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I'd like to have freights transported across my world by airship heavy cargo haulers with some passenger variants as well.

Imagine the scene with such airships soaring above the land, floating gracefully through the celestial dome propelled to where they are headed or perched on special docking mechanisms sticking out of the landscape and creating contrast.

Do you think that they could be plausible in a hard-science/speculative but not fantasy setting?

For additional information, the planet's gravitational pull is about 0.9 earth Gs, atmospheric pressure 1.5 atmospheres and the civilization living on it would have the technology to synthesize ultra-light materials (like carbon fiber, carbon nano-tubes and graphene) in considerable quantities as well as building modular nuclear reactors small and safe enough to be present on board the ships.

For example, do you think a combination of blimp, VTOL, ultralighteight materials and nuclear technology could achieve such feats?

The following image is from Simon Stalenhag to better illustrate the freight haulers concepts, taken from imgur:

Simon Stalenhag freight hauler concept

And here is the compilation: https://imgur.com/gallery/FjVNc

And this one for the cruise ship concept taken from Pinterest:

https://i.pinimg.com/564x/16/a0/32/16a03200a6adf4f1baaea437f137bba2.jpg

For a real world reference here is a video illustrating a concept for a nuclear powered aircraft carrier bomber developed during the cold war, which apparently had VTOL capability too: https://www.youtube.com/watch?v=d7KgjObskvM

About the nuclear reactors, what I have been thinking about is based on the recently developed modular designs, combined with the technology to use thorium as fuel rather than uranium and molten salt.

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    $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – L.Dutch
    Sep 1 at 1:53
  • $\begingroup$ Since the "Advanced technology" bit is speculative, could you have an ultra-light, ultra-strong material that would support a balloon "filled" with a vacuum? i.e. even lighter than hydrogen. $\endgroup$
    – colmde
    Sep 1 at 11:47
  • $\begingroup$ Is the power source limited to the reactor in the question? Other sources of power (whether generated or stored) may be more optimal, going by weight . $\endgroup$ Sep 1 at 14:52
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    $\begingroup$ Should look at "could 9" tensegrity spheres. A 1-mile wide tensegrity sphere could hypothetically lift a town's worth of mass and transport it anywhere $\endgroup$
    – BMF
    Sep 1 at 16:22
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    $\begingroup$ @JuimyTheHyena see this wiki and this SE:WB Q. I was surprised to hear it myself. It's easy to calculate the lifting capacity of one of these things. Even with large error margins, you're talking at least hundreds of thousands of tons for even small temperature differentials. $\endgroup$
    – BMF
    Sep 2 at 1:10

12 Answers 12

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Possible with minimal hand waving

Every few years, there's breathless coverage of the some airship startup that heralds lighter-than-air craft as the next big thing in aviation. A quick search of Popular Mechanics turns up articles like "4 New 'Blimp' Designs Bring Return of the Airship" (2009) and "Why the Return of the Airship Makes More Sense Than Ever" (2019). So there are people who believe that the technology we have today could support pretty awesome airships.

You're positing the existence of ultra lightweight materials and powerful nuclear reactors for power. Having large amounts of power without a lot of weight would let you build some kickass blimps. One restriction to your last image is lifting capacity. Even with a lower gravitational force, you'd need a lot of hydrogen to get a big craft off the ground if your atmosphere is like Earth's. One workaround would be having the lifting gas only support some of the weight and use engines to provide additional lift. At your technology level, you could use either ducted propellers or electric jet engines.

