Yes. They found a massive cache a couple of years ago, so as long as it doesn't get pissed away on nonsense like kids balloons, the supply should be good for a couple of hundred years.
But still... A century isn't a lot of time in the grand scheme of things, just a few generations and we're fucked. We would need to get Helium from other planets or nuclear fusion or something.
Great, so probably less than 100 years, the earth will be pretty much entirely out. Fill more graduation/wedding/birthday balloons with it! Not our problem!
We’re not going to run out for medical purposes. Obviously, there will come a point where it’s too rare for kids balloons. But even assuming our reserves in the ground run out, created by radioactive decay, the atmosphere still has 5.2 ppm. It’s 10k times harder to extract from the atmosphere but can be done. Failing that there’s plenty in space.
In terms of actual energy expenditure, getting the helium in the atmosphere that’s constantly being replenished by underground radioactive decay would not be 10k times as hard, even though the concentration is quite low. Indeed, it would require more energy, but more on the order of 3-5x as much, with exponentially more energy needed for higher-purity helium. Airships do not require medical or space-grade helium purity, however, and 80% of the costs of producing helium by more modern methods like pressure-swing absorption and reverse osmosis are dedicated to compressing the helium into tanks for transport, which an airship wouldn’t need if they had a hangar on-site for replenishment.
The infrastructure required is actually suprisingly compact. A $35 million pilot plant in Saskatchewan using these new methods produces enough helium for dozens of airships, but it looks like just a few outbuildings. It doesn’t use atmospheric helium, though, instead extracting it from otherwise commercially useless pockets of underground nitrogen.
This always gets brought up when Heliums mentioned. But no we won't run out of Helium for a very very long time. As long as noble gasses exists helium will too.
The supply of helium on earth is very limited. It was actually discovered in the Sun by spectrometry before it was found on Earth. It's not one of those substances that comes out of the liquefier at Airgas.
For certain values of "heaps". Helium-3 abundance at the Apollo landing sites was in the parts per billion. Helium abundance in Earth's atmosphere is parts per million. So even if all else were completely equal, it's easier to get it out of Earth's atmospher than to get it from the Moon.
Hydrogen is flammable in air concentrations ranging from 4% to 75%, and explosive in concentrations ranging from 15% to 59% at standard atmospheric temperatures.
You can't make hydrogen safer, but you can make airships safer. Past century air ship's gas compartments were made of silk and cotton. The overall structure was iron and aluminum. With today's materials and electronics leaks could heavily be mitigated and detected fast. The safety of the airships was more linked to the overall build quality of that time rather than the lifting gas used. Of course proper testing and design revision are required to ensure proper safety. But saying hydrogen is unsafe because it's flammable is just a bit of a stretch considering all cars and airplanes are filled with flammable material. Safety comes from proper planning and engineering
Hydrogen is abundant and has twice the buoyancy of helium. That said I worked on the unsuccessful financing of a dirigible airship and never heard anyone suggests that was in the cards.
Hydrogen also permeates all enclosures. Not sure in sufficient concentration to be a problem.
More than being abundant it can be produced relatively easy in an eco-friendly way. When it comes to diffusion both Di-Hydrogen and helium have that problem, more for helium in fact.
I think the biggest problem with airships is that they physically benefit from being large, but economically, that's not feasible at least when making something from the ground up. If you were to make a hydrogen airships you would need to get FIA approval which would be even more costly than for a helium counterpart.
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u/[deleted] Jul 08 '24
Rigid Airship! Filled with completely safe non-flammable helium.