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writing:airships [2025/11/19 18:53] – [Types of Modern Airship Design] JacobCoffinWriteswriting:airships [2025/11/20 03:44] (current) – [Relevant Technological Advancements] JacobCoffinWrites
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 **Trains** **Trains**
  
-The solarpunk favorite and for good reason. Trains are vastly more economical for carrying heavy, cheap goods like liquids, raw ore, unprocessed material inputs, etc. +The solarpunk favorite and for good reason. Trains are vastly more economical for carrying heavy, cheap goods like liquids, raw ore, unprocessed material inputs, etc. But that’s not all or even most of what they’re tasked with carrying. More expensive cargoes like finished manufactured goods and fresh food are often limited by volume, not weight, and vehicles carrying human passengers are always limited by volume, not weight. 
  
-But for passengers, compared to a train, an airship would actually have a slight edge most of the time, since passengers-as-cargo is right in the high-volume, low-weight, high-value zone which is most economical for airships.+And for passengers, compared to a train, an airship would actually have a slight edge most of the time, since passengers-as-cargo is right in the high-volume, low-weight, high-value zone which is most economical for airships.
  
-Trains are limited by volume for carrying passengers, not weight. You can only stuff so many people into a metal tube less than 10 feet wide and about 600 feet long. Most passenger trains carry anywhere between 200-1,000 people, which could be easily matched by a midsized-to-large commuter airship with similar ticket costs, as they can carry about 10 passengers per ton of payload capacity in a day configuration (which drops to 1.6 passengers/ton for overnight ships with private cabins, showers, lounges, etc).+You can only stuff so many people into a metal tube less than 10 feet wide and about 600 feet long. Most passenger trains carry anywhere between 200-1,000 people, which could be easily matched by a midsized-to-large commuter airship with similar ticket costs, as they can carry about 10 passengers per ton of payload capacity in a day configuration (which drops to 1.6 passengers/ton for overnight ships with private cabins, showers, lounges, etc).
  
 Also, though the fastest maglev trains in the world are faster than the fastest practical airships, high-speed rail average speeds are comparable to or somewhat slower than the optimal cruising speed for an airship over short distances, since they slow considerably for turns, tunnels, and more frequent stops, etc. “High speed rail” entails an average of at least 93 mph, and “very high speed rail” is at least 124 mph. Amtrak, meanwhile, averages at 45 mph. Also, though the fastest maglev trains in the world are faster than the fastest practical airships, high-speed rail average speeds are comparable to or somewhat slower than the optimal cruising speed for an airship over short distances, since they slow considerably for turns, tunnels, and more frequent stops, etc. “High speed rail” entails an average of at least 93 mph, and “very high speed rail” is at least 124 mph. Amtrak, meanwhile, averages at 45 mph.
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-==== Types of Modern Airship Design ====+==== Modern Airship Designs and Examples ====
  
 This section gathers broad categories of design and intended use This section gathers broad categories of design and intended use
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 **The LCA60T and Flying Whales** **The LCA60T and Flying Whales**
  
-This particular airship is highly specialized for maneuverability and aircrane operations at the expense of speed and range. It has the same operating wind limits as a normal crane or helicopter. 75% of its 32 electric motors and propellers are fixed in place exclusively for thrust vectoring purposes, only 25% are fixed for forward propulsion (and even those can use differential thrust for steering). Turning quickly isn’t really an issue in this case, as compared to classical Zeppelins that had only their rudders to turn with.+This particular airship is highly specialized for maneuverability and aircrane operations at the expense of speed and range, and is not suitable for long-distance rapid or heavy freight transport. It’s quite slow, even for an airship, with a top speed of about 60 mph. An actual dedicated cargo transport airship would be bigger, sleeker, and more powerful, with an optimal cruising speed anywhere between 70 and 170 miles per hour depending on the route length, and a payload in the hundreds of tons. 
  
-Similarly, large ships used to be cripplingly dependent on tugboats to maneuver, and were incredibly slow to turn, before the invention of things like azimuth propulsors and bow thrusters that now allow a cruise ship to pivot 360° within its own length. +The tradeoff is that it has the same operating wind limits as a normal crane or helicopter. 75% of its 32 electric motors and propellers are fixed in place exclusively for thrust vectoring purposes, only 25% are fixed for forward propulsion (and even those can use differential thrust for steering). Turning quickly isn’t really an issue in this case, as compared to classical Zeppelins that had only their rudders to turn with.
  
