Recent content by Ben W

What backs it up is that this is how humans learn, and neural networks are getting more and more humanlike, especially as they become E2E rather than modular / feature-engineered. Tesla has highly robust regression testing to ensure that the normal cases don't get destabilized by the retrained...

One hope is that the by training on enough unusual long-tail examples, the network will develop the abstract concept of "weird stuff", along with a strategy for identifying and dealing with it in a generic and reasonable way, much as humans do. Agreed that there are many categories of edge...

Amnon's argument has a significant foundational assumption in it, which I believe to be false. He assumes that the "long tail" of failure cases is independently distributed; that solving one of them will have no bearing on solving the others. I believe the opposite; that there will be a lot of...

Oh Elon, Pure Vision to the end. I would think that an IR camera could detect the hotspots (or any such abnormalities, such as mild unexpected heating between tiles) far sooner than visible-light cameras could. But I suppose if anything happens where it could be diagnostically helpful, they can...

That's a really good point. Until they can prove extreme reliability, they'll probably have to line up their reentries such that catastrophic failures would at least happen over the Gulf instead of over populated areas. I wonder if it will require marine restrictions for the first several Cape...

If there were e.g. a propellant depot on Deimos, a returning Starship could have enough extra delta-v to bleed off quite a bit of speed (~4km/s) approaching Earth entry, at the expense of transit time. But by the time this is happening regularly, ion propulsion may be a feasible and better...

Agreed, which is why connecting the tiles to the ship via physical interlocking may be a more robust solution than adhesive. If the ceramic were physically interlocked with e.g. a carbon-carbon skeleton, and the skeleton were physically interlocked with the ship’s stainless frame (perhaps via...

Does this imply that Starship’s reusable tile approach won’t work for Mars and Mars return? Could they simply make the tiles thicker to compensate for escape-velocity reentry heating? Re tiles falling off, is it known by what precise mechanism they tend to detach? Is it due to the brittleness...

Relative speed of spacecraft and atmosphere. The atmosphere spins along with the planet, so technically that should be taken into account. (E.g. there would be more heating when reentering from a high-inclination or retrograde orbit for this reason.) But to a first approximation, “absolute...

Part of the reason (I think) is that methane is really not the best liquid to use for transpiration. It pyrolizes in high temperatures, causing coking (similar to burning "fuel-rich") which could clog up the transpiration pores. LOX is not much better; pure oxygen is highly reactive. It's...

Brain fart, I meant HRSI ceramic. My point was that if connecting the current tile material directly to steel seems unreliable (as evidenced by tiles continuing to break/fall off), then tapering the material from HRSI on the outside to something tougher on the inside (perhaps via 3D-printing)...

Check your calculations? With Raptor v3’s anticipated 382s vacuum ISP, and 200T final mass (including landing fuel + reserve), I get ~408T of propellant needed to decelerate by 4166m/s. So a bit less than half a tank, but still a lot. Attaching the tiles directly to each other (via wires at...

Starship would need to have a nearly full tank (or at least 1/2 tank) to accomplish this, far in excess of its nominal payload capacity. This would require several extra Tanker flights and an orbital refueling stop per mission, but note that Tankers must also be able to reenter safely, without...

Temperature is determined by relative speed. Decelerating more slowly may counterintuitively mean a higher temperature for a longer period, though counterbalanced by a lower pressure. Effective heat flux is maybe a better metric. A secondary heatshield layer of e.g. honeycomb alumina underneath...

Ludicrous, Insane, Plaid... all they need is a 'Maximum' trim, and they'll be LIMP. Also, their full-self-driving software was first Beta, then Supervised... that's some BS right there. 🙃