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    $\begingroup$ Hmmm, excellent points and examples, especially the electric jet engines. I'll consider this settled then $\endgroup$ Aug 31 at 8:49
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    $\begingroup$ Once you get into lifting engines, though, the efficiency of the whole thing starts to take a big dive. Now it's a sort of fat, slow helicopter... and those things are terribly inefficient. Like, "how about we deliver goods in a Lamborghini supercar" inefficient. $\endgroup$
    – J...
    Aug 31 at 13:13
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    $\begingroup$ J... It's lifting engines combined with blimp technology, mainly to ensure that the 'blimp' part doesn't require a baloon with the radius of a kilometer and to make it fast compared with other modes of transportation. $\endgroup$ Aug 31 at 13:44
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    $\begingroup$ @J... The concept has been floated in the real world as well - it's called a hybrid airship. Especially for heavy-haul operation to remote locations where helicopter or truck operations may not be feasible, there's been a fair amount of interest. $\endgroup$ Aug 31 at 14:05
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    $\begingroup$ @SebastianLenartowicz Yes, but that concept is about engineering the airship to also have a lifting body that produces lift aerodynamically from forward motion. That's different from the suggestion above to use vertical thrust to directly add lift. The first concept can be quite efficient. The second, much less so. $\endgroup$
    – J...
    Aug 31 at 15:10
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Plausible

Airships are the dream of many a sci-fi / futurist / what-if worldbuilding project! I think you hit on the main points, materials, high enough tech, nuclear power source, all electrics.

Just about every detractor of airships points to the Hindenburg disaster and the airships that were designed in the 1920s and 1930s. That was a century ago! Hindenburg itself flew dozens of times without issue and there were other ships in service. Had the Hindenburg not exploded, or had the news coverage not been so tear-jerkingly emotional (Oh! The humanity!) it's quite possible, probable even, that airships would continue to be used in some capacity and the technology would evolve sufficiently to overcome various problems.

Keep in mind that early commercial jets also had their problems, the Comet coming to mind immediately. Yet we didn't give up on jets and as of now, air disasters, while rare, are not technological deal breakers as was the 1937 disaster.

I'd argue that your project is perfectly plausible given the technological and materials advances.

http://ib.frath.net/w/Aeroscrafts

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    $\begingroup$ To add to this, airship design has improved considerably. The Hindenburg for example was actively venting hydrogen as it was trying to land and its hull was a flammable material doped in a highly flammable material which meant that the hole where hydrogen escaped became quickly bigger which accelerated the burning process. By using a hybrid airship (no venting required) and modern materials (slows burning/stops burning by itself) and safe techniques like extra bladders around the hydrogen bladder and mixing with helium to reduce flammability could seriously improve their usefulness $\endgroup$
    – Demigan
    Aug 31 at 10:54
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    $\begingroup$ @Demigan You can also avoid the venting issue by using ammonia as part of the lift system. It can be evaporated OR condensed to liquid and stored. Not as light as hydrogen, but it has that critical control issue. Ammonia can also be decomposed to hydrogen and nitrogen (venting the nitrogen), or a mix of hydrogen and ammonia can be separated by condensing the ammonia out. So add lifting gas, condense lifting gas, and make lifting gas as needed. Or have a separate ammonia lift tank. $\endgroup$
    – DWKraus
    Aug 31 at 23:22
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One major problem with airships of any kind is their size. Assume hydrogen as the lifting gas: a rule of thumb (that will get you within a few percent of the actual numbers) is that to lift 1 kilogram of mass--which would be the airship itself plus payload--you need about a cubic meter of hydrogen or helium.

Hindenburg had a volume of 200,000 cubic meters, and a useful lift capacity (ship + cargo) of 232 tonnes. The ship itself massed 118 tonnes, which left 114 tonnes for fuel, passengers, supplies, ballast, and so on. Let's say modern materials get it down to 50 tonnes, which then gives you a total 182 tonnes for everything else, including things merely needed to fly the ship, such as fuel and ballast. Regardless, this is what this looks like in comparison to modern aircraft:

By Giant_planes_comparison.svg: Clem Tillier (clem AT tillier.net)derivative work: Timmymiller (talk) - Giant_planes_comparison.svg, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=13920306

The freighter version of the 747-8 can carry 140 tonnes of cargo, which puts it on par with an airship the size of Hindenburg. Now look at the difference in size. That has repercussions for everything from flight paths to ground handling because of the wind load it experiences. Just as a for instance, once a plane lands, except if the wind gets into storm force ranges, you don't have to worry about it. For an airship, anything over a stiff breeze may require constantly running the engines just to make sure it doesn't snap the mooring lines.

Imagining anything larger is, well, sort of hard.