-this particular ship is highly specialized for air crane operations over short distances, not efficient transport from A to B. It’s quite slow, even for an airship, with a top speed of about 60 mph. An actual dedicated cargo transport airship would be bigger, sleeker, and more powerful, with an optimal cruising speed anywhere between 70 and 170 miles per hour depending on the route length, and a payload in the hundreds of tons.  +It can carry cargo such as shipping containers or purpose-built structures (like portable hospitals) inside the cargo hold which runs the length of its keel, or dangle oversized loads like wind turbine blades, transmission towers, radio towers, prefab buildings underneath.
- +
-designed for maneuverability and transporting oversized loads, and is not suitable for long-distance rapid or heavy freight transport+
  
 === Passenger Liners / Cargo === === Passenger Liners / Cargo ===
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 This airship is a 2/3 scale prototype and training/laboratory ship that doesn’t carry passengers yet, only its crew, but it can be seen flying around San Francisco lately. While not technically a Zeppelin product, it’s a geodesic, electric modernization of the classic Zeppelin shape, with parts sourced from the Zeppelin Company, such as the fins and gondola. They collaborated heavily on the ship’s design. This airship is a 2/3 scale prototype and training/laboratory ship that doesn’t carry passengers yet, only its crew, but it can be seen flying around San Francisco lately. While not technically a Zeppelin product, it’s a geodesic, electric modernization of the classic Zeppelin shape, with parts sourced from the Zeppelin Company, such as the fins and gondola. They collaborated heavily on the ship’s design.
- 
-The actual full-scale production version can be used for passenger and/or cargo purposes, and comes in two sizes that we know of so far: one 3/2 the size of Pathfinder 1 carrying 20 tons, and one 5/2 the size of Pathfinder 1 carrying 200 tons. They’d have roughly 3,500 and 30,000 square feet of cabin space, respectively.  
- 
- The Pathfinder 1 is a 2/3 scale prototype and training/laboratory ship that doesn’t carry passengers yet, only its crew, but it can be seen flying around San Francisco lately. While not technically a Zeppelin product, it’s a geodesic, electric modernization of the classic Zeppelin shape, with parts sourced from the Zeppelin Company, such as the fins and gondola. They collaborated heavily on the ship’s design. 
  
 The actual full-scale production version can be used for passenger and/or cargo purposes, and comes in two sizes that we know of so far: one 3/2 the size of Pathfinder 1 carrying 20 tons, and one 5/2 the size of Pathfinder 1 carrying 200 tons. They’d have roughly 3,500 and 30,000 square feet of cabin space, respectively. The Hindenburg, for context, had a bit over 5,800 square feet of deck space.  The actual full-scale production version can be used for passenger and/or cargo purposes, and comes in two sizes that we know of so far: one 3/2 the size of Pathfinder 1 carrying 20 tons, and one 5/2 the size of Pathfinder 1 carrying 200 tons. They’d have roughly 3,500 and 30,000 square feet of cabin space, respectively. The Hindenburg, for context, had a bit over 5,800 square feet of deck space. 
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 ==== The Airship Niche ==== ==== The Airship Niche ====
 +
 +Airships aren't a magical solution to every transportation issue. Especially in our current society where speed and financial cost are the priorities, and externalities simply aren't accounted for. But even today there are several industries which would probably love the capabilities of an airship if they were available, but which aren't willing to pay the upfront cost to revive the industry themselves. In a future solarpunk society where harms to the public and world like CO2 output and pollution are factored into the decision making process, several current areas of operation tip even more favorably towards airships.
  
 === Cargo === === Cargo ===
  
-Don’t forget the exponential growth curve of the square-cube law. It’s a double-edged sword. Small airships are not competitive with other aircraft or trucks, but large ones are. Small and midsized airships are indeed niche, but the largest modern airships under consideration have payloads of 200-1,000 tons, depending on the design and manufacturer. The largest cargo planes today carry about 100-150 tons of cargo. That, in concert with large airships’ increased efficiency, would allow them to pose a credible threat to a decent chunk of shipping, particularly for higher-value cargoes and somewhat more time-sensitive ones, such as fresh fruit and seafood.  +This is probably the easiest starting point as far as finding a market where airships are competitive. Starting with the role currently filled by cargo helicopters, but extending to some of the work done by planes, trains, and trucks: 
-It would be more expensive than a ship, but cheaper than a plane, and currently the gulf between those two modes of transport is so vast that there are several profitable efficiencies to be found, once they’re actually built out. The “built out” is the hard part.  +
-Additionally, airships’ optimal speed increases drastically over shorter route lengths, due to the effects of fuel weight on payload and productivity. For 5,000 nautical miles, a typical rigid airship carrying 100 tons of cargo has an optimal cruising speed of 63 knots/72 mph. For 2,000 nautical miles, it’s 82 knots/94 mph. And for short-haul trips of 300 nautical miles, it’s 145 knots/167 mph.  +
-Do note those are the optimal cruising speeds, not the top speeds. Airships benefit from having reserve power capacity to account for headwinds without losing speed, in this case, the NASA study assumed a 15 knot headwind was reasonable, and calculated the optimal cruising speed (accounting for engine size, structural weight, fuel, etc.) accordingly.  +
-However, this study was done some time ago (mid-1970s), and modern propulsive systems have gone down in weight and up in efficiency tremendously since then. That could change the optimal cruising speed and feasible degree of excess power capacity for an airship, since those speeds are primarily dictated by the trade-off between fuel load and speed of cargo throughput. More fuel burn means faster, but also less cargo carried due to the weight of the fuel, hence why the optimum for shorter range is so much faster.  +
-For example, some modern airship designs assume a cruising speed of 115 mph is ideal over distances of several thousand nautical miles, rather than the 1970s optimum of 72-94 mph over similar distances. That’s not a trivial difference—to take an airship to 115 mph requires about four times as much power as that same airship traveling at 72 mph. Some modern designs just go ahead and keep the efficiency gains as savings rather than pressing to go faster, though. It really depends on the application. +
  
