Tuesday, April 27, 2010

Forbidden Planet


To the naked eye it is the loveliest of the celestial wanderers, from ancient times bestowed upon the goddess of beauty. Once it held a large and distinguished place in the human Solar System. In the pages of Heinlein its colonists rebel against tyranny not once but twice. That most unlikely of space SF writers, CS Lewis, made it the abode of the unfallen.

Then came the Space Age. If the Mars of imagination buckled under the weight of our probes, the Venus of imagination evaporated like whatever seas it might once have had. Real Venus resembles the abode of the fallen, in a theology far sterner that Lewis's. No surprise that it has largely fallen from grace in science fiction as well.

Yet Venus is not less worthy of our attention than the other planets. It has gotten some love from the Russians, one probe surviving more than two hours on the surface, and sending back images. Hell, like Mars, has lots of rocks.

Venus is Earth's near twin, the Solar System's other large terrestrial planet. Like Earth it is still geologically active. It is the ultimate cautionary example of global warming, and we would like to know how it got that way. Did it lose its primordial oceans, or - formed closer to the Sun, and farther from the 'snow line' - did it never have significant water to lose?

If we are to explore the Solar System in person, not only from a distance, we will explore Venus as well, at least from an orbital station. There, teleoperators can control surface activity directly, without the 5-25 minutes of light lag delay from trying to do so from Earth.


To my surprise there has even been some credible discussion of colonization - not of the hellish surface but the upper atmosphere, with aerostats AKA balloons. At 50 km above the surface the atmospheric pressure is equal to Earth's, and temperatures are near the human comfort zone, 0-50 C. Human breathing mix is a lifting gas on Venus (with roughly half the lifting power per cubic meter of helium on Earth), so the entire gas envelope can contain breathing air. Venus gravity, about 0.9 g, is suitable for human health, while Mars' third of a g is probably not enough.

Humans could even go outside, in principle with nothing more than a breathing mask, though protective clothing against those sulphuric acid droplets in the atmosphere would be a good idea. And don't lean over that rail too far. It's a looong fall, and nasty down below.

Reaching an aerostat base from orbit is (relatively) simple. Getting back up is challenging but not impossible, Venus orbit lift being a shade easier than Earth orbit lift.

If you really want to walk on the surface, consult the psychological or religious advisor of your choice. Returning to aerostat level is straightforward, a skyhook balloon, but that and your cooling system should be very reliable.


Could Venus ever be an economic center? I believe that the most valuable thing we will bring back from space is knowledge. What is the price tag on what Venus has already taught us about carbon dioxide in planetary atmospheres? That kind of value can be difficult to 'monetize,' as they say in the biz racket, but the University of Venus might pull in some hefty patent royalties.

I'm not a big fan of Space Mining, but the surface of Venus is a strange place, apparently repaving itself every few hundred million years; perhaps its alien geology has produced concentrations of rare elements that we won't find among all those small rubble piles.


So, what might be the roles of Venus in the new human Solar System?


The image, from Wikipedia, shows Venus as it would appear through the viewport - with full dazzle filter.

75 comments:

Z said...

I'm so glad Landis' notion of aerostat cities got some attention- I first read about it some years ago and it's been late-night stargazing/coffee/nightcap talk ever since, with a couple dozen new entranced acolytes. Just the notion that would could take a bubble, with a person inside it, and it would roll comfortably around the planet (with a 24 effective day with the wind speed at some latitudes,) and just build rafts of bubble cities above the clouds, (and you can make zero-pressure balloons any size you like, and there's not much in the way of turbulence at that altitude, either) and you could walk across the catwalks between them- just about the sexiest thing I'd ever heard- and no antigravity required.

Of course, the trade for having what might very well be the most habitable chunk of real estate in the solar system is that there's a pretty incredible shortage of anything you can make anything else from- carbon and oxygen and sunshine being only so useful on their own-even a few more ppm of water and you might be in a better spot for making plastics, plants, and people...

It's also a mighty fine place for airplanes- 92 bar at the surface and slighty less-than-one-gee, you can make anything fly- just not anything fast.

I'd suggest that you might be able to vacuum up enough rock from aerostat "drill rigs" to get catalysts, trace minerals, and whatnot- except that it'd be the longest, hottest drill string ever conceived of being drug across the ground at a few hundred kph thanks to the wind speeds at altitude...

South Pacific of the Solar System, anyone? Quite pleasant, but sparsely populated thanks to its limited resources, and only intermittently valuable as a waystation to elsewhere- resupply for opposition slingshots to Mars?

Dex said...

This is going to sound crazy.

Where terraforming Mars is largely about gardening and atmospheric manipulation, terraforming Venus is about playing gods. Venus's rotation (to me at least) indicates a very violent collision in the distance past. Like the theorized proto-Terra & Luna collision; something hit proto-Venus hard enough and at such an angle that the planet began to rotate the opposite direction.

Makes one wonder what the effect of intentionally slamming a comet into the planet would do (and which direction would you want it to rotate)!

kedamono@mac.com said...

There was a Anime that took place on a terraformed Venus, Venus Wars I think. Just thinking about how to get rid of 99% of the atmosphere just gives me headaches. The easiest way would be to hit Venus with a big enough rock to blast the atmosphere off the surface.

The hard way would be to build a collection of massive spaceships that literally filled up with atmosphere and took it someplace else... Mars perhaps?

The more practical way would be tailored air-algae that floats in the atmosphere, eating CO2 and crapping carbon pellets. Then you have to deal with all that oxygen and planet covered in carbon...

Mr. Blue said...

Venus would be the home of Cool and Awesome, that's what.
You can have Zeppelin Dreadnoughts, airborne aircraft carriers, pirates, stealth attacks, and even giant mecha (for fighting on the surface). An author can justify a lot of traditional space opera tech with a minimum of hand waving.

Of course, the big question is why. Is there anything there that would be profitable? Because, for a space pirate, raiding multinational research staions really isn't worth the delta v cost.

Anonymous said...

Volcanic rock usually contains significante amounts of heavy metals and rare elements...Venus is covered in volcanic rock; It seems to me that the Cloud Cities of Venus could be a major source of rare elements and isotopes. A nitch market, to be sure, but relitively profitable, nonetheless. Pirates would want to steal Yettium and Neodynium, ect. and sell it on the black market. Cloud City-states would want to protect their investments; both from other city-states and pirates/privateers by any means. Armed zepplins, Mechas, even fusion-powered biplanes dogfighting in intercity wars... Yes, Venus has once again become fertile ground for space opera, rocketpunk, and even a new type of futuristic steampunk... So, what would the civilization of the Venus Cloud Cities be like?

