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PaperclipPerfector  3d ago (text post)   1989 thread views

Friday Fun Thread for October 16, 2026

Be advised: this thread is not for serious in-depth discussion of weighty topics (we have a link for that), this thread is not for anything Culture War related. This thread is for Fun. You got jokes? Share 'em. You got silly questions? Ask 'em.

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SpaceX's demonstrated mastery of control of a flying object entirely based on a limited number of relatively low-power thrusters with very limited fuel.

I do wonder how much engineering here they're sharing with SpaceX. Falcon 9 uses and early Starship models used cold-gas Reaction Control System thrusters that would have been a lot like these (except using pure nitrogen instead of air), but surely the different optimal sizing would have meant they didn't use the exact same engines, and other SpaceX engines (small methalox and ullage-gas rockets on newer Starship, hypergolic on Dragon) are even more different. But the control problem for Tesla might be much less tricky. With Falcon 9 the hardest part is that, even with just one main engine active, they can't run at a low-enough power to land without a "hoverslam" that uses that higher power at the last second. Control software for cold gas thrusters that can be throttled arbitrarily up and down is probably easy by comparison.

IMHO the scary thing here for SpaceX fans is the Carbon-Overwrapped Pressure Vessels holding the compressed air. They're at least not dumping Roadster COPVs in liquid oxygen (which led to the unexpected failure mode that lost AMOS-6 a decade ago), nor will they have them in a vehicle full of hundreds of tons of fuel (like during the Starship 36 explosion that also trashed a test stand 16 months ago), but even without a force multiplier like that, hundreds of atmospheres of pressure can be scary stuff. It's still been less than a year since SpaceX had a booster turned to scrap by a COPV rupture.

Based on that, as well as the nature of it, it will probably never be useful outside of demos and stunts.

Yup. The flying "Rocket" model is sales-by-invitation-only; the direct target market there is basically "Hollywood" plus "hectomillionaires who like to drive hypercars". The value here is all indirect, trying to improve the brand status and to attract top engineers.

The suction fan is cool too, and might be possible to actually have on a production car sold to the public.

They're claiming it'll be even on the base-level "Performance" model sold to the public. On the other hand, they're only putting a "Not approved for public road use" asterisk on the "Rocket" model, suggesting that the intermediate limited-release "Thrust" model with just the rear "sub-1s 0-60" thrusters will actually be street-legal. I'm betting that's currently true in the sense of "nobody imagined needing a regulation to cover sub-1s 0-60 so it hasn't been written yet", but it might not be true in the sense of "that regulation won't ever be written". Might not be safe to put a deposit down on the Thrust model, at least not unless you're under the aegis of Florida Man.

Control software for cold gas thrusters that can be throttled arbitrarily up and down is probably easy by comparison.

It's not clear from the video, but it'd be interesting to see whether they're regulating the high-pressure air to a constant thrust, or just accepting that thrust varies as the tank empties. The former loses efficiency and adds weight, but the latter has a lot of added "fun" in the controls math.

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