I didn't know where exactly to put this, I don't think it's that 'advanced'. But since we're bound to discuss Venus colonization technology sooner or later, it's probably the best category.
Why isn't more effort being done on a long duration atmospheric probe on Venus? There's a lot more 'new' scientific knowledge to be gathered (per dollar spent) than yet another mission to Mars...
And getting a heavy, fragile lab floating on Venus seems easier than EDL on Mars.
- Let's investigate this supposed Earth-like region, and see how habitable it really is.
- Let's map the surface of Venus like we did with Mars. We found lots of things we didn't expect, who knows what we can find on Venus.
- Let's see how much sulfuric acid there is for ISRU.
- Let's see if we can find a way to remove the sulfur dioxide from the air so we can harvest the nitrogen and carbon dioxide.
- Let's see how much energy we can get from solar panels/solar furnaces/heat differences/heat pumps
- let's investigate the amount of turbulence/flows/weather patterns
A normal balloon will be moved around quite a bit, so we get to investigate many different locations/altitudes. More than a Mars rover could ever visit in its lifetime. If we want to get to specific locations, or get away from storms, we could use a small dirigible.
I can't imagine the sulfuric acid and sulfur dioxide prevent us from doing this. Sulfuric acid is used in hundreds of chemical reactions on Earth, these need to be contained in something. If the loss of lifting gas (H2 or He) prevents us to float something long term, we could just use a different lifting gas, like methane. If it still escapes over time, we could extract water from the sulfuric acid to make more methane. We could do a combo of descent with H2 to limit the needed mass, and conversion to CH4 as ISRU provides additional hydrogen.
IMHO a lot has to do with the idea that Venus is simply a "hell-world" with no value as compared to Mars which we can "land" on and walk around on. There is also the "fact" that Venus is "inward" rather than "outward" and not a lot of thought has gone into extended exploration "inside" Earth's orbit.
Technically we've done a pretty good job already with Magellan and radar mapping, but an in atmosphere "base" probe would allow us to do some "lander" probes much easier than the direct entry ones that have been done so far. We don't have to necessarily build the lander as "tanks" overall but more like ocean probes since they can "come-up" to avoid being destroyed by the heat and pressure of the surface.
Should be various chemical process' to do this. Any suggestions?
One of the main "arguments" I keep hearing against Venus floating colonies/stations/bases is the "hurricane" winds would tear any balloon apart. I've tried explaining the difference between "base" and "differential" wind speeds.
Strangely enough, on Venus the atmospheric gas composition of Earth (Oxy/Nitrogen) is ALSO a lifting gas with about half the efficiency of Helium if one were to go with that method.My preference at this point for "Green Dragon" is to use Hydrogen for the extra lift with replacement by small scale sulfuric acid ISRU.
Hydrogen is really scarce on Venus, so filling baloons with it might not be its optimal use.
Quote from: Nilof on 12/06/2013 06:24 pmHydrogen is really scarce on Venus, so filling baloons with it might not be its optimal use.Hmm.. if you could ensure it wouldn't leak, it would seem to be the optimal side use of it, for a floating colony. Better than, for example, storing it as water which is just going to be a net negative to buoyancy.
The difference between air and hydrogen in a CO2 atmosphere isn't really that large. A nitrogen baloon will give you a lift of 44 g/mol - 28 g/mol for a total of 16 g/mol. Hydrogen will give you 44g/mol - 2g/mol or 42 g/mol. So a nitrogen baloon will only need to be about 2.6 times as large, and it can be filled very easily with local nitrogen. Hydrogen is really scarce on Venus, so filling baloons with it might not be its optimal use.