Ferrell

Thucydides said...

Buckmaster Fuller once pointed out that a sufficiently large geodesic dome on Earth would become a hot air balloon, and once you reached sizes of about kilometer in diameter, there would be enough lift to support an actual town's worth of people and equipment inside.

Venus would be easier in one way, since the atmosphere is much denser, but also more difficult, since getting the temperature differential for lift would require more energy.

The real question is "why"? Getting material from asteroids and small moons seems easier than building aerostats trailing 100km long mining rigs, then generating 11km/sec delta V to boost the material into free space.

If anything, this may be another one of the marginal habitat areas where dissidents can settle in their "cloud nine" town bubbles and the rest of the Solar system will consider them quarantined by the high launch delta V.

Of course, should conditions change, then we have a planet of people with very strange beliefs suddenly bursting onto the scene...

Francesco said...

About stuff to be extracted on venus, the temperature differential between surface and the floating cities could be used to produce probably lot of free enrgy (I would have to do some calculations, but should be plentifull, and even if it resulted a bit low, well, venus is quite nearer to the sun, so some orbital station with solar panels would produce a lot of power to integrate), and this free energy could be used together with atmosphere extraction to produce a lot of nanotube wires, graphite-based nanochips, fullerenes and artificial diamonds.
And the byproduct would be oxygen, usefull for breathing and as an oxidant for rockets. The image I've in mind is something like the Bespin cloud city of Star Wars, a city with a long needle on its bottom, that goes down to extract energy and CO2...
Another possibility would be inseminating the venus clouds with some form of microbial products, to synthetize usefull materials, and harvest it (or maybe, for some SF stories, if it come out that some form of aerial organism already exist, like some scientist speculated some time ago, maybe some of their products could be
exotic/interesting stuff to harvest...)

Sabersonic said...

"You can have Zeppelin Dreadnoughts, airborne aircraft carriers, pirates, stealth attacks, and even giant mecha (for fighting on the surface). An author can justify a lot of traditional space opera tech with a minimum of hand waving." - Mr. Blue

"Armed zepplins, Mechas, even fusion-powered biplanes dogfighting in intercity wars... Yes, Venus has once again become fertile ground for space opera, rocketpunk, and even a new type of futuristic steampunk" - Ferrell

Such thoughts never even crossed my mind when I was writing out my setting mentioned in the Good Shepherd blog entry. Granted, I already had in mind Cloud City-esque Aerosat settlements that "evolved" from floating Cytherean research laboratories, but I never really imagined it to be such a fertile ground (or airspace, as the case seems to be) for Space Opera style conflicts between City-States. It makes me really reconsider the pre-World Nation history of Venus in my setting and add a few "boarder wars" here and there.

Now the only problem I got left is to justify the settlement of Cytherean Aerosat Townships beyond the Scientific Research and War Refugee reasoning in my settings early history and to warrant a plausible economical basis for the planet....

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Jim Baerg said...

At the 2009 Worldcon in Montreal, Landis gave a talk on Venus which included his idea of habitats floating in the atmosphere of Venus.

He was thinking of using photovoltaics to provide energy to such habitats. I noted that the habitats would be in the part of the atmosphere that is moving at a few 100 km/hr relative to the surface & putting a windmill on a tether down to where the atmosphere is moving some 10s of km/hr less would provide energy all the time rather than just when the habitat is on the day side. He 'liked' the idea, 'crazy enough to work' was the way he put it.

jollyreaper said...

It's always dangerous to make universal assumptions based on one or two examples, the classic one in scifi being that bipedal humanoid lifeforms being the most practical solution selected for by evolution and that's why we can sleep with the space babes. Devil's advocates will point out we have examples of convergent evolution on Earth but this is for critters all evolving from the same origins and living in the same environments. Icthyosaurs look like dolphins, the flying lizards bear a passing resemblance to bats, etc. Bats and birds represent two differing approaches to the same problem, flight by heavy organisms. (Heavy compared with the usual flying critter, insects.)

That being said, I have to wonder about the similarity in mass between Earth and Venus. If we accept the standard model of planet formation, that planets condense out of a stellar disk around the same time the primary forms, is it usual for the rocky planets to be Earth-like, especially within certain bands? Mars came out a little light but Venus is a really nice size, just got a bit unfortunate about location near the sun.

If that's the case, then as far as stories go there are so many earth-sized worlds because that's how the disks tend to clump in planetary formation. And thus given the odds, carbon-based life is likely to form on worlds that fall in the habitable belt around suitable stars. If that weren't the case, we wouldn't be here to notice it.

As for Venus' atmosphere, if we were terraforming wouldn't step 1 be to bombard it with rocks to provide oceans, step 2 create organisms that will sequester atmospheric carbon and let it fall to the ocean floor for eventual subduction back into the crust? (assuming venus has plate tectonics.)

Terraforming Venus wouldn't be easy or within our abilities for a long time but it's theoretically feasible.

Citizen Joe said...

I'm liking the aerostat cities. I do think you could harvest the heat/wind from below for 'free' power. While the temperature at that altitude could get cold, I suspect that it will be self regulating. Buoyancy bladders cool, city sinks lower into the atmosphere, picks up ambient heat, rises... Of course, you could simply draw heat from down below geothermal style.

I'm partial to keeping the hellish surface as such and dropping high temperature/pressure fabrication facilities. So you've got your bucky tubes, critical for space elevators, you've probably got high temperature structural products for reentry into atmospheres, I'd like to see silicon carbide processing into fusion shielding.

I'm liking Venus as source for fission products too.

Geoffrey S H said...

"You can have Zeppelin Dreadnoughts, airborne aircraft carriers, pirates, stealth attacks, and even giant mecha (for fighting on the surface). An author can justify a lot of traditional space opera tech with a minimum of hand waving." - Mr. Blue

"Armed zepplins, Mechas, even fusion-powered biplanes dogfighting in intercity wars... Yes, Venus has once again become fertile ground for space opera, rocketpunk, and even a new type of futuristic steampunk" - Ferrell

"Such thoughts never even crossed my mind when I was writing out my setting mentioned in the Good Shepherd blog entry. Granted, I already had in mind Cloud City-esque Aerosat settlements that "evolved" from floating Cytherean research laboratories, but I never really imagined it to be such a fertile ground (or airspace, as the case seems to be) for Space Opera style conflicts between City-States.” – SaberSonic

“You’ll have to navigate over this trench avoiding surface fire, until you come to this smokestack. Our analysts predict that it leads right down to the main boiler. A direct hit should destroy the entire aerial cannon-platform. But be careful, its chobham-armoured so you’ll have to use HEAT bombs.”- courtesy of Air-Marshall Dodonna.

