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by spir
967 days ago
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I was hoping somebody would chime in on the sustainability of helium for airships. I'm a total amateur here. Is there no hope of finding a new source of helium? Is there any opportunity for airship gasses that are reasonably competitive to helium but have a much more abundant supply? Is helium the only possible such gas (besides hydrogen)? Are competing gases 30% less efficient or 3,000% less? |
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Not on Earth, or anywhere in the Solar System except the interior of the Sun, as far as I know. Mining the Sun's core for helium is unlikely to be practical any time soon. :-)
> Is there any opportunity for airship gasses that are reasonably competitive to helium but have a much more abundant supply?
No. The problem is weight. More specifically, the weight of the airship in total including the gas inside, compared to the weight of an equal volume of air. So obviously any gas that is as heavy as or heavier than air won't do. And that only leaves, by my count, three possible gases that aren't already in air, that are lighter than air at all. The comparative weights are, roughly speaking:
Hydrogen: 2 Helium: 4 Neon: 20 Air: 29
So the maximum amount of weight available for all the rest of the airship--its structure, engines, passengers, cargo, etc.--would be, roughly speaking:
Hydrogen: 27/29 Helium: 25/29 Neon: 9/29
The hydrogen case is known to be easily doable, but of course it also has the huge downside of flammability.
The helium case is doable, but not easily: once you've done the structure and engines, the weight left over for any kind of payload, i.e., passengers and/or cargo, is not very much.
The neon case is simply not practical: there isn't even enough weight left over for a reasonable structure, let alone engines and payload.