 +  * Airships can fill a similar role to cargo helicopters, except that they're safer, able to operate in worse weather, able to carry far more per trip, and in some cases faster.
 +  * Airships are slower than airplanes but can carry more. The largest modern airships under consideration have payloads of 200-1,000 tons, depending on the design and manufacturer. The largest cargo planes today carry about 100-150 tons of cargo.
 +  * Airships are faster than ships, but can carry far, far less cargo. Bulk carriers can haul over 300,000 tonnes compared to the an airship's 200-1,000 tons.
 +  * Airships can carry far more cargo in one trip than a semi-truck and can reach locations without roads. But they're a poor fit for last-mile logistics.
 +  * Airships can't match a train in terms of cargo weight, but may be competitive in volume and speed, and they can reach destinations without tracks.
  
-Modern airships can outperform helicopters in pretty much every respect save for size. That’s why modern cargo airship designs are targeting the roles currently held by heavy transport helicopters first and foremost—in the most difficult and expensive part of getting a business off the ground, they perceive that as the matchup that is most favorable to them.  +This opens several (rather disconnected) potential niches airships could fit neatly into.
-An airship is overwhelmingly more efficient than a helicopter, can carry vastly more, and costs less to operate. They have far greater range, and operate in similar or worse weather conditions than a helicopter. They’re also far easier to convert to zero-emissions operations. The practical upper speed limit for a rigid airship is 200 knots, whereas most cargo helicopters cruise between 80-160 knots. With thrust vectoring, modern airships like the Zeppelin NT are also capable of maneuvering like a helicopter, which aids greatly in VTOL operations.  +
-Even in terms of speed, airships and airplanes have remained in similar positions since the 1930s—the cruising speed of a DC-3 is about 180 knots, and for an airship of that time period, it was 70 knots, or about 40% the speed. Today, the cruising speed for most airliners like the 737 is around 0.8 Mach, or 453 knots, but a Boeing study found the most productive cruising speeds for an airship carrying 100 tons for 300 nautical miles is 180 knots, which is still about 40% the speed. Granted, the optimal cruising speed for an airship does dip considerably over greater distances, with that same 100-ton-payload airship design’s optimal cruising speed dipping to 110 knots over 5,000 nautical miles, but many planes don’t fly that far anyway, and it’d still handily beat a helicopter carrying only 8 tons at 140 knots, but which would have to stop 17 times to refuel over that same distance, or over 200 times to carry the same amount the same distance. +
  
 +**General Cargo Operations**
  
 +When it comes to comparing transport capacities to trains or ships, the real question is what you’re transporting. Ships and trains are unbeatable when it comes to transporting cargo that is both extremely cheap and extremely heavy, such as crude oil and raw mineral ore. But that’s not all or even most of what they’re tasked with carrying. More expensive cargoes like finished manufactured goods and fresh food are often limited by volume
  
-Aside from carrying more weight, they could also carry things far larger, like wind turbine blades, prefab buildings, radio towers, etc. They can also hover, which is very useful, as evidenced by the fact that extreme STOL airplanes haven’t successfully replaced helicopters despite being wildly superior in practically every other way. +Airships are faster than a ship but slower than a plane, they can haul less than a ship but more than a plane, and in a capitalist society they're more expensive to operate than a ship, but cheaper than a plane. Currently the gulf between those two modes of transport is so vast that there are several profitable efficiencies to be found, once they’re actually built out. The “built out” is the hard part. 
  
-Navy airships I mentioned had about 1/3-1/2 the operating costs of planes with a similar payload capacity.  
-More to the point, though, airships wouldn’t necessarily be competing with cargo planes primarily, but rather cargo helicopters—which cost at least ten times as much as normal air freight per tonne/km. They can also just plain do things that no airplane or helicopter can do at any cost, such as carry giant wind turbine blades and other outsized cargoes.  
  
 +**Oversized Cargoes** 
  
 +Thanks to their maneuverability and outsized (for an aircraft) weight capacity, airships can not only transport more cargo, but they can transport things that no airplane or helicopter can do at any cost, such as wind turbine blades, prefab buildings, radio towers, etc. 
  
