This is a linkpost for https://lostfutures.substack.com/p/why-werent-hot-air-balloons-invented
Nice work! I spent some time thinking about the Montgolfier brothers a while back for similar reasons, and it's interesting to see your analysis.
Sporatic attempts at parachuting had taken place for 1500 years prior to the Montgolfier brothers' hot air balloon. But both the Montgolfier brothers' first hot air balloon demonstration and the first recorded public parachute jump took place in 1783, over 300 years since the first known depiction of a parachute. It's interesting that the parachute seems to have reached maturity at the same time as the parachute, rather than earlier, given the much longer history of parachuting attempts. It seems like a reasonable working assumption that something fundamental was permitting both to occur in 1783 - maybe advancements in textiles, aeronautics, or something else.
The first recorded parachute jump was by Louis-Sebastien Lenormand. His previous attempt was with two umbrellas, and his subsequent parachute jump was witnessed by Joseph Montgolfier. Lenormand had studied physics, was involved in the intellectual scene, and was apparently inspired by a tightrope-walker's use of a parasol for balance. Unfortunately, information about Lenormand's life is sketchy.
Medieval Europians had toy parachutes. Lenormand was embroiled in the French intellectual scene. He was a physicist. His first attempt using parasols seems to have been no more methodical than the attempt of the polymath Abbas ibn Firnas to use a big cloak to break his fall from a tower in 852. It connects the insight of the feeling of drag, the resemblance to bird wings, and perhaps knowledge of toy parachutes, to the possibility that a bigger, convenient sort of device might break the fall of a person.
There was a lot of conversation and images produced of parachute designs in the hundreds of years before Lenormand, so we needn't posit that Lenormand reinvented the idea.
Where Lenormand went further than Abbas ibn Firnas was in improving the device after his first attempt - upgrading from two parasols to a full parachute. And his improvement over, say, Leonardo da Vinci was in publicly testing a real working parachute.
I find it likely that that the coincidence of the Montgolfier brothers' and Lenormands' demonstrations in France in 1873 was no accident. There was something about that place and that time that motivated them. If I had to guess, it was something cultural: the idea of testing things in the real world, familiarity with hundreds of years of parachute designs, a critical mass of competitive and supportive energy in the nascent aeronautics space, increasing cultural familiarity with connecting physical intuitions with practical engineering to design"magical" machines.
Thanks for the detailed and informative response Breakfast! I think I largely agree with your post.
I find it likely that that the coincidence of the Montgolfier brothers' and Lenormands' demonstrations in France in 1873 was no accident. There was something about that place and that time that motivated them. If I had to guess, it was something cultural: the idea of testing things in the real world, familiarity with hundreds of years of parachute designs, a critical mass of competitive and supportive energy in the nascent aeronautics space, increasing cultural familiarity with connecting physical intuitions with practical engineering to design"magical" machines.
(1783* you mean.) A revolution in thought definitely aided the invention of the hot air balloon. Novel philosophical ideas and the scientific revolution inspired a more discerning examination of the invention space. But let me ask you this, do you believe the hot air balloon could not have been invented prior to these cultural ideas and parachute design knowledge? My intuition says no, especially given that the Montgolfiers' first balloon prototype was just a large sky lantern made of thin wood and taffeta lifted by burning paper.
IMO, the hot air balloon is an invention that had a fair probability of being invented anytime after the invention of the sky lantern but simply failed to materialize until the scientific revolution and aeronautics pushed said probability near 100%.
I think that question needs more precision. We could identify the most efficient series of actions a caveman, Roman, or Leonardo da Vinci could have taken to build a hot air balloon. We could ask how many person-hours would have been required to build a hot air balloon starting with the raw material inputs in each year from 0 AD to 1783.
On a broader level, if we assume that the intellectual ferment of 1783 France was the main cause of both hot air balloon and parachute, we can equally ask whether that ferment could have occurred at an earlier point in time.
If I had to guess, whatever structural factors supported urban agglomeration are the underlying causal factor here. Maybe advancements in agriculture and governance, or technology-centered arms races (Lenormand studied gunpowder and Montgolfier was stimulated by the potential of the hot air balloon to break sieges)?
