todofwar

But if we get engines that make ssto viable on earth, won't they still work better in a staged system?

Don't need to cool all that air down at once, just need to run it through a cold trap, at least for the water. A continuous flow system will net you all you need. The acids will dissolve into the water, and the HF will chew through most things and is one of the few chemicals i refuse to work with because its so toxic, so that will need to be separated somehow. For something on this scale zeolites might be the better way to get notrogen, they can be designed to trap certain gasses.

Note the poll itself said "used regularly". I am of the opinion (largely influenced by time on these forums) that SSTO just isn't practical on Earth. Staging is a great idea, and Elon has shown you can do reusable staging (eventually they'll get a reusable upper stage too). So, while it might not be impossible, I think it's just not a great idea for Earth based launches.

Well, in a sense yes. Nucleic acids are much harder, don't know if those will need something like a geothermal vent to get going. And of course it's a matter of timescale. That glycine build up happened over billions of years. You can get peptide strands, they'll just be very rigid. As for life, it will be much more complex than that. Probably the thing that amazes and fascinates me more than any other is the transition from prebiotic to biochemistry. The machinery involved is so complex now it's hard to think back to how it might have worked.

It's a radiation induced process I believe. Glycine is O-C-C-N, essentially. You link carbon monoxide and cyanide, slap on a hydroxyl radical to make HO2CCN, and reduce your CN to make glycine iirc. I haven't read up on it in a while

his scenario only requires them to survive a few decades. You don't need dedicated teachers, an sorrento system will work. And crafting tools will be another specialty sure. Notice I said you need a couple? But there are 500 colonists. Assume 250 of working age. That's enough to have 10 or so guys each in 25 different specialties. That's enough redundancy to keep yourself going for a few decades. I would even say a good chance of going for a few generations.

@Andrew Zachary Foreman might be, hard to say unless you go over there. We've had a few probes survive on a scale of a few hours on the surface, so give some advances and say you can get a decent sized craft to survive half a day. That half a day would have to be spent drilling, and drilling is going to raise your heat faster. But you might be able to haul more total material. There's a trade off somewhere I'm sure.

Do you know what it's really made of? Because wiki says it's just ammonium nitrate, but ammonium nitrate itself is a solid. So they must be making it a liquid somehow, or they melt it maybe? But heating a mixture of hydroxylamine and nitrate in the tank does not sound like a safe idea

Thing is, you can build in redundancy. Let's think about his scenario, not building new just sustaining one or two habitats. You need a couple repair guys, a couple guys in charge of growing food, a couple guys in charge of collecting resources, and a couple guys in charge of refining them. The other parts, like merchants and Lawyers and doctors, are luxuries. Not really needed. If we're talking about a civilization scale place than yes, it will get tough. But if it's just about staying alive? I'd say 500 is plenty. No one got upset at Watney being a Mary Sue, let's say this colony has ten Watnies that are also good at training others to be half Watney.

I loved that paper for the level of detail they put into analyzing frames. Like someone picking out the taxonomy of Martian squirrels.

Yeah, low life expectancy. Probably close to 50 or 60. But that's not a problem on its own. We got by for a long time without modern medicine.

Thing is, you don't need brain surgeons, you get a brain tumor you die. Such a colony won't replicate our life style, but it can keep itself going.

Not sure. You just need a cold bucket basically, things should deposit into it. Google iodine deposition to get a visual of what to expect.

@Andrew Zachary Foreman the idea is that on Venus it snows lead because the temp is so high lead sulphate can sublimate (go from solid to gas). Presumably other metal salts do the same, I purify metal compounds by sublimation all the time. Even tungsten will sublimate when bound to the right things. The idea is instead of scooping tons of rocks that need to be refined, you can go in blind and condense out the metals and bring them back with you. No drills needed, no need to longer on the surface for too long.