-With ships, they can compete sometimes (fresh food, high-value manufactured goods, etc), with freight trains, definitely not, but trucks? The largest airships can compete with trucks in terms of cargo cost per ton/mile, and are considerably faster, in addition to their capability to carry things too bulky and/or too heavy for a truck. That won’t detract from trucks’ ability to transport things last-mile, of course, but there’s certainly some useful applications. +This is essentially a capability our current society can't meet, and would allow for some really amazing stuff, from setting up ocean-sized wind turbines on land, (where overland transportation of parts was previously constrained by the size of roads and train tracks) to hovering over a disaster area and lowering a portable hospital onsite with far less of the setup time modern-day trailer/flatpack equivalents require.
  
  
-when it comes to comparing transport capacities to trains or ships, the real question is what you’re transporting.+**Reaching frontier locations**
  
-Ships and trains are unbeatable when it comes to transporting cargo that is both extremely cheap and extremely heavy, such as crude oil and raw mineral ore. But that’s not all or even most of what they’re tasked with carrying. More expensive cargoes like finished manufactured goods and fresh food are often limited by volume, not weight, and vehicles carrying human passengers are always limited by volume, not weight. The average Amtrak passenger train and average ferry both carry around 300 passengers, with outliers carrying 1,000 and 5,200 people, respectively.+Airships aren't generally a good fit for the work of a single truck, but trucks (and fleets of trucks) need roads and airships don't. There are still places where building roads is impractical or costly enough that it hasn't been done to date, or where the existing roads and trails aren't sufficient for a large heavy trucks. For example, a number of communities in remote regions of northern Canada rely on a network of seasonal ice roads for supplies which would be prohibitively expensive to transport by air using the current options. As those ice roads become less and less reliable, the Canadian government is looking at airships as a way to maintain service in those regions. This is because there’s a huge difference between the costs of temporary ice roads used seasonally, and all-weather roads (which can cost about $3 million per kilometer).   
 + 
 +It's also worth considering the condition of the road network in your solarpunk setting. The feasibility and cost effectiveness of trucks is subsidized by endless (often annual) road maintenance. If your solarpunk society has done what a sizable contingent in the scene would like and deprioritized cars, it's possible that the road network would fall apart rather quickly. After all, if most people aren't driving, and are reliant on denser, walkable communities and public transit, they'll probably want most of their taxes or labor going towards the stuff they personally use. Depending on the region and climate, damage to paved roads can accumulate quickly, between damage to road surface and footings from winter frost heaves and pot holes, to spring floods. And that's mostly for the standards of small passenger vehicles. 18 wheelers and the big double-trailer rigs used to transport grain or bulk cargo need even better roads. 
 + 
 +If your solarpunk society has resource limitations, as most societies do, and they're prioritizing big infrastructure stuff and public transit like new train lines, it's possible that roads in some regions might fall into disrepair badly enough that airships make economic sense even in areas we wouldn't currently consider 'remote.'  
 + 
 +This may be especially true if your solarpunk setting is rebuilding after our current society goes through a span of societal crumbles and leaves them with even more infrastructure debt. 
  
-If we are to assume the practical economic limit for an airship’s size to be around that of the Hindenburg, past which it would be more practical to just use two airships rather than an ultra-huge one, then the limits of an airship’s capabilities would be ably demonstrated by Lockheed-Martin’s slightly smaller hybrid rigid airship concept from 1999. It would have a range of 4,000 nautical miles, a cruise speed of 150 knots/180 miles per hour, a cargo capacity of 500 tons, and a cargo area of 65,000 square feet. That would put it just shy of the largest ferries in terms of passenger capacity, with space per passenger more similar to a train than a plane. However, it would be ten times faster than the ferry, and four times faster than Amtrak.  
  
 === Passenger Transportation === === Passenger Transportation ===
 +
 +It's likely that airship passenger service will only take off after cargo 
 +
 +If we are to assume the practical economic limit for an airship’s size to be around that of the Hindenburg, past which it would be more practical to just use two airships rather than an ultra-huge one, then the limits of an airship’s capabilities would be ably demonstrated by Lockheed-Martin’s slightly smaller hybrid rigid airship concept from 1999. It would have a range of 4,000 nautical miles, a cruise speed of 150 knots/180 miles per hour, a cargo capacity of 500 tons, and a cargo area of 65,000 square feet. That would put it just shy of the largest ferries in terms of passenger capacity, with space per passenger more similar to a train than a plane. However, it would be ten times faster than the ferry, and four times faster than Amtrak. 
 +
 +Vehicles carrying human passengers are always limited by volume, not weight. The average Amtrak passenger train and average ferry both carry around 300 passengers, with outliers carrying 1,000 and 5,200 people, respectively.
  