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    $\begingroup$ Consider that in my setting the overall mass would be effectively 10% lighter due to the planet's gravity, but aside from that the technology to be applied is completely different from that used to build the hindenburg. My proposal includes the use of much lighter materials and nuclear power for energy, which could be used to run the VTOL propulsors for extra vertical lift besides directional propulsion. $\endgroup$ Aug 31 at 7:16
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    $\begingroup$ @JuimyTheHyena 0.9g does not play that much of a big role, 1.5 bar is a more significant difference, also not a gamechanger but hindeburg size with all the assumptions of op would carry 1.5 times more mass aka 270t instead 180. $\endgroup$
    – MolbOrg
    Aug 31 at 7:34
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    $\begingroup$ Also: OP mentioned plane-ready nuclear reactors. That makes the increased fuel use of planes irrelevant $\endgroup$
    – Hobbamok
    Aug 31 at 9:29
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    $\begingroup$ So they are bigger, what about fuel consumption and safety? Keep in mind that aircraft at the time of the Hindenburg were very unsafe and the 747 has almost a century of continuous research and development behind it that made it safe. From simple accurate weather updates to redundancies to new materials and equipment. You would need to assume something like the airlander but as if it had been developed for over a century. $\endgroup$
    – Demigan
    Aug 31 at 10:41
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    $\begingroup$ @JuimyTheHyena, everything that you state that improves the quality of airships makes aircraft even better at a faster rate, thus why airships? $\endgroup$ Aug 31 at 22:55
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Plausible, with a different planet:

  1. We need a planet where traditional long range transport techniques aren't nearly as good as the options on Earth. How about a rather dry, very geologically active world where much of the surface is mountains of various ages and little of the surface is oceans or large rivers. Ships only do oceans and running trains through mountains is very expensive.

  2. Lets improve the lift: Make the atmosphere considerably more dense. While it wouldn't be survivable to a human there's no reason a creature couldn't have evolved to live in such a location.

Now, how about power? At first glance a nuclear-powered airship makes no sense, you can't haul the shielding and thus you fry the crew. Lets try a different approach, though--how about shielding our ship with the atmosphere itself? The reactor dangles on a long cable below the airship. This is not an insurmountable obstacle to landing--airship landing platforms have deep holes into which the reactor is lowered. The holes are well away from the platform itself--the airship approaches, a line from the airship engages a winch that pulls it in until the reactor is some feet underground. At that point another cable is hooked and the airship dragged down to the actual station--it remains far from it's reactor at all times. Lets say the planet is at 50 atmospheres--at that point the halving thickness of air is 10 feet. If your reactor cable is 1000' long that's the same as putting 20' of concrete between you and the reactor.

As for why they went nuke rather than solar--batteries are heavy, thus substantially decreasing the carrying capacity of an airship that can operate under clouds or at night.

Beware that the smaller the reactor the higher grade fuel it must use--I don't know how small you can get before you have fuel that could be diverted to bombmaking.

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  • $\begingroup$ I wouldnt't worry about bombmaking as a primary counterargument. A lot of stuff could be readily weaponized, but isn't. And we could have all nuclear powered blimps be in the hands of the one singular empire-owned shipping company (that is also intertwined with the singular official military) $\endgroup$
    – Hobbamok
    Aug 31 at 9:32
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    $\begingroup$ Not necessarily very non-earth like. For example, some of the lighter than air dirigible start ups mentioned elsewhere have been motivated by carrying loads above tundra and muskeg, such as in northern Canada and Siberia. The sort of place where trucking usually only happens in the winter on ice roads that freeze solid. Similarly, swampy areas anywhere.b $\endgroup$
    – Krazy Glew
    Aug 31 at 19:38
  • $\begingroup$ @KrazyGlew I can see it in specialized circumstances on an Earthlike world, I got the impression the OP is looking for it worldwide. Thus I'm giving a world that both makes lighter-than-air craft more useful, but also plays to their strengths. Note, also, the dense atmosphere for reactor shielding. $\endgroup$ Aug 31 at 23:45
  • $\begingroup$ I love the idea of a rope-towed reactor! :) $\endgroup$ Sep 1 at 12:38
  • $\begingroup$ Distance by itself is a shielding factor(lazy to google concrete and radiation maybe you counted that already), a 55MWA electric 175MW total setup weigths 2200t and is shielded enough to work there and servide it and its size is 6× 13,2×15,5 m, so if we take 15m(45ft) then whatever radiation there is at 1000ft it about 400 times less. Also such reactor can power 0.6x0.6x5 km blimp with about million tonn lifting capacity(gross) with methane. I do advocate for external towing solutions in some cases, and this one can be one of those, just pointing out some things. $\endgroup$
    – MolbOrg
    Sep 1 at 19:08
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They are viable, even on earth without all those boosts you imagine.

