Differences

This shows you the differences between two versions of the page.

--- writing:airships [2025/11/20 02:27] – [Lived Experience Stuff] JacobCoffinWrites
+++ writing:airships [2025/11/20 03:44] (current) – [Relevant Technological Advancements] JacobCoffinWrites
@@ Line 270: / Line 270: @@
 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 ===
@@ Line 297: / Line 315: @@
 === 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 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.]]
+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.
+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.
+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.
-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.
-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.
-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 ====