Buoyant structures in the atmosphere of Venus

There has been a wealth of concept art of balloons exploring or even human colonizing the upper atmosphere of Venus, where pressure as well as temperature is Earth somewhat median. These designs tend to involve classical balloons, or some fairly mundane variant thereoff. These would operate in a region in the Venusian atmosphere corresponding to where, “pressure wise” balloons would operate in Earth equivbalent regions, i.e. 1 atmosphere and less, corresponding to 50 to 100 kilometers from, the Venusian surface. That’s a long way up, correspondingly a good ways down. This does open up a possibility I haven’t so far heard anywhere – to deploy staggered vertical structures in the venusian atmosphere.

The difference between a balloon and a buoy is essentially the balloon, to a  large degree, maintains positive pressure. A “Buoy” is a hard surface object with as much underpressure as you can without the object being crushed. On Earth we deploy buoyant objects on the surface to float, but we also deploy them underwater as submarines. Submarines float because – even though thay are constructed of metal – the total weight of metal hull plus gaseous insides allows for well callibrated neutral buoyancy. 

You can clearly do the same on Venus, though not as effectively. But we can actually do better than that – If we were to deploy a large Hydrogen ior Helium balloon cluster at +50 kilometer (or higher – we should aim for the an optimal bouyancy versus temperature versus pressure versus strcture weight) from the surface (where the temperature is in the balmy 20s) we could in theory supend from this balloon a spherical reinforced metal “Buoy” from a corrosion resistant flexible cable – or actually down a tower. On Earth we can deploy rigid towers easily hundreds of meters high. We build rigid buildings up to a kilometer. 

Concluding from that we could thus deploy a ‘hanging tower’ much much longer, say 10 kilometers. That opens up some interesting possibilities. Considerations here would be heat, lateral gale force, corrosion and quickly mounting atmospheric pressure. But lets assume we can deploy more loosely stacked, “chain-like structures” that can flex with differential in wind speeds. At the top of these would be a large cluster of lighter than Venusian air balloons operating at about 1 Earth atmosphere, or about 25 degrees centigrade. Suspended from that would be a reinfored suspended tower with at regular intervals a set of floatation devices. 

The lowest those devices would thus be 10 kilometers lower, say, where the tenmperature is well in excess of 100 Centigrade, pressure is something like 10 atmospheres. We know that the weight of the atmospheric medium is about 6% that of water on the Venusian surface, so in essence an absurdly heat resistant human would allegedly be able to flap wings and fly down there. This atmospheric density isn’t enough to float actual equivalents of submarine-like structure, but we don’t want to go all the way down there just yet. I can visualise very rigid metal cylinders maintaining a vacuum (or be filled with underpressurized helium opr hydrogen, whatever would workl) that at 10 atmosphere would float, and be able to carry useful cargo. So in those ten kilometers we might have actual bouys ‘down there’, balloons all the way up – and a range of intermediate bouyant vessels with a range of materials that would be capable of the optimal passive lifting capacity to keep the aformentioned cable or strut structure in roughly the same place. The upper atmosphere of venus thunders around the planet at 300 kilometers pert hour, literally streaking over the underlying surface with considerable power, pushing this structure along just as fast. It wouldn’t be particularly noticeable but there might be considerable differences in wind speed between the upper section and 10 kilometers lower. 

If we think in terms of a rigid structure (which will have some interesting advantages, which I will speculate about a bit later) it won’t be for many decades before we have any chance of deploying that – it’s a lot of material to be safely dropped from orbit. We’d have to drop it having decellerated in space relative to the venusian atmosphere, because we can’t deploy stuff like this using typical heat shied braking – we drop this with parachutes, incrementally.  That means, stage by stage. Each stage we add balloons and “winch down” the tower every so gradualy. If we were to do so in increments of a hundred meters per go (counting the deployment of bouyancy devices, and support structure) it would take tens to a hundred such successive doployments before our dangled “anansi” analogue floatation device would be deployed to a depth where the temperature would become meaningfully prohibitive to continue. 

But is that true?

I may be operation under prejudice. Devices we deploy on the surface of Venus die in an hour or less, because of the heat. The Russian probes would be able to maintain a stable temperature using a paraffin melting process. They froze the probes before atmospheric descent. But what if we could use active cooling? Turns out if we have an uninterrupted structure connecting the upper surface to ever lower regions in the Venusian atmosphere we actually do have the potentia for active cooling. We could generate electrical energy and by above means we can visualise a means to convey that energy down into the infernal depths so to speak. Can we descend the full 50 kilometers? That’s an engineering challenge I do not have anywhere near the engineering skills to address. We would have maybe several different configurations of hard shell atmospheric bouys that woul have to be incrementally more heat resistant. We can’t reasonably deploy pressurized balloons where the atmosphere becomes too hot, not too mention wind speed differentials and electrostatic build-up,  corrosiveness, solar and cosmic radiation (Venus doesn’t have a magnetic field, and materials can get affected by high radiation levels over time). 

