Venus

Void · 2024-08-17 10:39:16

Greater minds than mine have looked into "Dynamic Soaring" at the Heliopause.

I think that such thinking may have merit for both Venus and Mars.

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Physics > Space Physics
[Submitted on 26 Nov 2022 (v1), last revised 29 Nov 2022 (this version, v2)]
Dynamic Soaring as a Means to Exceed the Solar Wind Speed
Mathias N. Larrouturou, Andrew J. Higgins, Jeffrey K. Greason

So, inertia of the device that would soar, is not the same sort of concern as for trying to accelerate a load to outer reaches beyond the edge of the solar wind.

Since orbit of an object is basically an energy storage opportunity, the device may not have to be as dry mass consirvative.

But much more to learn.

Done

Last edited by Void (2024-08-17 10:45:09)

Void · 2024-09-27 07:18:16

I have been traveling, fishing, and dealing with a computer malfunction, so I want to see if I can do a post.

I have been observing the site a bit by other means though, and was stimulated by this topic from kdb512: https://newmars.com/forums/viewtopic.php?id=10892

My parallel solution would not fit into that topic without disrupting it, so I will do it here.

Caliban has also provided stimulation as well, in a notion to send ice chunks to a sun orbit from Ceres that would eventually intercept Mars.

Here though I am thinking about Carbon to bombard Mars. The Carbon to be from Venus. The process could also have a separate method to deliver Nitrogen from Venus, at greater trouble.

Carbon from Venus, joined to molecules of solids from asteroids could support a one planet form of cycling spaceship, to deliver the Carbon.

The cyclers (Many) would be tied to Mars but should be convenient to receive materials from Venus. Just for giggles lets say you would have one for each day of a Mars year. They would not seek to intercept another planet, only Mars.

Materials delivered from Venus by some methos could intercept one of these as might be convenient, and eventually all of them in turn.

So, this leaves two questions. How do you get the materials from Venus to the cyclers? How can you do things we might consider beneficial to Mars with Carbon?

I will address a possible method to get the materials from Venus. I am thinking that in the orbit of Venus, if you can capture CO2, you can build things with Carbon. As for the Oxygen it is a common substance, and can be more used as a propellant. An Oxygen Mass Driver is one possibility.

A substance that it might be possible to construct with in microgravity could be Carbon Aerogel.
https://en.wikipedia.org/wiki/Aerogel
Quote:

Carbon aerogels are also extremely "black" in the infrared spectrum, reflecting only 0.3% of radiation between 250 nm and 14.3 μm, making them efficient for solar energy collectors. The term "aerogel" to describe airy masses of carbon nanotubes produced through certain chemical vapor deposition techniques … See more

But I think that the creation process for that is tedious. I am wondering if 3D printing could produce a similar structure.
It does not have to be as good at insulation as Aerogel but does need to be porous. Rocket Lab indicates that they have a fast creation process to build Neutron Rocket. So, other structures might be made of Carbon as well.

But also, in the orbit of Venus, it might be possible to aerobrake materials from asteroids to an orbit of Venus.

So giant bubbles of materials with a outer structure resembling Aerogel could be put into orbit of Venus, at a location where they may intercept thin atmosphere.

The Pseudo-Aerogel, being porous such molecules will intercept and penetrate the Aerogel, and tend to adopt the orbital characteristics of the devices. Of course, makeup propulsion methods will have to keep the "Bubbles" in orbit.

To assist visualization, imagine a cylinder constructed, with each flat end pointed to the solar polarities, of North and South. These flat faces could be quite cold, perhaps cold enough to condense CO2 as a frost.

But the cylindrical walls will be the Pseudo-Aerogel collectors.

So, then if you could condense CO2, that can be processed into Oxygen and Carbon. Oxygen can be shot out of a Mass Driver for propulsion. It is likely that some other gasses will be collected such as Nitrogen. I will not yet suggest how to collect those, but methods are likely possible.

I also suspect that materials like Atomic Oxygen will erode the Carbon structures, so, a method to repair them continuously will be wanted, perhaps 3D printing robotic devices.

So presuming Carbon can be refined from the atmosphere of Venus in this way, then a product to deliver to Mars would exist.

Methods to deliver the Carbon to the cyclers would be possible, I suggest making a solar sail out of Carbon, as some notion. Not very efficient I expect, but even so, with time and patience the Carbon could arrive at the Cycler. But it now occurs to me that the Carbon could in fact go to Mars on its own. That would be simpler of course. So, I may have destroyed the need for the Cyclers.

Anyway, upon arrival at Mars, we expect a collision with the Atmosphere. And a burning process. This may cause the creation of Carbon Monoxide, but possible some of the Carbon would crash onto a surface.

By adding Carbon to the Atmosphere of Mars you increase the air pressure, but of course you make it more toxic. It was already toxic from CO and for that matter CO2.

But we have added to two substances that biology can live on CO, and Carbon. As these can be added to a body of water that is anoxic, then biology can use the CO and Carbon as a fuel, and extract Oxygen from the Water and from stony materials such as Dune Materials. They would then produce CO2 to add to the Atmosphere.

As for the Atmospheric collectors around Venus, I think that if Carbon sheets could be delivered to Earth orbits and our Moon, then interesting things could happen such as collecting air from the Earth's upper atmosphere, and of course Carbon on the Moon would be very valuable.

Ending Pending

Seems like I can post with this computer now.

Ending Pending

Last edited by Void (2024-09-27 07:56:10)

Void · 2024-12-16 12:06:24

The first part of this video to some degree supports the idea that Venus never had habitable oceans.
https://www.bing.com/videos/riverview/r … ORM=WRVORC
Quote:

Venus Was NEVER An Ocean World…And More. (This Week In Space)
YouTube
Celestium (Formerly Astrographics)
962 views
4 hours ago

This is important, as the theory of the "Runaway Greenhouse Effect" was as I perceive it originated with a theory of why Venus is as it is that depended on Venus having a habitable period before now.

That theory has then been used by Socialist Globalists to do power grabs based on saving the planet Earth.

I do actually believe that greenhouse gasses can warm the Earth. However, there are forces that depend on the power they claim based on an impending disaster, which I am NOT! 100% sure is a real "Disaster". I am inclined to think that it may be a "Problem", and potentially a "Big Problem".

As for life in the clouds of Venus, I would still not rule it out as Panspermia, might have put it there from another world.
Yes, an extreme long shot though

For instance Mercury could have had a wet era before it lost much of it's stuff. With a lower gravity, it might have not retained as much atmosphere, so may have cooled of early on before the sun warmed up. And IO was perhaps not always dry. It might have had a life fostering moment in time. But it is a very long shot.

As I understand it, impactors that made Venus would have deposited much more energy than those that formed the Earth, as they traveled down though the sun's gravity well.

I also am going to guess that Venus and Mercury were more remote from the suns Snow Line. But they might have gotten a lot of Carbon. As for Nitrogen on Venus, perhaps it has never been able to absorb Nitrogen into it's crust.

If this is close to the truth about Venus, I still regard it as very valuable. I tend to think that it will be possible to air brake materials from small terrestrial crossing asteroids, to allow for activities in the high atmosphere of Venus and in the orbits of Venus.

It may eventually even be possible to mine the surface of Venus.

Ending Pending

Last edited by Void (2024-12-16 14:16:23)

Void · 2024-12-16 14:18:09

(th) did a post elsewhere: https://newmars.com/forums/viewtopic.ph … 00#p228600

Your hint about mining the surface of Venus caught my eye ....
I had a brief vision of a dirigible in the atmosphere of Venus diving down to just above the temperature and pressure that would cause it to collapse, dropping a line of some kind, and scooping up some regolith with jaws, and pulling the entire load back up before they melt.
I have no idea if materials exist that could perform that feat, but the Soviets ** did ** put landers on Venus that functioned for a short time.
(th)

On the surface of Venus, itself you would have to have robots with Electonics that can take the conditions. It is possible that windmills could supply power on the surface. Otherwise perhaps there is a way to beam power down, with microwaves or lasers. (Lasers would have to be hosted below the cloud bottoms which would be very hot).

