There’s a decent chance that in the last few days, you’ve seen images of Analemma, the futuristic proposal from Clouds AO to hang a skyscraper (or should that be “earthscraper”?) from an asteroid in orbit of the earth. The project has been difficult to avoid, having been picked up not only by much of the architectural media but also by NBC, CNN, Forbes, The Telegraph, The Daily Mail, Mashable, IFLScience—the list goes on almost as long as the building itself.
Is the design realistic? Obviously not, and it’s obviously not intended to be. It’s intended as a utopian thought experiment. Clouds AO has something of a pedigree in this field, as winners of a NASA-backed competition to design a Mars base with their idea for a building made of ice. As a result, it would be facile to join the internet’s collective bottom-of-the-page comment mob to point out that it would be prohibitively expensive, or that it might be more enjoyable to live on the ground anyway.
But is the design a useful utopian thought experiment? There are some design failures that better technology, or a lot of money, or the changed mindset of a futuristic society just won’t fix. So without further ado, here are a list of the problems that this out-of-this-world design would face, in chronological order, with the issues that make it impractical in our current world marked as “minor” and the ones that would undermine the proposal in any universe marked as “major.”
Step 1: Go fetch an asteroid and bring it into orbit around the earth
As surprising as some may find this idea, it’s actually becoming increasingly feasible, with NASA hoping to place a small piece of an asteroid in orbit of the moon by 2021. The much larger asteroid needed for Analemma would cost a lot more to capture, but as Clouds AO argues in their project description, “if the recent boom in residential towers proves that sales price per square foot rises with floor elevation, then Analemma Tower will command record prices, justifying its high cost of construction.”
Step 2: Build a 27 kilometer-tall skyscraper in Dubai
Minor problem: The image below clearly shows that the intention is to build the skyscraper on the ground first, before loading it onto the asteroid. However, the final building is proposed to extend from 32 kilometers in the air down to just above the height of the “tallest obstruction.” Under Clouds AO’s plan, a safe height is likely to be around 5 kilometers (more on this later), requiring a tower of 27 kilometers. There are all sorts of reasons that building a 27 kilometer-tall structure isn’t currently possible, especially one as slender as is shown in these images, ranging from wind-loading problems to material strength. For now, let’s assume that this will one day be possible.
Step 3: Attach a 35,754 kilometer-long cable to the asteroid
Minor problem: If you thought material strength was an issue in the previous step, this is a whole other level. Currently the strongest material known to us is Carbon Nanotubes; if we could, hypothetically speaking, make those longer than just 6,000 kilometers, they would snap under their own weight. A cable strong enough to support this design would likely need to be at least six times stronger. Let’s imagine that, at some point in the future, this material exists (which, incidentally, would also likely mean space elevators are not far from a reality).
Step 4: Lift the Building Off The Ground
Minor problem: Lifting such a structure off the ground would be incredibly tricky. Assuming it is lifted from the base, even a minor deviation from vertical would cause it to topple over uncontrollably. Also, all the comfortable, settled structural members would have sudden, unpredictable loads added to them as the building begins to move, and as discussed above, this structure is precarious to begin with.
Step 5: Attach the building to the cable hanging from the asteroid
Minor problem: More structural problems for the building. Structures that are efficient in compression (ie those built on the ground) are not necessarily efficient in tension (ie those hanging from an orbiting asteroid). Let’s hope future engineers are talented enough to build a structure that, even at 27 kilometers long, can do both efficiently.
Minor problem: The asteroid is in a geosynchronous orbit—one in which it completes one orbit at the same speed as the earth rotates, once every day. However, since Dubai isn’t on the equator, this orbit can’t be geostationary. That means, from the perspective of the construction site, the asteroid briefly slows down overhead once every day, then dashes off southward, eventually coming to a halt a few hundred kilometers east of southern Madagascar before making its return at the same time the following day. In other words, the building needs to be attached very, very quickly.