It vaguely seems to me like human history is a process of slow, self-reinforcing agglomeration and institution-building. The process accelerates itself. The rare things that were build close to the earliest possible moment we take for granted. We don’t ask whether the first stone tools could have been invented 10,000 or 100,000 years earlier. There’s just a few tantalizing inventions, like the hot air balloon, that make us think “maybe.”
Overall, I think structural forces dominate, but I also think that individual humans have perhaps a greater ability with time to individually influence those structural forces in lasting ways.
History is full of kings and emperors whose reigns seem to have amounted to just a lot of meaningless death. These days, even idiots who get elected can quietly make useful improvements in governance, because our planet is full of advisors who actually do consense on some policy issues that are more than partisan point scoring. We have social movements like EA that encourage people even in their teens and twenties to envision the pursuit of positive sum ambitions of world changing scope.
So I don’t know how likely it would be for the hot air balloon to have been built decades or centuries earlier than it was, or whether that would mean very much. I do think that we are narrowing the gap between when things are possible to build and when they do get built with every passing year.
According to Wikipedia, Joseph Montgolfier started building parachutes in 1783 two years after the first recorded public parachute jump and did parachute jumps himself.
It's possible that the parachute itself motivated the hot air balloon. If you know that you have a parachute that protects you when the hot air balloon fails, it's less scary to trust the hot air balloon.
It's interesting that the parachute seems to have reached maturity at the same time as the parachute
You likely meant something different.
My default assumption is that it took humans that long to get a clue (or shift a paradigm). We are remarkably bad at creating new thinking patterns. In my area of interest, fundamental physics, there are similar patterns aplenty. It took several decades to get from the first black hole metric to understanding black hole horizons, even though no new math was required. Similarly, it took several decades from EPR to Bell, and the math there was... very elementary. The most glaring example is the Euclid's Fifth Postulate (about parallel lines): It took some 2000 years (!) for mathematicians to notice what was literally in front of their eyes and under their feet: that there are cases where the first 4 postulates hold, but the 5th does not!
To be fair changing the 5th postulate requires some creative redefining of what a straight line is. In my experience when explaining non-euclidean geometries to muggles the hardest part is not the 5th postulate or its consequences but making people accept that on a sphere a straight line is really a great circle (the easier way being through the concept of a geodesic line but this was invented after non-euclidean geometries if I'm not mistaken.
Yeah, there are two equivalent definitions of a straight line, "don't turn" and "shortest path", both known to the ancient Greeks, I'm sure, but not formalizable in any easy way until differential calculus was invented, and not well until Riemann. Still, if someone actually asked Euclid "what do you think the closest thing to a straight line might be on a sphere, and which postulates hold there?" he would probably have done the rest.
Montgolfier's balloon was inefficient, cheap, slapped together in a matter of months
I agree the balloons were cheap in the sense that they were made by a couple hobbyists. It's not obvious to me how many people at the time had the resources to make one, though.
As for why nobody did it earlier, I suspect that textile prices were a big part of it. Without doing a very deep search, I did find a not-obviously-unreliable page with prices of things in Medieval Europe, and it looks like enough silk to make a balloon would have been very expensive. A sphere with a volume of 1060 m^3 the volume of their first manned flight) has a surface area of ~600 yard^2. That page says a yard of silk in the 15th century was 10-12 shillings, so 600 yards would be ~6000s or 300 pounds. That same site lists "Cost of feeding a knight's or merchants household per year" as "£30-£60, up to £100", so the silk would cost as much as feeding a household for 3-10 years.
This is, of course, very quick-and-dirty and maybe the silk on that list is very different from the silk used to make balloons (e.g. because it's used for fancy clothes). And that's just the price at one place and time. But given my loose understanding of the status of silk and the lengths people went to to produce and transport it, I would not find it surprising if a balloon's worth of silk was prohibitively expensive until not long before the Montgolfiers came along.
I also wonder if there's a scaling thing going on. The materials that make sense for smaller, proof-of-concept experiments is not the same as what makes sense for a balloon capable of lifting humans. So maybe people had been building smaller stuff with expensive/fragile things like silk and paper for a while, without realizing they could use heavier materials for a larger balloon.