Quote from: QuantumG on 12/06/2013 11:18 pmIndeed. One way to reduce leaks would be to store the hydrogen in a baloon inside the shell of your main air-filled habitat, as the difference in buoyancy would be minor. The downside of that approach would be reduced volume to structure ratio, the the risk involved in separating an oxygen atmosphere and hydrogen with just a thin membrane... This problem disapears if you have a separate baloon filled with nitrogen and no oxygen for extra lift.Getting leaked hydrogen back by filtering it from the nitrogen(or air) is an interesting problem. Industrial methods for separating gases tend to be optimized for energy efficiency, but on Venus the bottleneck seems to be mass rather than energy. If it's stored in air you could find a clever way to make the leaked hydrogen combust and condense the water.
Indeed. One way to reduce leaks would be to store the hydrogen in a baloon inside the shell of your main air-filled habitat, as the difference in buoyancy would be minor. The downside of that approach would be reduced volume to structure ratio, the the risk involved in separating an oxygen atmosphere and hydrogen with just a thin membrane... This problem disapears if you have a separate baloon filled with nitrogen and no oxygen for extra lift.Getting leaked hydrogen back by filtering it from the nitrogen(or air) is an interesting problem. Industrial methods for separating gases tend to be optimized for energy efficiency, but on Venus the bottleneck seems to be mass rather than energy. If it's stored in air you could find a clever way to make the leaked hydrogen combust and condense the water.
Quote from: RanulfC on 12/05/2013 10:34 pmIMHO a lot has to do with the idea that Venus is simply a "hell-world" with no value as compared to Mars which we can "land" on and walk around on. There is also the "fact" that Venus is "inward" rather than "outward" and not a lot of thought has gone into extended exploration "inside" Earth's orbit.I guess we agree that we need to study ALL terrestrial planets to understand how Earth formed, and to understand why we are so different. And how those differences allowed life to prosper here, or how much of those differences are caused by life itself. It'll be a first step into discrediting this 'habitable zone' stuff. (or misnomer, take your pick)
QuoteTechnically we've done a pretty good job already with Magellan and radar mapping, but an in atmosphere "base" probe would allow us to do some "lander" probes much easier than the direct entry ones that have been done so far. We don't have to necessarily build the lander as "tanks" overall but more like ocean probes since they can "come-up" to avoid being destroyed by the heat and pressure of the surface. I posted this right after viewing that video where you fly over Mars. I don't think the Magellan maps are that precise? And analyzing the Martian surface in great detail is what gave us the indication that there is periodically liquid water. Not to mention the added benefit of the recurring 'water on Mars', 'face of Mars', 'water on Mars', 'mice on Mars', 'water on Mars', 'rover spots alien on Mars', 'water on Mars' news flashes to keep the buzz going among the public at large.
QuoteShould be various chemical process' to do this. Any suggestions?You asked for it
Industrial companies burn the remaining H2S and exhaust the resulting SO2. We're not able to do that because we want to breathe. If we pass it through a tank with sulfur algea, these can fixate it and give us air instead. (6H2S + 6CO2 = C6H12O6 + 3O2 + 6S). You'd need to select the algea able to use even the smallest concentrations of H2S, and keep them on the brink of starvation to increase yield.Now, or after the second step, you might want to pass the air through a flame driven by additional H2, to convert the O2 to H2O so it can be recovered later.Use a nitrogen press to harvest the nitrogen. This couldn't be done before because the SO2 would damage the filter.At this point, you might want to convert some of the CO2 to CO and H2O, if you want additional air. This step takes a lot of heat, so you shouldn't exagerate.Cool it down, harvest all the water left, and get rid of te residual gas. Keep some of it for the next step. electrolyze the water to refill your stock of hydrogen you used for the flame and the CO2 conversion. Turn the water you gained from the sulfuric acid into CH4 (sabatier: CO2 + 2H2 = CH4 + O2 for easy and sustainable storage as a lifting gas. Store the CH4, O2 and N2 separatly to avoid fires and balance out the concentrations in the living area. The CH4 is basically a floating water tank because you could design a tap that looks like a water fosset, that consists of a flame and a cooling unit.You see it takes a lot of heating and cooling to make this work. That's why it's so interesting to know how much energy we can get at what altitude. More power up, more heat below to do the work for us, more sulfuric acid at a certain altitude. We could use all of this. Do we transport stuff from the farms (power and fuel above, water, nitrogen, CO2, oxygen,... below) to the habitat or do we keep them connected, or do we move the habitat itself around to produce what it needs when it needs it, using outside temperatures for heating and cooling? We need to know the conditions a lot better to know how we can work more efficiently.