 === Coast Guard Patrol / Search and Rescue === === Coast Guard Patrol / Search and Rescue ===
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 double hull of inert gas to keep out the oxygen that hydrogen needs to mix with in order to form a flammable or explosive mixture. That’s how fuel tankers were rendered safer after the SS Sansinena explosion, and airliners as well after the TWA Flight 800 explosion. Carbon dioxide and nitrogen, respectively, are used to inert the empty spaces in partially full fuel tanks, which would become giant fuel-air bombs otherwise.  double hull of inert gas to keep out the oxygen that hydrogen needs to mix with in order to form a flammable or explosive mixture. That’s how fuel tankers were rendered safer after the SS Sansinena explosion, and airliners as well after the TWA Flight 800 explosion. Carbon dioxide and nitrogen, respectively, are used to inert the empty spaces in partially full fuel tanks, which would become giant fuel-air bombs otherwise. 
 +
 +=== Hydrogen Safety Features ===
 +
 +Historically: Handling hydrogen safely for large airships used to be a matter of three things: purity, ventilation, and electrical conductivity. Zeppelins acted like giant faraday cages for lightning strikes and static electricity, keeping them surprisingly safe unless there was a major leak at an inopportune time (which is how the Hindenburg, whose skin was not fully electrically conductive under certain atmospheric conditions, ended up being the first and last fatal accident for the Germans’ civilian Zeppelin airline after nearly 40 years of operations, during a time when a plane fatally crashed after only a few hundred hours of operation on average). Ventilation between the gas cells and outer hull ensured that no dangerous concentration of hydrogen and oxygen could build up over time from gradual effusion. And, of course, pure hydrogen doesn’t burn, which is why Zeppelins were able to terrorize Britain in the first few years of World War One with near-impunity before the incendiary bullet was invented.
 +
 +In the modern day, though, we have higher standards for safety, and thus airliners and fuel-carrying ships both use inert gases like nitrogen or carbon dioxide to prevent explosive fuel-air mixtures from forming. An airship could do the same, using a balloon-within-a-balloon method, or by sealing the outer hull of a rigid airship and filling it with with nitrogen instead of just trusting to ventilation systems instead.
 +
 +Interestingly, we do know that this would work in a practical sense for hydrogen, because of experiments conducted by the British in World War I. Prior to late 1916, it was initially thought (before the discovery of helium on earth!) that the Germans had discovered a nonflammable lift gas, since simply shooting Zeppelins didn’t catch them on fire, and it took sustained artillery and flak barrages from ground batteries or teams of warships to actually sink the small handful of Zeppelins that they did manage to bring down. Others thought that the Zeppelins were using an inert gas to surround the hydrogen cells, and thus “armor” them against flame, possibly using exhaust gases.
 +
 +To test this, the Brits fired the experimental Very’s and Pomeroy incendiary bullets they were developing into a double-layered balloon of hydrogen and a nonflammable gas mixture. The Very’s and Pomeroy bullets were fired through the top where the hydrogen would escape, and burned all the way through the bottom of the balloon, which itself was flammable, and it still didn’t catch the hydrogen on fire. It was, in their words, “completely protected” against ignition.
 +
 +As it would later develop, the Germans were not in fact using inert gases in this way, instead trusting to hydrogen purity and ventilation, but the record still stands. Now imagine if the balloon itself was fire-retardant, like coated synthetic fibers, which would just melt rather than combust if subjected to a hot flame. Imagine if there were sensors to detect hydrogen leaks, and if the ship was constructed from all-conductive materials. They’d be essentially as safe as helium airships, which themselves proved to be much less prone to fatal accidents even during the rigors of World War II than ubiquitous modern helicopters like the Robinson R44 (fatal accident rate of 1.3 per 100,000 flight hours vs. 1.6). In the modern day, the Zeppelin NT semirigid airships currently used by Goodyear and sightseeing companies haven’t had a single fatal accident since they started operations in the 1990s.
 +
 +**Modern day features:**
 +
 +Passive Safety Features:
 +
 +To safely store Hydrogen an airship can have a double hull of inert gas like helium, nitrogen, and/or carbon dioxide to prevent fires or explosions, in addition to active safety measures. Alternatively, a direct mix of isobutylene and carbon dioxide can render hydrogen fires self-extinguishing and non-explosive across hydrogen’s entire ignition range, but this mixture has somewhat less lift than helium, thus probably isn’t as desirable as a double hull.
  
 === Electrification === === Electrification ===
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 === Helium === === Helium ===
  
-Cheap, abundant helium won’t run out until natural gas does, or possibly even after—since helium is often found in otherwise completely economically useless pockets of underground nitrogen, not just natural gas. In other words, nothing to worry about for hundreds of years. The shortages we currently face are an infrastructure problem, not a supply problem. Even once that’s gone, you can still get helium from the atmosphere, but presumably by that point we’d have implemented fireproofing methods to safely contain hydrogen. There are already two main methods to do so, it’s just a matter of properly engineering, testing, and certifying them. +The safe one. Helium has about 7-8% less less lift than hydrogen but it's inert (doesn't catch fire) so that's a pretty big advantage, not just for safety but for public perception and the acceptance of airships as a technology. 
  
