I would expect that the speed at which they get to Falcon 9 reuse would have an impact on the Falcon Heavy schedule (that speed, in turn, being relative to the rate that they keep landing them - the more they have on hand, the more risky they can afford to be in their return-to-flight testing program for them). Falcon 9 and Falcon Heavy cores are extremely similar and made on the same lines, and the engines are identical. So the more line capacity they free up, the more they can dedicate toward the Heavy.
I appreciate my posts are often opaque and I have great difficulty being understood from time to time
If you're finding this to be a recurring problem, then you might want to consider that perhaps the problem is not other people.
We're going to Mars because we can land on it and colonize it today, without terraforming it.
And the same thing applies to Venus, only even easier - plus the added convenience that you don't actually have to literally land. Once again, I'm failing to see why you keep making this statement of yours. And as long as you keep making that statement and not dealing with my reply to it, my reply is going to keep being the same. And this is going to continue to be a frustrating conversation for the both of us.
Summary of the problem you're having: saying "We're doing X, not Y because we can do X today and not Y" is a meaningless statement when we can actually do Y, and more to the point it's easier than X. If you disagree that one can do Y, you need to state reasons, rather than just being dismissive.
but the fact is they're not what anyone wants to do.
The fact is, as evidenced by this very discussion thread, very few people even know that it's a possibility. It's hard for people to prefer a choice that they don't even know exists. Bringing up a possibility that people are unaware of and educating them on the topic is not some form of tyranny, it's a perfectly reasonable course of action that you for some bizarre reason object to.
The scientific literature has been discussing colonizing the surface of Mars pretty much since spaceflight began. The first scientific paper on the colonization of Venus's cloudtops wasn't even written until 2003 (Landis).
BTW Saturn's bigger and has the same gravity as Venus and Earth,
The combination of some layer with Earth-surface gravity, air pressure, and temperature only exists in one other place in our solar system: Venus. Not Jupiter. Not Saturn. Not Uranus. Not Neptune. Not Titan. Just Earth's surface and Venus's middle cloud layer. On none of them is gravity near Earth norms at livable temperatures (it's only near Earth norms at liveable pressures on some of them), and on none of them exists the combination of livable pressures and temperature at any altitude.
And beyond all this, have you ever looked at transit times, launch windows, and delta-V requirements for Saturn? The local solar constant? How exactly do you plan to float a balloon of breathable air in hydrogen anyway? What's your local resource production tree?
Of course you don't have answers to any of these things because you weren't actually serious, you were just being dismissive of Venus - even though answers to a huge variety of topics related to a Venus colony have been discussed on this thread, and I'd be happy to discuss more. But again, you don't care about that either, you just want to be dismissive without having to substantiate your reasons.
plus the radiation
You do realize that radiation is one of the many reasons that Mars is a more difficult colonization target than Venus, right?
The most reasonable route would still be LA to Vegas first. Then SF to LA. Then Reno would be in trouble. Seriously, if people could hop a $20 ride/half hour ride to LA and then another one to Vegas, who would go to Reno? Reno would pretty much have to build a route of their own. But that wouldn't be easy, the terrain between Sacramento and Reno is pretty much custom-designed to be hostile to any form of high-speed surface travel. You'd have to take the Japan approach (drill through every mountain, bridge the gaps in-between). And I'm sure there'd be environmental sensitivity to such an approach.
Hmm, what's probably the easiest route... because I-80 is just so windy. Maybe US-50 east of Sacramento. There'd be reduced speed / minor tunnels / bridges from Placerville to Riverton, but spend most of the next leg through the mountains in a fairly straight valley and could probably just hug a wall and change tower heights... up until you get near Sierra-At-Tahoe, which would definitely need tunnels/bridging... maybe over to 89, bridge down to Sorensens, reduced speed through the valley around to Alpine Village, and then you're out onto the open plains for a final acceleration segment to the north (with slowdowns past Carson City). Hmmm.. honestly, I'm not sure that's any better than I-80.
Earthquakes make surfaces rough? That's news to me.
I assume you actually mean "out of alignment". Wherein, you need to read the Hyperloop Alpha document, they spend a good bit of time talking about isolation, maintaining alignment, and earthquake resistance.
You address costs (and I don't agree with you there), but how is HYPERLOOP! going to solve all the other problems that prevent us from building high-speed rail? Like politics and NIMBY and right-of-way.
That's the very reason for elevating it and designing the route to follow highways - to avoid most "politics and NIMBY and right-of-way." Well, that and the simplification of handling small elevation fluctuations.
That said, it's fair to point out that Hyperloop isn't a 1 for 1 substitution for HSR in terms of functionality; it's more like a functional intermediary between HSR and plane travel (but designed to be far cheaper and lower energy consumption than either). Air travel is very high speed, low capacity, low capital cost for new routes, direct point to point, no stops, limited in-town accessibility. HSR is low (by comparison) speed, high capacity, high capital cost for new routes, high in-town accessibility and numerous stops. Hyperloop is moderate (by comparison) speed (although closer to air than rail), moderate capacity, moderate in-town accessibility (it can be extended further into town than air travel can, but it faces some speed reduction), and while easier to have stop at intermediary points en route than aircraft is harder than HSR.
I think SpaceX erred in presenting it as an "alternative to HSR" - I feel they should have presented it as something new altogether. Rather than run LA to SF, I think they should have done a LA to Vegas route. HSR fans wouldn't feel threatened. Casino owners would go nuts for the Los Angeles market to be able to pop down to a station on a Friday night on a whim, pay $20, and half an hour later be blowing their money on slots. There's less vested interests in having intermediary stops on the route. Etc. But I know that doesn't interest Musk as much because he spends a lot more time in SF than Vegas.
Note: everything I write below pertains only to Hyperloop Alpha. As for whatever else passes as "Hyperloop" these days, I have no comment.
What, a bunch of gravel, some concrete, and two thick beams of steel on the ground.
Made of segments with two welds, polished, versus a single orbital weld, polished.
We make long cylindrical pressure vessels all the time. They're called pipelines. No, they don't cost a fortune (relative to the cost of HSR). Their cost/(cross section * length) ratio is similar to that proposed for Hyperloop. Of the differences, they're mixed pros and cons. For example, hyperloop doesn't carry toxic chemicals - permitting / environmental review (a major cost) should be far easier. But Hyperloop requires much straighter segments and requires internal polishing. Hyperloop doesn't deal with elevated temperatures and doesn't have to pump fluids. But it still has to have accelerator segments. It doesn't have liquid terminals, but it does have capsule terminals. Etc.
I ran the calculations on the volume of steel described in the Hyperloop Alpha proposal and compared them to current billet steel costs. The cost was a small fraction of what the proposal budgeted. For manufactured segments, delivered, they're probably right on.
You can make elevated regular high speed rail to reduce land acquisition costs.
The cost of elevating a track is almost directly proportional to its peak loading. The peak loading of Hyperloop is an order of magnitude less than that of HSR.
I think hyperloop will just be too expensive to build
Aerodynamic drag force does. 1/2 rho Cd A v^2. Of course, power is force times velocity, so that's cubic. But the (change in) energy is force times distance, and distance for the trip is constant, so it's only quadratic with velocity.