QuoteOne of the main "arguments" I keep hearing against Venus floating colonies/stations/bases is the "hurricane" winds would tear any balloon apart. I've tried explaining the difference between "base" and "differential" wind speeds.I was thinking more in the line of turbulence when you cross from nightside to dayside and oposite, and which altitude and latitude would be more stable/sunny/interesting. And what the denser atmosphere would do to our ability to move where we want to (and away from storms), and maybe take advantage of certain winds, like airplanes take advantage from the jetstream. And what the denser atmosphere would do to our ability to lengthen the day and shorten the night by actively moving the aerostat. Zeppelins (I don't think blimps are built for speed) could easily reach 100 km/h. That would allow 2,5 earth days of light per 1.5 earth days of darkness.
QuoteStrangely enough, on Venus the atmospheric gas composition of Earth (Oxy/Nitrogen) is ALSO a lifting gas with about half the efficiency of Helium if one were to go with that method.My preference at this point for "Green Dragon" is to use Hydrogen for the extra lift with replacement by small scale sulfuric acid ISRU.Using air as the main lifting gas sounds to me a bit like using salt batteries to run submarines (20000 miles under the sea). You need a massive balloon for that. Can you imagine what massive balloons we'd have to launch from Earth and inflate while freefalling? Maybe once we've got the necessary infrastructure to make more aerostats in situ, but not now. (which I think is easier than expanding a Mars base).
Hydrogen on the other hand has a lot more kick on Venus than it has here. Because of the denser atmosphere, the difference in lift between gasses becomes bigger. But hydrogen and helium quickly escape through the balloon. You wouldn't want to use it long term, because even hydrogen becomes expensive if it has to be constantly replenished.
But we can combine gasses: Use hydrogen for entry, to quickly reduce the velocity while only inflating a small section of the balloon while at breakneck speed. Later on, convert it to CH4, and harvest more hydrogen to compensate for the reduced lift. Methane escapes a lot slower, so doesn't need constant replenishing. CH4 has a little more lift on Venus than Helium has here. So your fully inflated balloon can be blimp sized (14*15*18m for a 7 people gondola). Early, unmanned missions will most likely be a lot smaller.
NH3 or steam is also a possibility if you expect a lot of vertical movement. Storing them around boiling point allows you to quickly adjust the concentration by cooling or heating just a little bit, preferably using the outside air. Boiling point and outside temperature vary with altitude, which might be exploited. But it can also be a nuissance.So yeah, I've done some reading and thinking :p
Yep that I did I was also hoping for a generic "size" for an experimental module while you were tossing numbers around Remember I'm trying to fit this into a "Cargo Dragon" capsule at the momemnt
I'm thinking that the NH3/Steam balloons would be used primarily for suface landers and return vehicles, "hopping" rovers, and sample gathering vehicles.One of the issues with the concept of the Red Dragon probe was that everything had to move in and out throught the hatch. I wonder if there is a way to arrange to "drop" the heat-shield once in the atmosphere that would not require to much modification?Randy
This is a great thread!
Imagine if "someone" builds an inexpensive BFR.
Long dangling sheaths (for temp) or electrodes (for electricity) could potentially capture energy from the atmosphere for creation of ISRU propellant combos for active steering or return to orbit or Earth.Given the chemistry, temp, and tectonics (or lack), I'm still suspicious that many high-grade rare metals are just laying around in vast quantities on the Venusian surface. Also, it may be possible to create artificial diamond at large scales using local energy (specifically thinking of BLEVE hammers using local geology (not enough known yet).