-Helium makes up a relatively constant portion of the atmospheric gas mixture, and has for hundreds of millions of years, due to its constant production via radioactive decay in the earth’s core. The atmosphere is like a full bucket underneath a dripping spigot—it’s constantly losing water over the edge, yes, but it’s also not being emptied either.+There are some downsides: Helium can't exactly be manufactured by humans, and is instead obtained from pockets underground where it is trapped, often alongside natural gas (which is often the primary reason for the drilling that recovers it). Helium is actually light enough to escape the earth's atmosphere. It's also important in specialized medical equipment such as MRI machines.
  
-The problem is that we waste literally 99% of the helium present in natural gas, simply because we don’t have the infrastructure installed to extract it before use. You could also distill helium from the air itself, but that takes about 3-5 times more energy due to the lower concentration, and with our current atmospheric fractional distillation capacity we’d only be able to meet about 1% of global helium demand (coincidentally about the portion that airships use). +The good news is that cheap, abundant helium won’t run out until natural gas does, or possibly even after—since helium is often found in otherwise economically useless pockets of underground nitrogen, not just natural gas. The shortages we currently face are an infrastructure problem, not a supply problem (at least for hundreds of years). Even once that’s gone, you can still get helium from the atmosphere, but by that point airship designs have hopefully implemented fireproofing methods to safely contain hydrogen. There are already two main methods to do so, it’s just a matter of properly engineering, testing, and certifying them. 
  
-People are actually drilling helium wells now, it is non-refundable but quite abundant.. Other deposits exist in Alberta and Wyoming, just within north America.  +Helium makes up a relatively constant portion of the atmospheric gas mixture, and has for hundreds of millions of years, due to its constant production via radioactive decay in the earth’s core. The atmosphere is like a full bucket underneath a dripping spigot—it’s constantly losing water over the edge, yes, but it’s also not being emptied either. You could distill helium from the air itself, but that takes about 3-5 times more energy due to the lower concentration, and with our current atmospheric fractional distillation capacity we’d only be able to meet about 1% of global helium demand (coincidentally about the portion that airships use). 
-https://www.minnpost.com/other-nonprofit-media/2024/07/what-to-know-about-minnesotas-richest-in-the-world-helium-deposit/+
  
-=== Hydrogen ===+One thing to address in a future where airships operate is that we waste literally 99% of the helium present in natural gas, simply because we don’t have the infrastructure installed to extract it before use. 
  
-Oh the humanity! +People are actually [[https://www.minnpost.com/other-nonprofit-media/2024/07/what-to-know-about-minnesotas-richest-in-the-world-helium-deposit/|drilling helium wells now]], it is non-renewable but quite abundant. Other deposits exist in Alberta and Wyoming, just within north America. 
  
-The astronomical improvements in aviation safety would more than make up for the difference in safety between hydrogen and helium, such that a properly designed modern hydrogen airship would be incomparably safer than a historical helium one, but that doesn’t change the fact that hydrogen is always going to be more dangerous. +=== Hydrogen ===
  
 +Oh the humanity! Hydrogen is a lighter gas than helium, and thus provides 7-8% more lift (which improves payload capacity). It's flammable, which makes it useful as a fuel, but also more of a safety hazard than helium. The astronomical improvements in the field of aviation safety should more than make up for the difference in safety between hydrogen and helium, such that a properly designed modern hydrogen airship would be incomparably safer than a historical helium one, but that doesn’t change the fact that hydrogen is always going to be more dangerous. 
  
 +The benefits, aside from more lift, include the fact that hydrogen is easier to make. It’s widely available. It can be generated via solar panels on the ship or ground. Thanks mostly to its usability as a fuel, the production of clean/green hydrogen through the electrolysis of water, using renewable electricity is a field with a lot of funding and ongoing research and development behind it, and they're making some significant advancements in efficiencies and storage. It can even be released from fuel tanks to provide extra lift, or be vented or put back into fuel tanks if lift needs to be sequestered. There is no more powerful lift gas. The principal disadvantage of hydrogen in other applications is its bulk, but an airship has literally millions of cubic feet of empty space in the hull to just put it wherever, so that disadvantage is totally moot for airships.
  