Minor problem: The instant the building is attached to the asteroid, the center of mass of the whole system will be moved lower than it was before. That means the system is no longer in geostationary orbit; it is now on a collision course with Earth, unless the whole assembly can be lifted higher very quickly. Even Clouds AO’s own diagrams show the asteroid itself at 50,000 kilometers, well above the 35,800 kilometer height of a geosynchronous orbit. This change in height would have to be done pretty quickly to avoid the asteroid crashing down to earth—which would take some powerful thrusters given the bulk of the asteroid. Then, once the assembly (including your building) has been lifted up 14,000 kilometers, what to do? Hopefully the engineer planned 14,000 kilometers of slack in that supporting cable.
Step 6: The building is now “in orbit”
MAJOR PROBLEM: Anything “in orbit” which is dangling a significant portion of itself into the atmosphere cannot be considered to be in a stable orbit (unless, perhaps, it is in a geostationary orbit, as a space elevator would be). Since the building would be moving at speeds of hundreds of kilometers an hour between the northern and southern limits of its geosynchronous orbit, it would experience significant air resistance, which would gradually slow down the asteroid and de-orbit the entire assembly. This effect could only be counteracted with a continuous injection of thrust, which would require a lot of fuel—in fact, to imagine how much fuel, try envisaging our 27-kilometer skyscraper, while still oriented vertically, with wings attached, flying around at the speed of a commercial airliner. This would be just as efficient.
Step 7: Move the building to New York
Clouds AO’s plan is to utilize the cheap construction costs in Dubai and then take advantage of high home prices in New York, making the project more economically feasible. Like the original capture of the asteroid, this change in orbit would take a significant amount of fuel, but since this is a one-time expense (rather than the continuous use of fuel outlined in step 6) we’ll let it slide.
Step 8: Put the building in a geosynchronous orbit that sits above New York at its northernmost reach and off the coast of Peru at its southernmost
Minor problem: The orbit diagrammed by Clouds AO simply isn’t possible. In any orbit, the northernmost latitude reached is matched by an equal latitude to the south. This isn’t a problem per se—it simply means that the building is going to travel almost 3,000 kilometers further south, stopping just north of the southern regions of Chile. But this demonstrates that orbits aren’t as malleable as the proposal suggests, and that the dream of waking up over Cuba, eating breakfast as you fly past Atlanta, stopping in New York at lunch and then seeing Haiti around dinner time is not going to happen.
Step 9: Attract residents with spectacular, low flying views of the city
MAJOR PROBLEM: As discussed above, the bottom of the tower needs to be high enough to avoid the highest obstacle. For this orbit, that obstacle comes in Peru in the form of the upper range of the Andes. Thus, to be safe, the bottom of the building should orbit at a height of around 5,000 meters—hardly the “reach out and touch the Empire State Building” kind of distance suggested by the renders. It’s possible that the orbit could be calibrated to rise higher in its southern reaches and dip low over New York, but the trade-off in doing this is that the building would then be moving faster when it reaches the city, which in itself creates more challenges.
Step 10: Build a tower that allows people to hop on and off the moving skyscraper
Minor problem: Some of the renders show brave residents base jumping out of their homes, which is inadvisable for all but the northernmost and southernmost portions of the orbit, since the building will be moving at an average speed of around 720 kilometers per hour relative to the ground. But the detailed plans also show a rather nifty transfer tower, which should give a handful of people a window of a few seconds in which they can step off the building each day. The challenge here is the precision required. A lot of factors can affect the precise alignment of orbits (especially when the orbiting body is dragging its tail through the atmosphere) so making sure the tower hits its mark exactly will be tough. Also, as discussed above the transfer tower may have to be up to 5,000 meters tall, which somewhat diminishes the cost benefits gained by building the main skyscraper in Dubai.
For all its problems, the biggest downfall of the Analemma proposal might be its specificity. As astrophysicist Dr. Jonathan McDowell told The Christian Science Monitor, “it is a fun idea that gets engineers and architects thinking outside the box, which is its purpose.” It might also be considered an ironic take on the astonishing price of New York real estate.
But if those are its strengths, outlining the proposal in such detail—allowing it to be picked apart as I have done—might be a mistake. While the proposal would do better to place itself in the fuzzy boundary between science fiction and everyday reality, the extreme detail of this proposal allows an incredulous public to take it more seriously than they probably should. That's great news for news publishers, who feed off of the outrage of their internet audiences. But it's less good news for architects, who are left explaining to their friends that no, they aren't totally serious about this and no, this isn't the kind of thing that most of the profession spends their time on.