually being created by solar wind reacting with rocks. I just don't think the flux is high enough to terraform Venus.

I'm not absolutely certain but I think the last bit (that's on the left, traditionally Japanese is written in top-to-bottom columns with successive columns added from right to left) does say "60% proof". Although commonly called "rice wine", sake is not a wine. It's fermented grain, which makes it a beer. I think it must have been distilled to reach 60%, though I don't know enough about sake to say if it is commonly done.

Gold is non-toxic as long as you're talking about the metal rather than gold salts. I've seen (and tasted) gold leaf in drinks before. My Japanese is terrible but the picture middle-left lists the ingredients, including rice, rice "kouji" (fungus used in the fermentation process) and gold leaf.

Consider a pure photon drive. When you stick a light bulb on the back of a spacecraft, you lose mass from your electrical power system in accordance with m = E/c^2 and are in turn propelled forward with a very tiny thrust. This is exactly the same principle as that of a rocket, just with the ultimate exhaust velocity and the need to take some relativity into account. If the electrical power is fed from external energy source such as solar panels you can gain mass at the same rate as you lose it, somewhat similar to a jet engine. This device--assuming for the sake of argument that it actually works--must obey the same principle.

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.

The story about us having digged up all the easily accessible minerals is a myth. Earlier civilisations had a harder time transporting ores and so were quite likely to make do with rubbish. Producing metal takes more fuel than ore, so they had to transport the ores to a place where fuel is plentiful or more likely find both very close together. Furthermore, there is a difference between the sort of deposit that is economical when mining by hand (depth matters more) or by machine (size matters more). Case in point: some of the earliest artisanal haematite mines in the world are still in operation in Southern Africa. (It has been used in cosmetics since thousands of years before smelting was discovered.) The iron ore that's exploitable under current market conditions still amounts to billions and billions of tonnes. Our coal won't run out anytime soon. There's something like 7x the carbon in the atmosphere still trapped in coal. Enough to realise any global warming nightmare you care to think of. Some of it is deep below the surface, true, but a lot of current coal mining is open-pit mining which pretty much implies that it's shallow enough to get to with hand tools. Charcoal, on the other hand, can not sustain iron production on an industrial scale. There's a reason Europe is no longer covered in forest--the blacksmiths burned most of it. That's why burning wood to make charcoal started being outlawed a few centuries ago, which caused the switch to coke. Anything other than steel is a rounding error in global metal production, so I'm not going to discuss them in detail. Suffice to say that it would be rather difficult to access things like aluminium (2nd highest production) or magnesium (3rd) without more advanced technology. If "civilisation collapses" means we don't remember how to make complex machinery, you couldn't make them. If it doesn't, Mr Gingery says you can make any machine you need from basic tools.

I've been thinking about the experiment. I'm still really uncomfortable with exposing it to direct sunlight. Here's what I have in mind: - We divide the experiment into two or three equal-volume concentric rings. Each of these will experience different levels of artificial gravity. - Our experiment should be to sprout some seeds. I'm thinking of the bean-sprouting experiment for kids, which is simple and gives us lots of educational potential. We can measure which plants sprout "correctly" with the root growing down (=out) and the stem up (=in), as well as the growth rate. These should be affected by the gravity in each ring. - Coriolis effects may also cause the plants to grow at an angle. This would give us some cool photographs for public outreach/education. - Because we don't want to sprout the seeds weeks before launch, we'll need some way of watering them during or after launch. I think some kind of fragile water reservoir would work well; designed to break during launch. We would need an exception to put a new water reservoir and seeds in after vibration/drop testing, but I think we could motivate it successfully. - We don't expose the experiment to direct sunlight. Instead, we have a small amount of light provided either by one or several LEDs or by reflections off the structure of the spacecraft incorporated into the design, or perhaps sunlight filtered through other spacecraft components that are semi-transparent. This not only prevents us from cooking the plants on the day side but also provides better insulation on the night side. - The light is mainly for the camera to see the experiment, but will also allow us to observe the plants grow (and photosynthesise) beyond the initial experiment. We'll need to design it carefully so that we don't give more light to either the outer or the inner rings if we do it this way. - We don't need a complex biosphere because the main experiment is quite short. Anything we get after that is a bonus. - It's easy for all forum members and the general public to test the basic conditions (common seeds in a small closed space) at home. - If we use beans, we get a plant that comes with its own nitrogen-fixing bacteria and is a food crop.

That's nutrition, not evolution. And 1.80 probably isn't representative of today's men. Your judgement is affected by the fact that the Dutch are an unusually tall nation.

Radio is a low-frequency analogue for laser light, with a resonating electrical current instead of the optical resonant cavity of a laser. A high-power radio antenna can certainly give you nasty radiation burns if you come too close and especially if you're stupid enough to touch it. This is true even in the higher power ranges used by HAMs. However, it's non-ionising so not especially harmful as long as you don't get close enough to be heated by it.

Months at least.

I believe you are. "Qualification testing is performed on an engineering unit hardware that is identical to the flight model CubeSat." For our own internal tests, we can of course go through as many cheap stand-ins as required.

http://www.cubesat.org/images/developers/cds_rev13_final.pdf Section 4.5.1: Qualification testing is performed on an engineering unit hardware that is identical to the flight model CubeSat. Qualification levels will be determined by the launch vehicle provider or P-POD integrator. Both MIL-STD-1540 and LSP-REQ-317.01 are used as guides in determining testing levels. The flight model will then be tested to Acceptance levels in a TestPOD then integrated into the flight P-POD for a final acceptance/workmanship random vibration test. Additional testing may be required if modifications or changes are made to the CubeSats after qualification testing. Edit: I may have misunderstood. It looks like you need to do either qualification testing or protoflight testing, not both.