That said, hot air balloons did have some practical applications:
- Military Ballooning—Hot air balloons can be used for reconnaissance
- Cartography—By providing an aerial view, balloons are useful for more accurate mapmaking
- Weather Observation—Balloons can be used to gain knowledge about parts of the atmosphere inaccessible from the ground
Tenses my rationalfic worldbuilder brain. Outputs: so I wonder if we'd have better international transparency cultures (faster surrenders/treaties, and fewer arms-races, and so a much greater chance of solving the alignment problem) as a result of the legacy of a long history of military ballooning for reconnaissance.
Military uses of a hot balloon are more "create a small mountain to climb up" and less "satellite imagery before satellite". They did not revolutionise warfare at the tactical or operational level, and even less at the strategical level.
Though ballistic weapons were more developed at the time hot air balloons were actually invented, presumably making it more dangerous / unfeasible to fly a balloon deep into enemy territory than if the balloon had been invented earlier
I'm pretty sure no ballistic weapon until well into the 20th century was a significant threat to a balloon flying at more than a few hundred meters above ground.
If a partially reusable and affordable rocket like the Falcon 9 was feasible in the 90s, then the answer is surely yes.
A similar rocket wouldn't have been feasible in the 90s as a rocket computer system of equivalent performance would have weighed too much to permit much, if any, cargo capacity.
Nor have I seen any industry experts claim such a thing would have been possible in the 90s.
Are contemporary rocket computer systems necessary for economical reusability? As I understand it, rocket launch costs stagnated for decades due to a lack of price competition stemming from the high initial capital costs involved in developing new rocket designs rather than us hitting a performance ceiling.
Yes, computers of sufficient performance are necessary for economic reusability, most importantly for the automated landings.
Eyeballing the chart here it looks like computers in 1995 were about 2-3 OOMs worse than computers in 2015. Payload capacity of Falcon 9 is measured in 1000s of kg. So you could cut off some of that payload capacity and have a 5000 kg computer in 1995. Would that be able to do the work of whatever computer they used in 2015? Well, how many kg did those computers weigh? More than 5kg? This thread has some info but no numbers.
idk, seems probable to me that computers weren't the limiting factor.
It took quite a few attempts to get the Falcon 9 to land correctly. A lot of the work to get it to land correctly like involved getting the computer models right. Everything that's involved in computer modeling got better over the 20 years.
Hardware in the rocket got cheaper. Compute for the offline models got cheaper. On the physics side, we likely learned lessons about how to model the airflow and other factors better.
Dragon runs a special version of Linux that's optimized for low latency. It's unclear to me whether a low-latency OS that would do the job was around in 1995.
I don't know anything about the requirements for the Falcon or Dragon computer systems, but I do know that in 1995, real-time operating systems had existed for many years. At that time, computers that I would guess (maybe wrongly) would be adequate for the task weighed in at 10s of kilograms. Of course, the ones I worked with weren't built to endure the rigors of space flight. Still, I would guess that the 1995 level of computer technology would not have been a show-stopper for such rockets being built, though the computing requirement would have added more to the cost than today.
But I wonder whether advances in materials science since 1995 might be crucial?
2 OOMs would translate into a 50 000 kg computer system in 1995 v. a 500 kg computer system in 2015, not 5000 kg.
It's a ballpark number, anything from 100kg+ would have made a 90s equivalent too heavy. The difference compared to consumer computers is expected once you realize it includes multiple interlinked triply redundancy systems and the wiring, mounting structure, power supply system, shielding, etc. for all that.
A100's weigh less than 4kg. Three of them would be 12kg. I find it hard to believe that Falcon 9's use 100kg worth of computer.
Would you consider the space shuttle doomed from the start then? Even without bureaucratic mismanagement, legislative interference, and persistent budget cuts? The market for rocket development in the 80s and 90s seems hardly optimal. You had OTRAG crushed by political pressure, the space shuttle project heavily interfered with, and Buran's development halted by the collapse of the Soviet Union. A global launch market didn't really even emerge until the 2000s.
As a broader point, even if you chalk up the nonexistence of economically competitive partially reusable rockets to Moore's law, that still leaves an apparent gap in the development of more cost-effective expendable systems. Launch prices stagnated from the early 1970s until the 2000s. Surely expendable rockets in the 70s were not already as optimized as possible without 2000s computers.
Would you consider the space shuttle doomed from the start then?
Yes, but not primarily because of computer performance issues. The gliding descent profile, along with the rest of the operations, could have been entirely manually flown or manually controlled by ground based staff if necessary. Though that would have been economically less efficient.