For transport of materials upwards, my notion is a dirigible like airplane. If we could add fluids to it we might ballast it down to glide to the surface. Fluids could be liquid CO2, Liquid Nitrogen, Liquid Sulfuric Acid, and perhaps Liquid water.
The device would likely have skids to land on the surface, as I think wheels would be fragile, and not necessary.

Critical equipment on the craft could be kept cool with boiling fluids.

These also may run turbines to make electricity.

You would probably want to limit the time on the surface, so cargo loading would need to be expidited.

Once you boiled off enough fluids, then you could fill the body of the vehicle with Nitrogen or perhaps water vapor, maybe somehow Hydrogen. (Probably not Hydrogen).

The force of flotation at 90 atmospheres of 93% CO2, should be very strong. Even so, if the craft had lifting surfaces, then it could fly like a plane as long as its "Steam" turbines were strong enough to drive propellers. (Steams of Water, or Nitrogen, or perhaps even Sulfuric Acid).

I would then expect the craft to proceed up to about the 10 Bar level in the atmosphere which I believe is at the base of the clouds. So, it would still have a lot of lift.

https://en.wikipedia.org/wiki/Atmosphere_of_Venus
Image Quote:
Quote:

30(km) 222(degC) 9.851(Bar)

That is still pretty harsh, but might be closer to what robots can work with. Perhaps the device has to move higher than that to get lower temperatures.

But it happens that the Sulfuric Acid clouds decompose from the heat at the bottom of the cloud deck and H20 and Sulfur Oxides result, as I understand it. Where and how you liquify other liquids such as Nitrogen and CO2, I don't know. You need power.

And of course these are all environments that are at least a little hostile, where humans may stay and extremely hostle further down.

So, this is almost "Clark-Tech", but perhaps in many, many years.......From now.

As for down on the surface, it might be possible to deliver liquid CO2 to a building to keep it cool if that was needed.

Anyway far beyond what we could hope to do now.

For now, I would hope to get rocky materials from Venus crossing and other asteroids.

Ending Pending

Last edited by Void (2024-12-16 19:28:39)

kbd512 · 2024-12-17 00:15:56

Void,

With an atmospheric density approaching 70kg/m^3 near the surface, a piece of equipment could literally "glide down" atop s stainless steel honeycomb "surfboard". No known material limits will have been exceeded in terms of temperatures or pressures. At the temperatures and pressures encountered near the surface, CO2 is almost but not quite a supercritical fluid.

Photonics-based chips can operate at temperatures up to 1,000C or so, thus photonic "chips" and waveguide materials (fused Silica), would have no real issue operating at the surface of Venus. These computers would use around 1,000,000X less power than electronics, so powering them is rather trivial.

Silicon-based CVD coatings will solve the corrosion problems. Ceramic coatings are another option, but I can't speak to their long-term durability in such a hellish environment. The aforementioned Silicon coatings are already used in similarly hostile chemical plant environments here on Earth, so I'm reasonably sure those will hold up fine.

Eglin ES-1 steel (a low-cost low alloy steel used in bunker buster munitions, with a small amount of Tungsten added, which provides its high yield strength at high temperature) maintains 95% of it's room temperature strength to a temperature modestly above the surface temperature on Venus. It's yield strength is 191,400psi at 482C. That's a very high room temperature yield strength for any kind of steel except maraging steel, let alone at 482C. We also have much cheaper ladle-refined (not vacuum processed) alloys with Silicon vs Tungsten that can perform to nearly the same level. These steels can be corrosion protected with Silicon. Some kind of specialty high-Manganese alloy steel is required for rock crushing to begin mining operations. I'm not sure how to protect them from corrosion damage, though. I would guess (and it's just a guess), that we'd add enough Molybdenum to the rock crushers to prevent embrittlement of the Mangalloy at high temperatures. Any kind of rock hauler / shovel / crusher will require said steel. There are processes that can use CO2 as a solvent for ore extraction.

Even so, mostly supercritical CO2 will do a number on most metals at the temperatures involved here:
Experimental Study of Structural Materials for Prolonged Venus Surface Exploration Missions

Ti-6Al-4V was evaluated in the study link shown above, and found to be suitable for prolonged use on the surface of Venus. This material is at least as strong as competing steel alloys, but much lighter.

Using CO2 with high pressures, temperatures, and mixing breaks down the rock structure and enables greater extraction of energy-relevant elements like Ni and Mg, which are then converted to metal carbonates (NiCO3, MgCO3).

The Venera probes detected the signatures of Silicon, Aluminum, Magnesium, Iron, Calcium, Potassium, Titanium, Manganese, and Sulfur. Other probes have subsequently found Lead, Tin, Antimony, Bismuth, Zinc, and Arsenic.

The greatest problems, as I see it, will be suitable lubricants and delivering sufficient motive power to heavy metal equipment used to move about on the surface and mine for ores. Dry Graphite-based lubricants can potentially solve the metal-on-metal issue, but the temperatures and presence of supercritical CO2 means this issue remains unsolved.

So... How do you provide motive power to all that equipment?

How about thermal chimney wind turbines which use insulated chimneys and hot rising CO2 to produce mechanical power output that is stored in molten Lead or Lead-Bismuth eutectic alloys to power machines equipped with high temperature radiators?

The mechanical power from the rising CO2 drives a rotor that creates resistance heating as its output to super heat Lead-Bismuth Eutectic (LBE), which has a boiling point of 1,670C. LBE alloy would be heated to just below its boiling point, stored in insulated tanks to retain heat (1,670C vs 482C is still a big difference), and subsequently transferred into the "fuel tanks" of various mining machines to provide motive power in conjunction with a radiator.

Let's use 1,418.5J/kg°C as our energy storage value for LBE, so 1,600C to 600C becomes our usable energy range, or 1,418,500J/kg or 394Wh/kg. This is about as good as or better than the very best Lithium-ion batteries. LBE remains in its molten state even when left in the tank of a parked vehicle, so it can be pumped back into the power plant for reheating. A mining truck equipped with a 1,000 gallon diesel tank has 19,875,000Wh of available energy to consume if its diesel engine is 50% efficient. On Venus, LBE is 50,444kg. Venus gravity is 91% of Earth gravity, so 45,904kg. LBE is 10,500kg/m^3, so the "battery compartment" is only 4.8m^3. 1,000 gallons of diesel is 3.786m^3 for comparison.

Edit: I was "off" by 1 decimal point. I should've known that was too good to be true. It's 141.85J/kg°C, not 1,418.5J/kg°C. It should be 141,850J/kg, which means our energy density is a paltry 39.4W/kg, which is no better than a Lead-acid battery. I was very excited for a moment there, but now that moment's gone.

Lithium metal, on the other hand, has a much higher specific heat capacity of 3,489J/kg°C. 1,200C to 600C gives us 2,093,400J/kg, or 581.5Wh/kg. That means we'd need 34,179kg of Lithium metal, which would also remain liquid at ambient temperatures. However, the size of our battery gets huge, about 64m^3. That said, this battery is lighter by quite a lot.

We will use a supercritical CO2 gas turbine to power the vehicle, so our engine weight and volume will be drastically reduced when compared to an Earth-bound diesel powered mining truck. Our power-to-weight ratio and total power plant weight will be similar enough. The C175-20 ACERT (V-20) diesel engine that powers the Caterpillar 7975F mining haul truck has a 23,400kg dry weight and comes equipped with a 2,000 gallon diesel tank. We will need segmented steel tank tracks vs rubber tires, obviously. That means our vehicle may not be quite as efficient.

The chassis weight of the 797F is 215,217kg. The body weight is 43,000kg. If we have a tracked vehicle with sCO2 power and a giant LBE "battery", then our chassis can still come very near to the same Earth weight of a 797F. If we use some Titanium alloys instead of steel, I'll bet we can carry a LBE battery that provides equivalent energy storage to the 2,000 gallon diesel fuel tank of a 797F.

The 797F mining truck by Caterpillar is made with a cast frame that's over 80% cast steel, with the remaining portion being fabricated steel plate:
Frame
The frame is made of nine individual metal castings, with the smallest weighing 500 lbs and the largest weighing 12,000 lbs. The castings are made by Harrison Steel Castings Co. in Indiana and Amite Foundry and Machine, Inc. in Louisiana.
Box-section design
The frame has a box-section design with two forgings and 14 castings in high-stress areas. The frame also has deep penetrating and continuous wrap-around welds to resist twisting loads.