Firstly, if you use air within the tunnel that 1) increases drag and 2) the compression of the air will heat the air causing issues. Secondly, maglev provides the propulsion as well as lifting the vehicle to reduce friction.
As per Hyperloop Alpha, air bearings produce significantly less drag than maglev for the given application. As for the bulk air, in Hyperloop Alpha, the compressor shunts air ahead of the vehicle to behind it (it's exceedingly sparse). Lastly, in Hyperloop Alpha, total drag was so low that propulsion segments were only needed rarely, very spaced out along the track.
Of course, the new competitors are so different from Hyperloop Alpha as to render the term "Hyperloop" meaningless.
Though the Hyperloop air bearings provided a solution that's cheap per unit distance and very low drag, they were not without flaws. Foremost was the very narrow gap (0,5-1,3mm) between the bearings and the walls (needed for high lift at low pressures/drag). That said, those gaps are positively gargantuan compared to some air bearing applications - hard drive air bearings float at heights often no more than a couple nanometers over the surface. But that still means close tolerances. Hyperloop Alpha's solution for construction was a polishing robot that drives down the tunnel with a circular polisher, grinding off any unevenness in the welds or the bulk pipe. Achieving 0,1-0,5mm tolerances with such a system isn't particularly far fetched.
No harder than a high pressure tube that's hundreds of miles long (pipeline), and we do that all the time. The cost of the steel for the proposed route isn't much over $1B, if I recall the numbers correctly.
It was. I don't even know what "Hyperloop" is supposed to mean anymore, as SpaceX held an official Hyperloop competition and selected as winners craft that were absolutely nothing like in the Hyperloop Alpha design. Their test track is designed to allow for all kinds of vehicles, maglev or not... but most of the teams were focused on maglev. No compressors, either, meaning that they can't shunt air from in front to behind, meaning either high drag or requiring a hard vacuum for operation.
I personally find the deviations from the Hyperloop Alpha design to basically ruin the entire concept.
There's a very long list of jobs to do on a Venus colony - some quite high tech, some that would be right at home in the pioneer days.
Early on at least, since every new bit of robotics infrastructure you want to develop comes with a sizeable price tag and even here on Earth robotic agriculture is a serious challenge, agriculture would be conducted by hand. Planting, inspections, harvesting, potentially even pollenation. Some agricultural tasks are less obvious - for example, mushroom farming, or potentially even beekeeping.
All agricultural products are in their raw state. Want to fry something? You better press your oil first. Want to make bread? You first have to thresh/winnow the grain and grind it in a flour mill. Etc. Speaking of bread, you have to keep a live yeast culture, just like was done in primitive times, because you can't just run to the store to pick up a packet of yeast.
Concerning cooking in general - feeding a whole crew, combined with the significantly increased labour of food processing, makes this a full time job. Some "cooking" tasks aren't even edible. Soap, for example, would be made just like in the "olden days" - ashes from the incinerator boiled with fat. Even paper-making (if you don't want to wipe with plant leaves/your hand/a reused brush, and don't think a bidet alone is enough, then you need this) is a kitchen task - fibrous plant matter soaked with ash hydroxides, strained in cheesecloth, blended, then pressed in a cheese press or manually spread/pressed on tensioned cheesecloth.
For a colony that wants to survive on agriculture, and where that agriculture is being conducted in a very different environment, botany / plant science is an important skillset for a crew member. Another important position is a medical staff member. Venus is too far for telemedicine, and people can't simply return to Earth for treatment. The same individual would also double as a compounding pharmacist, dentist and, when livestock raising begins veterinarian. Speaking of livestock, caring for them is no trivial chore.
All habitats will require maintenance. On Venus, you need to clean plant debris, remove any accumulated dust / grime on the envelope, make repairs as needed, and near end-of-life do major reconstruction in sections. There's ample mechanical and particularly chemical systems, to the point that you may even want a full time chemical engineer on hand, to not only maintain but also expand systems for progressively increasing local production capability. New hardware sent from earth requires installation. A small machine shop is needed for fabrication, with trained operators. Heck, even janitorial services are needed. And some chores will be less pleasant than others. The toilet, for example, would compost and/or dehydrate solid waste, but eventually you're going to have to bring it to the incinerator. Don't expect people to pay for the development and launch costs of a "robotic butler" to do all of the work for you.
Obviously researchers are going to be wanted. The more data you can gather from samples locally, the less you need to send to Earth (and the more selective you can be about what you send). On Venus, surface probes need low-latency operators; commands sent from Earth would have totally impractical round trip times when your total dive time can be no more than a couple hours. Surface probes need to be docked, unloaded, and samples hauled up to the lab and processed. The same laboratory hardware doubles as a chemistry lab for production of small batch-scale chemicals, everything from medicines to catalysts and so on down the line.
For quite some time, most effort would simply be directed toward trying to improve crew safety, sustainability / self sufficiency, and comfort. When these needs are met, however, a huge need for increased labor arises in terms of local production of new habitats. All of the huge numbers of components you already have? You need to make more of them - and bigger. No matter how much money you spend on trying to develop robotic systems to assist you, much of the construction work is still going to require humans. Quite a lot of them.
I could keep going, but I think you get the picture.
Good point, though I was more thinking about storms. Earth certainly gets storms energetic enough to tear apart anything flying, though I have no clue how high up on Venus you have to be before that stops being a worry.
Storms are driven by convective potential energy, not how fast the bulk of the winds are moving relative to a surface 50km away.:) Just like how an aircraft flying within a fast-moving jet stream on Earth is usually more stable than flying lower down in the atmosphere. Most of Venus's atmosphere is, like Earth's stratosphere, dynamically stable. However, there are some layers - among them, the middle cloud layer (the habitable zone) where convective potential exists. While our experience directly flying within this layer is limited to just Vega (combined with remove observations), it appears to be roughly similar to Earth's troposphere.
If you want more specifics about Vega's measurements of turbulence: 2 balloons, 54km, 60-hour design lives (battery-powered), different parts of the planet. Vega 1's peak velocity fluctuations were about 2m/s. Vega 2's were about 1m/s. Most of the time it was significantly less. There were calm intervals and turbulent intervals. There were both small scale turbulent patches and large-scale ones. The small scale patches were about 30-130 seconds, fairly abrupt transitions, random timing. The larger ones were more periodic / slower transition, 30-90 minutes. These are interpreted as different kinds of convection cells - the small ones several hundred meters across, and the larger ones tens of kilometers across. Mariner, meanwhile, was monitoring the clouds at the balloon locations and visually spotted cloud features corresponding to the more turbulent episodes. This is extremely useful, as it gives us a way to assess the conditions in Venus's atmosphere over much longer timescales even though we no longer have any probes floating in it (that said, we definitely still need more long-term prep missions!:) ).
If you were to drop random balloon probes at the 500mb level on Earth, getting the sort of turbulence data that was received from Vega would not be at all unusual - it's neither abnormally high nor low. Nor has satellite data indicated that the Vega balloons were in some sort of abnormally calm timeperiod.
That sounds a lot safer - depending on moving parts never failing is just asking for trouble.