Anonymous said...

Geoffrey S H said:"“You’ll have to navigate over this trench avoiding surface fire, until you come to this smokestack. Our analysts predict that it leads right down to the main boiler. A direct hit should destroy the entire aerial cannon-platform. But be careful, its chobham-armoured so you’ll have to use HEAT bombs.”- courtesy of Air-Marshall Dodonna."

I'm still laughing! Yes, that was kind of what I was thinking of.

Thinking of what might be some elements of Venus society: what would be the most valuable substance on Venus? Wouldn't that back whatever currency used there? Local use mining-products should be less expensive than those imported from off-world. You should need a local source (time-sensitive) of building materials because humans have a tendency to expand their population when they spend more that just a short time in one place. The population of Venus will most likely stay small, even if you had dozens of New York/LA/Mexico City/Hongkong sized city-states, the population would likely remain far below 1 billion, forever. If people find significant amounts of some rare element or substance whose cost would be economical to ship off-world, then local pirates (other than food/oxygen thieves) and unscruplous off-world governments might become a threat; or, precived as threats or potential threats. Those Cloud City-States might develop armed forces to defend themselves against those real or imagined threats; then, their neighbors become nervous and form their own armed forces...then others develop new military capabilities and the original City-States take this as proof that they were right all along... I don't see Earth becoming united any time soon...actually, in some notes I've made for stories set in a distant future, this era of humans' history is refered to as "The Terran Disunity"... This gives Venus a lot of room to exist without interferance from Earth.

A NeoVictorian culture developing in the Cloud Cities would be a wonderful challage to any author. I think I'll explore that in some future stories of my own...

Ferrell

Mr. Blue said...

You know, if the mining thing doesn't work out, Venus would be a great place for resorts and cruise ships. It's (relativly) close to Earth, nice to look at, and building/ maintaining Cloud City Resort and Casino is a bit less of a nightmare than the Saturn's Ring Resort. You don't need to have spin gravity for starters.

In fact, I kind of like the Carribean model for the future Venus. Start with colonial powers exploting the territory for resources (with lots of privateering), move on to a more settled group of Colonies (with pirates), add a bit of slavery and forced settlement (with a few revolutions), and finish with senic Resorts (with some independant and semi-independant states).

Stevo Darkly said...

I think my post just got swallowed up ... testing. (Excuse me.)

Stevo Darkly said...

Yep...

Well, it was a post about the "Pirates of the Cytherean!" in a world of floating city-islands and fighting airships.

I also explained how the cloud-pirates would always be worried about the poisonous atmosphere of Venus seeping into their ships through hard-to-detect leaks and becoming dangerous over time. This would especially be a worry aboard fighting ships that were always being damaged by weapons-fire.

Remembering stories and proverbs about coal miners using canaries as early-warning detectors of toxic gases -- because birds' super-pneumatic breathing systems make them especially sensitive to such airborne poisons -- paranoid pirate captains who worry about air-quality would take up a colorful habit of always carrying a bird of some sort upon their shoulder ... SQUAAWWK!

Markus said...

I'd like to be a bit skeptic about zeppelins in a conflict situation. Sorry about the long-windedness of this post.

I'm sure some of you have thought of it already, but no one has mentioned so far that it is incredibly easy to down an airship. The main reason is that you have the huge balloon which cannot really be armored. Consider a rigid, spherical balloon of 1 km diameter. With a surface area of three million square meters, even a hypothetical light-but-strong nanocarbon armor of 2000 kg/m3 density and thickness of 1 mm (not enough to stop, like, anything) would weigh some 6300 tons. The mentioned balloon would, in 1 kg/m3 atmosphere, lift about 3100 tons, so even that shallow armor is not possible.

This means that you can destroy a city or any aerostat facility by firing a missile, cannon or whatever at its balloon. One hole is enough to seep the balloon full of atmospheric gas and eliminate its lift-generating capability. This creates a situation much like good ol' Mutually Assured Destruction in Cold War, with the sides having capability of destroying each other completely in a short amount of time. Also, this is the terrorist's paradise.

Of course, low-intensity conflicts like pirate raids might not cause balloon-popping. Facilities might also have some emergency rocket engines to slow down their fall in case the balloon is destroyed, which could save the facility. But I would imagine the situation would necessitate some agreements to limit total war, which generate their own problems of some people deciding not to obey the treaties.

- Markus

P.S. I hope the formatting comes out right. Notepad messed it up first.

Markus said...

Whoooops. Somehow I slipped a totally wrong number in my post... my mistake.

The lift generated by the 1 km balloon is enough to lift 534 kilotons, not 3 kilotons as I stated. This would enable about 8 cm of the armor I mentioned, which is much better but still not enough to stop a decent weapon (and in that case most of the lifting capability would go into armor).

- Markus

Luke said...

Markus

Small holes are not much of a problem - gas will leak out only slowly because there is not much of a pressure difference across the hole. The fabric may even be self-sealing. Explosives that rip huge holes will be more problematic, but explosives fuses might have a hard time detonating against something as flimsy and radar-transparent as balloon fabric. The airships can be made even tougher by interior compartmentalization - blow open a few compartments and the airship can still float. In an extreme, you could fill the airship with something like an aerogel, giving almost continuous compartmentalization and keeping lifting gas from leaking from any hole (although this might make refilling the airship with lifting gas more of a problem).

8 cm of some sort of advanced nanoscale carbon armor will provide some pretty significant protection, likely stopping all smallarms, heavy machine guns, and possibly light autocannon. Of course, the pirates might be armed with deadlier, more penetrating weapons than modern firearms as well, so it could cancel out. Lots of armor severely reduces the amount of other good stuff you can lift, though, so I mostly see airships using the flimsy but tough strategy outlines above.

Citizen Joe said...

I don't think that holes in the balloons would be immediately disastrous. At that altitude, equilibrium pressure of the gasses inside (breathable N2 and O2) and outside (CO2) results in lift without excessive diffusion of the gasses. Holes in the top would be problematic but not catastrophic. Of course, once you start dropping in altitude, problems will escalate exponentially.

Gridley said...

I really like the notion of blasting away a large portion of Venus' atmosphere and splashing it onto Mars. Let's do a WAG for this exercise in mega-engineering.