It simply was too oversized and heavy for the vast majority of projected, and actual, missions.
Even without bureaucratic mismanagement, legislative interference, and persistent budget cuts?
It might have had much better economics if they had enough legislative support to approve the initial efficient designs, without needing to rely on the backing of the Air Force, who demanded nearly all of the cost growth as their condition.
Surely expendable rockets in the 70s were not already as optimized as possible without 2000s computers.
They were, some Soviet engine design from the 70s were the best for their niche until the late 2010s.
Manufacturing improvements a la SpaceX might have been possible in the 90s but at a much steeper price, as they were very niche and pricy techniques back then, so they wouldn't have made expendable rockets any cheaper, unless ordered in huge quantities.
Hmm, I should rewrite the Falcon 9 sentence to clarify my intent. I meant to express that more affordable rockets were possible in the 90s compared to what existed, rather than that the F9 exactly was possible in the 90s.
They were, some Soviet engine design from the 70s were the best for their niche until the late 2010s.
Given that the Soviet Union collapsed soon after and that no competitive international launch market really began to emerge until the 2000s this isn't surprising. There was no incentive to improve. Moreover, engines are just one component of the rocket launch cost equation.
From NASA:
The technical problems leading to high space launch costs have been identified and cures proposed, but the long delay until the recent reduction in launch costs suggests that cultural and institutional barriers have hindered implementing potential technical improvements.
One study suggested that the record low cost of the Saturn V could be reduced by a factor of 5, to a cost similar to the Falcon Heavy.
The fundamental cause of the past high commercial launch cost seems to be lack of competition. The US launch industry has been a monopoly, the United Launch Alliance (ULA), and its main customer has been the US government, NASA and the military, which need high reliability and had little incentive to exert cost pressure. The ULA lost most of the commercial market to Russia and Arianespace which are also heavily subsidized by their governments
In 2010, NASA compared SpaceX’s cost to develop the Falcon 9 to the cost NASA’s models predicted using the traditional cost-plus-fee method. Using the NASA-AF Cost Model (NAFCOM), NASA estimated that it would have cost NASA $1,383 million to develop these systems using traditional contracting. The estimated SpaceX cost was $443 million, a 68% reduction from the traditional approach.
Until recently, virtually all major players in this space (heh) were monopolies, whether public or private. These organizations had little incentive to improve and were known to be highly inefficient. Why assume the Soviets reached a magical price floor that was impassable prior to the 2010s?
And what incentives to improve could there have been?
If you mean on some alternate earth where human incentive structures are different and they had some Apollo sized project going on in their equivalent of our 90s, sure it probably would have been feasible to drive down the price of expendable rockets by a factor of 2 or 3 at their equivalent of 90s technology. Assuming they made it in huge quantities and the opportunity cost of capital was zero.
NASA commissioned rockets under cost-plus contracts. Those contracts don't produce incentives for the manufacturers of the rockets to cut costs.
If you want lower costs you need manufacturers to compete by making fixed-price bids.
But nobody would have taken a fixed price contract to build rockets in our version of Earth, actual U.S., circa 1990s, without a huge profit margin built into it because rocket manufacturers also have access to accountants and actuaries, etc., who can price out possible risks. It didn't help that there really only was one or two companies willing to invest capital into doing so. Which precluded the possibility of selecting a lower bid.
And no one else in the U.S. wanted to invest capital to establish a third manufacturer for the reasons described above.
Which is why the Pentagon hasn't moved entirely to fixed price contracts, because for many systems there's literally no competition for their business, so it would probably increase the price over cost-plus contracts since corporations have to borrow at higher interest rates for debt then the government can.
But nobody would have taken a fixed price contract to build rockets in our version of Earth, actual U.S., circa 1990s, without a huge profit margin built into it because rocket manufacturers also have access to accountants and actuaries, etc., who can price out possible risks.
It's okay to grant them a huge profit margin with priced-out risks. That way, if they manage to reduce their costs, they make a bigger profit.
it would probably increase the price over cost-plus contracts since corporations have to borrow at higher interest rates for debt then the government can.
The government essentially guaranteeing the loans of companies does reduce the interest rate on the debt, because it means that if the project fails the government pays for the losses.
It also means that the chance that the project succeeds at its initial price is less because the company has no incentive to stay within the budget.