Nor do you use just one engine to drive the prop:) A common approach with electric aircraft motors is designs that can be chained end to end, either with a common central rotor, or linked outer rotors in the case of outrunners. Look up, for example, the EMRAX series by ENSTROJ. Each one would have its own independent inverter, and ideally the drive current would be split among multiple cables, each linked to a solar bank in a different portion of the lower portion of the craft (solar is directly printed onto the plastic, using it as a substrate; PTFE is common in usage with solar already)
During production, but only because I hadn't thought of the other. It doesn't take must sulfur to be pretty unpleasant. But then, I'm sure we have plenty of data on how much sulfur crops can absorb before it's an issue - just hope it isn't cumulative.
Permeation is one of those things which people tend to forget - I'm sure you've noticed that helium party balloons, for example, don't stay full forever;) No plastic membrane is fully immune, although there's a wide variation. Sometimes people ask why the Vega balloons weren't fitted with solar panels - it wasn't simply about having to add solar, but also about the extra helium they'd need to compensate for leaks. Vega was from old-school PTFE, which is fairly porous (which, combined with its hydrophobic nature is why it makes breathable waterproof fabrics when expanded, ala Goretex
Venus's diameter (at height) at 70 degrees/54km latitude divided by VIRTIS and VERA data on zonal winds at 70 degrees.
Winds do drop off as one approaches the poles, but not as fast as the radius of travel diminishes, so the day length shortens.
Is there a wind band that actually moves that fast?
Yes. Venus's atmosphere undergoes "superrotation", in that it rotates significantly faster than Venus's surface. It's sort of like having a planetwide jet stream (although it's not constant velocity, as mentioned previously, there are altitude/latitude differences)
The propulsion is to stay in the band?
Yes, the above is just about zonal (planet-circling) winds. There's also meridional winds (toward the poles and equator) as well as vertical flows. Propulsion is needed to overcome the meridional winds. Vertical winds - as well as changes in craft mass due to local production and buoyancy changes due to temperature, also have to be compensated for (except in superpressure balloons, but those are far too heavy for large scale operations). The two main means for this (without discharging mass and the like) is to have an ammonia-water phase change envelope located within the ballonets, against the outer wall (to avoid the risk of ammonia permeation into the living envelope). This passive stabilization system has been tested here on earth with ALICE - as the altitude drops, increasing amounts of ammonia boil off, increasing lift, while at higher altitudes it condenses out..
The nice thing about a floating city is the lift is passive (though I guess you trade the dangers of living in a pressure vessel on Mars for living on a pressure vessel on Venus)
A note: while there is an overpressure, it's small - a couple hundred pascals. Not really much of a pressure vessel, and only a source of slow leaks in the case of a rupture. Also, it's extremely difficult to actually sink it; there's a tremendous amount of ballast (most of the craft's weight) that can be dropped - surplus water, locally produced hardware for maintenance / construction of new habitats, return-rocket propellant (the heaviest single element), and in the worst case, the return rocket itself. The habitat can be reduced to a tiny fraction of its original mass. It's also possible to create more lift via venting collected/produced breathable gases into the envelope, unbreathable gases into the ballonets, etc - as well as using propulsion for lift (during the daytime, at least)
Very, very hard to sink.
As a side note: contrary to what one might expect, the safest place (and lowest-mass configuration) for the living space is near the top of the envelope, not the bottom. From a mass perspective, it shortens the cables hanging from the top catenary curtains, which is a mass savings. From a stability perspective, you want the ballonets taking up most of the bottom. And from a simple safety reason, in the event of a severe leak, CO2 would pool at the bottom of the envelope; you don't want it smothering people.
but very fast winds seems like they'd have some very energetic turbulence
They don't. The speeds are fast relative to the surface, but that's over 50 kilometers away. Some degree of surface effects have been shown to propagate up to the cloud deck over Ishtar Terra (gravity waves), but they're weak.
You may note that Earth's jet streams are also very fast, yet they're popular for passenger jet travel. And they're far closer to the surface.
The conditions in Venus's cloud deck aren't speculative - we've actually flown there (see VEGA). Not for very long, but enough to get a general sense. The atmospheric conditions there are fairly reminiscent of flight in Earth's troposphere, with periodic storms separated by regions of calm. Als
One of my favorites of the more recent ones was the big hoopla over "Liquid water found flowing on the surface of Mars!" - which would have more accurately been headlined as, "Transient damp, toxic rocket propellant found flowing on the surface of Mars";)
I do find astrobiology quite interesting. But I've seen little to come out of most Mars astrobiology work other than overblown press releases. Tiny amounts of methane (a common volcanic gas) and the like doesn't do it for me.
The biggest factor in space travel is energy. To get to Mars you need 6.5km/s worth of evergy (E=1/2mv^2). To get to Venus, you need 12.7km/s of energy, almost twice as much). This is spent slowing down to fall towards the sun.
Slowing down lowers your orbital radius while speeding up increases it up to sqrt(2) orbital speed (at your current orbital radius) which will send you off to infinity, aka escape velocity.
The biggest factor in space travel is energy. To get to Mars you need 6.5km/s worth of evergy (E=1/2mv^2). To get to Venus, you need 12.7km/s of energy, almost twice as much).
This is incorrect. A LEO-to-Mars-intercept trajectory and LEO-to-Venus-intercept trajectory take an almost identical amount of delta-V - about 4,7km/s for Mars and 4,2km/s for Venus (the exact delta-V depends on what sort of assumptions you make, so you'll see some variation in reported figures; these are on the more pessimistic end). You're probably confusing some combination of "from the surface of Venus to LVO" delta-Vs and/or assuming capture by retroburn rather than aerocapture.
A 300kph wind doesn't do anything to a plane for example
You meant sarcasm, but you're precisely correct. Earth's jet streams are upwards of 400kph. Airplanes deliberately fly in them whenever possible.
As multiple people have pointed out to you, you're mixing up wind speeds relative to the surface with turbulence. Venus has high wind speeds relative to its (almost stationary) surface. It does not have high turbulence (as far as we've sampled thusfar) in it. The speed of the air mass relative to a surface over 50 kilometers below it is practically irrelevant.
I'll bet you don't think acid is an issue either
Already more than well addressed elsewhere in this thread.
It may surprise you to learn that we have plenty of chemicals that are essentially completely inert in strong acids. PTFE (Teflon), probably the most famous, is much easier to describe by what it's not inert to than what it is inert to. But the list hardly stops with it.
The real problem is not reactivity, it's permeation. But modern PTFE copolymers like NXT and FEP keep it down to reasonable levels, and liquid crystal polymers like vectran even lower.
And yes, there has been ample lab work, both in the US and Russia/USSR, including a wide range of constructed and tested balloons. And actual flown PTFE balloons on Venus (only designed for short-term operation, but enough to gather data).
I have trouble reconciling your post with you having read mine. You wrote:
A significant difference between Mars and Venus is that we can land someone on the former before terraforming it... until we can deal with the fact that virtually anything we drop into it is going to dissolve within minutes, perhaps even seconds, assuming it doesn't melt first, and assuming it's not enclosed in something strong enough to prevent it from being crushed before it's melted and dissolved, it's not a planet that's going to capture any proto-colonists' imagination..