Earth's atmosphere masses 5x10^18kg, with a surface pressure of 101kPa. Let's call this ideal. Venus has 480x10^18kg and 9,300kPa, and has 90% of Earth's surface area. We'd need to suck away about 99% of that. OK, that's 475x10^18kg. We want to hit Mars with about 1.5*10^18kg (~30% of Earth's surface area), or about 0.3% of what we threw. Seems like there's some potential there.

What if we ship atmosphere from Venus to Mars? Well, we're still moving about 1.5*10^18kg. Let's say we've got something the size of a (ULCC) supertanker - that can haul 500*10^9kg. We'd need to make 3,000,000 trips. Oh, and of course we'd still need to blow over 4x10^20kg off Venus - preferably keeping almost all the Nitrogen there or for shipment to Mars and just loosing CO2.

If I'm reading Atomic Rockets right, there's a Hohmann window for Venus/Mars transit every 11 months, and the trip will take a little over 7 months. Let's imagine two tanker fleets of 1,000 ships, one leaving Mars and one leaving Venus every window, spending a little under 4 months at each end for crew down-time, maintenance, and of course on-loading and off-loading cargo. It'll take them 2,750 years. Yikes.

Gridley said...

A quick note on holes in the aerostat cities - sounds like a problem akin to damage control aboard ocean-going ships. You'd have pumps, crews (or robots) ready to do quick patch jobs, and some way to compartmentalize near the surface. Borrowing a page from rigid airships, you might well design your city with positive bouyancy and routinely carry dumpable ballast. A weapon nasty enough to overwhelm your DC efforts probably would have done a number on a 'normal' city anyway.

Luke said...

Gridley

I usually go farther than you - I say the best option for terraforming Mars is to crash Venus into it. After all, you need to add a lot of mass in order to get a liveable gravity.

(disclaimer - this is a joke. It is only a joke. In the event of an actual seriousness, the laughter you just heard would have been choked off and a mock serious face would have been adopted.)

Anonymous said...

Luke, I've heard a similar proposal to smash Europa into Mars. In this case the proposal was serious.

If you want to terraform Venus, I suggest biotech for atmospheric processing. Design a few plankton species to sequester carbon, dump a few vats of these plankton into the atmosphere, and give Venus its very own oxygen catastrophe. As for rotation, if we're willing to talk about smashing Venus into Mars surely speeding Venus's rotation would take less energy than that.

But I've got to say, I find the idea of the Cloud Cities of Venus to be a lot more interesting than yet another Generic M-Class Planet. Cloud cities drifting above a venomous furnace, dangling windmills into the hurricane breeze below.

The resource situation reminds me a bit of fishing, with independent boats and corporate trawlers vying for control of rich currents. There are lots of light elements in Venus's atmosphere. Perhaps Venus could compete in the biotech field.

Ian_M

Citizen Joe said...

Plant life should flourish with those kinds of CO2 levels. All you need is water. Many flowers and some trees (oaks) even like acidic conditions.

I'm wondering if the buoyancy of the atmosphere, possibly combined with the high speed winds might make for a good air launch. If so, then food production on the floating cities of Venus, then packed with dry ice at the Cyrethean L2 point. That grants more launch windows out into the rest of the solar system than from Earth.

Another possibility is as a testing ground for gas giant operations.

Gridley said...

Luke, my plans for mega-engineering generally stop JUST short of altering the orbits of planets. On the other hand, I'm not opposed to laying out Dyson rings...

If we're going to crash planets together, though, surely we should smack Mercury into Mars? Or set up a really nice bank shot where we snap Mercury past Venus just close enough to snag a good chunk of its atmosphere, then continue on to impact Mars, neatly increasing its core mass and giving it an atmosphere at one fell swoop? Drop in a few comets and asteroids for flavor. Bonus if you can make a smiley face from impact craters. :-)

Francesco said...

With a bit of advanced biotech, maybe you could even engineer some kind of mega-organism self-floating... I guess something of the giant-flying-tree kind. It could use multiple fruit-like pods to concentrate lifting gas, with wood as structural element. Self-repairing, self-growing, only to be farmed a little to ensure proper behaviour. The main problem would be water, for what I understand Venus atmosphere is quite poor of hydrogen in any form and bond... but i guess some source could be found, even if it would mean having instead giant flying cacti...:)

Citizen Joe said...

You can pull hydrogen out of the sulfuric acid clouds. But you'd need to bond the sulfur to something else. Perhaps a cybernetic plant... At the core, there would be some sort of reactant chamber. The plant would dip into the sulfuric acid clouds which would react with lead (or something) that generates an electric charge. This would then reel up a carbon nanotube which was trawling through the ground pickup up various metallics. The weight drags the plant to a lower altitude, higher heat, higher pressure, where it then reacts the sulfuric acid with the metallic compounds forming free hydrogen. The sulfates then precipitate out and the plant rises back up into the higher atmosphere. There it reacts with the carbon dioxide and nitrogen to grow. As it drifts to the dark side, it dips back down into the sulfuric acid clouds and repeats the process. Eventually the core becomes too corroded and needs to be replaced. These plants would act as surface miners and water/oxygen producers.

Anonymous said...

Or you could use sulphur-eating bacteria to clean up the hydrogen. Why spend billions on processing facilities when you can do the same job with goo in a bucket?

Ian_M

Citizen Joe said...

They don't actually free up the hydrogen. They take the sulfuric acid (H2SO4) and convert it to Hydrogen Sulfide (H2S). Basically it liberates the oxygen.

Now if we cyberize that bacteria with some rust (Fe2O3) we get this reaction:

Fe2O3(s) + H2O(l) + 3 H2S(g) → Fe2S3(s) + 4 H2O(l)

Once all the iron has been sulfited, that portion needs to be taken out of operation and reconverted.

2 Fe2S3(s) + 3 O2(g) + 2 H2O(l) → 2 Fe2O3(s) + H2O(l) + 6 S(s)

What we're really doing is pumping gasses through the reaction chamber, alternatively oxygen and Hydrogen Sulfide, both created by the bacteria in sulfuric acid. This results in the creation of water and elemental sulfur, which precipitates out (insoluble in water).

Never the less, Hydrogen is in very short supply, so water is going to be treated like it is in Dune. On the plus side, there's a higher concentration of Deuterium on Venus due to the lighter hydrogen floating off. They might trade heavy water for light water at a decent rate. I'm pretty sure that they won't be using Hydrogen as remass though. My suggestion would be dry ice (CO2) frozen in Venus's shadow. These would of course be specialty ships. I can see lots of organics going out with hydraulics coming in.

Markus said...

