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Comment by wombat-man | Hacker News Reader

I saw the pictures but it wasn't clear to me that it was empty. I certainly saw comments saying it was. It looked like it was flat.

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There is zero rebound when it lands, that's a bit weird. I replayed that part a couple of times, it doesn't look like there is any vertical velocity at all when it lands, which, given SpaceX's ability to do this with much heavier objects should be no surprise but it makes it look as if the vehicle has very little mass. If the tanks contain 250Kg of compressed air (which means it is pretty much liquid) and you toss that out in ~1 second or so then you'll be near the end of the depletion so if the vehicle would be launched just a little bit higher it would slam into the ground instead of gently landing. There isn't much reserve there.

er, but it's also being propelled. Maybe they are able to ease off the thrusters so it's a soft landing.

I do think that this could only work for a short timespan and getting it to work perfectly each time with variances in weight would be hard. I'd imagine the thrusters and the tank would would wear out over time too, would be a nasty landing if only some of the thrusters worked.

I've read there was nobody in the car when they did that. 'For safety'. Never mind the extra 80 Kg of weight, that had nothing to do with it.

I mean, yeah? Would you have put someone in the car?

No, but I suspect that if they had that the whole demo would not have worked.

yes, if the car is sold as something for someone to be in

That is a prototype.

Ah... I thought it's the real deal finally

His other company catches rockets, and there's no telling what mass would be remaining when it lands, since the exact path would only be estimated prior. I doubt it would have made a difference if it had 150kg off, whatever computer is controlling the thrusters is calculating in real time.

Its about the capability of the cold air system to handle the mass with the pressure in the tank not about stabilisation.

There was an Optimus in the driver’s seat. There’s video.

Any pressurized tanks or vessels have a finite lifespan. The multiple cycles from high to low pressure over time cause stress fractures in the tank. Take scuba tanks for example. They require periodic testing to certify that the tank is still safe to be filled to over 3000psi. That said this car not only would cost stupid amounts of money but would also require specialized expensive lifetime maintenance. Lastly as for the rocket flips and insanity I can only see that making sense to use in one scenario and that is a collision detection and the jets fire and the billionaire driving is magically saved and does die.

So they used some AI/drone-type balancing to work on gas tanks, then made it work for something as big as a car. That's the tech.

They were tossing around an oversized shell of a car and it is only physically capable of holding about as much as it used in the short demo, is that about right?

So what even is the point of this thing? What possible function in the world does this farting car serve besides... driving up Tesla's stock price?

Some guy did that for drones with bottles of compressed air. This is trivial from a control theory point of view.

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