My post has nothing to do with colonizing Venus's surface. Nothing to do with the high temperatures there. Nothing to do with the high pressures there. To a Venus colony, the surface is only secondary - for exploration and low-throughput collection of valuable / low quantity minerals. Both the living area and the main source of raw materials is the atmosphere itself.
An early to mid-stage Venus colony doesn't even need a surface probe.
Also, what you wrote is hyperbole. There are plenty of materials that tolerate Venus's environment well. Two popular ones these days are PTFE and vectran. VEGA used PTFE, although modern variants involving copolymerization with for example PPVE (Teflon NXT) or HFP (Teflon FEP) perform better in a lot of key aspects. VEGA also wasn't reinforced with a high tensile ripstop; the PTFE itself was loadbearing and the balloon superpressure, which is obviously not a scalable solution (it was more like a party balloon than a blimp;) ).
It's quite possible to envisage us colonizing Mars before its terraformed too.
That is precisely what I was writing about, colonizing Venus before terraforming it.
If your issue is with people's mistaken perceptions about Venus what a colony on Venus would be like, that's indeed something I seek to change. People tend to think of Venus as its surface. But the habitable area is the middle cloud layer.
No, actually it doesn't. HAVOC has studied this, various astrobiology-potential papers have studied this, etc - I can point you to some if you'd like. The HAVOC lead author is fond of pointing out that there are places in Canada that would have a higher radiation exposure than their astronauts would be exposed to;) A colony on Venus doesn't need added radiation shielding like one on Mars or the Moon does.
(I'm not actually much of a fan of the HAVOC proposal... but it is applicable in this case)
So you set yourself up somewhere high up. How exactly do you propose to come by non-gaseous resources?
Let's compare individual resources, shall we?
Water:
Mars: frozen in permafrost, mixed in with sand and gravel, containing perchlorates, hexavalent chromium, and other toxic chemicals. Have to build and deploy a Martian equivalent of a bobcat and scrape it out (note that mining equipment is famous for high maintenance needs). If chunks are too big they need to be run through a rock crusher. They then need to be loaded into a bin and pressure sealed, then heated, with the steam driven off creating the necessary pressure for water to be able to exist at a liquid state and flow off through filters (which will need periodic cleaning); the sand and gravel has to be emptied. The contaminated saltwater now has to either be distilled or run through reverse osmosis, the latter being unfortunately rather contaminant sensitive. It's enough of a headache that most near-future proposals just call for bringing the water (or just hydrogen to make it) from Earth.
Venus: Acidists naturally condense or absorbed (see an above post on the subject) and run straight into a boiler. There they're heated. Free water is driven off and H2SO4 decomposes, emitting more water. The steam is isolated and condensed.
The latter is much easier.
Oxygen.
Mars: There are two main proposals for oxygen production. One is electrolysis. Electrolysis systems as used on ISS have however proven to be rather finnicky, and you're dependent on the water mining above to replace any water loss in the system (which will happen over time). The other proposal is to be tested on Mars 2020: MOXIE. Martian air is drawn in and compressed, troublesome impurities removed, CO2 frozen out then reboiled at pressure, then run through a SOFC which uses a lot of electricity to turn CO2 into O2 and CO.
Venus: SO3 decomposes at elevated temperatures (much faster in the presence of a catalyst) into O2 and SO2. So the only added step here over water production is the catalyst. Separation from SO2, O2, and other elsser chemicals can be done in a specialized stage or in distillation.
Again, winner: Venus.
Let's look at starting to form an industry. So, let's look at the top 10 industrial chemicals on Earth
H2SO4: This is the number one produced chemical on Earth. Do we even need to go into how much easier it would be to get on Venus? N2: Venus's atmosphere is denser than Mars's and N2 is about in the same percentage concentration, so the advantage is again to Venus. C2H4: The process is roughly the same on both Venus and Mars O2: Already covered. Chlorine (Cl2): On Venus, this is conducted by the Deacon process (4 HCl + O2 = 2 H2O + 2 Cl2). You get free HCl from distillation and you have cheap O2. On Mars, this would be done by the much more energy-intensive electrolysis of brine. Furthermore, you'd need to either isolate out brines containing specifically chlorides first. Ethylene Dichloride (C2H2Cl2): Used for PVC, which honestly isn't a great material for either Mars or Venus. The routes are basically the same on both Mars and Venus. Phosphoric Acid (H3PO4): On Venus, this comes for free during distillation. On Mars... honestly, we don't really know. We've found phosphate minerals (chlorapatite and merrillite) but no concentrations of them. Ammonia (NH3): Haber process, same on both planets. Sodium Hydroxide (NaOH): Ah, finally something Mars can win at! Various hydroxides will be produced as a byproduct of chlorine production. As far as is known, both sodium (and similar-use potassium) can't be gotten from the atmosphere (although they're abundant in any surface rocks that may be mined for other purposes - Venus's surface-mining throughput potential being lower than that of Mars'). That said, Venus lends itself perfectly to cation recycling. Any waste (plant, human, industrial
Wind speeds are only relevant to someone anchored to a fixed point. Venus's zonal winds are evenly moving air masses. There's still convective systems within them like on Earth, but it's anything but hundreds of kph shear.
Also, you overstate the velocity for the target altitude / latitude.
As for your "acid clouds" comment, I have to wonder if you've actually read what I've written. Incredulity is not a counterargument.
I can only gather from your post that you didn't actually read mine, given that you seem to think that the conversation is about living on the surface of Venus.
I would assume Martian dust isn't quite as problematic as Lunar dust is, since the former gets moved around more and hence has fewer sharp edges.
3) perchlorates; 4) hexavalent chromium;
You're not supposed to stick Martian soil in your mouth.
Martian and lunar dust have both similarities and differences. Martian dust particles are finer, athough it doesn't make them less hazardous. Despite attempts to minimize it, some exposure to the dusts will be inevitable; it's fine, ubiquitous and sticks to everything. It's well recognized as a significant hazard in mission design. One hazard of martian dust over lunar dust is that it appears to contain significant more chromium, and it's often hexavalent (a highly toxic form rarely found in nature on Earth). A number of other compounds such as arsenic appear to be of relevant risk as well.
Yes... but fail at landing, and you'll plummet into a 450 degree C hellhole. A rough landing on Mars might kill you, a rough landing on Venus kills you before you hit the surface.
Expecting to survive a crash landing on Mars is far beyond positive thinking.
The landing processes on both planets start out roughly the same. But the processes on Venus end before the hardest parts of a Martian landing end. Once you're down to under 100m/s or so on Venus, you're ready to start with deployment**. Once you're down to ~100m/s on Mars, you still have the part that's most likely to kill you remaining.
** - Although any type of reentry system works, a ballute reentry seems particularly well-suited for Venus, as it give you an initial inflation of warm, light gases. Ballute reentry has been proposed on a number of Venus proposed Venus probes, but so few Venus probes ever get funded due to Mars' domination in the budgeting process.
And Mars has quite a bit of water. More than Venus, probaly.
Not probably - it does. But it's not in the atmosphere. It's frozen in permafrost, mixed with sand and gravel and contaminated with a good number of toxic substances. And Martian backhoes aren't exactly dime-a-dozen / low-maintenance objects.
Venus's water for a colony comes from the mists. There are two potential sources: 1) direct absorption, and 2) condensation.
