[ben-schaaf]

Reading that article I see no proposed solutions to this sail problem. They mention wind as an issue for delivery times but not safety. There's also no acknowledgement that the "scaling law" that makes building huge airships lucrative also makes these problems worse.

[wang_li]

You're failing to see the secret that is exposed by the fact that their Chief Engineer comes from hyperloop. They're going to dig tunnels connecting all their destinations and run the airships underground in a vacuum sealed network. No atmospheric drag at all! Bingo!

[withinboredom]

How can you call yourself an engineer and work on the hyperloop. Literally only takes about 30s of thought to realize it is an impossible idea.

[alluro2]

I don't particularly defend feasibility of Hyperloop, but did want to point out that your comment sounded awfully like when people were ridiculing the idea of human flight, landing on the moon etc... Finding engineering solutions to what looked as "impossible" challenges were some of the best feats of humanity so far.

[dr_dshiv]

Please reveal the impossibility of the idea?

[withinboredom]

Sure.

If you put it above ground, you are a few short bullets from killing everyone in the loop. Hitting a wall of air in a vacuum at hundreds of miles per hour is going to be like hitting a brick wall. Ask any reentering spacecraft.

The same problem exists underground, the weakest points being the stations themselves which can be bombed.

A failure in the system itself (even just a power outage or malfunctioning equipment) would mean people suffocate inside after a matter of minutes.

So, sure, it is possible to create it, but it is impossible to make any sort of safety guarantees. In other words, literally any other mode of transport would be safer, including a hydrogen-filled dirigible.

So, sure, the concept itself might be possible, but an engineer doesn't concern themselves with possible. That is for scientists. An engineer considers what is realistic AND possible, because that is an engineer’s job: to make the possible real. This cannot be real; literally no regulator would ever sign off on it.

[yellowapple]

> So, sure, it is possible to create it, but it is impossible to make any sort of safety guarantees.

Right, because cars and planes and trains and boats and bicycles and footpaths and airships all famously have 100% perfect safety track records, right?

[withinboredom]

They have mitigations. If a plane breaks down, it can glide. If a regular vehicle breaks down, it can be moved off. If a train breaks down, people can just get off the train. On a hyperloop, where are they going to go when surrounded by a vacuum? What about whatever is behind them also waiting?

There are no mitigations and the only option is death. Maybe you can repressurize the tubes ... assuming there is power to do so ... to evacuate people. This is the main issue, there is no air outside your vehicle. If a window breaks (see: airplanes where this happens every so often) everyone inside is dead. No discussions, no second chances.

That's the problem. The main problem and you can't engineer around it. There are no emergency procedures because if you have an emergency, you are dead; and there will be emergencies.

[incrudible]

> The same problem exists underground, the weakest points being the stations themselves which can be bombed.

Few if any modes of transportation are safe when bombs come into play.

[withinboredom]

Blowing up an empty train station doesn't kill everyone on a train.

[milo256]

Huh? In what world is a hyperloop going maybe 700mph comparable to a spacecraft reentering from orbit at 17,000mph? Also, maybe there's something I'm missing but spacecraft can and do renter from orbit intact, thus proving that this problem is solvable even when the forces at play are orders of magnitude greater. Apply your safety argument to passenger airliners or even ordinary trains and you'll see that they are also "impossible to make safety guarantees" for.

[withinboredom]

> In what world is a hyperloop going maybe 700mph comparable to a spacecraft reentering from orbit at 17,000mph?

In that case, the air can just "go around" the space craft. Try pushing down a syringe with the end capped. Bet you can't do it. Now imagine that at 700 mph; you will get a lot of heat and destruction. No heat shielding will save you.

> Apply your safety argument to passenger airliners or even ordinary trains and you'll see that they are also "impossible to make safety guarantees" for.

See sibling comment.

[0xCMP]

Right, I am not saying they're right or wrong (not something I would know anything about), but it seems they've been vaguely aware of the issues from the start. Namely, before the SpaceX engineer and starting the company.