-The other downside is that while hydrogen is not a greenhouse gas in itself but it competes for hydroxyl ions in the atmosphere with methane, a powerful greenhouse gas. Basically, every hydrogen molecule in the atmosphere extends the lifespan of one methane molecule. [[https://en.wikipedia.org/wiki/Hydroxyl_radical|The hydroxyl radical is often referred to as the "detergent" of the troposphere because it reacts with many pollutants, often acting as the first step to their removal.]] +And an airship that's already using hydrogen as a lift gas is partway to using it for propulsion as well. While liquid or compressed, it’s heavier than air and can be used as ballast. Fuel cells or hydrogen-burning turbogenerators are extremely efficient but still produce vast amounts of waste heat that can be recycled to provide a whole separate means of buoyancy control—applying superheat to increase buoyant lift by up to 30% on demand. Hydrogen Fuel cells also produce clean water, which in addition to being useful on board for the crew or passengers, also weighs significantly more than the weight of the fuel that was burned, meaning the ship doesn’t even need to vent lift gas to maintain heaviness, just retain some of the water it produces.
- +
- +
-There are ways to make hydrogen far safer, on a purely passive level. For example, after the SS Sansinena and TWA Flight 800 exploded, fuel tankers and airliners started inerting their potentially explosive fuel vapors with inert gases. This has proven highly effective. Similarly, an airship can have a double hull of inert gas like helium, nitrogen, and/or carbon dioxide to prevent fires or explosions, in addition to active safety measures. Alternatively, a direct mix of isobutylene and carbon dioxide can render hydrogen fires self-extinguishing and non-explosive across hydrogen’s entire ignition range, but this mixture has somewhat less lift than helium, thus probably isn’t as desirable as a double hull. +
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-Most people working in the airship space agree—whether quietly or publicly—that hydrogen is just too spectacularly useful as a fuel and/or lift gas for airships to completely forgo using. As a fuel, you can reduce the fuel load by roughly two-thirds, saving tens of tons for payload. It generates its own clean water for ballast or passenger use. It’s widely available. It can be generated via solar panels on the ship or ground. It can even be released from fuel tanks to provide extra lift, or be vented or put back into fuel tanks if lift needs to be sequestered. There is no more powerful lift gas. The principal disadvantage of hydrogen in other applications is its bulk, but an airship has literally millions of cubic feet of empty space in the hull to just put it wherever, so that disadvantage is totally moot for airships. +
- +
-Handling hydrogen safely for large airships used to be a matter of three things: purity, ventilation, and electrical conductivity. Zeppelins acted like giant faraday cages for lightning strikes and static electricity, keeping them surprisingly safe unless there was a major leak at an inopportune time (which is how the Hindenburg, whose skin was not fully electrically conductive under certain atmospheric conditions, ended up being the first and last fatal accident for the Germans’ civilian Zeppelin airline after nearly 40 years of operations, during a time when a plane fatally crashed after only a few hundred hours of operation on average). Ventilation between the gas cells and outer hull ensured that no dangerous concentration of hydrogen and oxygen could build up over time from gradual effusion. And, of course, pure hydrogen doesn’t burn, which is why Zeppelins were able to terrorize Britain in the first few years of World War One with near-impunity before the incendiary bullet was invented. +
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-In the modern day, though, we have higher standards for safety, and thus airliners and fuel-carrying ships both use inert gases like nitrogen or carbon dioxide to prevent explosive fuel-air mixtures from forming. An airship could do the same, using a balloon-within-a-balloon method, or by sealing the outer hull of a rigid airship and filling it with with nitrogen instead of just trusting to ventilation systems instead. +
- +
-Interestingly, we do know that this would work in a practical sense for hydrogen, because of experiments conducted by the British in World War I. Prior to late 1916, it was initially thought (before the discovery of helium on earth!) that the Germans had discovered a nonflammable lift gas, since simply shooting Zeppelins didn’t catch them on fire, and it took sustained artillery and flak barrages from ground batteries or teams of warships to actually sink the small handful of Zeppelins that they did manage to bring down. Others thought that the Zeppelins were using an inert gas to surround the hydrogen cells, and thus “armor” them against flame, possibly using exhaust gases. +
- +
-To test this, the Brits fired the experimental Very’s and Pomeroy incendiary bullets they were developing into a double-layered balloon of hydrogen and a nonflammable gas mixture. The Very’s and Pomeroy bullets were fired through the top where the hydrogen would escape, and burned all the way through the bottom of the balloon, which itself was flammable, and it still didn’t catch the hydrogen on fire. It was, in their words, “completely protected” against ignition. +
- +
-As it would later develop, the Germans were not in fact using inert gases in this way, instead trusting to hydrogen purity and ventilation, but the record still stands. Now imagine if the balloon itself was fire-retardant, like coated synthetic fibers, which would just melt rather than combust if subjected to a hot flame. Imagine if there were sensors to detect hydrogen leaks, and if the ship was constructed from all-conductive materials. They’d be essentially as safe as helium airships, which themselves proved to be much less prone to fatal accidents even during the rigors of World War II than ubiquitous modern helicopters like the Robinson R44 (fatal accident rate of 1.3 per 100,000 flight hours vs. 1.6). In the modern day, the Zeppelin NT semirigid airships currently used by Goodyear and sightseeing companies haven’t had a single fatal accident since they started operations in the 1990s.+
  
 +With the current state of the art in terms of containment vessels, a hydrogen fuel load weighs about half as much as a kerosene fuel load (even with kerosene tanks being far lighter) of equivalent energy content. Given that a hydrogen fuel cell system burns 5-6 times less fuel weight per hour than a comparable turboprop with liquid fuel, that’s a huge amount of buoyancy compensation that no longer needs to be done, and more weight that can be devoted to range, speed, and/or payload.
  