1) The habitat requires propulsion no matter what. This is because in addition to the strong zonal winds that comprise the superrotation, there are weaker meridional winds that would cause a craft to drift from its desired location. While the zonal winds are too strong to overcome (nor would you want to), the meridional winds are nothing particularly challenging for an airship. An aircraft under propulsive load will have a constant stream of air moving past it - fastest directly in the propeller wash. Hence, the best way to get lots of mist along lots of surface area is to handle steering with a flexible windsock-style thrust vectoring system comprised of permeable tubing for direct absorption, and/or hydrophilic collection/drainage surfaces (see #2). Hence, the collection system is little added mass over the base propulsion system. In the case of absorption, the absorption fluid would be weak H2SO4.
The ideal situation involves large volumes of air moving at (relatively) low speeds. This means a large propeller. Hence, the ideal design for launch on a mid-sized rocket involves a propeller with two 6m folding blades stowed vertically in the center of the packed habitat during launch and cruise, rather than multiple smaller propellers stacked horizontally. A large prop is also more efficient.
2) Direct collection on the envelope. While the original Vega data was interpreted as there being no condensation/rain on the balloons, some more recent work has challenged that view, suggesting that it indicates progressively increasing mass loadings as moisture collects, then peaking as runoff rates matched collection rates. This is intere
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I would expect that the speed at which they get to Falcon 9 reuse would have an impact on the Falcon Heavy schedule (that speed, in turn, being relative to the rate that they keep landing them - the more they have on hand, the more risky they can afford to be in their return-to-flight testing program for them). Falcon 9 and Falcon Heavy cores are extremely similar and made on the same lines, and the engines are identical. So the more line capacity they free up, the more they can dedicate toward the Heavy.
If you're finding this to be a recurring problem, then you might want to consider that perhaps the problem is not other people.
And the same thing applies to Venus, only even easier - plus the added convenience that you don't actually have to literally land. Once again, I'm failing to see why you keep making this statement of yours. And as long as you keep making that statement and not dealing with my reply to it, my reply is going to keep being the same. And this is going to continue to be a frustrating conversation for the both of us.
Summary of the problem you're having: saying "We're doing X, not Y because we can do X today and not Y" is a meaningless statement when we can actually do Y, and more to the point it's easier than X. If you disagree that one can do Y, you need to state reasons, rather than just being dismissive.
The fact is, as evidenced by this very discussion thread, very few people even know that it's a possibility. It's hard for people to prefer a choice that they don't even know exists. Bringing up a possibility that people are unaware of and educating them on the topic is not some form of tyranny, it's a perfectly reasonable course of action that you for some bizarre reason object to.
The scientific literature has been discussing colonizing the surface of Mars pretty much since spaceflight began. The first scientific paper on the colonization of Venus's cloudtops wasn't even written until 2003 (Landis).
The combination of some layer with Earth-surface gravity, air pressure, and temperature only exists in one other place in our solar system: Venus. Not Jupiter. Not Saturn. Not Uranus. Not Neptune. Not Titan. Just Earth's surface and Venus's middle cloud layer. On none of them is gravity near Earth norms at livable temperatures (it's only near Earth norms at liveable pressures on some of them), and on none of them exists the combination of livable pressures and temperature at any altitude.
And beyond all this, have you ever looked at transit times, launch windows, and delta-V requirements for Saturn? The local solar constant? How exactly do you plan to float a balloon of breathable air in hydrogen anyway? What's your local resource production tree?
Of course you don't have answers to any of these things because you weren't actually serious, you were just being dismissive of Venus - even though answers to a huge variety of topics related to a Venus colony have been discussed on this thread, and I'd be happy to discuss more. But again, you don't care about that either, you just want to be dismissive without having to substantiate your reasons.
You do realize that radiation is one of the many reasons that Mars is a more difficult colonization target than Venus, right?
The most reasonable route would still be LA to Vegas first. Then SF to LA. Then Reno would be in trouble. Seriously, if people could hop a $20 ride/half hour ride to LA and then another one to Vegas, who would go to Reno? Reno would pretty much have to build a route of their own. But that wouldn't be easy, the terrain between Sacramento and Reno is pretty much custom-designed to be hostile to any form of high-speed surface travel. You'd have to take the Japan approach (drill through every mountain, bridge the gaps in-between). And I'm sure there'd be environmental sensitivity to such an approach.
Hmm, what's probably the easiest route... because I-80 is just so windy. Maybe US-50 east of Sacramento. There'd be reduced speed / minor tunnels / bridges from Placerville to Riverton, but spend most of the next leg through the mountains in a fairly straight valley and could probably just hug a wall and change tower heights... up until you get near Sierra-At-Tahoe, which would definitely need tunnels/bridging... maybe over to 89, bridge down to Sorensens, reduced speed through the valley around to Alpine Village, and then you're out onto the open plains for a final acceleration segment to the north (with slowdowns past Carson City). Hmmm.. honestly, I'm not sure that's any better than I-80.
Earthquakes make surfaces rough? That's news to me.
I assume you actually mean "out of alignment". Wherein, you need to read the Hyperloop Alpha document, they spend a good bit of time talking about isolation, maintaining alignment, and earthquake resistance.
That's the very reason for elevating it and designing the route to follow highways - to avoid most "politics and NIMBY and right-of-way." Well, that and the simplification of handling small elevation fluctuations.
That said, it's fair to point out that Hyperloop isn't a 1 for 1 substitution for HSR in terms of functionality; it's more like a functional intermediary between HSR and plane travel (but designed to be far cheaper and lower energy consumption than either). Air travel is very high speed, low capacity, low capital cost for new routes, direct point to point, no stops, limited in-town accessibility. HSR is low (by comparison) speed, high capacity, high capital cost for new routes, high in-town accessibility and numerous stops. Hyperloop is moderate (by comparison) speed (although closer to air than rail), moderate capacity, moderate in-town accessibility (it can be extended further into town than air travel can, but it faces some speed reduction), and while easier to have stop at intermediary points en route than aircraft is harder than HSR.
I think SpaceX erred in presenting it as an "alternative to HSR" - I feel they should have presented it as something new altogether. Rather than run LA to SF, I think they should have done a LA to Vegas route. HSR fans wouldn't feel threatened. Casino owners would go nuts for the Los Angeles market to be able to pop down to a station on a Friday night on a whim, pay $20, and half an hour later be blowing their money on slots. There's less vested interests in having intermediary stops on the route. Etc. But I know that doesn't interest Musk as much because he spends a lot more time in SF than Vegas.
Note: everything I write below pertains only to Hyperloop Alpha. As for whatever else passes as "Hyperloop" these days, I have no comment.
Made of segments with two welds, polished, versus a single orbital weld, polished.
We make long cylindrical pressure vessels all the time. They're called pipelines. No, they don't cost a fortune (relative to the cost of HSR). Their cost/(cross section * length) ratio is similar to that proposed for Hyperloop. Of the differences, they're mixed pros and cons. For example, hyperloop doesn't carry toxic chemicals - permitting / environmental review (a major cost) should be far easier. But Hyperloop requires much straighter segments and requires internal polishing. Hyperloop doesn't deal with elevated temperatures and doesn't have to pump fluids. But it still has to have accelerator segments. It doesn't have liquid terminals, but it does have capsule terminals. Etc.
