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Atomic Oxygen Detected In Martian Atmosphere (cnn.com)
An anonymous reader quotes a report from CNN: Atomic oxygen has been detected in the atmosphere of Mars, according to NASA. The atoms were discovered in the Martian mesosphere, the upper layers of the red planet's atmosphere. This discovery will enable researchers to have a better understanding of the elusive Martian atmosphere. Atomic oxygen can help scientists determine atmospheric erosion and how other gases escape Mars. It also affects the radiative cooling from the carbon-dioxide bands in the Martian thermosphere, which is above the mesosphere. The atomic oxygen discovery was made using an instrument on board the Stratospheric Observatory for Infrared Astronomy, or SOFIA. SOFIA is a Boeing 747SP jet that has been modified for research purposes to carry a 100-inch diameter telescope. Using the German Receiver for Astronomy at Terahertz Frequencies, known as GREAT, allowed researchers to distinguish between oxygen from our atmosphere and that of the Martian atmosphere. They discovered half the amount of atomic oxygen expected, most likely due to variations in the atmosphere itself, and scientists will continue to use SOFIA to study the Martian atmosphere.
Quick! Send in the homeopathic astronauts!
Because Venus sure as hell isn't any better (92 times the atmospheric pressure, 400 degrees hotter, sulphuric acid clouds, etc.) even if it is closer, and Mars is further from the Sun than Earth (1.5 AU instead of 1 AU).
Hence it's the nearest sensible suggestion and we have to deal with radiation on ANY long space trip anyway because there's not much like Earth's protection anywhere else. If we can't cope with the radiation on Mars, we might as well just give up now.
Because Venus sure as hell isn't any better
If only there was a suitable planet between Mars and Venus....
Klingons circling Uranus?
From a practical standpoint, colonizing the moon makes more sense than Mars. But humans are not practical animals, and they find Mars more interesting.
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Venus is far better than Mars. Specifically, Venus's cloudtops - say, 54km altitude, 70 latitude (poleward might be even better, but you start facing more risk from the polar vortices, so we'll just compare 70). Earth by comparison will be equatorial, and Mars will be surface-average.
Gravity (earth relative): Earth: 1.0; Mars: 0.38; Venus: 0.9
Air pressure (atm): Earth: 1.0; Mars: 0.006; Venus: 0.5
Temperature (avg, C): Earth: 26; Mars: -30; Venus: 31
Daily variation (C): Earth: 4-30; Mars: 90; Venus: 15
Day length: Earth: 24; Mars: 24.5; Venus: 48
Ability to relocate / explore new terrain: Earth: moderate; Mars: poor; Venus: high
Overhead radiation shielding mass (meters H2O equivalent): Earth: 10,3; Mars: 0.36; Venus: 5.2
Magnetic field: Earth: 25-65uT, intrinsic; Mars: induced, 20-40nT MPR, 5-20nt magnetosheath; Venus: induced, 40-80 nT MPR, 10-40nT magnetosheath
Health hazards: Earth: those humans evolved to; Mars: 1) Fine, abrasive electrostatic dust, 2) silicosis; 3) perchlorates; 4) hexavalent chromium; 5) other chemical hazards; Venus: 1) Corrosive acid mists; 2) hydrogen fluoride; 3) probably others of relevance
Other local hazards: Earth: those humans evolved to; Mars: marsquakes, landslides, dust storms, probably others. Venus: poorly understood - lightning (although we don't know at what altitude), gusts/shear (probably Earthlike, but poorly quantified), icing (probably not, but maybe), possibly others. Needs more study, but Mars gets the lion's share of the planetary exploration budget and everything else competes for the scraps.
Delta-V to habitable area from LEO (km/s, aerocapture assumed): Earth: 0; Mars: 4.7; Venus: 4.2
Delta-V from habitable area to LEO (km/s, aerocapture assumed): Earth: 9.8; Mars: 10.0; Venus: 15.5
Transit time (months): Earth: 0; Mars: 9; Venus: 5
Launch window frequency (months): Earth: 0; Mars: 25; Venus: 19
Landing difficulty: Earth: moderate (dense atmosphere, oceans to land in, compacting soil, readily available rescue); Mars: hard (reversed conditions of Earth): Venus: easy (no landing at all; your landing ellipse is "a large chunk of the planet")
Solar energy (29% triple-junction W/m): Earth: 290; Mars: 45; sometimes almost none; Venus: 400
Capturable wind energy: Earth: moderate; Mars: effectively none; Venus: high
Diversity / value of resources: Earth: moderate (that which we're used to); Mars: probably less than Earth, but not "poor"; Venus: the planet acts as a natural refinery, baking / dissolving minerals from rocks and redepositing them in other forms; surface appears to be highly enriched in "incompatible elements" (many of which are rare and valuable on Earth) and the planet is highly enriched in deuterium.
Accessibility of resources: Earth: moderate (that which we're used to); Mars: like Earth, but hindered by mobility and the difficulty of removing overburden; Venus: mixed high/low; a large resource base is available to be drawn directly from the atmosphere and which can be distilled /decomposed by simple heating/cooling (for example, 85% H2SO4 -> H2O + O2 + SO2) - the list of known/likely elements in the clouds is very long, even involving significant iron in the form of iron chlorides). However, surface access requires heat-tolerant phase change balloons (the high atmospheric density makes "dredging" with the same fan used for maneuvering a reasonable approach)
Venus is grossly underappreciated as a destination for human settlement, and for exploration in general. Normal Earth air is its own lifting gas. Rather than living in a cramped pressure vessel, colonists would be living in an expansive, bright space perfect for cultivation. Don't like one of your coworkers? Go hang your "room" from a catenary cable on the opposite side of the habita
Monkeywrench Ex Machina.
Also note that if you were to concentrate Martian air to 1ATM and simply add oxygen to reach an Earthlike O2 partial pressure, it would be highly toxic. 1% CO2 causes drowsiness, while 7-10% is lethal. Also, Mars's atmosphere is 0.0557% carbon monoxide, which while not acutely lethal is well above the toxicity limit where acute symptoms and irreversible, accumulative neurological damage occurs.
Monkeywrench Ex Machina.
In simplest terms, it is single atom oxygen molecules, or O, whereas normal oxygen we think of is O2, and Ozone is O3.
A real engineer will only say "not possible" if the laws of physics need to be broken. Otherwise, you'll probably get a quote. It might be completely unaffordable, though.
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
Monkeywrench Ex Machina.
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.
Monkeywrench Ex Machina.
I hope it doesn't explode.
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
Monkeywrench Ex Machina.
Thag: Someday, man will fly through the air, like a bird!
Grak: When, Thag?
Thag: In five years, or ten an the most!
Grak: That's impossible, Thag. You're talking like Arl after that wildebeest kicked him in the head.
Varg: Shut up, you two! You're scaring off the antelopes!
There was.
Then we started to turn the clouds sulphuric and potentially initiated runaway greenhouse effects which started to turn it into an inhospitable barren desert with un-survivable atmospheric heat.
Or was that Venus again, I forget?
It would be far easier to colonize the oceans on this planet than the surface of Mars.
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.
Monkeywrench Ex Machina.
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).
Monkeywrench Ex Machina.
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.
Monkeywrench Ex Machina.
Most scientists are against manned spaceflight.
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
Monkeywrench Ex Machina.
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.
Monkeywrench Ex Machina.
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?
Monkeywrench Ex Machina.