Right, so the upfront sticker price of a fixed price contract to build rockets in the 90s would have been much higher then that of a cost-plus contract.
Maybe after you include the delays, overruns, etc., it would turn out to be a lower price. But NASA didn't need the votes at some future date, they needed the votes at the time of approval, in order for the project to happen.
Thus it would never get past Congress unless somehow NASA could guarantee that the congressmen voting for it would still be in power to benefit from the possible future savings, which is impossible in a democracy.
The problem is a mix of economic illiteracy of congressmen and corruption.
If we would make more fixed-prize contracts you could start attacking politicians who make cost-plus contracts on the basis that they cost the tax-payer a lot of money. If you try to enforce a standard of "any politician who makes cost-plus contracts that then run above budget is to blame for that", you could shift the system to be more productive.
You write newspaper articles that blame the responsible politicians. You say that their actions resulted in a lot of wasted money and talk about how they took campaign donations from interests that profit from the government being responsible for the losses instead of private industry.
Elon Musk pushed for more space contracts to go fixed-price. In both space and defense, you could research who's responsible for moving things in the right direction and who blocked it and resulting in wasted money.
If someone at Vox would decide they want to do something good for the world they could do it.
I don't see how this could overcome the counter-efforts of those who currently benefit from cost-plus contracts. They after all have a lot more to lose, individually, then a society of several hundred million, where the per person costs may be a couple hundred dollars total in any given year.
Getting enough votes and maintaining voting discipline to enforce any standard at all is incredibly tough in the U.S. elections systems.
If a project goes fails and you write about how John is responsible for wasting a lot of tax-payers money because John decided to to a cost-plus contract instead a fixed-price contract, it's hard to argue that John isn't blameworthy if you can't say who's supposed to get the blame.
Avoiding opportunities to get blamed is a very strong motivator for many politicians.
What it takes, is enough reform-minded journalists who are willing to consistently talk about it for 1-2 decades.
This would work if it was the only contentious topic at stake during an election. However in reality, given recent trends, there will likely be dozens of hot button topics at stake and only a few viable candidates, and virtually all other topics carry more emotional appeal, and more motivated voting blocs, then fixed-price contracting standards.
It seems exceedingly unlikely that this issue would get enough oxygen for it to be decisive in selecting any elected candidate.
When writing about this, I think it would make sense to suggest what you consider the pieces that are necessary for hot air balloons. That would make it much easier to clearly agree and disagree.
One question that occurs to me is what the... engine, I guess... looked like.
Like, I'm imagining that the engine and passengers are in a wicker basket. You probably don't want to just light a fire in the middle of one of those. In a modern balloon I'd probably expect a gas burner, but if you don't have one of those?
I wonder if you have something like a cast-iron stove, possibly with bricks to insulate the bottom of it and stop the basket from burning. That sounds pretty heavy. Maybe there was a limiting factor here?
Wikipedia doesn't say what the original used, but two other things caught my eye. In the section above, premodern and unmanned balloons:
The notable balloonist Julian Nott, in the 1970s; hypothesized that two millennia ago, the Nazca Lines geoglyphs' creation could have been guided by Nazca leaders in a balloon, possibly the earliest hot air balloon flights in human history.[7] In 1975 to support this theory, he designed and piloted the Nazca Prehistoric Balloon, claiming to have used only methods and materials available to the Pre-Inca Peruvians 1,000 years ago.[8][9]
I'm skeptical on general principles here, but there could be something interesting to learn. And in the section below, modern balloons:
Modern hot air balloons, with an onboard heat source, were developed by Ed Yost, beginning during the 1950s
Where did early balloons have their heat source, if not onboard? Unless that word means something different than "the fuel and the thing burning the fuel both being carried in the basket"? My guess would be there was a transition at this point that had something to do with the heat source, but was not what I would describe as "not-onboard to onboard".
I enjoyed this investigation a lot; it's fascinating to think of the uses to which this could have been put.
You may be interested in a related (ongoing) project I've been working on, to survey ‘paths untaken’--cases of historical technological delay, restraint, or post-development abandonment, and to try and assess their rationales or contributing factors. So far, it includes about 160 candidate cases. Many of these need much further analysis and investigation, but you can find the preliminary longlist of cases at https://airtable.com/shrVHVYqGnmAyEGsz/tbl7LczhShIesRi0j , and an initial writeup and pitch of the project at: https://forum.effectivealtruism.org/posts/pJuS5iGbazDDzXwJN/the-history-epistemology-and-strategy-of-technological -- I'd be interested to hear any thoughts or comments.