@Luke & Citizen Joe
True, I hadn't really thought of that since I assumed we had a totally empty, zero-pressure balloon to get rid of the mass of that gas. But indeed the security obtained by filling the balloon with lighter gas than the atmospheric CO2 would probably outweigh the lost lift capability while assessing risks. And I hadn't thought of compartmentalization, either. Good points.


About the shortage of hydrogen and water on Venus: One thing that's troubling me is that Venus, having no significant magnetic field, is taking quite a lot of solar wind, which is mostly ionized hydrogen. Wouldn't it be possible to trap this hydrogen by slowing it down with, say, some electromagnetic fields of large size? We would use a magnetic field to collect protons and electrons from a large area and then route them to a platform which slows them down with electrostatic fields.

We would probably lose energy in the process (situated in space, the platforms projecting the fields would have to hold themselves in place with engines opposing the wind), but it's still one possible source, though only complementary to the chemical methods discussed above. We would also need very large areas covered with the magnetic fields to gather usable amounts of hydrogen.

I'm not sure, but we would actually get some energy from slowing the particles down and then recombining the protons and electrons and the resulting atoms into molecules, but all of this and more would be lost with the engines holding the platform in place. The engines would use something more abundant as reaction mass. Is this about right?

- Markus

Citizen Joe said...

I wonder if that is what is causing the lightning on Venus. Solar winds ionizing hydrogen and blowing off the protons would leave an excess negative charge. I'm not sure that there is enough hydrogen left that the process is still going on, but it would need to be addressed for terraforming reasons. I bet that L2 station could attract those particle somehow and reform them into hydrogen. How far out is the Cyrethean L2 point? Could a space elevator be stationed there thus completing the circuit (and powering the elevator).

Rick said...

Wow. I had no idea what I was letting loose amid the clouds of Venus! I should have known: zeppelins and cloud cities are the geek brain on drugs.

Of course, the big question is why. Is there anything there that would be profitable? Because, for a space pirate, raiding multinational research staions really isn't worth the delta v cost.

This is always the big question, when it comes to Exceptionally Cool Stuff in Space.

Of course, for purposes of Romance, your explanation merely has to sound convincing.

Anonymous said...

Lanthanum, Yetterium, Neodynium,Niobeium, ect...water, oxygen, food, and anything else that ensures life, health, and wealth; Cloud Cities could be a primary source of complex food, medicine, biotics, and Rare Earth elements; if you're a pirate, why buy something valuable when you can steal it? After all, if you weren't willing to risk your life by going out a'bucceneering...then you probably wouldn't be a pirate in the first place.People will always find a way to make a living...whether legal or not.

Ferrell

Citizen Joe said...

Piracy may be more akin to pulling up someone's lobster pot and stealing the lobsters. The Ferrosulfide water mining bacteria things would probably be cast out to drift into the sulfuric acid clouds with transponders and some rudimentary guidance mechanism (like a balloon. When full and needing a recharge, they might send out a beacon call to 'authorized entities'. Then they'd get the signal, drop out of the clouds and interceptors would pick them up for processing. But unauthorized access is also possible. Likewise, surface mining would probably involve chemical reactant balloons to lift the ore to the cloud layers. Again, sky pirates could swoop in and steal your haul.

Thucydides said...

While poaching "lobster pots" might not sound very exciting, this is the way pirates operate, minimum risk, maximum reward.

Real pirates in the age of sail usually had small ships with very few guns; they could overwhelm merchantmen because 40 or 50 pirates swarming over the rail would be enough to convince the 12 or so crewmen to surrender peacefully. Modern day Somali pirates coming aboard with AK-47's and RPG's usually have few issues from the small number of crew aboard modern tankers or container ships either.

The largest pirate operations were actually run as military operations, taking port towns by siege or storm. This actually makes perfect sense because the British encouraged piracy starting in the Elizabethan age as an adjunct to the real wars against Spain and France. Once the Spanish Main was not so "Spanish" anymore, the British were pretty ruthless in suppressing piracy.

Will Venusian pirates start off by receiving Letters of Marque from the Kingdom of Mars or the Trailing Trojans Empire?

Michael said...

The clouds of Venus seem like pretty forgiving terrain for pirates also (from a certain point of view).

A fission powered aircraft could thrust and maneuver via the atmosphere, sucking it in, compressing it, and hurling out the back, so no big reaction mass tanks are needed. The atmosphere plus curvature of the planet makes detection downright lousy compared to open space. The pirate craft might even carry balloons to inflate so they could just hang in the atmosphere like a tiny cloud city.

On second thought, auxiliary balloons are probably required for docking. If a lifting body pirate craft wants to dock with a city that is just floating on the wind, it would be a lot easier to do if the two were going the same relative speed. So you get close to your port of choice, kill velocity and deploy balloons to get in the same frame of reference, and then just use maneuvering thrusters to bring your ship in.

kedamono@mac.com said...

Nuclear thrusters are all well and good, but what cloud pirates really need are sailing ship!

I know that sounds a lot like Space: 1889 and the like, but with the winds and all that, why not take advantage of the environment and use just the wind to propel you lot of scurvy dogs on a raid to Aphrodite City?

Rick said...

A problem with 'sailing' is that all nonpowered balloons are simply carried along with the wind. The only form of directional control is raising or lowering yourself into a different wind stream. (Which might be all you need; I have no idea how winds on Venus operate.)

Note that winged flight is constrained by lack of atmospheric oxygen - you have to carry your entire power/fuel supply, with no free oxidizer from the air. Basically this limits you to rocket plane flight durations.

Existing nuke plants are far too heavy for aircraft (even apart from shielding, it's basically a steam powered airplane, an aviation nonstarter). For nuke heavier than air flight you need a bit of technomagic in the power plant.

Citizen Joe said...

A stirling differential drive. Get a 'tall' aircraft with hot stuff coming in down below, then it cools off up high where the wind speeds are faster, thus increasing the cooling.

Wikipaedia has a nice bit on Venusian atmosphere and you get many varying wind patterns. By moving towards the poles, you slow down. During the daytime, the upper regions migrate towards the poles but towards the equator on the night side. Descend and you have a reverse effect, as well as a general slowing. So, a skilled navigator could go all over the place by simply moving up and down in the atmosphere (barring such things as getting fried, frozen or eaten alive by acid).

Jim Baerg said...

Rick said "A problem with 'sailing' is that all nonpowered balloons are simply carried along with the wind. The only form of directional control is raising or lowering yourself into a different wind stream. (Which might be all you need; I have no idea how winds on Venus operate.)"

This gives a pretty good overview of Venusian winds.