Caterpillar 797F Front Quarter:
CM20221201-e6ecc-d6ab0?wid=1000&hei=600&op_sharpen=1&qlt=100

Caterpillar 797F Rear Quarter:
CM20221201-91ed3-231c4?wid=1000&hei=600&op_sharpen=1&qlt=100

We can deliver a steel-tracked Titanium alloy chassis variant to the surface of Venus (empty), fill its "fuel tank" with LBE on the surface of Venus, and then use some kind of advanced Tesla-variant robots to operate and maintain the vehicles like normal mining trucks. Refined metal ingots can be lifted from the surface of Venus using BNNT cables (chemical attack and heat resistant materials with the tensile strength of CNT) attached to balloons orbiting at higher altitudes, and from there the ingots will be delivered to orbit using CO/O2 powered rockets with lots of thrust. Eventually, rail guns will be built to eliminate the need for so much CO and O2 production.

I can see Venus becoming our "go-to" heavy industry planet, with metals mining at the surface and the Venusian atmosphere used to create CNT, Carbon Fiber, and plastics.

We can have a 3 or 4 planet system of colonies that trade with each other. Mercury and Venus can be involved in structural materials production. Venus and Mercury will be home to heavy industry (structural metals and advanced fibers, plastics, industrial chemicals), because they are power-rich due to their proximity to the Sun. Mercury can supply Helium gas collected from the stellar wind for the Venusian mining colonies, as well as Uranium, Thorium, and Sulfur to Martian colonies. Mars and main belt asteroids can extract specialty metals (Copper, Silver, Gold, Platinum, Nickel, Cobalt). Earth can provide people, organic goods, and luxury items (textiles, wood, computers, AI-enabled robots, etc). The moon can supply Helium-3 for fusion, whenever we get that working.

There will be some local production of a bit of everything, but the economy of energy tells us to go to where the desired material and power is abundant, and then extract what's available. If you have the tech to live there, to come and go as you please, then stop trying to fight physics.

Last edited by kbd512 (2024-12-17 01:47:29)

kbd512 · 2024-12-17 02:52:24

Void,

Molten Lithium metal is compatible with Titanium and Tungsten. The more modest hot storage temperature (1,200C) remains within the range of what Titanium is capable of withstanding. Unfortunately, Titanium's tensile strength drops like a rock above 500C, so the gas turbine components, and potentially the vehicle's radiator core and heat exchange tubing, likely need to be fabricated from Tungsten. A 3MW sCO2 gas turbine is absolutely tiny, however, so there's that. Tungsten has about 8X greater thermal conductivity than Titanium. Since Lithium melts at 180.5C, far below the 482C ambient surface temperatures on Venus, I wonder if liquid Lithium metal could directly power the turbine, eliminating supercritical gases for thermal power transfer. This would be more ideal, because I think the turbomachinery could be smaller still. We could have a relatively light Titanium vehicle chassis, a much smaller (than a 4,000hp diesel engine) but rather hefty thermal power prime mover, steel tracks for traction unless we find a suitable spring steel for airless steel tires.

At 482C, cast / wrought steel alloys used in the frame of the Earth-bound Caterpillar 797F have already lost 20% to 40% of their room temperature strength, which was nothing to write home about to begin with. That makes me think we could get away with using Titanium for most of the chassis and the molten Lithium "battery" box.

Take a look at page 10 of the brochure linked below see the vehicle's frame design:
Caterpillar 797B Mining Truck

Caterpillar 797F Mining Truck

It's mostly steel castings with a few forgings or fabricated weldments. A tracked vehicle design would have improved frame rigidity, lower CG height, lower total vehicle weight (a feature of virtually all heavy duty off-road vehicles- tracked vehicles always end up being lighter than wheeled vehicles with equal load carrying capacity, contrary to popular belief), and improved traction, but it would be slower than a wheeled vehicle, which is likely not practical on the surface of Venus (although I could be wrong about that), and use more energy as a result of the relative efficiency of wheels vs tracks. Finding a spring steel that retains its temper at 500C will be the determining factor as to whether or not we stick with the original design, albeit with "airless" spring steel tires, or switch to a new chassis design using tracks.

tahanson43206 · 2024-12-17 08:17:23

for kbd512 re #481

Your post deserves a "like" if we had a "like" feature.

The key benefit I see in #481 is the discussion of materials that might survive on the surface.

In other topics recently, and in the weekly Google meeting, you've been thinking about photonics as a technique for computation. It crossed my mind to wonder if photonic computers might be able to operate at Venus ground level temperatures. That possibility seems worth investigating.

I was curious to see the beginning of the topic. Terraformer created the topic back in 2008 (2008-04-15 16:06:18) and according to a post by RobertDyck a system crash occurred some time between 2008 and 2011. The entire topic looks worth a read from top if someone has the time.

Void's latest contribution (one of many over the years) has renewed interest in the topic. A lot has been learned since 2008. I'm hoping the Venus topic will eventually contain all the information a mission planner would need. It will take a while, but we (humans) have time, and the Mars Society is kindly paying the bills for this site.

From reading your post, I get the impression it might be possible to design a machine that would handle conditions on the surface of Venus comfortably. It still needs a bit of refinement, and fortunately we have members who can help.

In addition, this forum is open to admission of new members who might like to make a contribution to this topic or any of the many already created. Please see the Recruiting topic for procedure.

(th)

tahanson43206 · 2024-12-17 09:52:04

In the first 25 posts of this topic, we had quite a bit of talent assembled, and most of the participants are still here.

While GW's fusion idea was on the dramatic side, someone (it might have been RobertDyck) reported on Carl Sagan's idea of engineering microbes to eat a component of the atmosphere (it might have been sulfuric acid). I like Sagan's idea (assuming I am remembering it correctly) because it would self-propagate the microbes around the planet, and eventually the sulfuric acid would be absorbed and presumably deposited on the surface in some non-volatile form.

I'd definitely be interested in seeing if anything has happened with that idea since it was first published.

(th)

tahanson43206 · 2024-12-17 09:56:34

In creating the following post, I have not read the entire topic from the top, so this may very well have been covered in earlier work.

In thinking about the report of Carl Sagan's idea of using engineered life forms to carry out useful functions at Venus, it occurred to me that a floating forest might be possible. At least one science fiction writer has considered exactly that scenario, although in that case, the writer imagined the floating plants would be indigenous. It seems to me likely that if such plants are ever found at Venus, it will be due to human invention.

Never-the-less, the vision of such plants can be extended to imagine a forest floating around the entire planet, and thus cooling the surface because the sunlight would be either consumed by the plants or reflected back to the sky.

(th)

kbd512 · 2024-12-17 10:19:04

tahanson43206,

Using photonic computers capable of surviving to 1,000C, specialty lubricants (Graphite, Molybdenum Disulfide, Boron Nitride), Titanium / Tungsten / high Silicon or Silicon coated steel alloys capable of surviving Sulfur-based chemical attacks and supercritical CO2 solvents at elevated temperatures, I think long-term durable computer control systems and machinery is possible to run on the surface of Venus. I also get a 9% weight reduction on Venus, as compared to Earth, so my machinery is under less strain with a given load, and every little bit helps at significantly elevated temperatures.

Running electrical systems on the surface of Venus is not practical. The temperature is far, far too high. Electrical resistance charts for Copper wiring only go up to about 180C or so. Any higher than that, and your wiring, even Copper or Silver wiring, starts to become more akin to a stainless steel resistance heating element than any sort of useful electrical power conductor. Using energy and computing systems capable of comfortably running at extreme temperatures and pressures is very important.

The tempering temperature for 17-7 PH stainless steel springs is 900° F (482° C). At this temperature, 17-7 PH stainless steel exhibits elastic properties similar to those of alloy spring steels and music wire.

Does this mean if I raise and hold the temperature of 17-7 PH and get a good "airless" spring steel tire, or will my steel "get soft" on me if I hold at tempering temperature?

Only a metallurgist could answer that one. If 17-7 PH is suitable, then it means we can stick with the original Caterpillar 797F design with some material substitutions to reduce weight and improve strength at elevated temperatures.

Can I substitute Silicon or ceramic aerospace coatings to resist the chemical attack so I can still use ordinary Iron-based alloys?