Military Ballooning—Hot air balloons can be used for reconnaissance
Military use them the most obvious.
Cartography—By providing an aerial view, balloons are useful for more accurate mapmaking
Maps are valuable but the amount of capital invested in map-making was relatively small. The people making the maps likely didn't have the capital to try to build hot air balloons.
Weather Observation—Balloons can be used to gain knowledge about parts of the atmosphere inaccessible from the ground
I think there's a good chance that people didn't know that there was any worthwhile weather observation to be done by gaining knowledge about the upper parts of the atmosphere.
Prestige—The invention of the hot air balloon had tremendous psychological repercussions across the world. In an earlier time with slower technological diffusion, the first state to develop the hot air balloon could use it to boost prestige for decades or longer.
This is essentially what the Montgolfiers targeted. They pitched their prototype to the king instead of just building the ballon in their hometown where their paper mills are located. Out of that, they got a noble title for their father.
I think it's very counter-intuitive that you can actually steer a hot air balloon well because the wind direction is different at different heights. You need that steering ability for military applications.
The sky lantern was invented by the Chinese by at least the 3rd century AD. Constructed from paper and a small fuel source, sky lanterns operated using the same principles as manned hot air balloons, well over a thousand years prior to the invention of the latter.
A sky lantern can get away with a lot more errors. If it breaks that's okay. When a hot air balloon breaks someone dies.
Funny you should say that, the king of France initially wanted condemned criminals to be the first test pilots for that very reason.
I sometimes wonder if asking why should something have been invented earlier is not also an important question to ask in these types of inquiries.
Arguably the hot air balloon perhaps should have been invented shortly after Archimedes' "Eureka" moment. But why would such an application of the principle of buoyancy have been applied to floating in the air at that time? One idea might be that it should have been invented then IF the idea that air (gases) were basically just like water (fluids). But there would also have to be some expected net gain from the effort to make doing the work worthwhile. Is there any reason to think the expect value gained from the invention and availability of the balloon was seen as anything more than a trivial novelty or toy (such as the Chinese seemed to think)?
After all, a balloon is not much like a ship which can be steered and the value of higher ground limited to just how far one can see clearly, and with sufficient detail.
The Archimedes example might be an easy case, but I'm wondering if there are not things to look into regarding the motivations for the work on an invention at the time that offer some type of change in the "environment" (social or intellectual/level of knowledge) that point to why no one did something we now think of as obvious.
Thanks for the response jmh!
One idea might be that it should have been invented then IF the idea that air (gases) were basically just like water (fluids).
I dunno if this is an intuitive jump but it seems unnecessary. Sky lanterns were built without knowledge of the air acting as a fluid. I don't see why the same couldn't be true for the hot air balloon.
But there would also have to be some expected net gain from the effort to make doing the work worthwhile. Is there any reason to think the expect value gained from the invention and availability of the balloon was seen as anything more than a trivial novelty or toy (such as the Chinese seemed to think)?
As I understand it, expectations for the hot air balloon were placed too high rather than too low. In the 1600s, Francesco Lana de Terzi envisioned that a hypothetical airship (which he deemed impossible) could break sieges (ofc airships are not the same as hot air balloons, but at the time there was no distinction). A very valuable use case. After the invention of the hot air balloon, lofty expectations continued for some time. From Wikipedia, "The military applications of balloons were recognized early, with Joseph Montgolfier jokingly suggesting in 1782 that the French could fly an entire army suspended underneath hundreds of paper bags into Gibraltar to seize it from the British. Military leaders and political leaders soon began to see a more practical potential for balloons to be used in warfare; specifically in the role of reconnaissance."
After all, a balloon is not much like a ship which can be steered and the value of higher ground limited to just how far one can see clearly, and with sufficient detail.
This wasn't known prior to the invention of the hot air balloon. Bartolomeu de Gusmão, who allegedly built a prototype of something similar to a hot air balloon in the early 1700s expected it to be steerable like a ship.