Quote from: RanulfC on 12/09/2013 02:30 pmYep that I did I was also hoping for a generic "size" for an experimental module while you were tossing numbers around Remember I'm trying to fit this into a "Cargo Dragon" capsule at the momemnt For a sulfuric acid treatment plant, you wouldn't need anything near a dragon capsule.
So you would need little more than 300 kg. Make it 500 for things I haven't foreseen. That's a large safety margin and still quite reasonable.
Maybe you want to add a methane production stage to mitigate losses. It's built for minimum size. Want a higher production? Just scale it up. But I think the amount of sulfuric acid you can gather is going to be the limiting factor.
For an air treatment plant, that's a lot more hypothetical. I don't even know if it works, so I suggest doing an experiment here on Earth for proof of principle. It'll be enough of a hassle to get everything working properly, let alone getting it to fly. The inefficiencies in the process might make you vent a lot of much needed hydrogen. And I don't know if there are any sulfur algae out there that can bring down concentrations far enough. But not being able to purify the air would be a showstopper. You can't have astronauts living in a toxic fume or in a constant smell of rotten eggs. That's why I added it.
QuoteI'm thinking that the NH3/Steam balloons would be used primarily for suface landers and return vehicles, "hopping" rovers, and sample gathering vehicles.Similarly, I'd eventually split up the land-and-return rover into a lander and a 'heavy lifter'. That way, the landers can scout and gather for as long as possible, without running the risk of the highly pressurized CO2 gradually flowing into the lifting gas. And it might be easier to have only one (+ backups) vehicle capable of manoeuvering payloads vertically and docking with the aerostats and rovers. That way the rovers only have to be purpose built for the surface. Less complex machines --> less failure.
I'm thinking that the NH3/Steam balloons would be used primarily for suface landers and return vehicles, "hopping" rovers, and sample gathering vehicles.
QuoteOne of the issues with the concept of the Red Dragon probe was that everything had to move in and out throught the hatch. I wonder if there is a way to arrange to "drop" the heat-shield once in the atmosphere that would not require to much modification?One of the ideas for an EDL system on Mars for heavy landers is a heat shield that is connected by a rendezvous in space. So that should be easy to detach.
One of the issues with the concept of the Red Dragon probe was that everything had to move in and out throught the hatch. I wonder if there is a way to arrange to "drop" the heat-shield once in the atmosphere that would not require to much modification?
Ok there "wise-guy" YOU started a thread on "Venus Atmospheric Probe" so I toss out my idea for a low-cost "probe" and its too BIG? Yeesh, come on work with me here it's a "baseline" idea ::::grin:::::
As I recall a "cooled" surface exposed to airflow is needed which begs the question of where that's goiing to be put and how much does all that mass?
I'd hold off on the ECLLS for now, get the basic data first the add extension to the next flight.
Quote from: RanulfC on 12/10/2013 04:40 pmOk there "wise-guy" YOU started a thread on "Venus Atmospheric Probe" so I toss out my idea for a low-cost "probe" and its too BIG? Yeesh, come on work with me here it's a "baseline" idea ::::grin::::: I meant: a dragon capsule would give you a lot of room to spare for other equipment.
QuoteAs I recall a "cooled" surface exposed to airflow is needed which begs the question of where that's goiing to be put and how much does all that mass?For cooling: outside air being blown around the pipe section that needs cooling. That outside air could be in a separate pipe that connects to the outside. For air flow: a few little fans don't add a lot of mass. All very small size, because for a first mission, you only need very low quantities. The important question is: what materials are the the pipes made of where the liquid/gas flows through. It needs to resist sulfuric acid, heat, pressure, not to mention launch and reentry. Glass is probably not a good choice.