I know the Silicon coatings will survive Sulfuric acid attack at high temps, because that's what they were originally intended to do. It also needs to survive supercritical CO2. I'm less certain if it can survive the combination of Venusian surface conditions.

Titanium will cut my chassis weight in half, roughly speaking, with strength about equal to what the cast steels provided near room temperature, back on Earth. Titanium is not a good choice for the body / dump bed, though, because we need a hard alloy to resist abrasion and denting from having giant rocks dropped on it by the power shovel.

For a Venusian mining colony, we need:
1. Working Tesla robots with photonic computer "brains" to operate the equipment on the surface
2. We want the mining equipment to be as simple and robust as possible, meaning any computer is aboard the Tesla robot, not the vehicle itself, so only sensors are present aboard the vehicle
3. We need to test all the materials and equipment mechanisms at relevant temperatures and atmospheric conditions to evaluate long term durability (you don't need to build a full scale machine and put it in a pressure chamber with a corrosive atmosphere, just a small chamber to test coupons of materials, particular fabricated structures if they were welded, stuff like that)
4. Delivery mechanisms can be rather simplistic because the atmosphere is so dense near the surface. Recall that the Venera probes floated to the surface using special parachute materials, which only needed to survive for a handful of minutes. That means HIAD plus parachutes, no retro-propulsion or other pointless complexity. If the parachute material only needs to "live" for 15 minutes before the heat and chemical attack destroys it, then designing to survive for 15 minutes is all we spend time and money on. This is purpose-driven scientific development, rather than making a science project out of every single design element.
5. We need to figure out how to devise CO2-based solvent extraction of metal ores, and refining methods that use chemistry / heat / pressure, rather than consuming huge amounts of electrical power, which will be difficult to come by.

Overall, I'm trying to devise practical methods for moving heavy industry off-Earth. After we're up and running, all the pollution that Earth would otherwise suffer can be drastically curtailed. Nobody will complain if the surface of Venus has been "destroyed by mining". Nobody can live there, regardless of how much mining we do. To achieve that, we need to first devise practical methods for shipping metals between the planets, which implies advanced propulsion methods. Pure speed is far less important than steady and predictable supplies of metals. If it takes a year to ship something back to Earth, but a year's worth of metal is "sitting in the pipeline" at all times, then there is no actual problem. We're going to consume metals from now until eternity, so this is long term thinking being applied here.

To wit, we really want to bring all that Lead, Bismuth, Antimony, Tin, Molybdenum, and Zinc back to Earth. Lead is good for Lead-acid batteries. Lead-acid batteries are themselves "good" because they're durable, nearly-100% recyclable, and they can survive abuse that would kill Lithium-ion. If Lead is incredibly abundant and widely available, then more people will start using Lead. We also want Zinc and Carbon to make batteries, and Venus has lots of that. If it turns out that Venus has galena ores coming out the wazoo, then however theoretically great Lithium might be, Lead is still a better option if we can source enormous quantities of Lead. Similarly, there is Gold on Mars and 16 Psyche, so rather than sifting through enormous rock volumes here on Earth, we go directly to whatever is readily accessible on other planetary bodies.

tahanson43206 · 2024-12-17 10:43:36

For kbd512 re #485

Your discussion of the difficulty of using electricity on Venus at the surface shows that while electron flows may still be possible, they won't take place using methods that have worked for hundreds of years on Earth.

My concern/interest is in delivering useful command signals to machinery. I come away from a first reading of your recent posts with the impression you are optimistic that materials exist that can handle the conditions on Venus' surface. Indeed the Soviets demonstrated short term viability of equipment. Your description of the very short (but very practical) lifetime of the parachute subsystem was one I have not seen before.

Assuming for a moment you (and co-workers) are able to design a machine able to navigate on the surface of Venus and to perform useful functions such as transporting material from one place to another, it is still necessary to provide rotational power to turn axles or gears, so mechanisms to perform those functions at Venus ambient are needed, along with control mechanisms.

My guess is (without investigating) is that there are probably a very small number of humans thinking about the Venus problem alive on Earth at any one time. This forum is perfectly situated to bring those few individuals together, if they know about the opportunity.

If there is a reader "out there" who would like to interact with kbd512 in this specialized study, please see the Recruiting topic for procedure.

(th)

kbd512 · 2024-12-17 17:36:23

tahanson43206,

There are lots of materials that can handle the surface temperatures and pressures found on Venus, but none of them are cheap or easy to work with. Fiber optic cables are made from pure Silica- the same material that the high-temperature Space Shuttle tiles were made from. I'm not terribly worried about them surviving 482C.

Q: What is the maximum temperature for fiber optic cable?
A: Depending on material(s) used, the limit for high temperature applications is 600°F (315°C) (constant exposure), using a typical high temperature designed epoxy. If special assembly techniques are used, standard borosilicate fiber can be used in component parts for high temperature applications up to 900°F.

500°C-Rated Optical Fiber for High Temperature Applications

If we use purely optical computing systems, then we have a variety of standard materials solutions that can take the heat.

My gut-feel tells me we have suitable high temperature lubricants, but lubricating methods are a weak point, I think. For example, the differential in that Caterpillar mining truck, as well as all other mining trucks, is an oil bath / "splash lubrication" (a puddle of oil sitting in the bottom of the differential casing). That won't work with a powder, so far as I know, which means some kind of metering device that periodically injects a small amount of lubricant between the gear teeth is required. That also means powder from the bottom of the case needs to be collected and reinjected into the device feeding the dry lubricant to the gears. This is very non-standard.

We have suitable metals. That really shouldn't be a major problem. Aluminum or CFRP anything is a total non-starter. Only Iron, Titanium, or Tungsten-based alloys have a real shot at proper function. Aerospace engineers don't typically have a lot of experience working with these materials, because they're fairly heavy. Titanium might be a possible exception, because it surrounds the hot turbofan engines of most modern fighter jets. The operating environment, however, will be completely alien to almost all engineers except chemical engineers.

To the best of our ability, anything that needs to be sealed from the environment needs to either be solid material, so the extreme atmospheric pressure can't produce a leak, or over-pressurized with something like supercritical Argon, hence the potential serious issue with dry lubricants. Precision machining of mating surfaces and special stainless MLS gaskets will need to be used everywhere. It's too hot for Silicone or Teflon. Polymer and elastomer compounds simply won't survive. That makes sealing a rather tricky affair.

For that reason, there won't be a bunch of physical linkages. The Tesla robot will plug in its fiber optic connector, and the vehicle will be steered via a fiber optic cable leading all the way to the vehicle's steering gear. The fewer the number of physical connections, the better. No kind of driver's instrument cluster will exist, merely photonic signals sent between the vehicle's sensors and the "photonic brain" of the Tesla robot, wherein a software program tells the controlling robot exactly how to operate any piece of machinery, provides full schematic details for maintenance and repair, etc. I figure that the robots will simply stand on a platform that provides visual line-of-sight around the vehicle. A dump truck might be crewed by 2 to 4 robots acting as operator / maintainers, with one attached to each corner of the vehicle so that they can operate the vehicle without crushing their fellow robots or crashing into other pieces of nearby heavy machinery, such as the power shovel.

Long story short, the same basic operating principles still apply, but very different materials and methods for solving problems are required. It's an engineering exercise, though. No fundamentally new materials or science is required to make this work. We only have to decide it's worth doing and that we are going to do it.

Void · 2025-01-08 12:26:30

I am under the impression that I shall be accursed should I intrude in "Index» Science, Technology, and Astronomy» Pure Carbon burned with pure Oxygen Analysis" https://newmars.com/forums/viewtopic.php?id=10976

But as the owner has said, there are plenty of topics where speculation is allowable.

I am already aware of pulverized coal burners. A big device like a bearing grinds coal to a dust and then I believe that flue gas is used to carry the dust to a combustion event. This could probably work with "Pure Carbon" as well.

Here is an article: https://en.wikipedia.org/wiki/Pulverize … red_boiler

Another thing I stumbled on was that Carbon can be burned in Sulfuric Acid, producing CO2, SO2, and H20.
The burn process may require an input of external heat, which may not be a problem lower down in the atmosphere of Venus.