some blimp pros for earth

The energy efficiency of blimps is on pair with railroads, it takes 3rd place this way - sea ships(0.3), railroads(1x), blimps(2x of railroads energy-wise), trucks (4x), airplanes(10-30x). Comparisons are very approximate and rely on that I remember the number for blimps correctly and didn't screw my calculations back then and that blimps move quite slow(20-40kph).

Blimps are one and pretty much only one which can use high(8-20km) altitude Jet streams having some "free" energy for long-distance hauling. Its next competitors are solar-powered airplanes, but those aren't that impressive fragile and have other problems including complexity and EROEI.

In the capacity to lift and deliver bulky cargo - blimps are the only ones that can deliver something like oil platforms from the assembly point to installation point in one go(ignore the fact it is built in the same places where ships are, it is just an example of capacity and size). And not only those are a problem, and it could be an improvement if we had such capacity. At the moment it is - or a complicated transporting problem, or requires all kinds of moves from design to installation procedures.

Blimps are the only cargo transport that can cover 100% of the planet's surface.

Blimps do not require loading unloading at coast ports and can deliver directly to a consumer, faster than a sea ship, with less energy spent than a ship(if we rely on jet streams, okay okay I hear you solar panels, not necessarily a great idea but "free" energy anyway) and if we consider that from a port this cargo has to be delivered further by trucks (often) or railroads(also often) then energy efficiency can be even higher and maybe even sufficient to compete with railroads or maybe more(no loading unloading procedures, delays, etc).

If one needs a port for cargo for blimps then such port can be built anywhere, you can choose an optimal place for that type of cargo. Seaport, for bulk cargo transporting, is a huge system - with roads, railroads attached to it, with places to store cargo, load-unload and places for it are limited to the coastline - we did cope with that but it does not mean things could not be better.

In a time when we begin to see bulk gas transporting - blimps can be used for that, and it hard to tell who's the winner - ship or a blimp, so besides bulk cargo transporting it another one where blimps can compete with sea ships transporting directly, again cutting corners (literally) by not being bound by channels, and deliver directly to gas storages, directly from gas "wells" meaning cutting pipes, deliver faster(2-3x) than doing so by ships, be flexible and more responsive for demand changes. The pipe is a winner for fixed places hands down, but there is not always a pipe, and one can test and build up production to a level when a pipe investment makes sense - so more flexibility and blimps rather win over ships.

  • the probably least useful case for the op, with modular reactors and such, as the same reactors can be used for what most of that gas is used for.

City to city transportation can be more efficient - essentially flexibility of a helicopter for a price(energy-wise, delivery) 0.5x of a truck, with direct routes, higher loads(more than 40t), more efficient lower loads(0.1-1-5t), better prospects of making drones out of those, etc - those can be attractive points.

op's materials, energy source

The importance of different points changes slightly, due to reactors' use, but overall it is the same. Gravity and density of atmosphere have minimal influence on all those points. Stronger cheaper materials are beneficial, but so are they for other things, I mean they are not a game-changing factor and not required but sure they are a good thing.

reactors

Given that nuclear reactors don't work for heavier-than-air flight, lighter-than-air flight seems even less plausible. The high surface area of lighter-than-air vehicles does make solar a more viable option, though. – @jdunlop

This one is wrong. Reactors definitely are more plausible for blimps. There are few reasons for that - liftoff energy consumption may be low percents of full throttle, while on airplanes it is one of the intense moments. Not necessarily a big deal for combustion engines, but reactors do not like jumps in power for many reasons, including for reasons of processes of chain reactions happening in nuclear fuel. The difference is not necessarily huge, but a similar difference is enough to not have turbines on bikes and cars(it is not only it but one of them).