How far can we take this set of premises? Again, I am no engineer. I entertain possibilities and try to visualise their functionality largely in a cinematic style, a presentation format that would feel and sound plausible to the typical viewer if outlined in a documentary or movie. But’s let’s rolls with it ad wade ever deeper into the proverbial pits of hell, and beyond the continental shelft of everyday scientific scepticism.

It’s the year 2117. In a high orbit around Venus is an orbital structure with 48 scientists. These are not typical humans – they look somewhat human – but they are clearly cyborgs, and their organic parts have been genetically tampered with. They do however act recognizably human. They joke around, watch entertainment, wear clothes, they sleep intermittently. They speak english, most likely. The orbital structure is quite big – a total mass not much dissimilar to a 100.000 ton aircraft carrier that assembled from parts that started arriving in unmanned missions in the 2070s, assembling with automated systems. The first humans arrived in 2098, stayed a month to do science, returned back home to the well-developed Earth-Moon system. The Earth-Moon archipellago has been subject of exponential growths in terms of orbital populations since the 2030, the total number of people in L5, L4 and on the moon doubling every 5 or so years, so let’s assume it by 2100 the population in space exceeded a hundreds of thousands. That would mean a manned Venusian mission wouldn’t be such a big overhead any more. It does take time to get to venus, because in order to get large amounts of mass in terms of useful mass into the inner solar system, you either have to juggle very precarious and time consuming Hohman transfer mechanics – or you bruteforce it whenever you can deploy the raw propulsion output to make such a trip in under two months. 

So we find in 2017 it’s been close to two decades we had the equivalent of an Antarctic base in a high orbit above the cloud decks of Venus, all this monitored by dozens of scientists. So a few years ago we had an Elon Musk kind of visionary and slightly crazy “unorthodox thinker” who went beyond established rules and postulated an outrageous plan to get humans down to surface of Venus – and stay there. 

It would be a monumental undertaking, and putting down landers would be categorically unacceptable, no matter what the BBC would have you believe. It’s just too risky. But there is a way to do this within accetable margins of safety. So humanity sets out sending huge amounts of deployable structures in quite large space tankers to a high orbit over Venus, literally a hundred of such shipments over two decades and more to come.

The first deployment occurs in 2017. There are already numerous manned observation platforms hovering on balloon platforms since the 2080s, so deploying stuff to the cloud tops is an aquired skill by now. But the failure rate is still pretty high even in the 2010s, so you have to come with a comprehensive and absolutely rock solid plan to get permission to risk human lives.

The first deployments look not unfamiliar to earlier balloon missions, just bigger. They are hexagonal matted stuctures that break their orbital speed, so they fall pretty much vertical down into the atmosphere. They do NOT want to waste shielding mass on aerobraking manouvers – it’s easier to to the breaking in highh orbit, tumble down vertical and use tried and tested VTOL propulsion to position the descend stage precisely where you want it. The descenders pop opebn with a loud bang, discard their carapaces into the atmosphere, unfold quickly in a rigid frame balloon of a permeability resistant fabric, containing a mixure of hydrogen and helium. The unwrapped hexagonals are bright reflective mirror fabric lillypads each 75 meters diameter, and they huddle close together to form a very large surface of interlocking Hexagonals, surrounding a central semi-rigid platform netting to catch conscutive descenders. 

The process then heats up so to speak, and meaningful construction materials go down to the Venusian cloud city at a rate of one every few days. And look down underneath the floating sky-base we see splindly robotics assemble a rigid structure of interlocking regular spokes and rods and cables. Right underneath the sybase, in the the shadow, there is a large construction space composed of tent material, cables and fixed gridwork. In this space the robots keep adding suspension tower, and hinch it down. Before long the accumulated mass of the dangling structure starts to weigh so much as to pull the entire platform base down by hundreds of meters and the temperature, artmospheric haze and pressure become a problem. 

The next stage is to winch downmassive reinforced triple layer shiny metallic foil cylinders, each pulled to close to a vacuum. These cylinders float even as high as several hundred meters so as they are lowered with lift structures they yank on the struts in the gusting winds of the atmosphere. The tower needs a near uninterrupted sequence of these buoyant cylinders – all this robot activity and cables and struts and cranes yields a lot of nett mass, and all that mass pulls down, whereas that’s not where we want to go.