So, Sulfuric Acid could serve as an Oxidizer, instead of Oxygen. The Sulfuric Acid may also work as a coolant, I suspect, but handling it would be a real bit of trouble. But Glass may work. Glass and Ceramics we are familiar with are seen as brittle. But is the same true at high temperatures down below on Venus? Perhaps at those temperatures they may have more suitable qualities.

And then we have the Ceramic Engine: https://en.wikipedia.org/wiki/Ceramic_engine

I would look into turbines though, and there is a problem with lubricants, as I think has been mentioned by other members.

I find it hard to understand how you can invent a new thing without speculation. But that is just me, I guess.

Ending Pending

This has prompted me to speculate that if you could create UV tolerant plastic bags. you could grow algae or cyanobacteria in them with very little weight. Such "Balloons" could then support a heavy structure(s) with robots in them. You could then subject the algae or cyanobacteria to pyrolysis, to yield a Carbon rich material to be a fuel.

The Carbon brought down to the surface could be heated to the temperatures normal there. And then you might think to burn it in Sulfuric Acid collected above, and dropped down to the surface for that purpose.

Ending Pending

Last edited by Void (2025-01-08 12:45:35)

Void · 2025-01-09 12:05:46

OK, if you have a thick slurry of Carbon or organic Carbon Dust mixed with Venus atmosphere, the suspension will be much easier than for Earth atmosphere. If you have ceramic ice engines or turbines......

Then can you have liquid metal lubricants? Possibly also liquid metal coolants, maybe also salts.

So, if you could grow algae or cyanobacteria in bags in the clouds, then you could provide your source of fuel.
Others have suggested LOX as the Oxidizer. I am still considering Sulfuric Acid as Oxidizer as it is quite available in the cloud tops.

Burning Carbon/organics, in Sulfuric Acid needs an additional heat input to sustain, but that heat is available on the surface of Venus.

I could be wrong about the Sulfuric Acid, maybe LOX is a better way. But I have read that Carbon and Sulfuric Acid with a heat input will create CO2, SO2, and H20.

If you start with a liquid (Sulfuric Acid) and a solid (Carbon), and the results are all gasses, I expect that that may be able to power a motor. But of course as I have said, I am not sure of it.

Ending Pending

Last edited by Void (2025-01-09 12:17:39)

kbd512 · 2025-01-09 17:26:10

Void,

Silicon Carbide / SiC is highly resistant to Sulfuric acid at incredibly high temperatures. It can also maintain its shape while subjected to extreme internal pressurization from a working fluid like sCO2. The reason we can consider other oxidizers and fuels, such as Sulfuric acid and Carbon, is that we're externally heating this external combustion engine (similar to a ship's boiler) which has its working fluid sealed inside. Said engine could use sCO2 or it could use liquid metal as its heat transfer medium, especially if all components it flows through are made from SiC. A liquid metal working fluid would have an internal pressurization near-zero, unlike sCO2 (250-1,000bar). Molten metal of the varieties being considered here, Tin or Lead or Lead-Bismuth eutectic, is effectively incompressible. There will be some thermal expansion, but that can be accounted for in the system design, and of course, it's never dipping below 482C, so the entire system thermally "soaks out" to that temperature within an hour or two of arrival on the surface.

I would still recommend that we use sCO2 in gas bearings for the rotating machinery. A gas bearing is a minimal-contact method of "lubrication", CO2 is available in extreme abundance at the surface of Venus, and "changing the oil" is as simple as pumping in fresh CO2. For reduction gearboxes, that is where using a liquid metal lubricant makes more sense to me. That said, there is a product called "DSF-5000", a grease, which can withstand continuous temperatures of up to 815C.

https://www.superior-industries.com/dsf … t_122.html

It's used to lubricate rotating parts of metal foundry equipment. We could probably use that for gearboxes on the surface of Venus. Some gearboxes use grease and others use oil. I don't know how well "splash lubrication" works with greases, though. My guess is that it doesn't. If not grease, supercritical CO2 or Argon "air bearings" are already used in these high temp sCO2 gas turbines. Some kind of molten metal will perform better as a working fluid than as a lubricant. Argon is definitely "more inert" than CO2, so perhaps supercritical Argon is the fluid of choice for high temperature air bearings. The molten metal working fluid idea was entirely related to achieving crazy-high power density without a lot of pressure in addition to a lot of heat. That helps a lot with material creep (continuous parts growth over time due to high heat and pressure) and fatigue resistance from thermal cycling. Creep is a common problem with parts in the hot section of gas turbine engines. With these sCO2 or molten metal power cycles, every part of the machine is "inside the hot section".

Although it probably seems a little funny, these very hot parts also require better-than-average insulation to avoid "loosing heat" to the surrounding environment, which is true on Earth, but will be especially true on Venus where the engines are submerged in 93bar CO2, which will rapidly sap heat from any exposed components, despite the fact that the surface is a very toasty (to plants and animals) 482C.

tahanson43206 · 2025-01-09 18:48:41

For kbd512 re sCO2....

We do not currently have a topic that contains sCO2 in the title....

It may be too early to consider creating such a topic, but I would like to point out that you seem to be making a consistently strong case for use of that substance at Venus. I decided to ask Google for a definition of the substance, and it came back with text that looks similar to what you've been posting for some time:

Supercritical carbon dioxide (sCO_2) is carbon dioxide that's held at or above its critical temperature and pressure. In this state, sCO_2 has properties of both a gas and a liquid. [1, 2]
Properties [3]
• Density: sCO_2 has the density of a liquid, but behaves like a gas. [3]
• Efficiency: sCO_2 is an efficient working fluid for generating power. [3]
• Nontoxic and nonflammable: sCO_2 is safe to use and has been used in dry cleaning and decaffeination. [2]
Uses [2, 4]
• Power generation: sCO_2 is used in power cycles that generate electricity.
• Dry cleaning: sCO_2 has been used in dry cleaning processes.
• Decaffeination: sCO_2 has been used to decaffeinate coffee.
Research [5]
• Researchers are developing sCO_2-based power cycles that are low-cost and high-efficiency. [5]
• Researchers are also working to couple sCO_2 power cycles with nuclear reactors. [4]

Generative AI is experimental.
[1] https://www.energy.gov/supercritical-co2-tech-team[2] https://www.swri.org/supercritical-carb … er-systems[3] https://www.energy.gov/sco2-power-cycles[4] https://www.youtube.com/watch?v=6cQCbmzN8Ew[5] https://netl.doe.gov/node/7552
Not all images can be exported from Search.

It is likely that you have already published details about sCO2 in your posts. That said, I am hoping you might be willing to write something ** really ** concise that shows how sCO2 matches up with the ambient conditions at the surface on Venus.

If you think that sCO2 is of sufficient importance as a potential bedrock element for a Venus based mining operation, please think about how (and where) a topic might be created for it.

As I am trying to follow along as you develop your ideas, it seems to me the elements needed for exploration and then mining are swirling around each other, but I have not yet seen anything that looks like a plan for a set of machines that would work together to achieve objectives.

We seem to have a problem sourcing a nuclear power plant for a Venus venture in the United States. However, Great Britain/UK is independent of the United States, so it might be able to design, build and deploy a base station for the mining enterprise you are describing. Naturally, such a station would be at the heart of any such venture, which means the UK would be at the heart of such a venture.

What is more important from my perspective is that such a power plant would be a crucial component of a submersible exploration vehicle that would operate just above the surface on Venus for months or years at a time.

Thus, the builder/operator of such a vessel would be in possession of all data collected by the vehicle, and thus in a position to know where useful resources might be found.

(th)

Void · 2025-01-09 19:24:07

Thanks for your work kdb512.

Ending Pending

Last edited by Void (2025-01-09 19:27:07)

Void · 2025-01-10 11:42:41

So, I am happy to be insufficient on my own for motor concepts for Venus.

We now have notions of ICE Engines or Turbines that could work on Hydrocarbon fuels and LOX.

As I have said before, I think that if a form of plastic film that could be made to endure the UV, and acid conditions would be possible, then in the interior you could have a spray mechanism that would spray water and fertilizers onto the inner surface of a balloon to promote the growth of photo-microbes. And from this you could get Oxygen and biomass that could be converted into fuels.

An aircraft that was part lighter than air and part airplane, could run on those consumables.

A liquid fuel may be appropriate. Anything from Methane to thick oil. These could be used as coolants as also LOX could be as well.