The atmosphere. Temperature on Venus reaches reasonable temperatures pretty quickly, in terms of altitude

Something can be physically possible but practically not useful, like a space fountain or space cannon, or impossible, like a space elevator Edit: and it's phrased as (most ridiculous) or (impossible), some people might think all of these are possible but some more ridiculous than others

I see what you did there. I think I should have specified earth based for the launch options in the poll.

I believe the scenario is a few hundred trying to survive Watney style, not full colony, but I'll let the OP reply. And to get things from the atmosphere is allot simpler on Venus. Because you just need to cool it down. For seawater, there's no good molecular scale filter right now, so you have to boil away the water and then sort through the tons of salt. For Venus, you just need a cold trap. Gas goes in, water and acids condense out, gasses leave. It will take a while to accumulate things, but again you just have to make up losses not grow. Similar principle for collecting things like lead, they are in a gaseous state and you just need to condense them.

Space loop is a giant magnetic track, launches things similar to a space cannon but over a much longer distance. Only works if your constantly launching things because the centripetal force of the launches keeps it up.

Not really. Just a good filter. Just need to flow the atmosphere through at a high rate. You only need scale to serve the hab, not a civilization. People are picturing earth level industry, but that's for earth level needs.

So these often come up, and I was wondering which tech people found to be the worst of the worst. I'm going with space elevator, because it's pretty much impossible. Then again, the EM drive is probably tied with it.

There is hydrogen on Venus, low amounts but its there as sulfuric acid, hydrochloric acid, and even some water. You can set up a cold trap and leave it running for a few weeks and you'll start collecting stuff that can be used. People freak out about acid, but you can store them in most plastics without too much trouble. Recycling would be the order of the day, and in this scenario new habitats aren't getting built so you only need to take in a few materials from the outside. You can use the water and CO2 to grow plants, and use the biomass as feedstocks for plastic production. Once the hydrogen is fixed as plastic, recycle until it has become too warn out, then burn it, trap the water, and keep it going. People have been working for decades to use carbon based materials (organics) for pretty much everything. Organic transistors, organic solar panels, organic circuits. Unfortunately all the papers I might pull are behind pay walls, but really about 90% of things can likely be made purely of organic material in the next couple decades. Now, for earth based applications they are rarely as economical as the alternatives (silicon comes from sand, and the processing cost vs efficiency keeps pace with organic replacements). On Venus, such products can very easily become the order of the day. Another way to mine Venus would be to not go all the way to the surface. Drop a line of something with a high melting point, maybe a steel chain or something, but you need a way to keep it cold. Lead sulphate and other things will sublimate and deposit themselves on the line, which can then be hauled up for processing once it gets to a certain weight. Not sure what all you will collect that way, I think the theory right now is its mostly lead, but there's probably other metal salts that will come along with it. Edit: lower the line to within a few Km of the surface, but you will need to keep the habitat well above this level. Will probably need a specialized unmanned airship for this purpose.

Don't forget, humans made most of our advances while believing in all kinds of superstitions. Newton thought there were secret codes in the bible, pythagorous was one part mathematician one part mystic one part cult leader. Superstitious belief and science know how are not mutually exclusive.

http://link.springer.com/article/10.1134/S0038094612010042 Half life 3 life on Venus confirmed!

I don't know, I think anything big ad a protein will have a hard time dissolving in methane, even polyethylene at comparable molecular weights won't dissolve in boiling hexane (which isn't that hot but much hotter than liquid methane). There has been talk of polycyanides that can act as photocatalysts, maybe they're just consuming the acetylene. If they convert some of it to cyanide, and that polymerizes to another active polycyanide chain, would that count as life? Serious question. You also highlight one of the reasons I set up this matchup. Earth chemistry is so varied because we have week and strong interactions and interplay between them. But on Venus you get only strong interactions, on titan only week interactions. Most biochemistry relies on covalent bonds top hold things together, but hydrogen bonds to direct and organize things. With only one or the other what do you get?