I ran the calculations on the volume of steel described in the Hyperloop Alpha proposal and compared them to current billet steel costs. The cost was a small fraction of what the proposal budgeted. For manufactured segments, delivered, they're probably right on.
The cost of elevating a track is almost directly proportional to its peak loading. The peak loading of Hyperloop is an order of magnitude less than that of HSR.
Cost estimates are not based on "feelings".
Aerodynamic drag force does. 1/2 rho Cd A v^2. Of course, power is force times velocity, so that's cubic. But the (change in) energy is force times distance, and distance for the trip is constant, so it's only quadratic with velocity.
Assuming a constant Cd, of course.
As per Hyperloop Alpha, air bearings produce significantly less drag than maglev for the given application. As for the bulk air, in Hyperloop Alpha, the compressor shunts air ahead of the vehicle to behind it (it's exceedingly sparse). Lastly, in Hyperloop Alpha, total drag was so low that propulsion segments were only needed rarely, very spaced out along the track.
Of course, the new competitors are so different from Hyperloop Alpha as to render the term "Hyperloop" meaningless.
Though the Hyperloop air bearings provided a solution that's cheap per unit distance and very low drag, they were not without flaws. Foremost was the very narrow gap (0,5-1,3mm) between the bearings and the walls (needed for high lift at low pressures/drag). That said, those gaps are positively gargantuan compared to some air bearing applications - hard drive air bearings float at heights often no more than a couple nanometers over the surface. But that still means close tolerances. Hyperloop Alpha's solution for construction was a polishing robot that drives down the tunnel with a circular polisher, grinding off any unevenness in the welds or the bulk pipe. Achieving 0,1-0,5mm tolerances with such a system isn't particularly far fetched.
No harder than a high pressure tube that's hundreds of miles long (pipeline), and we do that all the time. The cost of the steel for the proposed route isn't much over $1B, if I recall the numbers correctly.
It was. I don't even know what "Hyperloop" is supposed to mean anymore, as SpaceX held an official Hyperloop competition and selected as winners craft that were absolutely nothing like in the Hyperloop Alpha design. Their test track is designed to allow for all kinds of vehicles, maglev or not... but most of the teams were focused on maglev. No compressors, either, meaning that they can't shunt air from in front to behind, meaning either high drag or requiring a hard vacuum for operation.
I personally find the deviations from the Hyperloop Alpha design to basically ruin the entire concept.
On a test track, the G forces are irrelevant.
There's a very long list of jobs to do on a Venus colony - some quite high tech, some that would be right at home in the pioneer days.
Early on at least, since every new bit of robotics infrastructure you want to develop comes with a sizeable price tag and even here on Earth robotic agriculture is a serious challenge, agriculture would be conducted by hand. Planting, inspections, harvesting, potentially even pollenation. Some agricultural tasks are less obvious - for example, mushroom farming, or potentially even beekeeping.
All agricultural products are in their raw state. Want to fry something? You better press your oil first. Want to make bread? You first have to thresh/winnow the grain and grind it in a flour mill. Etc. Speaking of bread, you have to keep a live yeast culture, just like was done in primitive times, because you can't just run to the store to pick up a packet of yeast.
Concerning cooking in general - feeding a whole crew, combined with the significantly increased labour of food processing, makes this a full time job. Some "cooking" tasks aren't even edible. Soap, for example, would be made just like in the "olden days" - ashes from the incinerator boiled with fat. Even paper-making (if you don't want to wipe with plant leaves/your hand/a reused brush, and don't think a bidet alone is enough, then you need this) is a kitchen task - fibrous plant matter soaked with ash hydroxides, strained in cheesecloth, blended, then pressed in a cheese press or manually spread/pressed on tensioned cheesecloth.
For a colony that wants to survive on agriculture, and where that agriculture is being conducted in a very different environment, botany / plant science is an important skillset for a crew member. Another important position is a medical staff member. Venus is too far for telemedicine, and people can't simply return to Earth for treatment. The same individual would also double as a compounding pharmacist, dentist and, when livestock raising begins veterinarian. Speaking of livestock, caring for them is no trivial chore.
All habitats will require maintenance. On Venus, you need to clean plant debris, remove any accumulated dust / grime on the envelope, make repairs as needed, and near end-of-life do major reconstruction in sections. There's ample mechanical and particularly chemical systems, to the point that you may even want a full time chemical engineer on hand, to not only maintain but also expand systems for progressively increasing local production capability. New hardware sent from earth requires installation. A small machine shop is needed for fabrication, with trained operators. Heck, even janitorial services are needed. And some chores will be less pleasant than others. The toilet, for example, would compost and/or dehydrate solid waste, but eventually you're going to have to bring it to the incinerator. Don't expect people to pay for the development and launch costs of a "robotic butler" to do all of the work for you.
Obviously researchers are going to be wanted. The more data you can gather from samples locally, the less you need to send to Earth (and the more selective you can be about what you send). On Venus, surface probes need low-latency operators; commands sent from Earth would have totally impractical round trip times when your total dive time can be no more than a couple hours. Surface probes need to be docked, unloaded, and samples hauled up to the lab and processed. The same laboratory hardware doubles as a chemistry lab for production of small batch-scale chemicals, everything from medicines to catalysts and so on down the line.
For quite some time, most effort would simply be directed toward trying to improve crew safety, sustainability / self sufficiency, and comfort. When these needs are met, however, a huge need for increased labor arises in terms of local production of new habitats. All of the huge numbers of components you already have? You need to make more of them - and bigger. No matter how much money you spend on trying to develop robotic systems to assist you, much of the construction work is still going to require humans. Quite a lot of them.
I could keep going, but I think you get the picture.
Storms are driven by convective potential energy, not how fast the bulk of the winds are moving relative to a surface 50km away. :) Just like how an aircraft flying within a fast-moving jet stream on Earth is usually more stable than flying lower down in the atmosphere. Most of Venus's atmosphere is, like Earth's stratosphere, dynamically stable. However, there are some layers - among them, the middle cloud layer (the habitable zone) where convective potential exists. While our experience directly flying within this layer is limited to just Vega (combined with remove observations), it appears to be roughly similar to Earth's troposphere.
If you want more specifics about Vega's measurements of turbulence: 2 balloons, 54km, 60-hour design lives (battery-powered), different parts of the planet. Vega 1's peak velocity fluctuations were about 2m/s. Vega 2's were about 1m/s. Most of the time it was significantly less. There were calm intervals and turbulent intervals. There were both small scale turbulent patches and large-scale ones. The small scale patches were about 30-130 seconds, fairly abrupt transitions, random timing. The larger ones were more periodic / slower transition, 30-90 minutes. These are interpreted as different kinds of convection cells - the small ones several hundred meters across, and the larger ones tens of kilometers across. Mariner, meanwhile, was monitoring the clouds at the balloon locations and visually spotted cloud features corresponding to the more turbulent episodes. This is extremely useful, as it gives us a way to assess the conditions in Venus's atmosphere over much longer timescales even though we no longer have any probes floating in it (that said, we definitely still need more long-term prep missions! :) ).