Prior to this I thought of dropping such ships down with Cryogenic fluids, to power turbines. But now the other members have indicated combustion processes being possible.

So, access to the surface may be possible. Could such a device be self digging? It seems that volcanism on Venus has much less water than Earth, so lava flows may be more common than large deposits of volcanic ash. But then a lack of water might reduce the cementing process for volcanic ash.

I will check: https://en.wikipedia.org/wiki/Volcanism_on_Venus
Quote:

Global web icon
Wikipedia
https://en.wikipedia.org › wiki › Volcanism_on_Venus
Volcanism on Venus - Wikipedia
Radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus 's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank. See more

Any dune fields on Venus? It seems possible: https://www.newscientist.com/article/21 … d-surface/

If we have ash deposits that have not cemented to rock and also sand dunes, then an aircraft with fuel and LOX could drop down and vacuum up a payload to lift up to the clouds.

While it may be possible to get into true mining operations, this would be a lower hanging fruit, which may remove the need for permanent installations on the surface of Venus. Of course you could not be fussy, you would have to take what was available.

But I think that a vacuum system could work very well in a 93 bar CO2 dominated atmosphere.

This could be primarily volcanic dust. I am hoping that it exists.

https://awesomeocean.com/guest-columns/ … s-surface/
Quote:

Earth’s Underwater Sand Dunes Are Eerily Similar To Venus’s Strange Surface

Quote:

Earth’s Underwater Sand Dunes Are Eerily Similar To Venus’s Strange Surface
Guest Columns
SAND DUNES
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Featured Image Credit: NASA/History Archive/REX/Shutterstock
By Sarah Sharkey

Scientists have found a new approach to understand Venus’s sand dunes. By using the sand dunes found on the shores of Earth, we can start the process of understand exactly how the similar surface of Venus was formed.
First of all, how do we know that there are sand dunes on Venus? Back in the 1970s, Venus lander missions provided evidence that there is fine-grained sand like material on Venus. And then in the 1990s, the Magellan spacecraft’s synthetic aperture radar showed that there are sand dune-like structures on the planet’s surface.

So, I think about half of the surface of Venus is supercritical, and perhaps the other half is less so. I am hoping that there is no process that would cement dust particles together in dunes but am not sure, of course.

So, a craft to dive to the surface might be attached to a larger floating platform and ballasted down with a hydrocarbon fuel and LOX. Both of those can serve as coolants. The ship would detach, and glide down to the surface where it would vacuum up dust/dunes. It would have to be careful not to collect too heavy a burden. As the propellants were consumed, buoyancy would improve. Once enough of the dust/dunes were collected it would attempt a powered/buoyant assent back to the floating platforms.

It is possible that at the 10 bar level it could connect to another powered vehicle to be brought to a processing facility at some altitude, perhaps higher, maybe even as high as 1 bar.

So, from my point of view, a Venus development process could start with materials minded from terrestrial asteroids, and then enter the clouds primarily with robots, and then develop this dive vacuum collection method.

Quite a bit in this post, I would not mind getting input from others.

Ending Pending

Last edited by Void (2025-01-10 12:17:39)

Void · 2025-01-10 17:30:17

So, then we might start with collecting materials from asteroids to Venus, and then go to "Divers" that could vacuum up dust/dune materials to lift to the clouds. Then eventually true mining on the surface as kdb512 has worked on.

In the clouds I have this proposal:

So, the tree-like objects would simply be balloons, which would assist in flotation of a platform, and where microbes would grow on the inner wall of the balloons. Nutrients would be sprayed with water onto the inner surface of the balloons. As the biomass would grow, it would sag down to the bottom to be collected.

As balloons would age they would be changed out, and then repurposed to something else.

Quite long in development we could consider "Bean stocks" where you would build from the clouds down to the surface, and would collect condensate from the clouds and drop it to produce hydroelectric power. Absolutely difficult, I expect. But the power would be immense, and after the liquid arrived at the surface you would boil it to produce even more energy. In time the Sulfuric Acid would decompose to H20 and SO2 or SO3, and you would have water, perhaps a bit acid flowing down the bean stocks.

In time better idea will emerge, I hope, but this is a pointer to some possibilities.

Ending Pending

Last edited by Void (2025-01-10 17:37:48)

kbd512 · 2025-01-10 22:24:53

tahanson43206,

Q: Is the co2 at the surface of Venus supercritical?
A: Yes, the carbon dioxide (CO2) at the surface of Venus is considered a supercritical fluid, meaning it exists in a state with properties of both a gas and a liquid due to the extreme pressure and temperature conditions on the planet; essentially, the CO2 acts like a dense, hot liquid that flows around the surface like a gas.

I wouldn't say that sCO2 is absolutely mandatory, but it's an exceptionally good option because Venus has so much sCO2 available for use, anywhere you happen to land. Venus also has small amounts of Argon, but nowhere near as much as Earth has. I could see sourcing local Argon for air bearings used by power turbines, but that's about it.

The major advantage of sCO2 is that it's an extensively proven high temperature / high pressure working fluid finding increasing use here on Earth in our latest power plant designs. No fundamentally "new" or "different" tech is required to use sCO2, which is what a variety of gas turbine engineers have noted about using sCO2- it's only a new application of existing working knowledge, and no longer a novel science experiment relegated to university research labs. sCO2 is rapidly maturing into a commodity commercial power plant technology. Steam turbine engine tech is very similar to sCO2 gas turbine tech, but the power density of steam is not comparable to sCO2. We can apply what we already have or are actively developing to Venusian exploration and mining applications.

This is in stark contrast to space-rated nuclear reactor designs, which functionally don't exist and never have at power output levels that would make them useful for anything beyond robotic deep space probe / military satellite missions. MSRs have existed for decades. Nobody has a commercial MSR reactor design, or merely an experimental MSR design that's been operated long enough to discover what the long term problems will be. I would love for BWXT to build the hardware and for NASA to test it in space, but thus far that hasn't happened, and I think basing your entire exploration and commercialization program on a technology that's never been test in its intended operating environment is a great way to kill your entire program for want of a functional power plant.

Additionally, zero kilograms of sCO2 need to be delivered to the surface of Venus, all the way from Earth. sCO2 is a natively available working fluid product after some filtering has been applied to remove contaminants, primarily dust, Suluric acid, and Sulfur dioxide. If any sCO2 is ever "lost" by the power plant, then it can be easily and swiftly replenished. CO2 provides the base stock to synthesize pure Carbon powder and Oxygen. This solves a major logistical problem. The working fluid for the power cycle, the oxidizer, the fuel, and the diluent gas to keep combustion temperatures under control are all "the same thing". Whenever more CO2 is required, stick a hose into the atmosphere and start pumping. For all practical purposes, you'll never run out of Carbon and Oxygen on Venus. As long as you can generate power, you can make more fuel.

The general idea behind the Allam-Fetvedt cycle is that 95% of what flows into / past the combustor is pure CO2, with a small amount of injected Carbon powder and Oxygen being combusted to add more heat. That CO2 present in the "combustion chamber", which is external to the actual "engine" portion of the power plant which generates shaft power, is also a hot / dense supercritical fluid. You'd think it'd be really hard to ignite the Carbon powder, but it's not. The flame is very stable in hot- so hot that some of the sCO2 briefly becomes CO and free Oxygen atoms, which then rapidly recombine or combust with the Carbon powder, adding even more heat.

Thus, the Allam-Fetvedt cycle "conserves" or "recycles" waste heat from combustion by recirculating some of the combustion gas back through the "combustion chamber" before it's finally exhausted into the atmosphere, or used to drive the recompression gas turbine after it cools to about 400C. Imagine if your car's engine had an EGR valve that was able to feed nearly all the thermal power that normally goes right out the tailpipe, back into the engine, because the actual engine was physically separated from the thermal power input. Normal piston-driven internal combustion engines cannot do that in a practical way, because the exhaust is inhibiting the combustion process and the piston needs a "cold" compressible gas to use to generate power. External combustion engines and closed-loop power turbines don't have that problem. The net-net is that the Allam-Fetvedt cycle uses lower sCO2 pressures while keeping thermal efficiency very high. It's around 60% after all plant losses have been accounted for. Since we will not have a power-hungry air separator unit to feed-in pure O2, we might be able to get as much as 70% of the potential stored thermal power in the Carbon and Oxygen, back out of the cycle.