Power to weight ratio is less important for a blimp, the range is wider - if a blimp can lift one, then it does not matter that much if it delivers 1MW or 50MW - the difference is cruise speed, but not the ability to fly if the airplane does not have sufficient power it just can't take off, even if this power would be sufficient to hold some cruise speed.

Solar panels for airplanes and blimps are not necessarily such a cool thing - there are airplanes like those so it can be seen(quite fragile construction to which op's materials could be a great help btw), for blimps it may be a better option than for airplanes, but it hard to tell if it better than some jet stream sail as an example, which can work 24.7 without batteries.

In an airplane, one can't distance himself from a reactor, while on a blimp there is more distance between the crew and a reactor, which may mean lesser shielding requirements(thus mass, etc). A blimp can tow a blimp, from start to finish, essentially making an external engine, this is used for ships, but airplanes, it is used for gliders but beyond that, it is even harder to imagine a Boeing size thing towing another Boeing - but a blimp towing another blimp, not a big deal.

More airplanes did crush than blimps burned - (anonymous)

misc

Safety-wise it is hard to argue what's better, essentially we are noobs blimps making and did perfect designs for ships and airplanes for more than a hundred years. And despite that there are spectacular design failures for ships in history('70s, 80's, in essence, worse than titanic in terms of mass/cargo loss), so as cruise ships incidents in this century. Airplanes are not an exception, we all know that, airplanes do have some problems landing as well and it is hard to imagine it going away any time soon(it can, with better technologies, like smart matter but when it happens is unknown)

Better materials make blimps more useful already, and some are in limited use for inspecting and such as a replacement for ground vehicles and helicopters. This is far from potential it has, but it is, even more, a sign that blimps can offer unique advantages. So as for safety materials are an improvement and not only materials but other technologies like detecting gases - nothing of that was possible back in the days but still, some blimps of that era had million+ km's under their belt.

They tend to descend than to crash is definitely more friendly for reactor placement, not as good as tends to sink in water, but still.

Mooring lines - what about a 3km landing strip, eh?. Airplanes usually do not idle in hangars they fly in and out as much as they can - so storing is overrated.

Autopilot for airplanes works well enough, take-off and landing are still a procedure but great improvement here as well, for blimps drone-like capacities are even easier and that (combined with Starlink) can offer unprecedented opportunities, and if you still care about storing problems - here as well.

So in general with or without reactors and more new materials blimps look like an attractive idea, there are interconnected factors why it does not happen as of today, including we did bend our processes to not need them, but it does not mean they have no chance for resurrection, and for places where their development wasn't abandoned and they continue to evolve and processes were shaped for their use - most likely our system would be unimaginable and not viable.

If someone can beat sea transporting then they will have all the chances to spread that technology to other places - they will have technologies and money for that as SpaceX did. And one of the avenues is transporting gas overseas and from small places.

