Recent content by Ben W

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. 🙃

Projections, not "expectations". See page 73: https://courts.delaware.gov/Opinions/Download.aspx?id=359340 At the time of the negotiations in Dec 2017, Tesla's internal projections already showed them reaching 11 of the 16 operational milestones by 2020, even without further involvement by...

If Robotaxi is a much different form factor (smaller) than S3XY, it would presumably require its own specific network, similar to how Cybertruck apparently requires it. Also, if the Robotaxi sensor suite is significantly different from S3XYC (e.g. +radar, +lidar, +ultrasonics, +more/different...

Chemistry-wise, I'm not sure what happens to orbital-velocity methane as it reenters. (Thermodynamically, LEO speed is roughly equivalent to the gas being heated to ~80,000C.) It may spontaneously disintegrate into carbon and atomic/molecular hydrogen when it hits another molecule traveling that...