Obviously we have to put more power in than we can ever get out, but what forms the input power takes is highly germane to how practical the overall operating concept is for stationary surface bases and mobile mining equipment.

Imagine that we're trying to power a base and a mining truck. The base can be powered by a nuclear reactor or an ambient pressure differential used to provide refrigeration power or electricity to split Carbon and Oxygen. I incorrectly referred to this as an "atmospheric trompe" in previous posts. The correct terminology is an "updraft tower". The Carbon and Oxygen are loaded into tanks that supply the fuel and oxidizer to the mining equipment. The mining equipment is used to extract metals from the surface of Venus.

Solar updraft tower

A "solar chimney" built in Spain:
SolarChimneyManzanares_view_from_8km_south_direction.JPG

Vortex Engine

Imagine how much more powerful an updraft tower / vortex engine could be when the atmospheric density is 93bar.

It's impractical to power a mining truck using a nuclear reactor or an electro-chemical battery. The mining truck needs a very energy-dense fuel, or all the mass allocation, which might otherwise be useful ore load, gets gobbled up by its power / propulsion system. Tesla semi-trucks have this problem in a far more benign operating environment. There's very little free Oxygen available on the surface of Venus, so a vehicle must also carry an onboard oxidizer supply to combust its fuel. Oxygen is the most practical oxidizer that we have in abundance, after CO2 has been split into C and O2. There's a substantial energy cost associated with splitting CO2 into C and O2, so the overall net efficiency of any piece of powered mining equipment is very consequential to the support equipment requirement for CO2 splitting. More thermal efficiency is more better until it starts significantly driving up machine weight and complexity.

Combusting pure Carbon supplies 32.8MJ/kg. If we can extract 70% of that energy as shaft power, then we get to use 22.96MJ/kg, or 6,378Wh/kg. Diesel fuel contains 43.5 to 45.5MJ/kg, or 12,083Wh/kg to 12,639Wh/kg. If the diesel is burned in a 50% thermally efficient diesel engine, then you 6,319Wh/kg of fuel can be converted into shaft power. That means pure Carbon fuel, when used to power an Allam-Fetvedt cycle sCO2 engine, is about equal to the most thermally efficient diesel engines.

The fuel tank on a Caterpillar 797F mining haul truck has a capacity of approximately 1,200 gallons of diesel fuel, occupies 4.542m^3 in volume, and provides 54.6GJ of energy to power the truck. Carbon powder with equivalent energy density, when consumed in a 70% thermally efficient Allam-Fetvedt cycle powering a sCO2 gas turbine engine, would weigh about 1,665kg, and occupy 0.8325m^3. Let's call it 1m^3 for good measure, to include in-tank machinery used to sift / stir the Carbon powder and pressurize the tank with sCO2 so that a siphon pump can suck up fluidized Carbon powder in order to feed it into the combustor. We need about 4,440kg of pure O2 to completely combust 1,665kg of pure Carbon. Pure O2, pressurized to 750bar, at 427C, is 326.4kg/m^3, so 13.603m^3. A 1m diameter capsule with a side length of 3m has a volume of about 2.87979m^3, so we'd need 5 of those O2 cylinders to completely combust 1,665kg of pure Carbon fuel. Let's say we have 6 of those cylinders onboard, that each O2 cylinder has 100mm thick walls, and total volume per cylinder is 1.41791m^3. If the cylinders are made from steel (7,850kg/m^3), then weight per cylinder is about 11,131kg, for an oxidizer / fuel storage subsystem mass of 66,786kg of steel for all 6 cylinders. That does not include the weight of the fuel or oxidizer itself, which further increases total subsystem mass to 72,891kg, but only 65,929kg on the surface of Venus. 66t is very close to the combat weight of the latest up-armored M1A2 Abrams MBT.

We probably want a Titanium alloy or ES-1 steel Metal Matrix Composite (MMC) with Carbon Fiber sintered into a metal matrix, perhaps with a Silicon Carbide surface coating on the metal to inhibit corrosion. This implies vacuum fabrication processes and somewhat novel induction heating of the MMC, being sure to keep the temps below 2,000C to avoid damaging the Carbon Fiber. In an inert atmosphere or vacuum, the CF should retain its tensile properties after the fabricated pressure vessel cools down. That should drastically reduce the weight of these storage tanks. The 100mm thick steel tanks presumed the use of Eglin ES-1 steel. At 750bar, the hoop stress from the high pressure O2 represents a bit less than 1/3rd of ES-1's yield strength at 482C. That ought to be sufficient, but creep testing must be performed. If we had a 60% T700 fiber fill, then at 2,000kg/m^3 for the CF, our total tank mass for all 6 cylinders is reduced to 36,922kg. The Caterpillar C175-20 diesel engine genset weighs somewhere between 25,000kg and 30,000kg for comparison purposes. I don't know what the engine, transmission, fluids, and fluids containers weigh, as oppose to the dry (no fluids) genset weight. I would wager it's at least 35,000kg, though, because that truck has more gallons of fluids than gallons of fuel by a lot. That said, we can tolerate a modest power plant mass increase due to the lower gravity on Venus. We cannot tolerate a doubling of that subsystem mass over its Earth-bound equivalent.

Speaking of weight savings, we could make the chassis and dump bed from the same materials- common T700 fiber sintered into a suitable steel. That one material / manufacturing change would remove about 45% of the weight off the vehicles, probably more. There's an obvious cost to this fabrication process, but a 142t 797F vs a 258t 797F would mean we have the lightest and most fuel efficient mining trucks in the world. The brakes, tires, and transmission would last much longer as a result. Here on Earth they can run on compressed natural gas or coal-water slurry fuels, whichever is readily available at the mining site and therefore cheapest. Large-scale implementation of Allam-Fetvedt cycle sCO2 gas turbines and MMCs for structural applications would represent a significant change for heavy machinery technology, as well as ship engines and hull plating / armor for that matter- steel plate far stronger than any metal alloy, with a total weight at equal volume nearly identical to Titanium. Titanium MMCs stronger than any steel, with a weight similar to Aluminum, would also be possible.

The ever-present weight and operating cost problem is why maximizing the thermal efficiency and power density of the engine is so critical to successful surface mining operations on Venus. The extreme operating environment demands extreme performance from all power and propulsion systems. The goal should be to make total power plant, fuel, and oxidizer masses similar to equivalent system masses powering our diesel-fueled Earth-bound analogs, using high performance materials to withstand the incredible pressures and temperatures involved, and having to carry onboard oxidizer in addition to the fuel. Such mining trucks and power shovels will cost a pretty penny to engineer and fabricate, but the end result will be capable of long-term surface mining operations on Venus, which is no small feat of materials science and engineering.

tahanson43206 · 2025-01-11 07:36:42

For kbd512 re #495

This post appears to contain a number of concepts that might work on Venus.

One detail that I'd appreciate your looking at more closely .... the exhaust from the turbine is given as 400 Celsius, but the ambient temperature is on the order of 500 Celsius. Your heat engine in the mining vehicle needs to heat the incoming CO2 to a value higher than 500 Celsius in order to expand the material to drive the turbine blades.

The tower you've described is interesting. The cylinder might be made from brick made from local resources, assuming there are local resources that could be made into brick with the required properties.

Do we have knowledge of the temperature variation with altitude at the surface of Venus? How tall would the tower have to be to achieve a useful flow of CO2?

In earlier discussion, we have considered nuclear power as a source of energy for this project. In dismissing nuclear fission as a source of heat energy, it seems to me your vision is going to be challenged to supply heat to raise the ambient gas temperature above 500 Celsius.

The following statement is incorrect. It was written on the first pass through the document.
Energy is not available at the surface of Venus, so it must be brought in from outside.

Clarification: There is plenty of energy in motion at the surface of Venus. What is NOT present is a cold sink into which that energy might flow. The concept of a tower to harness some of the energy at the surface depends upon the tendency of lighter gas to rise in the presence of a colder gas that is greater in density.

Energy would be available if you had a supply of free carbon and free oxygen.

There is no source of energy to separate carbon from oxygen at the surface of Venus.