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  • $\begingroup$ Even the Hindenburg reached up to 120km/h, while most airships of the time still flew relatively close to the ground in order to give more spectacular views for the passengers. Mooring problems could be solved by using heavier-than-air airships which use a combination of gas, wing surfaces and vectored thrust to land and take off. This removes the need for extensive ground crews and still allows an airship to take off and land at extremely short airstrips, and depending on the design even as a VTOL. $\endgroup$
    – Demigan
    Aug 31 at 11:23
  • $\begingroup$ By eliminating the dangers of landing (no skilled mooring personel, no venting of hydrogen), by using new materials to replace the flammable envelope and bladder materials, by relying on new materials to improve sturdyness, by relying on new techniques for designing airships and by relying on the already inherent redundancies and resiliance of airships, the safety of a modern airship would be an order of magnitude higher than any other aircraft in the history of aircraft, including military ones. $\endgroup$
    – Demigan
    Aug 31 at 11:28
  • $\begingroup$ Taking off a plane with a nuclear reactor shouldn't be a problem - jet engines don't like sudden jumps in power either, they take time to get going! The way they deal with this is by having long enough runways that it doesn't matter, or by holding the brakes while the engines rev up. No problem. $\endgroup$
    – user253751
    Aug 31 at 12:47
  • $\begingroup$ @user253751 turbines from idle to 100% they are quite fast - it seconds. But yes sure it not a huge problem, did I mention it as a hard stopper? $\endgroup$
    – MolbOrg
    Aug 31 at 15:31
  • $\begingroup$ @Demigan which ground crew, which century you are living in lol - used caterpillar with hook grapple and the thing won't go anywhere. speed 20-40kph is eco mode, it is similar to bulkers making 10-12 knots, while we have much faster ships - energy spend per tonne per km is pretty much proportional to the square of the speed and most of the tonnage moves not much faster than that in half of the cases(awkward way to say sea ships aren't that fast). the problem of airships they have to make economical sense, some unconventional fixed routes could help that. $\endgroup$
    – MolbOrg
    Sep 1 at 11:49
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Operating in any kind of windy or turbulent conditions is a major practical constraint, even for modern airship designs on Earth. Wind that moves at a constant speed at a given altitude, such as the jet stream, is not a problem, and high-altitude airships can use such currents to their advantage. The problem occurs with turbulent air or with winds near the ground. One possible solution to this constraint is to construct a world in average wind speeds are much slower than they are on Earth.

The major question you will have to address is why airships have come to dominate air travel in your world when heavier-than-air craft have proven to be so much more practical in our world. If your world has a sufficient level of technology to make airships feasible, then it also would have the science and technology to make airplanes feasible. Perhaps the world once experienced a world war that was facilitated by high-speed airplanes and rockets, and such technology is now banned by international law or cultural taboo.

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  • $\begingroup$ Nice first answer with added value. Welcome to worldbuilding Craig, enjoy the site. $\endgroup$ Aug 31 at 21:31
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Probably not on Earth

We can't significantly improve on WW2 era airships here on Earth, because those designs already used the best lifting gas allowed by physics.

H2 is the lightest atomic gas - can't get smaller than one proton per nucleus. This puts a hard upper limit on the lift you can generate, which makes practical airships difficult.

Think Titan

Titan's atmosphere is thicker than Earth's, which means you'll get more lift for the same lifting gas. This is good.

Also good is that Titan has significantly lower gravity. Between these two factors, you should be able to build much smaller and more efficient airships. Since there's very little O2 in the atmosphere, you don't need to worry about hydrogen explosions either, so that's a bonus.

The view of the endless hydrocarbon dunes is going to be... spartan, not unlike your sample images. But probably still beautiful.

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    $\begingroup$ Did you even read the question? OP already said, only 90% gravity with 1.5x the air pressure $\endgroup$
    – Hobbamok
    Aug 31 at 9:30
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    $\begingroup$ You can use lifting surfaces like a hybrid airship. Hybrid airships are heavier than air (in other words they have a minus lifting capacity) but like an aircraft they can use lifting surfaces to get airborne, as well as vectored thrust like a VTOL aircraft, but require much less of it to get airborne. This has many advantages, like not needing towers and ground crew to land and still providing a lot of the redundancies and safety that an airship offers. $\endgroup$
    – Demigan
    Aug 31 at 11:01
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    $\begingroup$ @Hobbamok - When I answered, there was no mention of air pressure.... I didn't think 90% gravity really changed the equation much. $\endgroup$
    – codeMonkey
    Aug 31 at 14:00
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    $\begingroup$ @Hobbamok - Air pressure doesn't mater much on itself. What matters is air density. In Titan air density is high due to very low temperature. A combination of cold, 1.5x air pressure and an appropriate air composition can easily halve blimp volume - and even more. $\endgroup$
    – Pere
    Aug 31 at 18:30
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The fundamental problem with airships is that they have a large surface area, and need a large input of power to make progress against a headwind, or even a side-wind. This makes them very inferior to heavier-than-air aircraft for moving passengers, or even cargo, to a predictable timetable. (It also makes them slow, even in good conditions). Nuclear-powered airships? ... er, no.

