Comment by standingconcern | Hacker News Reader

Comment by standingconcern | Hacker News Reader

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standingconcern

A broken light bulb or a spark on the ceiling are enough to ignite Hydrogen; and that is why facilities that process it must have ventilation.

"A covered Hydrogen filling station must have electricity for ventilation." Agree or disagree?

And what about microwave energy beaming? Can microwave wireless energy transfer cause a hole in an airship? What about freak lightning storms while inspecting high energy power lines in a balloon filled with flammable and explosive gas?

It looks like it may be possible to store Hydrogen in Sodium Bicarbonate.

There are aerospace-grade hydrogen tanks that aren't supposed to explode in a crash landing, but what about midair collision and war?

There are people working on drones that hover in midair (that do not add flight and ground risk) that efficiently use the air currents too.

I'm afraid [this airship firm] hasn't done a sufficient level of testing to determine how easily the product can become a war liability, and I don't think FAA should clear Hydrogen airships for energy infrastructure inspection.

They are in France so the FAA doesn’t apply, but you think the FAA shouldn’t approve hydrogen airships because in the event of war, attackers will not go for cities or nuclear power plants or military bases or national scale gas storage or highway bridges but will instead target hydrogen lifted blimps in remote areas?

If a small drone explodes and takes down an electricity pylon in nowheresville in the middle of a war, I reckon most people would be very grateful that’s all that happened and willing to fund drones just to draw fire from more important areas and nothing else.

What a weird set of concerns.

Civilian aircraft aren't generally expected to be able to withstand midair collision or war. Why would this drone be any different?

Most aircraft today contain some kind of power storage that can ignite dangerously; 100LL or Jet-A in the case of airplanes and helicopters and some drones, lithium-ion batteries in the case of many drones and upcoming eVTOLs (and for aux power in many modern airplanes as well).

Regulatory frameworks and engineering practices are absolutely able to be used to consider the risks of fires in energy storage systems.

If positioned in a fixed location over critical energy infrastructure , this drone is on another level.

Rockets that contain hydrogen have self-destruct, and NASA doesn't want to load a rocket with Hydrogen while astronauts are onboard on the ground; though rocket fuel hydrogen is chilled and pressurized with lots of energy.

The true cost of guarding a hydrogen blimp that's guarding the critical infrastructure? Is it as much as guarding an upriver reactor cask that's under ordinance spec?

Compared to grid scale battery farms for energy storage, would Gravitational Potential Energy and/or CAES Compressed Air Energy Storage (which are less lossy, anyway) be less of a liability if in the flight path of a slow to fixed hydrogen airship?

Aerospace-grade [hydrogen, jet fuel,] tanks are probably more impact resistant than any airship ever?

Which critical energy facilities have procedures for handling a hydrogen airship in their airspace with and without a wind event?

Gravitational Potential Energy in old mines is enough energy storage for domestic US needs FWIU, but supercapacitors or ultracapacitors may be necessary to handle renewable load spikes when the sun shines across the grid.

Sparks such as from damaged electronics are hot by the way, hence their ability to ignite flammable gases (unlike, evidently, bullets).

Why are you worried about microwaves, or a flaming gas bag during a war? Rockets seem to supersede those concerns entirely. Or the much more valuable infrastructure targets that would also be vulnerable if a craft like this was vulnerable.

Re freak storm; then it catches fire, like many other things that get struck by lightning.

Bullets cause cylinders under pressure to explode.

It is feasible that microwave power beaming or similar could affect the wind or the airship directly.

Drones are very inexpensive. Ukraine's latest are probably sufficient to cause operational failure for airships.

It is appropriate to be concerned about flaming gas bags positioned over critical energy infrastructure.

We don't know how to fly a flaming gas bag out of the way when there is a Hydrogen fire.

> Bullets cause cylinders under pressure to explode.

They don't actually - they cause pressurised containers (propane for example) to outgas but they don't cause an explosion or even ignition.

You can shoot clean through a propane tank with a 50 cal bullet and not even see (from a distance) the effect .. unless the air temp and humidty is enough to condense water about the outgassing.

Go and check out some "let's shoot a propane tank" videos - no explosions UNLESS someone rigs an ignition source (lit flare, etc).

You've been getting your 'facts' from Hollywood.

Then how did an aluminum aircraft contacting a building cause enough of a spark to cause an on-impact jet fuel explosion?

Indeed we easily could find some pre-existing videos of pressurized cylinders exploding and there being flames. I don't think you're going to convince me that flammable pressurized canisters do cannot cause thrust when punctured.

Does there have to be another existing fire for punctured [propane] tanks to rocket upward like in the movies?

Does a drone RPG carry a light? Really.

As I said, bullets don't cause pressurised propane cannisters to explode.

> aluminum aircraft contacting a building cause enough of a spark

Read the accident report - static electricity, not a bullet, not a pressurised propane container.

> Does there have to be another existing fire for punctured [propane] tanks to rocket upward like in the movies?

Usually a pulley system or another Hollywood trick.

> Does a drone RPG carry a light?

No. Also, not a bullet, it's a Rocket Propelled Grenade.

Just to clarify, here's a slow motion video of a bullet fired into an unsecured pressurised propane tank (small) with a lit flare next to it.

https://youtu.be/ptend5StNB8?t=62

You can see the tank outgassing and falling off the 44 gallon drum (doesn't "rocket into the air"), the gas eventually (in slow motion it takes a while) lights up from the lit flare and there's a dramatic fireball (burning gas) but no explosion as such - after all is over and done with the propane tank will look a little singed, have two holes in it, but won't look "exploded".

There are other videos with no flares .. much the same happens save there are no fireballs, the gas just expels and expands out into the atmosphere.

So the scenarios should include:

- static electricity

- lightning

- flame

- puncture

- midair collision

- birds, flying fish

- acts of war: projectiles, flames, jeers

- solar flares; Carrington events; EMP

- meteors, meteorites

- combinations thereof; static + puncture,

- chance presence of combustible gases and particulates; [grain dust,] + spark/static

Your focus is on the wrong thing. The hypothetical gas bag is not the vulnerability - an enemy having direct access to your energy infrastructure is your vulnerability in this scenario.

And, frankly, flaming gas bag is not a serious threat. It would be neat to see, but a small undirected hydrogen fueled fire without access to any other fuel source is not scary. I'd be more concerned about the body of the deflated vessel causing a short than anything

"Procedure(s) for removing a [flaming] dirigible from high energy power lines, hangar masts, and other energy infrastructure" would be a good start

Could an airship or similar (maybe over an ocean) capture atmospheric helium?

There is a shortage of Helium (and 3He and 4He for fusion), which the sun makes out of Hydrogen with heat and radiation from fusion and fission.

There is no significant amount of atmospheric helium. It's not something that can captured.

Our helium supplies come from natural gas wells. In some areas the natural gas contains enough helium to be worth separating and storing.

Basically no. Its very small, not very reactive, and I guess also has a tendency to escape the atmosphere and trail off into the void.

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