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Comment by ravenstine | Hacker News Reader

I hate to be that guy, but won't this contribute to the depletion of our helium reserves? What would be so bad about hydrogen in relatively small balloons? It's not like they'd all be little Hindenbergs, right?

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Hydrogen balloons are much safer than people realize. The outside of the Hindenburg was made of solid jet fuel (which also happens to be decent airtight paint), which is what made for the really dramatic pictures.

(Safer != inherently safe, to be clear)

If you are without valuable payload in 18-25km height there is nothing you can harm really even if you blow up. so maybe it may even make sense to add a self-destruct (ignition) of the balloon, if it malfunctions.

Space launch vehicles have self-destruct buttons (including the Space Shuttle) but they also carry enormous kinetic force. A balloon gone wild doesn't need to be destroyed. To your broader point, it doesn't seem especially risky to put hydrogen in modern balloons.

> The outside of the Hindenburg was made of solid jet fuel (which also happens to be decent airtight paint)

No, it wasn't, and no, it doesn't. (The usual, but also wrong, story is that it was coated in solid rocket fuel.)

https://www.airships.net/hindenburg/disaster/myths/#rocket

The plan has always been to move to cheaper hydrogen but it's logistically difficult because it's explosive (so everything needs to be done automatically & remotely at the launch site).

Do balloons use a significant portion of the total helium production? I cannot find the number but I believe the vast majority is used in industrial processes, not these large balloons...

Technically balloons use "balloon gas", which is essentially helium thats not pure enough for industrial applications. So I doubt a few hundred of these make a meaningful dent.

Are you saying that helium, a non reactive noble gas, can not be purified, or more properly, separated from other gas components?

It can be purified but it's probably cheaper to not purify since there's a market for the impure versions and even the pure version is being sold very cheaply.

The point is it's a poor excuse to frivolously use helium simply because it's dirty.

Do balloons use a significant portion of the total helium production?

The problem is that we can't make new helium, and the rate at which it's being used far exceeds what we capture from natural gas production. A decade ago this was considered a serious problem. https://phys.org/news/2010-08-world-helium-nobel-prize-winne...

I know the problem is real. But what is the point of paying attention to balloons if they only contribute to a negligible portion of the problem?

Because they're contributing to the project and not, say, fixing it.

Might be the ultimate damper on the technology too. (Though I still think it won't get off the ground, antennas getting cheaper all the time.)

Not sure, I just imagine people attempting to shoot them down for absolutely no good reason. You would at least want to make them not blow up (especially aviation organisations).

If they're high enough, blowing up might actually be the safest option. Better that all the hydrogen burn off up there than on the ground, when it doesn't have enough to be bouyant but still enough to do damage.

It's going to be a disaster in R&D or when you want to land them down for some maintenance...

Won't they be way up high? Even if one blew up, it'd be too high to hurt anyone. In fact it'd probably be tough to make one blow up from that distance. The best one could do is shoot at it, which won't ignite the hydrogen.

I think you are underestimating the effort people will go through to go viral on LiveLeak.

Hydrogen doesn't explode. It burns.

Hydrogen is explosive -- the flame front and thermal expansion exceed the speed of sound -- at concentrations from 18% - 60%. It is flamable at concentrations as low as 4% to as high as 75% (and to 95% in a pure oxygen mix).

Hydrogen very much can and does go "boom".

https://chemistry.stackexchange.com/questions/8498/how-explo...

http://people.clarkson.edu/~wwilcox/Design/flamlim2.pdf

In this context, the hydrogen mix is nearly pure, and therefore not explosive. The hydrogen in the leaking balloon would be well above 60%, so it should burn at the source of the leak.

The same effect is why natural gas stoves don’t explode in normal use.

The balloons will fly higher than anyone with civilian weapons can hit. And shooting a hole in a hydrogen balloon wouldn't cause it to blow up anyway. The gas would just leak out.

Can't someone just launch A cube sat with an incendiary attached? Don't know how they would hit it, but theoretically wouldn't that get you within reach with a weapon that mortals can afford?

Someone could shoot their neighbor, set fire to every kindergarten, or make a sequel to Titanic. But, luckily, people tend to use their energy and creativity for better endeavors.

On this logic, we wouldn't have planes though.

These balloons don't carry people. People are more inclined to create property damage for entertainment than they are to murder people.

There isn't really a helium shortage.

Why does everyone think there is?

There were several articles written about it.

https://www.forbes.com/sites/brucelee/2019/05/24/there-is-a-...

Afaik the jist of it is that once it is used it escapes the atmosphere and there is a finite amount of it.

There isn't technically a shortage because the government hasn't imposed any price controls. However the price has increased drastically in the past 10 years. My gas costs for scuba diving are way up.

Price increase indicates a shortage, since the purpose of a price increase is to select which sunset of consumers receive the product when not all can. Price increases are either free market rationing (a response to shortage) or a disappearance of readily accessible inputs.

That's not how shortages work. A shortage only exists when some external constraint prevents the market from clearing.

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