(2019 Archived) - Buckminster Fuller’s Cloud Nine and The Floating Cloud-Cities of Venus

Having written this in 2019, and originally published in 2021.. when I was 15 and 17, there would be inaccuracies that I would correct here. Having removed it, I'm publishing  again, for sake of completion so that the efforts wouldn't have gone to vain: Most of what's written still stands true today - although the logistics for creating such a thing would be inconceivably hectic. 

Colonizing Venus with floating cloud-cities, eh? The concept might be of some advantage; but how exactly are we to make a city float? Is it even possible? Yes, it is possible and the laws of physics allow it; But first, I’d have to take you on a tour of geodesic domes, tensegrity structures and Buckminster Fuller’s Cloud Nine.

A geodesic dome is typically a “hemispherical thin-shell structure based on the geodesic polyhedron” ^[5], which is built-up from triangular elements. Those triangular elements are very structurally rigid, and they collectively give the geodesic dome their unique ability to distribute structural stress. This speciality of stress-distribution makes the geodesic domes able to withstand enormous loads for their scale ^[5]. The renowned architect Buckminster Fuller was infamous for working with these geodesic domes. However, the reason I bring him to this book isn’t for his architectural masterpieces; rather, one of greatest unrealized plans with regard to geodesic ‘domes’ – the tensegrity spheres of Cloud Nine.

Fuller proposed Cloud Nine to be airborne habitats, created from geodesic spheres, which are made to float by slightly heating the air inside it; that is, above ambient temperature ^[6]. Whoa! Literally a city made to float by slightly raising its internal temperature?

Figure 1: This is a conceptual illustration of the floating geodesic spheres of Cloud Nine. They are covered with some skin, to trap air inside.

Before further questioning, it must be known that the strength of a geodesic sphere is directly proportional to its size. That is; the larger the geodesic sphere, the stronger it is. This relationship exists owing to the unique and efficient distribution of stress in the structure’s surface. Moreover, as a sphere grows larger, the volume it encloses will increase at a much higher rate, than the mass of the structure itself ^[6]. But, how does this help Cloud Nine to float? How can we use these principles to create a floating metropolis?

Prior to showing where the magic comes in, let’s take a Cloud Nine with a diameter of 0.8 kilometres as our standard model: Without going through all the complex-yet-accurate surface-to-volume calculations, it leads to the staggering conclution that the weight of the structure is only equivalent to ~1/100^th of the air it encloses! ^[7].

C’mon, isn’t it just amazing! I mean the Cloud Nines in the above conceptual illustration are as tall as the cliffs its background! Yet, it does so by simply exploiting this scenario. It’s almost magic; Using this principle, even an un-skinned sphere of that calibre, could float as easily as a hot-air balloon just by increasing the inside temperature by a single degree ^[7]! In simpler terms, the mass of the geodesic sphere is negligible compared to the mass of the air it encloses, and if the air inside the sphere were to be heated even by one degree higher than the ambient temperature of its surroundings; the sphere could become airborneand float upwards into the sky ^[6]. I believe that this is one of the few instances where, the square-cube law (which,by the way, limits the maximum size if mammals) works for us, rather than against us.

I also believe that the mass scaling of a Cloud Nine would not be a problem, because the mass of the structure would always be negligible relative to the mass of the air inside. Therefore, if we have the ability to heat the air inside, even slightly above ambient temperature – we would be fine. This also gives us another advantage; the ability to add more mass to the structure – specifically much more mass (which is sacrificial for excess lift). Much more mass – perhaps in terms of a city? Voilà!

For instance, we could have a large geodesic sphere with a diameter of 1.6km could support a city, which would in-turn sustain a population of several thousands of people ^[7]. Some other features of a Cloud Nine are that it “could be tethered, or free floating, or manoeuvrable so that it could migrate in response to climatic and environmental changes” ^[7]. I’d also imagine Fuller to have conceptualize the cities to be many geodesic spheres to be combined in a cloud-like fashion – thus the name; Cloud Nine.

                                          Figure 2: A cross-sectional diagram of the interior of a Cloud Nine.