The steady wind in one direction with a vertical velocity gradient means that the balloon cities will be carried around the planet in a few earth days, & raising or lowering a balloon will allow it to move east or west relative to another balloon. For North-South motion you could sail by lowering a sail on a tether to where the windspeed is significantly slower & holding it at an angle to produce a north or south force.

I already mentioned in an earlier comment the possibility of wind power by lowering a windmill to where the windspeed is significantly less than where your balloon city is.

Thucydides said...

So a little scenario building here:

Venus is a relatively important cog in the solar economy due to the huge supply of carbon dioxide; which the Venusians render into Super Carbon Nano Stuff(tm). Lately, the Republic of Mars has been putting plans into effect to import megatonnes of raw CO2 to bulk up their atmosphere as part of the Terraforming project.

The Trailing Trojan Empire is not thrilled with the prospect of a powerful and attractive terraformed Martian Republic becoming the political and economic hub of the asteroid belt, supplanting Imperial power, and have secretly issued Letters of Marque to some unsavoury characters to disrupt the Martian plans. Some technical support is coming from the Uranus Space Navy, since they see an opportunity to spike the 3He market and reap some financial gains for their home team with the turmoil and extra space traffic in and around Venus.

Pirates try to avoid the floating cities and their patrols, using zeppelins to poach "lobster pots" and fusion powered lifting bodies to get the loot to orbit.

The Venusians are not pleased at the prospect of loosing production and profit to a bunch of scurvy pirates, and even less at becoming the proxy battleground for a conflict between other powers. On the other hand, enlisting the aid of other powers like the Imperial Jovian Space Navy will bring more players into the fray, and compromise the independence of the Venusian balloon city states.

Elukka said...

You'd get a similar payload fraction to modern jets if you could manage a reactor + shielding system comprising about half the vehicle's total mass. (In essence replacing the fuel tanks.)
This is where I note that I have no idea where the engineering limits for power/mass go.

There was quite a bit of research into nuclear jets during the cold war. Look up the Tupolev Tu-119 and Convair X-6. Sadly, information appears to be scarce and a lot of it on Wikipedia isn't properly sourced.

To my understanding, the reason that the nuclear aircraft programs ended up being cancelled had more to do with a lack of a mission requirement rather than them not being workable.

Mr. Blue said...

Yaaaarrg, Pirates and poachers,

So, we have our floating city states with a few confederations mixed in. Each one would likely claim the swath of latitude it flies over. Partly for security (you don’t want AGM’s in your path) and partly for mineral rights.

So, how do you keep the poachers from unauthorized (and unpaid) mining of your territory? And how do you keep the pirates from stealing from the miners that have paid good money for leases? It all depends how big, rich and powerful the state and military is.

The big, powerful, rich city states/ confederations with large, powerful militaries can keep a pretty good eye on things. Expect frequent patrols and lots of control of mining. Mining vessels and “lobster pots” will be registered, watched, and frequently inspected. The fees for mining rights and leases will be high. However, even though the profits may be lower, there would be a high safety factor. The bigger, more established companies would like this.
Pirates and poachers would likely avoid these territories. It’s too much trouble.

Next, the slightly smaller city states would likely not be able to afford enough navy to both protect it and its mining right. So, it may combat poachers and pirates by authorizing Privateers. The state would sell both mining licenses and letters of marque. The letter of marque would allow the bearer to seize any unlicensed mining vessels and destroy any pirates, with the city state receiving a percentage of the value of the vessels or cargo.
Pirates and poachers may take the risk of popping over into their territory on the off chance the patrols are a bit late.

And then there’s the international territories. No leases needed, but better spend some cash on some good weapons. You’ll need them.

Also, for some reason, I doubt that Venus will be the weak sister in Interplanetary politics. Too many resources, lots of room for expansion, and lots of free solar energy.

Mr. Blue said...

As for the role of Venus in interplanetary politics- I think that Venus and Earth may wind up as rivals for interplanetary hegemony. It may be that Earth winds up in the same role as England in the late 19th century, with the largest and most experienced space navy. As such, many of the independent colonies around the Solar system would then be able to focus their scarce resources on developing a merchant fleet and expansion while allowing the Earth navy to keep peace.
And, after many years of growth, a wealthy and independent Venus may find itself in the same position as Germany in the late 19th century- rich, powerful, and desiring both off world colonies and a large space navy of its own. This can lead to an arms race of deep space warships between the two planets… and some very interesting story ideas.

Citizen Joe said...

I've been looking more into the sulfur eating bacteria (and there are loads of them). One of them takes sulfates (SO4 or sulfuric acid crystals) and oxidizes it with organic material (like CO2) and then throws off a waste product of Hydrogen Sulfide (rotten egg smelling poisonous gas, H2S). Meanwhile the Purple Sulfur Bacteria takes CO2, H2S and sunlight to produce H2O, elemental Sulfur and formaldehyde (CH2O). Formaldehyde is a precursor for various resins. So when you combine readily available carbon fiber (not the super stuff) with readily available resins and a corrosive hot atmosphere, I could easily see Venus as having a disposable culture. Rather than making stuff to last a long time, they make stuff easily replaceable... except for water. Waste water and they'll pull it out of your corpse.

Anonymous said...

It occures to me, that like a Lunar or orbital habatat, living on a Cloud City would require that you be polite to each other...excessive aggression could be viewed as a threat to the city...throw in a 'historical revival' and you have the basis of the development of a NeoVictorian society... there are other methods of producing thrust in an atmosphere: other chemical reactions other than oxidation to produce heat; ordinary rockets; some complex sail scheme; pressure differential; battery powered microwave heating of compressed Venus-air; "ionic breeze" type propulsion; RTG-electric powered prop engines; the list could be endless, especially if you mix and match. It might behoove any wouldbe pirates to have both 'low-speed' and 'high-speed' propulsion systems. One for crusing and the other for quick getaways...Oh, and pirates might need harpoons (attached to cables) to haul in their prey. Besides, modern reactor design is lighter than it was in the 1950s; a hybrid zepplin-airplane-sailing ship the size of a 707 or even a 747 and powered by a miniture reactor or a large RTG, could be a a good canidate for a prototype for either a pirate ship, military vessel, or commercial transport...take your pick!

Ferrell

Geoffrey S H said...

That's without factoring in the potential for new gases to lift airships being researched and produced.

On the subject of armouring an airship- perhaps multiple redundant gasbags withing a ballenite encased frame?

One more thing- can anyone think of a name for an airship that is one syllable and not "blimp". Just Trying to not use naval terms to describe such aircraft...

Luke said...