-it would take a huge amount of testing to make sure that a hydrogen airship was fireproof under all edge cases and conceivable flight conditions. It would require active fire suppression systems (alarms, hydrogen and oxygen detectors, fire extinguishers, etc.) and even more extensive passive measures (proper electrical conductivity, fireproof materials, a double hull of inert gas like helium or nitrogen and/or a direct gaseous mixture to alter the hydrogen’s explosive and ignition range even when exposed to air, etc.) to achieve a sufficient level of safety. Such things are possible—airliners and fuel tankers now explode far less often, thanks to inerting the fuel vapors in their tanks with nitrogen or carbon dioxide. +The downsides are safety - it would take a huge amount of testing to make sure that a hydrogen airship was fireproof under all edge cases and conceivable flight conditions. It would require active fire suppression systems (alarms, hydrogen and oxygen detectors, fire extinguishers, etc.) and even more extensive passive measures (proper electrical conductivity, fireproof materials, a double hull of inert gas like helium or nitrogen and/or a direct gaseous mixture to alter the hydrogen’s explosive and ignition range even when exposed to air, etc.) to achieve a sufficient level of safety. Such things are possible — airliners and fuel tankers now explode far less often, thanks to inerting the fuel vapors in their tanks with nitrogen or carbon dioxide. But this additional research and development, testing, and regulatory approval is part of why modern airships will likely use helium, at least until the industry has maneuvered an entirely new class of vehicle through the aviation regulatory environment. 
  
 +The other downside is that while hydrogen is not a greenhouse gas in itself it competes for hydroxyl ions in the atmosphere with methane, a powerful greenhouse gas. Basically, every hydrogen molecule in the atmosphere extends the lifespan of one methane molecule. [[https://en.wikipedia.org/wiki/Hydroxyl_radical|The hydroxyl radical is often referred to as the "detergent" of the troposphere because it reacts with many pollutants, often acting as the first step to their removal.]]
 ==== Docking Facilities ====  ==== Docking Facilities ==== 
  
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 What might riding in an airship be like? How many crew? What might riding in an airship be like? How many crew?
  
 +
 +**Size**
 +
 +The size of an airship can vary rather widely based on its purpose, and the resources and technology level of your setting. The lower end of the spectrum is mostly set by economics (smaller airships can exist but they'd have very niche roles to fill where they still make sense over an alternative) and the higher end is mostly set by physics (there comes a point where it makes more sense to use the same resources to make two airships rather than one giant one). 
 +
 +Airships become exponentially less efficient the smaller they are, so the minimum size cost viability for a combi passenger airship would be 40 passengers and 6 tons of cargo, according to [[https://www.hybridairvehicles.com/news-and-media/overview/news/airlander-feasibility-study-for-highlands-and-islands-of-scotland/|recent studies]] published by island-dominating airlines that have placed orders for such airships, such as LoganAir and Air Nostrum. 
 +
 +In other words, for anything that requires fewer than 100 passengers or 10 tons of cargo, or some combination thereof, it is more cost-effective (albeit not necessarily more efficient) to transport things via other methods, be it cargo van, boat, semi truck, mail plane, or what-have-you. For a lot of those, you'd still need roads, but even factoring in the cost of those roads, they'd still be more cost-effective. 
  
  
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 Alternatively, a society transitioning towards solarpunk might consider pricing in the negative externalities of flying quickly (with private jets and the like, which have exploded in popularity recently) and use that to subsidize ultra-low-carbon transit like airships (whether that's additional research and development, or just mass production to improve availability). Speed is a luxury and allowing the people who are willing and able to pay a high premium for speed to offset costs for everyone else who just needs to travel might make sense in some settings. Alternatively, a society transitioning towards solarpunk might consider pricing in the negative externalities of flying quickly (with private jets and the like, which have exploded in popularity recently) and use that to subsidize ultra-low-carbon transit like airships (whether that's additional research and development, or just mass production to improve availability). Speed is a luxury and allowing the people who are willing and able to pay a high premium for speed to offset costs for everyone else who just needs to travel might make sense in some settings.
 +
 +
 +**Manufacturing**
 +
 +This is one area where airships have a profound advantage over conventional aircraft: in terms of basic manufacturability by a very small polity like a city or local company, they're comparatively easy to make. An Airbus A380, for instance, has over 4 million unique parts manufactured in over 20 countries, using alloys and materials that are as varied as they are expensive and difficult to manufacture. A successful large airship, by contrast, can be (and has been) manufactured from as few as 11 standardized parts to make up the main hull, and even in modern airships, they're still overwhelmingly making use of very basic, easily-manufactured (or recycled) materials like aluminum, polyester, and polyurethane. Much smaller, cheaper, simpler engines or motors can also be used relative to the huge, miraculous space-age turbines used in modern aircraft.
 +
 +However, that does mean that you'd be taking a big speed hit. 48 hours to cross the Atlantic versus 8. Cargo might not care that much, but passengers are impatient. Airplanes may take on more of a Concorde-like superfast role, but there'd still be a place for them, especially small airplanes like Cessnas.