QuoteI'd hold off on the ECLLS for now, get the basic data first the add extension to the next flight.Definitely. It's only when we get to sending people over there that we would have to solve this. But as it's the main argument why sending people would be impossible, tackling it early on (in a proof of principle on Earth) might shut up most of the nay-sayers. That would increase your chances of getting the required funding to send any mission in the first place.
Quote from: Nilof on 12/06/2013 06:24 pmThe difference between air and hydrogen in a CO2 atmosphere isn't really that large. A nitrogen baloon will give you a lift of 44 g/mol - 28 g/mol for a total of 16 g/mol. Hydrogen will give you 44g/mol - 2g/mol or 42 g/mol. So a nitrogen baloon will only need to be about 2.6 times as large, and it can be filled very easily with local nitrogen. Hydrogen is really scarce on Venus, so filling baloons with it might not be its optimal use.Venus's atmosphere is very dense (92 bars) so you shouldn't need any gas for the baloon, but rather an empty (i.e. pumped out) rigid structure capable of withstanding high pressures. Sort of like a submarine. I suppose one could call it a subaerial vehicle.
Quote from: Garrett on 12/11/2013 09:45 amQuote from: Nilof on 12/06/2013 06:24 pmThe difference between air and hydrogen in a CO2 atmosphere isn't really that large. A nitrogen baloon will give you a lift of 44 g/mol - 28 g/mol for a total of 16 g/mol. Hydrogen will give you 44g/mol - 2g/mol or 42 g/mol. So a nitrogen baloon will only need to be about 2.6 times as large, and it can be filled very easily with local nitrogen. Hydrogen is really scarce on Venus, so filling baloons with it might not be its optimal use.Venus's atmosphere is very dense (92 bars) so you shouldn't need any gas for the baloon, but rather an empty (i.e. pumped out) rigid structure capable of withstanding high pressures. Sort of like a submarine. I suppose one could call it a subaerial vehicle.Uhm, are you thinking "vacuum" lift?Randy
Quote from: RanulfC on 12/11/2013 08:02 pmQuote from: Garrett on 12/11/2013 09:45 amQuote from: Nilof on 12/06/2013 06:24 pmThe difference between air and hydrogen in a CO2 atmosphere isn't really that large. A nitrogen baloon will give you a lift of 44 g/mol - 28 g/mol for a total of 16 g/mol. Hydrogen will give you 44g/mol - 2g/mol or 42 g/mol. So a nitrogen baloon will only need to be about 2.6 times as large, and it can be filled very easily with local nitrogen. Hydrogen is really scarce on Venus, so filling baloons with it might not be its optimal use.Venus's atmosphere is very dense (92 bars) so you shouldn't need any gas for the baloon, but rather an empty (i.e. pumped out) rigid structure capable of withstanding high pressures. Sort of like a submarine. I suppose one could call it a subaerial vehicle.Uhm, are you thinking "vacuum" lift?Vacuum lift? Remember the Hyperloop tubes? Just a few meters in diameter and needed half inch steel walls to withstand 1 bar of pressure. How thick and heavy do you suppose they would be to withstand 92 bars?
Quote from: Garrett on 12/11/2013 09:45 amQuote from: Nilof on 12/06/2013 06:24 pmThe difference between air and hydrogen in a CO2 atmosphere isn't really that large. A nitrogen baloon will give you a lift of 44 g/mol - 28 g/mol for a total of 16 g/mol. Hydrogen will give you 44g/mol - 2g/mol or 42 g/mol. So a nitrogen baloon will only need to be about 2.6 times as large, and it can be filled very easily with local nitrogen. Hydrogen is really scarce on Venus, so filling baloons with it might not be its optimal use.Venus's atmosphere is very dense (92 bars) so you shouldn't need any gas for the baloon, but rather an empty (i.e. pumped out) rigid structure capable of withstanding high pressures. Sort of like a submarine. I suppose one could call it a subaerial vehicle.Uhm, are you thinking "vacuum" lift?
one problem: the 50 km level is below most of the clouds. Solar power will be limited at that altitude.