Note that you can do better than the rocket equation in an atmosphere, even if you have to bring your oxidizer along with you. This is because you only need to provide fuel and oxidizer (energy), the propellant (change in momentum) comes for free from the atmosphere. You take a hit in energy density - specific heat of combustion goes from about 40 MJ/kg to about 10 MJ/kg. If you are still using chemicals for fuel, you either need a more efficient method of extracting that energy (jet turbines are about 30% efficient, piston engines about 20% - perhaps very high temperature turbines or fuel cells could be used for increased efficiency) or you won't go so far on one load of fuel. Something like a sailplane could still go for a very long distance, however.

For large aircraft, something like the SAFE-400 space nuclear reactor could give you enough power-to-weight for unlimited cruising, excepting only down-time for maintenance (the SAFE-400 is a bit over half a tom, and provides 130 HP).

If your setting pushes "battery" technology to the very limits of what chemically bonded matter can provide (battery, here, also includes things like flywheels, torsion springs, capacitors, superconducting inductors, superconducting microwave resonant cavities, and other energy storage devices that can directly give you electrical or mechanical power), you can get back to maybe 40 MJ/kg - except that this can be available energy rather than just heat, without the inefficiencies of running it through a heat engine to produce work. At 40 MJ/kg, you would get about 3 times the amount of work per kg of "fuel" if it was used to drive an airscrew or rotary wing (turbojets are intrinsically heat engines, so a jet plane would only do about as well per unit mass on ultra-batteries as on kerosene). You might want to throw in a safety factor of two or three to prevent your ultra-batteries from exploding at the slightest jolt, however, bringing you closer to the specific work of modern hydrocarbon fuels.

If you are flying above the cloud layer, solar powered sailplanes can give you unlimited endurance - assuming the long Venusian night did not exhaust the batteries well before dawn. Modern cutting edge technology is on the verge of being able to make this trick work on Earth.

If your aircraft are meant to work near a bubble city, they could use beamed power from lasers powered by the city's on-board reactor.

And if you want to go completely off on a bizarre tangent, have your heroes ride the half-ton giant Azhdarchid pterosaurs, with 10 meter wingspans and standing 4.5 meters from feet to top of the head on firm ground (the height of a giraffe). Give them life support, of course, so that they can breathe when outside.

Rick said...

Welcome to another new commenter!

Some good points regarding aircraft, from combined wing/airbag forms to the advantage of using energy to turn airfans rather than direct rocket thrust.

I don't think there's much if any prospect of new lifting gases, but if you need more lifting power than breathing air provides, hydrogen does not have the Hindenburg problem in Venus atmosphere.

On commerce and piracy, the sort of piracy where you actually steal the cargo and fence it off works best for high value/mass goods, not bulk goods.

Note that Somali piracy is somewhat a different game. So far as I can tell, they don't usually take and sell cargoes, instead holding ship, crew, and cargo for ransom. Different of trades and political environment, different modes of piracy.

Thucydides said...

Based on this and other past posts and comment threads, I suspect the bulk of the readers and posters here are interested in SPACE OPERA (include hugely amplified reverb sound effect here).

There are a lot of great ideas being floated (heh) in this and other threads, and they can be bashed together in many different orders to create a wide range of scenarios. I even believe that "fighters" can be justified using aerospaceplanes designed for atmosphere scooping (making transitions between the atmosphere and space for those amazing turns and popping out for laser or missile runs).

The starting point is figuring out why people are out there in large numbers in the first place...

Rick said...

Space opera? Naaah, what would lead anyone to a conclusion like that, just because we went straight from 'aerostats' to pirate zeppelins in the clouds of Venus?

An emerging theme of this blog is how how much opera can be done within Realistic [TM] technical constraints. The really heavy lifting is not technological but economic. (Though of course economic level is tied to techlevel.)

Thucydides said...

Just thinking out loud here, but I suspect one of the reasons Space Opera tropes are so prevalent is they reach back to historical analogies we can understand, while what little of space we have seen and experienced (however vicariously) is so alien that the mind recoils.

Humans are great at finding patterns, even to the point that some of us can see patterns where there are none (the Face on Mars, Fingerprints of the Gods, the many explanations of the history of the Knights Templar and Masonic lodges, 1421 and the Chinese round the world cruise etc. [Alt history is a secret passion; it combines history with fantasy!]).

When we look at the "Space War" threads here, or take a long read of "Atomic Rockets", we discover space fighters are not possible, "small" space warships will have the size, mass and manouoevre capability of a ULCC oil tanker, cargo will not go by tramp freighter but sealed in small containers in ballistic orbits, and settlement needs to start with massive Island 3 structures to get the shielding, redundancy and stability needed to survive in space.

Everything is backwards compared to what we know and expect, this "Alice in Wonderland" experience is very unsettling. Far easier to have Heinlein's "sodbusters" and George Lucas' "X wings". Realistic Space Opera is possible; but there is a lot of hard work in the set-up, which only few of "us" will appreciate.

Anonymous said...

Geoffrey S H:
"One more thing- can anyone think of a name for an airship that is one syllable and not "blimp". Just Trying to not use naval terms to describe such aircraft..."
How about "Zepp"?, "Wing"?, "Bird"?, "Soar"?, "Flug"?...take your pick.

Ferrell

Geoffrey S H said...

Thanks, just reflecting that such a term is invariably attachted to a vehicle "class" over time. Aircraft are "planes" or "jets", watercraft are "ships' or "boats" and I'm beginning to lean towards calling spacecraft "thrusts" or "torches" in settings.

"zepp" or "blimp" it probably is then...

Stevo Darkly said...

Personally, I think it's cool to speak of airships in naval terms, but other possible terms for such craft (trying to stick with one syllable, but not succeeding):

- Bloat

- Floater

- Floaterplane (if also using aerodynamic surfaces for lift)

- Bloon

- Jettelin (if using jet propulsion)

- Lift

- Stogie (from the shape)

- Cythe (re airships specificically for use in the Venusian, or Cytherean, atmosphere)

Hmm. "Cythe" (pronounced like "scythe") might be the coolest -- especially if the airship had a vaguely sickle shape to it. Sort of like the airship vehicles depicted here, but curvier instead of angled:

http://www.jpaerospace.com/atohandout.pdf

(The PDF is about "airships into orbit" which is a fascinating idea itself, but IIRC it has encountered some technical problems -- especially concerning drag -- that make the concept less likely. Google "airship to orbit" and see "Orbital Airship" in Wikipedia.)

Stevo Darkly said...

Hmm, sort of a cross-post.

Also, nix the suggestion of "stogie." I meant "cigar-shaped" but just found out that "stogies" are simple log-like cylinders that don't taper, hence probably not appropriately descriptive of the an airship.