So after 6 months the incoming landers, the continuous caravan of added struts, balloons, atmosphere buoys, robots, construction equipment, etc. is startiong to add up. We see a much larger type of hexagonal lifting balloons being anchored around the hexagonal central landing nave of sky city. We see that there are now three interlocking towers leading down, and 400 meters lower, barel;y visible in the thick atmospheric fog we see the buoys keeping the whole structure in a very predible equilibrium. The suspension towers have now advanced a kilometer down, and it’s pretty hairy down there. It’s over 70 degrees, and pretty gusty. The cameras occasionally spot St. Elmo’s fire – there’s a lot of volcanic dust and mean little droplets of chemical burn even this high. 

It’s 2118 and the first human goes down to the cloud tops of Venus. He arrives in a little habitat that looks like a symmetrical cluster of 21 spheres, a bit like a regular cluster of grapes, each set with large observation windows. It’s a very intimidating place to look down on the cloud below. There isnt much to see other than urine colored clouds, but to consciously know what is down there puts the fear of Great Cthulhu in every human being.

2119, the hanging tower is now 5 kilometers, and we are deploying a new type of heat resistant rigid frame suspension bag. It’s the weght effective and same time the most resilient solution for an ever worsening problem,. Temperatures there are in the mid 80s Celsius, it;’s terribly gusty, there’s a type of  evil lightning you can’t see, but it can short equiment and it gives of EMP pulses. The corrosion is bad, but well within the boundaries of material tolerance margins. The construction continues unabated. 

It is the year 2120, and there’s now a 6 person team living in the clouds. They celebrate Christmas and Newyear as the lowest central antenna array underneath the cloud city has descended to ten kilometers into the clouds. 

Now comes the hard part. The booyancy devices that are winched down start looking a lot meaner – harsh military analogue style hexagonal tubes each 15 meters long, 5 meters diameter and they are elevatored down in discrete batches. These things look like they can withstand a nuclear war, and the need to at temperatures over 120 degrees Celsius, searing winds. They need to be tough as space marines. They can’t fail under any circumstances. Even a minor failure would trip the emergency shorts, and a series of explosive bolts would drop the whole structure to save the cloud city above. But Murphy is not welcome to this party and the process continues unabated, years progress, every bigger landers arrive, cloud city is now a sequence of miles of big interlocking silvery slabs. You can see landers coming down their descent stages roaring in the atmosphere, mostly at night. It’s a beautiful sight, the blazing blue signal beacons strobing, and then the whole thing dropping in the nets, a crane grabbing the payload, 30 minutes later the next lander comes in, and this goes on stage after stage after stage. The Cloud city is now big enough that there’s the capacity to have return-to-orbit systems in place. These rockets are evil, using an extremely effective fuel in terms of weight/propulsion capability, but the gunk is super toxic. But since now no longer have to meticulously recycle and repurpose the components of the landing systems, we are working a lot more efficiently. The new landers are really big, silvery square rockets 50 meters high, plump and thick and ugly industrial bricks. These come from the zenith in a blue actinic flame, winch down their cargo, and go up again with 4 G acceleration and leave the Venusian gravity well with a brutalist rythm and regularity. 

What’s going down into the atmosphere is now a very solid looking fabric covered cylindrical lattice work of cables and struts and vins. Inside the fabric there’s no wind, there are no droplets of acid, there’s no dust. It’s still searing hot down there, and it’s all automated winches with very little robots having to do anything. The building is now a clockwork repetetive deployment in sequential stages, like a tube of tooth paste. 20 kilometers down there’s a six ton scientific module taking ladar measurements in a roaring wind. It’s 10 atmosphere and over 250 degrees centigrade. We no longer have active assembly happening at those depths – it’s too evil down there. The city winches down new constituent buoys, struts, cables in a simmering howling inferno of winds and orange yellow smoke. 

It is time for the cap stone. It’s 2125 and one of the biggest landers ever deployed roars like a Leviathan into the atmosphere. Human eyes in the Sky city gaze in terrified disbelief and awe at  the monstrosity that descends, many kilometers distant. It’s a hexagonal structure 50 meters tall, 50 meters diameter, set with dozens of rockets. It descends and illuminates the atmosphere in blue and green for minutes. Then it manouvers into place downwind and lands on the surface. It is a static structure – no active machinery. And one day, years from now, it will be the connection point from the surface to Sky city. A literal 50 kilometers down. But before we get there we have a lot of work to do.