If you were to drop random balloon probes at the 500mb level on Earth, getting the sort of turbulence data that was received from Vega would not be at all unusual - it's neither abnormally high nor low. Nor has satellite data indicated that the Vega balloons were in some sort of abnormally calm timeperiod.
Nor do you use just one engine to drive the prop :) A common approach with electric aircraft motors is designs that can be chained end to end, either with a common central rotor, or linked outer rotors in the case of outrunners. Look up, for example, the EMRAX series by ENSTROJ. Each one would have its own independent inverter, and ideally the drive current would be split among multiple cables, each linked to a solar bank in a different portion of the lower portion of the craft (solar is directly printed onto the plastic, using it as a substrate; PTFE is common in usage with solar already)
Permeation is one of those things which people tend to forget - I'm sure you've noticed that helium party balloons, for example, don't stay full forever ;) No plastic membrane is fully immune, although there's a wide variation. Sometimes people ask why the Vega balloons weren't fitted with solar panels - it wasn't simply about having to add solar, but also about the extra helium they'd need to compensate for leaks. Vega was from old-school PTFE, which is fairly porous (which, combined with its hydrophobic nature is why it makes breathable waterproof fabrics when expanded, ala Goretex
Venus's diameter (at height) at 70 degrees/54km latitude divided by VIRTIS and VERA data on zonal winds at 70 degrees.
Winds do drop off as one approaches the poles, but not as fast as the radius of travel diminishes, so the day length shortens.
Yes. Venus's atmosphere undergoes "superrotation", in that it rotates significantly faster than Venus's surface. It's sort of like having a planetwide jet stream (although it's not constant velocity, as mentioned previously, there are altitude/latitude differences)
Yes, the above is just about zonal (planet-circling) winds. There's also meridional winds (toward the poles and equator) as well as vertical flows. Propulsion is needed to overcome the meridional winds. Vertical winds - as well as changes in craft mass due to local production and buoyancy changes due to temperature, also have to be compensated for (except in superpressure balloons, but those are far too heavy for large scale operations). The two main means for this (without discharging mass and the like) is to have an ammonia-water phase change envelope located within the ballonets, against the outer wall (to avoid the risk of ammonia permeation into the living envelope). This passive stabilization system has been tested here on earth with ALICE - as the altitude drops, increasing amounts of ammonia boil off, increasing lift, while at higher altitudes it condenses out. .
A note: while there is an overpressure, it's small - a couple hundred pascals. Not really much of a pressure vessel, and only a source of slow leaks in the case of a rupture. Also, it's extremely difficult to actually sink it; there's a tremendous amount of ballast (most of the craft's weight) that can be dropped - surplus water, locally produced hardware for maintenance / construction of new habitats, return-rocket propellant (the heaviest single element), and in the worst case, the return rocket itself. The habitat can be reduced to a tiny fraction of its original mass. It's also possible to create more lift via venting collected/produced breathable gases into the envelope, unbreathable gases into the ballonets, etc - as well as using propulsion for lift (during the daytime, at least)
Very, very hard to sink.
As a side note: contrary to what one might expect, the safest place (and lowest-mass configuration) for the living space is near the top of the envelope, not the bottom. From a mass perspective, it shortens the cables hanging from the top catenary curtains, which is a mass savings. From a stability perspective, you want the ballonets taking up most of the bottom. And from a simple safety reason, in the event of a severe leak, CO2 would pool at the bottom of the envelope; you don't want it smothering people.
They don't. The speeds are fast relative to the surface, but that's over 50 kilometers away. Some degree of surface effects have been shown to propagate up to the cloud deck over Ishtar Terra (gravity waves), but they're weak.
You may note that Earth's jet streams are also very fast, yet they're popular for passenger jet travel. And they're far closer to the surface.
The conditions in Venus's cloud deck aren't speculative - we've actually flown there (see VEGA). Not for very long, but enough to get a general sense. The atmospheric conditions there are fairly reminiscent of flight in Earth's troposphere, with periodic storms separated by regions of calm. Als
One of my favorites of the more recent ones was the big hoopla over "Liquid water found flowing on the surface of Mars!" - which would have more accurately been headlined as, "Transient damp, toxic rocket propellant found flowing on the surface of Mars" ;)
I do find astrobiology quite interesting. But I've seen little to come out of most Mars astrobiology work other than overblown press releases. Tiny amounts of methane (a common volcanic gas) and the like doesn't do it for me.
The biggest factor in space travel is energy. To get to Mars you need 6.5km/s worth of evergy (E=1/2mv^2). To get to Venus, you need 12.7km/s of energy, almost twice as much). This is spent slowing down to fall towards the sun.
Slowing down lowers your orbital radius while speeding up increases it up to sqrt(2) orbital speed (at your current orbital radius) which will send you off to infinity, aka escape velocity.
This is incorrect. A LEO-to-Mars-intercept trajectory and LEO-to-Venus-intercept trajectory take an almost identical amount of delta-V - about 4,7km/s for Mars and 4,2km/s for Venus (the exact delta-V depends on what sort of assumptions you make, so you'll see some variation in reported figures; these are on the more pessimistic end). You're probably confusing some combination of "from the surface of Venus to LVO" delta-Vs and/or assuming capture by retroburn rather than aerocapture.
You meant sarcasm, but you're precisely correct. Earth's jet streams are upwards of 400kph. Airplanes deliberately fly in them whenever possible.
As multiple people have pointed out to you, you're mixing up wind speeds relative to the surface with turbulence. Venus has high wind speeds relative to its (almost stationary) surface. It does not have high turbulence (as far as we've sampled thusfar) in it. The speed of the air mass relative to a surface over 50 kilometers below it is practically irrelevant.
Already more than well addressed elsewhere in this thread.
It may surprise you to learn that we have plenty of chemicals that are essentially completely inert in strong acids. PTFE (Teflon), probably the most famous, is much easier to describe by what it's not inert to than what it is inert to. But the list hardly stops with it.
The real problem is not reactivity, it's permeation. But modern PTFE copolymers like NXT and FEP keep it down to reasonable levels, and liquid crystal polymers like vectran even lower.
And yes, there has been ample lab work, both in the US and Russia/USSR, including a wide range of constructed and tested balloons. And actual flown PTFE balloons on Venus (only designed for short-term operation, but enough to gather data).
I have trouble reconciling your post with you having read mine. You wrote:
My post has nothing to do with colonizing Venus's surface. Nothing to do with the high temperatures there. Nothing to do with the high pressures there. To a Venus colony, the surface is only secondary - for exploration and low-throughput collection of valuable / low quantity minerals. Both the living area and the main source of raw materials is the atmosphere itself.
An early to mid-stage Venus colony doesn't even need a surface probe.
Also, what you wrote is hyperbole. There are plenty of materials that tolerate Venus's environment well. Two popular ones these days are PTFE and vectran. VEGA used PTFE, although modern variants involving copolymerization with for example PPVE (Teflon NXT) or HFP (Teflon FEP) perform better in a lot of key aspects. VEGA also wasn't reinforced with a high tensile ripstop; the PTFE itself was loadbearing and the balloon superpressure, which is obviously not a scalable solution (it was more like a party balloon than a blimp ;) ).
That is precisely what I was writing about, colonizing Venus before terraforming it.