The less fundamental problem is that hydrogen is problematically inflammable or explosive if air gets in, and helium is problematically expensive.

For getting heavy cargo to a remote location without roads, or for heavy lifting where it's difficult to deliver a large enough crane, an airship has some merit. Here, getting the job done at reasonable cost can afford to wait for a day with low wind. It's possible that the Hindenburg disaster is so deeply etched into our memories, that nobody can get the concept of a large hydrogen airship past the money-men. Maybe elsewhere, with modern materials and no adverse history, it would fly.

Incidentally a methane-filled airship would need about twice the volume of a hydrogen-filled airship for the same lift, but methane is far easier to contain without leaking, and far less of a fire or explosion hazard if there are small leaks.

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One big issue is load management.

You go from A to B with 100tons. At B you either have to get an equal mass load, or you have to vent lifting gas. The easiest way to do this is to use water. You can load it with pumps, discharge by gravity. This is a major logistics issue if you are delivering to some place in the middle of nowhere. They have to get tanks ready that hold as much mass as what you drop off. I can see the merit in floating aerodromes on medium size lakes, or protected bays. You anchor, then a barge positions itself to receive 12 seacans by winch. The barge on position gets lines from the airship so there is no reaction as the cargo is released. Meanwhile the airship drops a hose and is pumping water into ballast. Tension meters on the ropes indicate how close to balance the airship is.

In flight you don't have to exactly balance buoyancy an weight. If the lifting gas is in bladders, you can pump it into high pressure storage tanks. This is useful for minor changes. In flight you can also be slightly heavier or lighter than air and compensate with the bow pitch. You have to get this fairly close to spot on at landing time.

One of the options for lifting gas is hot air. High tech solution: Make the outer shell out of a mixture of glass and carbon fiber that is foamed in a vacuum. Put a reflective layer of aluminum on both faces. A 1" thickness of this would have a high R value as well as being impressively strong. Carbon fiber and resin would make up the frame, much like a graphite bicycle.

The lift of hot air is roughly p * K/Kambient. Where p is the density of air, K is the temperature inside the envelope, and K ambient is the temperature around you. If K is twice ambient, so 580 K in the envelope you get about .6 kg of lift per cubic meter. This is about half what the same volume o H2 gets you.

The win on this is that your ballast problem goes away. The lose is that you have to regulate the temperature. 1" of multi layer vacuum would keep heat in quite well, but you would need to discard hot air replacing it with cool air whenever you dropped a load. You will also have issues when you descend from colder air to warmer air, as you lose lift. Some ballast operations would be necessary to increase lift FAST. Or if the lifting gas is fresh, you could directly burn propane inside the envelope to raise the temperature in a hurry.

Landing might be semi-automated by running somewhat bow-light, then dropping a 500 foot rope at approach. This is attached to a winch that pulls you in to the mooring mast like big fish.

Mooring masts have to be sturdy enough to withstand whatever normal storms you have locally. Call it 70 MPH for non-coastal (non-hurricane) areas. These are not going to be tall graceful spires but more likely to look like concrete obelisks. Severe storm warnings would result in one of:

  • Airships flee out of reach.
  • Airships are deflated and anchored to the ground (blimbs)
  • Airships are parked in underground hangers (expensive)

Read up on other airship crashes. The navy ship Shenandoah is a good story.