The Archimedes example might be an easy case, but I'm wondering if there are not things to look into regarding the motivations for the work on an invention at the time that offer some type of change in the "environment" (social or intellectual/level of knowledge) that point to why no one did something we now think of as obvious.
The scientific and budding industrial revolution motivated a "spirit of invention". The idea of being an inventor by profession took root and led to more people taking a detailed look at the invention space. IMO, this shift in thinking turned the hot air balloon from an invention that some lone inventor with sufficient capital could have invented into a statistical inevitability.
For all things invention, intellectual property rights are an important thing to take into consideration. The fact you could create things and patent then and then profit, meant that many people started to be creative. And I guess it can be argued that it impacted the Zeitgeist so much that even in a neighbor state that was still facing an absolutist regime, the impact was felt, even with less property rights.
I don't think you could invent the air balloon, enter the Senate and wait for a patent nor any kind of glory. If my peers are joining the Roman Army, I'd rather joining too than pursuing a career in engineering.
if someone has a creative impulse and there are no property rights enforcers around to protect it from other people who also thought of it, does it make a sound?
TL;DR
Hot air balloons certainly could have arrived at least decades earlier and there's a high chance they could have arrived centuries, possibly even millennia earlier.
Jason Crawford asks, "Why did it take so long to invent X?" The post is an invitation. It asks the reader to identify low-hanging fruit, inventions that could have been invented far earlier but weren't. Now, most technologies don't fit the bill. Not everything could have been invented long before it was. Many relied on recent advancements. The airplane only became possible once engines became powerful enough to lift them into the sky. But for other inventions such as the cotton gin or flying shuttle, neither scientific nor technological barriers seem present. To this list of mysteriously absent inventions, I'd like to propose an addition: The hot air balloon.
Ancient Balloons?
The notion of the ancient or medieval world having hot air balloons makes for exciting counterfactual history. Floating Roman military lookouts, ornate balloons arriving with Zheng He’s fleet in South Asia, balloon cartographers in the age of exploration… It’s all very eye-catching, but is it realistic?
In actual history, there were no Roman, Umayyadan, or Imperial Chinese hot air balloons. In fact, highly dubious claims of ancient South American balloons aside, no one in the classical or medieval world is known to have constructed a manned balloon. The first verified flight occurred in 1783, amid the industrial revolution. This early balloon was created by the Montgolfier brothers, French industrialists in the paper industry.
Why Manned Balloons Could Have Been Invented Sooner
Previous Inventions/Historical Precedent
Mini Hot Air Balloons
The sky lantern was invented by the Chinese by at least the 3rd century AD. Constructed from paper and a small fuel source, sky lanterns operated using the same principles as manned hot air balloons, well over a thousand years prior to the invention of the latter.
Human Flight Before Balloons
Beyond this, the concept of human flight was by no means novel to Dynastic China. Man-lifting kites were likely developed shortly before the time of the Sui Dynasty (581–618). Such kites became widespread enough throughout East Asia for the Japanese government to have prohibited them at a time.
The First Hot Air Balloon Didn’t Take Long To Invent
While Joseph-Michel Montgolfier, having created parachutes in the past, possessed preexisting knowledge of aeronautics, the brothers did not begin experimenting with balloons until the winter of 1782. By the end of the year, the duo had successfully built two prototypes, the second of which had so much lifting force they lost control of it. The prototype would proceed to float for nearly two kilometers (1.2 miles) before landing. Upon touchdown, it was ripped apart by frightened passersby. By October 1783, the first manned flight occurred, and a month later on November 21, 1783, the first untethered manned balloon flight was performed.
The Montgolfiers' Balloon Was Inefficient
The Montgolfier brothers created a functional hot air balloon without understanding the underlying physics. They believed that it was the smoke rather than hot air that caused the balloon to rise. Because of this, they burned materials that would produce thick smoke such as wool, straw, and even old shoes. Hardly optimal. A functional hot air balloon could be constructed without relying on the most efficient fuel sources available to late 18th-century engineers or a rigorous understanding of the science behind its operation.
Additionally, the first manned Montgolfier balloon was covered in an ornate gilded finish and lavish drapery, adding unnecessary weight to the craft. Yet, in spite of this, the balloon had no problem ascending the full height its tether would permit (around 80ft). Within a few months, an untethered flight would reach an altitude of some 3,000ft! This suggests their balloon could have been even less optimized and still successfully flown.