If your issue is with people's mistaken perceptions about Venus what a colony on Venus would be like, that's indeed something I seek to change. People tend to think of Venus as its surface. But the habitable area is the middle cloud layer.
You know, you could actually read the post. Something that you still clearly have not done.
Dang it, I knew I overlooked something! ;)
No, actually it doesn't. HAVOC has studied this, various astrobiology-potential papers have studied this, etc - I can point you to some if you'd like. The HAVOC lead author is fond of pointing out that there are places in Canada that would have a higher radiation exposure than their astronauts would be exposed to ;) A colony on Venus doesn't need added radiation shielding like one on Mars or the Moon does.
(I'm not actually much of a fan of the HAVOC proposal... but it is applicable in this case)
Let's compare individual resources, shall we?
Water:
Mars: frozen in permafrost, mixed in with sand and gravel, containing perchlorates, hexavalent chromium, and other toxic chemicals. Have to build and deploy a Martian equivalent of a bobcat and scrape it out (note that mining equipment is famous for high maintenance needs). If chunks are too big they need to be run through a rock crusher. They then need to be loaded into a bin and pressure sealed, then heated, with the steam driven off creating the necessary pressure for water to be able to exist at a liquid state and flow off through filters (which will need periodic cleaning); the sand and gravel has to be emptied. The contaminated saltwater now has to either be distilled or run through reverse osmosis, the latter being unfortunately rather contaminant sensitive. It's enough of a headache that most near-future proposals just call for bringing the water (or just hydrogen to make it) from Earth.
Venus: Acidists naturally condense or absorbed (see an above post on the subject) and run straight into a boiler. There they're heated. Free water is driven off and H2SO4 decomposes, emitting more water. The steam is isolated and condensed.
The latter is much easier.
Oxygen.
Mars: There are two main proposals for oxygen production. One is electrolysis. Electrolysis systems as used on ISS have however proven to be rather finnicky, and you're dependent on the water mining above to replace any water loss in the system (which will happen over time). The other proposal is to be tested on Mars 2020: MOXIE. Martian air is drawn in and compressed, troublesome impurities removed, CO2 frozen out then reboiled at pressure, then run through a SOFC which uses a lot of electricity to turn CO2 into O2 and CO.
Venus: SO3 decomposes at elevated temperatures (much faster in the presence of a catalyst) into O2 and SO2. So the only added step here over water production is the catalyst. Separation from SO2, O2, and other elsser chemicals can be done in a specialized stage or in distillation.
Again, winner: Venus.
Let's look at starting to form an industry. So, let's look at the top 10 industrial chemicals on Earth
H2SO4: This is the number one produced chemical on Earth. Do we even need to go into how much easier it would be to get on Venus?
N2: Venus's atmosphere is denser than Mars's and N2 is about in the same percentage concentration, so the advantage is again to Venus.
C2H4: The process is roughly the same on both Venus and Mars
O2: Already covered.
Chlorine (Cl2): On Venus, this is conducted by the Deacon process (4 HCl + O2 = 2 H2O + 2 Cl2). You get free HCl from distillation and you have cheap O2. On Mars, this would be done by the much more energy-intensive electrolysis of brine. Furthermore, you'd need to either isolate out brines containing specifically chlorides first.
Ethylene Dichloride (C2H2Cl2): Used for PVC, which honestly isn't a great material for either Mars or Venus. The routes are basically the same on both Mars and Venus.
Phosphoric Acid (H3PO4): On Venus, this comes for free during distillation. On Mars... honestly, we don't really know. We've found phosphate minerals (chlorapatite and merrillite) but no concentrations of them.
Ammonia (NH3): Haber process, same on both planets.
Sodium Hydroxide (NaOH): Ah, finally something Mars can win at! Various hydroxides will be produced as a byproduct of chlorine production. As far as is known, both sodium (and similar-use potassium) can't be gotten from the atmosphere (although they're abundant in any surface rocks that may be mined for other purposes - Venus's surface-mining throughput potential being lower than that of Mars'). That said, Venus lends itself perfectly to cation recycling. Any waste (plant, human, industrial
Wind speeds are only relevant to someone anchored to a fixed point. Venus's zonal winds are evenly moving air masses. There's still convective systems within them like on Earth, but it's anything but hundreds of kph shear.
Also, you overstate the velocity for the target altitude / latitude.
As for your "acid clouds" comment, I have to wonder if you've actually read what I've written. Incredulity is not a counterargument.
I can only gather from your post that you didn't actually read mine, given that you seem to think that the conversation is about living on the surface of Venus.
Martian and lunar dust have both similarities and differences. Martian dust particles are finer, athough it doesn't make them less hazardous. Despite attempts to minimize it, some exposure to the dusts will be inevitable; it's fine, ubiquitous and sticks to everything. It's well recognized as a significant hazard in mission design. One hazard of martian dust over lunar dust is that it appears to contain significant more chromium, and it's often hexavalent (a highly toxic form rarely found in nature on Earth). A number of other compounds such as arsenic appear to be of relevant risk as well.
Expecting to survive a crash landing on Mars is far beyond positive thinking.
The landing processes on both planets start out roughly the same. But the processes on Venus end before the hardest parts of a Martian landing end. Once you're down to under 100m/s or so on Venus, you're ready to start with deployment**. Once you're down to ~100m/s on Mars, you still have the part that's most likely to kill you remaining.
** - Although any type of reentry system works, a ballute reentry seems particularly well-suited for Venus, as it give you an initial inflation of warm, light gases. Ballute reentry has been proposed on a number of Venus proposed Venus probes, but so few Venus probes ever get funded due to Mars' domination in the budgeting process.
Not probably - it does. But it's not in the atmosphere. It's frozen in permafrost, mixed with sand and gravel and contaminated with a good number of toxic substances. And Martian backhoes aren't exactly dime-a-dozen / low-maintenance objects.
Venus's water for a colony comes from the mists. There are two potential sources: 1) direct absorption, and 2) condensation.
1) The habitat requires propulsion no matter what. This is because in addition to the strong zonal winds that comprise the superrotation, there are weaker meridional winds that would cause a craft to drift from its desired location. While the zonal winds are too strong to overcome (nor would you want to), the meridional winds are nothing particularly challenging for an airship. An aircraft under propulsive load will have a constant stream of air moving past it - fastest directly in the propeller wash. Hence, the best way to get lots of mist along lots of surface area is to handle steering with a flexible windsock-style thrust vectoring system comprised of permeable tubing for direct absorption, and/or hydrophilic collection/drainage surfaces (see #2). Hence, the collection system is little added mass over the base propulsion system. In the case of absorption, the absorption fluid would be weak H2SO4.
The ideal situation involves large volumes of air moving at (relatively) low speeds. This means a large propeller. Hence, the ideal design for launch on a mid-sized rocket involves a propeller with two 6m folding blades stowed vertically in the center of the packed habitat during launch and cruise, rather than multiple smaller propellers stacked horizontally. A large prop is also more efficient.
2) Direct collection on the envelope. While the original Vega data was interpreted as there being no condensation/rain on the balloons, some more recent work has challenged that view, suggesting that it indicates progressively increasing mass loadings as moisture collects, then peaking as runoff rates matched collection rates. This is intere