But, the cross-sectional diagram of an individual Cloud Nine reveals it to be disappointingly empty space! Even if it were to achieve its purpose, would it be worth the expense when majority of the structure is air? Rest assured, I promise you that it would; specifically because, Fuller designed Cloud Nine to float on the Earth. That would require the Cloud Nine to lessen the density of the air inside it, even by a simple degree. But, the mass of the air would be so great that, it would require a very large heating system to do so. And the convectional currents might generate some strong winds. It is why I believe as to the actual habitat being protected by metre-thick water sheaths. However, a habitat with an area of 2.0114km² and a height of 100m is still quite tremendously large. Several thousands of people would be able to call it home.

Moreover, to our joy, it isn’t the case on Venus. Still, how exactly would a Venusian Cloud Nine (let’s call it ‘cloud-city’ for short) work? To propose the true effectiveness and efficiency of a cloud-city, a succinct lesson of high-school physics is of need:

It is hopefully universally known that Helium is a lifting gas in regular air. But, why does it do so? Why does a Helium balloon rise in the air, while a balloon of regular air would sink? It is because the Helium in the balloon and the balloon’s fabric are combinedly, lighter that the air they displace. Hence, the Helium balloon would then rise to an altitude, where the weight of the balloon is equal to the weight of the air it displaces. From a different approach; the pressure and density of the air at that altitude would be equal to both the pressure and density of the Helium in the balloon; the system would be at equilibrium?

Similarly, regular air is a lifting gas in Carbon Dioxide, which is the dominant gas in the Venusian atmosphere; Air is naturally buoyant in the Venusian atmosphere. Here is the turn-over:  What if we were to fill a balloon or a cloud-city with regular air and take them to Venus?  The weight of the balloon or the cloud-city will be lighter than, the Venusian air it displaces, and float. About the cloud-city; it is assuming that it has no heating system whatsoever!

Even if we were to fill a cloud-city with the air that you and I are breathing now, the structure would still float above the Venusian cloud-tops! Why? Because the density of the air inside the habitat, which is the density of the air you and me are currently breathing, is equal to the density of the Venusian air above the cloud-tops (The most Earth-like place in all of Venus, and the solar system). In concise terms, the Venusian cloud-tops is aerodynamically equivalent to that of near (and at) the Earth’s surface. On a different simpler approach; if we were to take a Venusian Cloud Nine to Earth, it won’t float! It would just stay on the surface (or perhaps float merely a millimetre or centimetre above). Similarly, if we were to bring a working Cloud Nine for Earth to Venus, it would float much higher above the Venusian cloud-tops^[1]!

As for the skin of the cloud-city: “Normal glass such as for house windows would be fine also for the outside windows – or lighter plastics” ^[8]. The skin of the spheres won’t necessarily have to be opaque leather or similar material; transparent materials, as glass or plastics (which could easily be manufactured from the Venusian soil and atmosphere, as we shall see later in this book) supported by a steel frame, would be quite alright. The mass of the frame and skin would still be dwarfed by the mass of the air it holds. And as long as the air inside, doesn’t diffuse to the outside, a Cloud Nine  on the Venusian cloud-tops, is a completely feasible option^[1], for building up a city and eventually a civilization.

Well, the only question now is: How would the Venusian Cloud-Civilization and Martian Civilizations compare? Which one is better and more worthy for humanity to live-off?

[5] Wikipedia (at 2019, February) Retrieved from (https://en.wikipedia.org/wiki/geodesic_domes).

[6] Wikipedia (at 2019, February) Retrieved from [https://en.wikipedia.org/wiki/cloud_nine_(tensegrity_sphere) ].

[7]   Baldwin, J. (1997). Buckyworks: Buckminster Fuller’s ideas for today. [John Wiley and Sons]. Page 190.

[8]  Walker, R. (2014, January 12). Will we build colonies that float over Venus like Buckminster Fuller’s “Cloud Nine?”  Retrieved from (https://www.science20.com/robert_inventor/will_we_build_colonies_that_float_over_venus_like_ buckminster_fullers_cloud_nine-127573).

 (Fig.1). Retrieved from (https://upload.wikimedia.org/wikipedia/en/2/2f/Project_for_Floating_Cloud_Structures_%28Cloud_Nine%29.jpg).

 

(Fig. 2). Retrieved from (https://worldbuilding.stackexchange.com/questions/36667/can-cloud-nine-be-built). 

Achinthya Nanayakkara (30.03.2025)

Originally published - 2021 (now removed)

Originallly written - 2019