Please create a post that explains how you would supply energy at the surface of Venus.

To help our readers, please concentrate on just this critical part of the problem. Everything else flows from success in providing reliable and abundant power (ie, heat) at the surface of Venus.

A nuclear reactor would provide energy to heat the local gas to 1000 Celsius or thereabouts. The difference between ambient 500 and generated 1000 is what provides the power to drive a turbine. In dismissing nuclear fission power, we need to find a substitute.

The following statement was written in the first pass through the document.
Building a tower is a way to encourage gas to flow up the tower if heat is supplied at the bottom, and that heat must be greater than the ambient temperature of 500 Celsius.

On second reading, I get the impression you are thinking of harnessing the natural exchange of hot gas for colder gas higher up in the atmosphere.

There must be heat flows on Venus, just as there are on Earth. Glider pilots and birds navigate great distances on Earth riding thermals. There must be thermals like that on Venus, because the hot gas near the surface will naturally tend to rise through colder gas higher up.

Your concept of a tower purpose build to facilitate flow of hot gas from the surface seems (to me at least) to be a way of tapping the natural flows that must exist on Venus.

If that is indeed your concept, then it should be possible to quantify the flows that are possible.

A tower able to perform useful work would have a size set by the available flows.

I'll bet that there are few people on Earth who have thought along these lines.

But then, I'll bet there are few people on Earth who have thought about Venus at all.

(th)

tahanson43206 · 2025-01-11 07:53:09

for kbd512 re concept of tapping natural circulation of gas at Venus.

A tornado on Earth is an extreme example of a mechanism to deliver hot gas at the surface to a colder layer of gas above.

A rising column of hot gas on Earth, used by birds and glider pilots to gain height, is a very large and diffuse body of gas.

The column you've described to harness the potential energy that is available is a way of concentrating the flow of gas so it can be harnessed.

In order for this concept to be practical, it must be possible.

Let's address the possibility first.

Are there materials on Venus (at the surface) that could be used to make a tower of ** any** size?

Then, what size of tower is needed to achieve a useful flow of hot gas from the surface of Venus to some higher altitude.

There will be some relationship between the height of the tower and the power that might be produced.

It would be helpful to have some numbers to work with.

I am betting that the "practicality" of this idea is less than the "practicality" of making a fission reactor that can operate on Venus.

The energy to make the tower must come from somewhere, and chances are that energy will come from Earth.

What is the nature of the energy that is going to be coming from Earth?

(th)

tahanson43206 · 2025-01-11 12:21:56

As a follow up to the post above to kbd512, I decided to ask Google's Gemini about the Venus atmosphere and about the prospects for harnessing the upward flow of hot gas from the surface. I think the bottom line is that we do not yet have enough information to know where best to site a wind funnel such as must exist naturally on Venus.

<snip>
By focusing on these factors, we can have a more nuanced discussion about the costs and benefits of Venus exploration.
You're also correct that human ingenuity and the capacity for parallel work are vast. It's entirely possible to pursue multiple avenues of research and development simultaneously, including both space exploration and addressing pressing challenges on Earth.
I am still under development and learning to better understand and respond to nuanced human language. Thanks for your insightful observations!

(th)

tahanson43206 · 2025-01-11 12:25:32

The post above #498 captures the bottom of a long series of exchanges.

Here is the opening sequence:

The concept your friend describes has a strong foundation in basic physics: heated gases expand and become less dense. This principle drives many natural phenomena, including terrestrial thermals.
However, directly applying this to Venus presents significant challenges:
* **Extreme Surface Conditions:** Venus has a scorching surface temperature (around 864 degrees Fahrenheit) and an incredibly dense atmosphere (over 90 times the pressure of Earth's). These conditions would severely limit the viability of any ground-based technology.
Comment: I think this summary reflects pessimistic source documents. The presentation is dragged down by comparison to
Earth.
* **Atmospheric Composition:** Venus's atmosphere is primarily composed of carbon dioxide, a potent greenhouse gas. This thick atmosphere traps heat, making it difficult for localized heating to create significant upward air currents.
Comment: I think the conclusion is weak. The hot gas HAS to rise, so it WILL rise. I would expect that the gas has no "difficulty" rising.
* **Super-rotation:** Venus's atmosphere rotates much faster than its solid surface. This super-rotation would likely disrupt any localized upward air currents, making them unpredictable and difficult to harness.
Comment: this is an interesting statement. The surface does not rotate at all, except if the perspective is from the Sun or some other remote location. However, the overall observation about the rapid movement of the atmosphere with respect to the surface ** is ** interesting and pertinent to this inquiry. kbd512's idea of a vertical chute to harness vertical movement of gas from the hot surface might well be enhanced by the circulation of the atmosphere above the surface.
I would note that kbd512's concept (if I understand it which I may not) is to guide "localized upward air currents", so the activity in the upper atmosphere is separate and distinct from the activity near the surface.
**Despite these challenges, research has been conducted on atmospheric dynamics on Venus:**
* **General Circulation Models:** Scientists use sophisticated computer models to simulate the Venusian atmosphere. These models provide insights into atmospheric circulation patterns, including winds, temperatures, and pressures at various altitudes.
Comment: these will be worth investigating, although I'd be surprised in anyone has data about how hot gases from the surface find their way up to cooler regions.
* **Space Missions:** Missions like Magellan and Venus Express have collected extensive data on the Venusian atmosphere, including temperature profiles, wind speeds, and cloud structures. This data is crucial for understanding atmospheric dynamics.
**Finding Specific Studies:**
* **NASA and ESA Websites:** Search the websites of NASA and the European Space Agency (ESA) for publications and datasets related to Venus atmospheric research.
* **Scientific Databases:** Explore databases like NASA's Astrophysics Data System (ADS) and Google Scholar for peer-reviewed articles on Venusian atmospheric dynamics.
* **Keywords:** Use relevant keywords in your searches, such as "Venusian atmospheric circulation," "thermal convection on Venus," "general circulation models of Venus," and "spacecraft observations of Venus."
**Important Note:** While the concept of harnessing rising air currents on Venus is intriguing, it faces significant hurdles due to the planet's extreme environment. Further research and technological advancements would be necessary to assess its feasibility.
I hope this information is helpful!

It seems to me possible that computer models of Venus' atmosphere might be capable of modeling the movement of gas from the hot surface to higher altitudes. I would expect that something like hurricanes and tornadoes must exist on Venus. All that incoming Solar energy is going to be moving mass around, and the rapid movement of the atmosphere may be the easiest feature for our (human) instruments to see.

This topic is available if we have a member willing and able to do the research to see if kbd512's idea would work on Venus (a) and (b) if the physical structures needed are achievable by humans this century.

(th)
(th)

Void · 2025-01-11 13:11:41

I don't know if I want to be confined to the terms you dictate (th).

It is my impression that the atmosphere of Venus does not turn over very much vertically. Otherwise, it would have radiated off much of the heat down below.

The atmospheric super rotation higher up causes very strong horizontal winds between the day and night though. I think those rotate once every four days.

If you want to make a vertical structure and can cope with the winds, for vertical strength space elevator materials might do. But they are likely to react with the corrosive atmosphere. Therefore, you might want a protective sheath around your elevator.

In building a vertical structure you are free to include floats appropriate to altitude. So, unlike a space elevator, the structure would not depend downwards so much from a floating island. Neither would it have to have the compressive strength to rise from the surface. Your vertical structure could use tensile and compressive strengths relieved periodically with floats.

To some degree, if you had Carbon tensile structures, you might cloak those in some sort of acid proof plastic materials. Outside of that you might have glass shingles, so that liquids condensing on the outside could flow downward and even be collected to turn a turbine.

If you brought the H2SO4 downward to a hot location you might cause it to decompose into H20 and SO2. And you might let those gasses flow upward, to condense into water which you could allow to flow downward internally to wash the Carbon of acid, The SO2 you could vent.

Clean water flowing downward internally could generate power going down as a liquid, and then you could boil it to turn a turbine and let the gas flow up.

Floats.

But way beyond our level at this time.

Ending Pending

If you had such a "Beanstalk" then water running down could cool some installations on the surface as well.

And you might be able to bring solid materials up and down inside the "Beanstalk".

Ending Pending

Last edited by Void (2025-01-11 13:23:19)

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