Fast Dissemination
The Montgolfier balloon experiments were no Apollo Program. The barrier to entry for building a hot air balloon was low. After its invention, news quickly spread of this new and exciting technology. Balloonomania gripped the public. Throughout Europe, hot air balloons were being built left and right. Within twenty years, a hot air balloon was built in Japan out of washi (a kind of Japanese paper). The quick dissemination and seemingly wide variety of materials used indicate the materials needed to build a hot air balloon were already plentiful and common throughout the world by the late 18th century.
Arguments Against The Hot Air Balloon Being Invented Earlier
It was Invented During The Industrial Revolution
This evidence is purely circumstantial, but it is admittedly suspicious. The industrial revolution and the century before it did comprise a revolution in thought. It heralded the birth of a new profession, the mechanical philosopher. Empowered by the idea of progress and the promises of improvement, these individuals eagerly began to tinker and experiment. Maybe the answer is as simple as the fact that few people before the Montgolfiers seriously worked on developing a manned balloon, despite it being possible.
However, at the same time, the industrial revolution marks an era in which scientific knowledge and industrial technology began advancing steadily. Perhaps we've overlooked a key detail. A seemingly trivial technological advancement that turned out critical to the hot air balloon's invention. Maybe unseen technological barriers previously prevented a practical hot air balloon from being developed. Textile production certainly did progress substantially in the 18th century. The quality and price of cloth available to the Montgolfier brothers were likely better than what would have been available to inventors centuries prior. This leads to a second counterpoint.
The Flying Shuttle
By the time of the Montgolfier balloon, the flying shuttle had fully disseminated into the wider French economy, having been introduced to the country decades prior by John Kay. This invention not only significantly increased the output of weavers and lowered textile prices, but also allowed for larger pieces of continuous cloth to be woven. A balloon constructed during an earlier time would have to likely contend with higher textile prices as well as more stitching of smaller pieces. If this stitching proves too “leaky”, then additional patching cloth will add additional weight. However, the flying shuttle widely permeated British industry by the 1750s, meaning that despite our medieval balloon fantasies being dashed, the invention was still twenty years late.[2][3]
Textile Quality
The Montgolfier balloon was constructed out of a skin made of the very lightweight textile taffeta (a form of silk) while paper was applied to the inside, providing the envelope with greater rigidity. The history of taffeta dates back to the middle ages in the Islamic world. It’s hard to find information on whether another textile available earlier could have served as a suitable alternative. In case there wasn’t, then the hot air balloon did arrive centuries later than it could have, but not a thousand years or more.
Ultimately, both of these arguments are plausible but must contend with the countering evidence. Montgolfier's balloon was inefficient, cheap, slapped together in a matter of months, and relied on faulty scientific premises. That said, I do not have the necessary knowledge of textile history to give a definitive answer.
Importance
So if the hot air balloon could have been invented sooner, what does this mean? Two questions come to mind:
To answer the first question, slightly different but not radically. The invention of the hot air balloon was not nearly as important as Newcomen's steam engine or Gutenberg's printing press. It did not revolutionize any industry in particular and mostly remained a curious novelty. (A niche it continues to occupy today.) That said, hot air balloons did have some practical applications:
Developed during an earlier age, other possible uses come to mind:
As for the second question, that's harder to answer. One could be dismissive and write off the nonexistence of the medieval balloon as a curious but trivial observation. However, careful observation through the Progress Studies lens uncovers hidden specks of practical knowledge for our own times. To understand technological progress, we must not only understand why, when, and how innovation happens, but also why sometimes it doesn't happen. Our modern economy is much more efficient and complex than its medieval counterpart. It isn't likely many inventions with low capital intensiveness like the hot air balloon have been ready for decades, but simply not created yet. (If anyone has any counterexamples in the past 30 years I'd love to hear them!) But could there be other gaps? Could there be structural barriers preventing inventions feasible decades ago from appearing? Probably. It's easy to find contenders. If a partially reusable and affordable rocket like the Falcon 9 was feasible in the 90s, then the answer is surely yes.
https://www.aps.org/publications/apsnews/200611/history.cfm
It's interesting that the hot air balloon was invented in France rather than Britain, the industrial epicenter at the time
Anton Howes concluded the flying shuttle itself could have been invented centuries prior to its actual appearance