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  • $\begingroup$ "At B you either have to get an equal mass load, or you have to vent lifting gas." you said it yourself, "you can pump it into high-pressure storage tanks." and storage tanks can be those bladders. if a payload is 50% of total lifting capacity, then it 2 bar pressure in tanks - fiber-reinforced something should be capable of such tricks. so are there more special cases that may offer other options as well - unloading point is a gas station 2in1 as an example $\endgroup$
    – MolbOrg
    Sep 1 at 12:49
  • $\begingroup$ Indeed, but you have to have high speed high volume pumps, which need an engine and a compressor. The required wall thickness for storage tanks goes up with the with diameter. When you compress it, you do work on it, so the gas heats up, making your pumps work harder. Thicker bladder walls, heavy compressors, engines to run compressors all eat into your payload. Pumping water in and out seems a lot easier. $\endgroup$ Sep 2 at 3:20
  • $\begingroup$ Yes correct. Industrial compressor can compress 43'000 cubic meters of air to 10 bar(1.1MPa as absolute lressure, so 0.2MPa abs, 1bar it will do 10x of that), with 3.5MW on the shaft, there are such things as turnine+outlet for compressed air, they can be quite compact. But yes it requires energy. Water is an option when it is an option, and it is easier, it just not always an option. Point was - there are ways around, more than one. Semi rigid envelope can be under some pressure to begin with, for purposes similar rocket tanks, yes it adds envelope mass, but modern materials are good enough. $\endgroup$
    – MolbOrg
    Sep 2 at 9:10
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Make Helium abundant.

Perhaps there are pockets of helium underground, trapped during some exotic process in the past? Much like our oil, gas and coal. It is trickling out, and is generally seen as more of a nuisance than anything.

You could make blimp repair-hubs around large reservoirs, even in places with bad roads and such..

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I've done a lot of thinking about airships. See: https://worldbuilding.stackexchange.com/questions/tagged/airships

Short answer: yes it's entirely feasible.

There are no good alternatives to helium (apart from https://en.wikipedia.org/wiki/Vacuum_airship which will fit some worldbuilding scenarios but not others), so you should make sure your planet has abundant helium resources. IRL, helium is harvested along with natural gas deposits underground. Alternatively, it can be harvested from space.

https://www.flying-whales.com/solution build a transport ship called the LCAT60T with the following specs: it can haul 60 tonnes (a Boeing 737 hauls about 20-23 tonnes), is 200m long, has a cargo bay that is 96m × 8m area and 7m high

The ML866 is a similar cargo airship: https://en.wikipedia.org/wiki/Worldwide_Aeros_Corp#Aeroscraft and is 169m long, hauls 66 tons. The same company ultimately plans to build a ML86X with a length of 920 feet (280 m), a height of 215 feet (66 m), and a width of 355 feet (108 m), with the capacity to carry 500 tons.

Note that all these carrying capacities are dwarfed by trucks, ships, roads. There are container ships that can carry over 500,000 tonnes. But airships have their use cases, like remote landlocked areas (remote=no roads or rail, landlocked=no waterways), or for the romance of it.

Feel free to ask me follow-up questions, as we're working on overlapping projects.

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This has been attempted in Germany in the 90ies and failed mostly for financial reasons. I don't see why it would be technically impossible:

https://en.wikipedia.org/wiki/CargoLifter

"This service was based on the development of a heavy lift airship, the CL160, a 550,000 m3 (19,000,000 cu ft) vessel designed to carry a 160 t (160,000 kg; 350,000 lb) payload."

From the German article about the airship itself, translated with DeepL:

https://de.wikipedia.org/wiki/Cargolifter_CL160

Description CL160 was designed as a keel airship. The keel was to be made of carbon-fiber-reinforced plastic and to carry quarters, load, tail unit and propulsion extending from the bow tip to the stern. Eight General Electric CT7-8L shaft turbines of 5882 kW (8000 hp) each were planned for the latter, half of which were to be used for steering only. Many details of the design remained unresolved, but some components had been manufactured before the bankruptcy.

A fundamental hurdle to the design of large cargo airships is the extensive buoyancy compensation required for loading and unloading the airship. A load exchange method was envisaged for the CL160, which was also tested in practice on the Cargolifter CL75 AirCrane. CL160 was to be anchored above the loading area to pick up cargo and then pick up the payload by means of a built-in load frame. When setting down the load, it was intended to pick up ballast water from tankers on the ground to compensate for the weight loss. A ballast water recovery system was also reportedly planned. In the end, however, there were no more than basic technical ideas for solving the problem.[1]

Translated with www.DeepL.com/Translator (free version)

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