Geoffrey S H said...

Its not so much that I dislike the idea of naval terms, but more of a problem in cross-service terms. Space/Air/Wet Navies could duplicate alot of terms if they refferred to equipment, ranks etc in such a way...

Citizen Joe said...

How well does CO2 block UV rays? UV tends to tear up epoxies, so if everything was built from carbon fiber and epoxy, it would decay quickly without protection.

VonMalcolm said...

Blimp:

Lens (the plural is semi-awkward)

Rug / Rugby

Pig / Pigskin (works on two levels)

Link / Sausage (more pigs in space?)

Bomb / Bombshell

Torp / Torpedo

ummm. . . that's all for now!

VonMalcolm said...

Any thoughts on using Venus's CO2 as a fuel source? From what I gather the high temperatures and pressures would be beneficial for converting CO2 into useful fuels (if one could work in such an environment!).

link

link

link

Jim Baerg said...

"Any thoughts on using Venus's CO2 as a fuel source?"

Zubrin in _The Case for Mars_ advocated using a small nuclear reactor on Mars to convert water & CO2 to methane & oxygen for use as fuel for the rocket to go back to earth. That should work for Venus too.

Citizen Joe said...

I think the primary problem is the lack of hydrogen, particularly in the form of water.

Now if you can somehow capture the solar wind, that's free inbound hydrogen in the form of plasma.

Rick said...

Nomenclature, hmmm. 'Airship' is already an established term, and 'zep' is a strong contender, because 'zeppelin' is probably the best known term in the pop culture. Other alternatives seem a lot less likely.

But another approach is to invent a brand name that goes generic, or a term like 'tank' that arises by historical fluke.

Jim Baerg said...

"I think the primary problem is the lack of hydrogen, particularly in the form of water"

The sulfuric acid droplets that make up the clouds of Venus should be an adequate source of hydrogen for a few ballon cities & the rockets to get from them to Venus orbit.

If you want to terraform Venus then many orders of magnitude more hydrogen is needed, but that's a different question.

BTW regarding motivations for building Venus cloud cities: Somewhere I saw mention of evidence that *something* condenses out as a sort of frost or snow on the higher altitude parts of Venus. This would be a 'frost' that condenses at oven temperatures.

This might be some fairly mundane material or it might be useful concentrations of some rare & valuable element. If the latter we have an economic motivation.

Anonymous said...

Jim Baerg said: "BTW regarding motivations for building Venus cloud cities: Somewhere I saw mention of evidence that *something* condenses out as a sort of frost or snow on the higher altitude parts of Venus. This would be a 'frost' that condenses at oven temperatures.

This might be some fairly mundane material or it might be useful concentrations of some rare & valuable element. If the latter we have an economic motivation."

The Cloud Cities of Venus...and its sequal: The Frost Miners of Venus! Thanks Jim!

Ferrell

Citizen Joe said...

"Beneath the Acid Skies: What a Long, Strange Trip It's Been."

VonMalcolm said...

Blimp: I agree that Zepp is the best contender, though in imagining an oppressive regime in a Steampunk story that uses ever-present zeppelins as an overbearing part of its police force I can imagine phrases like: 'Careful: Pigs are Flying', 'Watch Your Tongue: Pig Ears Above', or 'Be Cool: Pig Overhead' being uttered with ease!

Stevo Darkly said...

I tried to find some information about what the Venusian mountaintop "snow" might be. I found this:

http://news.wustl.edu/news/Pages/633.aspx

Apparently the leading contenders are lead sulfide and bismuth sulfide. The headline makes this sound more definite than it is, I believe.

Frustratingly, this research announcement is undated. However, upon searching further I found that the same announcement also ran in Science Daily in February 2004:

http://www.sciencedaily.com/releases/2004/02/040210074951.htm

Although in November 2005, the BBC was reporting as if other substances were still in the running:

As for what the snow is made from, the rare metal tellurium and iron pyrites, or "Fool's Gold", have both been proposed as candidates.

Recent work by a team at the Washington University at St Louis suggests the metallic frost is more likely to be sulphides of lead or bismuth.


http://news.bbc.co.uk/2/hi/science/nature/4335628.stm

-- Stevo Darkly

Damien Sullivan said...

CO2 wouldn't be a "fuel source", it'd be a feedstock for storing energy otherwise obtained. Like breaking water up to make hydrogen using nuclear or renewable power.

My own idea for terraforming Venus starts with a planet-wide sunshield, to let it cool off and freeze out. Not sure of the time scale, though.

VonMalcolm said...

Fuel Source / Feedstock: Same Difference?

Definition of Source via yourdictionary.com: 'that from which something comes into existence, develops, or derives: the sun is our source of energy'.

Feedstock maybe better/more specific: but I think people understand what I mean!

From wired.com:

The prototype will be about the size and shape of a beer keg. It will contain 14 cobalt ferrite rings, each about one foot in diameter and turning at one revolution per minute. An 88-square meter solar furnace will blast sunlight into the unit, heating the rings to about 2,600 degrees Fahrenheit. At that temperature, cobalt ferrite releases oxygen. When the rings cool to about 2,000 degrees, they're exposed to CO2.

Since the cobalt ferrite is now missing oxygen, it snatches some from the CO2, leaving behind just carbon monoxide -- a building block for making hydrocarbons -- that can then be used to make methanol or gasoline. And with the cobalt ferrite restored to its original state, the device is ready for another cycle.

http://www.wired.com/science/discoveries/news/2008/01/S2P#ixzz0on84hVOf

Rick said...

There's a subtle but important distinction between energy sources and energy storage media - between solar energy per se, for example, and biofuels that store it.

I've often heard the term 'feedstock,' but I'm slightly hazy on where it fits in that picture. Make that just plain hazy. I associate it with a raw storage medium, like corn fed into a bioreactor?

Anonymous said...

Feedstock is used at the front end of a proccess; often it results in the creation of a fuel or other desirable product, like plastics or chemical compounds.

Ferrell

Rick said...

Well, I kinda sorta got it half right!

Randy Campbell said...

As to "nomenclature" of flying vehicles on Venus, "Xities" (for eXtraterrestrial-cITIES") has been suggested by relative articles in the Moon Miners Manifesto.

That could be extended to include Lighter-Than-Air vehicles, (Xepplins) or hybrid or heavier than air vehicles (Xerodyne)which would pretty much boil down to the short versions of:
Xep and Xero (Zep and Zero)

Possibly working it's way into seperate Xity-States being refered to as "Zits"?

Just tossing it out.

Randy