Starship's Third Flight Test [video] • Hacker News Board

Re: Starship's Third Flight Test [video]

#401

Post by atonse » Fri, Mar 15, 2024, 3:25 PM UTC

Hamuko wrote: post #119

atonse wrote: post #83

Earlier quoted context omitted.

Twitter was a video platform before Musk took over. They were doing Thursday night football (NFL) and other things. Looking at the SpaceX feed, they seem to be using whatever tech they got from the Periscope acquisition (at least the servers were still pscp.tv).

Twitter was not a video platform – it had (some) video features. Very different. And people always considered Twitter videos to absolutely suck.

Yes just to be pedantic, twitter has never been "a video platform" – but that they've had support for streaming live events for years.

So take with that whatever it means, that it's just not going to be as first-class citizen like in Youtube. But the CDN etc must be good enough as those things are easier to do nowadays.

Re: Starship's Third Flight Test [video]

#402

Post by usrusr » Fri, Mar 15, 2024, 3:36 PM UTC

DarmokJalad1701 wrote: post #316

usrusr wrote: post #301

Earlier quoted context omitted.

Iirc F9 had its main challenge in that final suicide burn. Usually the boosters made it there just fine and then "only" failed to get the parameters aligned just right. Based on what we saw today, the main chokepoint for Starship might be right in that hot reentry telemetry blind spot. Debugging without logs.

Unlike with F9, in this case they most probably had high-bandwidth telemetry all the way till the vehicle broke up (if the high-def video stream is anything to go by). So, they probably have a lot more data this time. Even the video can yield information - for example, given that the cameras were mounted on the flaps, they can probably back out the actuation angles from that.

Video feed interruption was very much expected, and went through a series of on/off before the final signal. From what we saw in the live presentation, both scenarios are possible: breakup while transmission was up, transmitting as long as latency allows, with hopefully good explanations in the log, or a disconnect from the challenging radio situation in the reentry plasma long before something went wrong.

Unless they do find some failure buildup in the logs they did receive, it will be difficult to tell disconnect due to breakup from breakup (long) after disconnect. Gradual signal loss on the receiving side would indicate that it's likely the latter, but I'm not sure a signal loss unrelated to breakup would necessarily be gradual. I'd guess atmospheric properties can change fast at reentry velocity.

Re: Starship's Third Flight Test [video]

#403

Post by 93po » Fri, Mar 15, 2024, 3:46 PM UTC

Shawnj2 wrote: post #383

93po wrote: post #382

Earlier quoted context omitted.

How do you explain how the Ariane 5 used for the JWST, with a mass to GTO half that of Starship, was able to position the JWST without 60 launches?

Simple, it’s designed to launch a payload into lunar orbit and starship isn’t. To move something using starship into lunar orbit you need to move an entire starship there while the Ariane 5 is designed to do it in 1 launch at the expense of much less payload capacity and no reusability.

I still don't follow. The Ariane 5 launched the JWST with enough fuel to get where it's needed. Starship can launch the exact same payload, plus twice the entire weight in extra fuel. Starship also offers no-reusability launch options for stuff just like this.

Re: Starship's Third Flight Test [video]

#404

Post by dotnet00 » Fri, Mar 15, 2024, 5:14 PM UTC

usrusr wrote: post #402

DarmokJalad1701 wrote: post #316

Earlier quoted context omitted.

Unlike with F9, in this case they most probably had high-bandwidth telemetry all the way till the vehicle broke up (if the high-def video stream is anything to go by). So, they probably have a lot more data this time. Even the video can yield information - for example, given that the cameras were mounted on the flaps, they can probably back out the actuation angles from that.

Video feed interruption was very much expected, and went through a series of on/off before the final signal. From what we saw in the live presentation, both scenarios are possible: breakup while transmission was up, transmitting as long as latency allows, with hopefully good explanations in the log, or a disconnect from the challenging radio situation in the reentry plasma long before something went wrong. Unless the…

In the livestream they mentioned that they lost signal on both Starlink and TDRS simultaneously, which is why they figured it had broken up at that point. They were prioritizing the telemetry over video frames on Starlink, and TDRS can only handle telemetry.

Re: Starship's Third Flight Test [video]

#405

Post by usrusr » Fri, Mar 15, 2024, 5:27 PM UTC

dotnet00 wrote: post #404

usrusr wrote: post #402

Earlier quoted context omitted.

Video feed interruption was very much expected, and went through a series of on/off before the final signal. From what we saw in the live presentation, both scenarios are possible: breakup while transmission was up, transmitting as long as latency allows, with hopefully good explanations in the log, or a disconnect from the challenging radio situation in the reentry plasma long before something went wrong. Unless the…

In the livestream they mentioned that they lost signal on both Starlink and TDRS simultaneously, which is why they figured it had broken up at that point. They were prioritizing the telemetry over video frames on Starlink, and TDRS can only handle telemetry.

Thanks, must have missed that detail in the stream. Hope they find a good explanation candidate in the data!

Re: Starship's Third Flight Test [video]

#406

Post by iwontberude » Fri, Mar 15, 2024, 7:33 PM UTC

dang wrote: post #254

iwontberude wrote: post #141

Earlier quoted context omitted.

[flagged]

Please don't replace the text of comments like this once they have replies. It's unfair to the users who responded because now their comments lack the necessary context to be understood. We're all wrong sometimes and it would be fine to add an "Edit:" after the original text followed by an explanation or retraction or whatever you want.

I agree, please revert the edits

Re: Starship's Third Flight Test [video]

#407

Post by senectus1 » Sat, Mar 16, 2024, 2:18 AM UTC

dotancohen wrote: post #388

senectus1 wrote: post #366

Earlier quoted context omitted.

the weights isn't the only upgrade, the SIZE is another very important metric.... They'll be able to get much larger objects up there without having to piece them together up there. Especially important for habitable objects and factory objects.

The current iteration of Starship has a payload bay door fit only for the Starlink satellite.

"The current iteration" is also just a proof of concept. Their published plans include fliptop and large bay doors. not to mention the HLS (Human Landing System) that includes an airlock.

Re: Starship's Third Flight Test [video]

#408

Post by dang » Sat, Mar 16, 2024, 3:24 AM UTC

iwontberude wrote: post #406

dang wrote: post #254

Earlier quoted context omitted.

Please don't replace the text of comments like this once they have replies. It's unfair to the users who responded because now their comments lack the necessary context to be understood. We're all wrong sometimes and it would be fine to add an "Edit:" after the original text followed by an explanation or retraction or whatever you want.

I agree, please revert the edits

That's kind of you, but I think it's enough if you'll simply fix the problem going forward.

Re: Starship's Third Flight Test [video]

#409

Post by exDM69 » Sat, Mar 16, 2024, 8:53 AM UTC

dotancohen wrote: post #395

exDM69 wrote: post #391

Earlier quoted context omitted.

1000m is much higher than real rockets pitch over, but good for KSP with forgiving aerodynamic stress. It's just a convenient round number and gives a few seconds of breathing room to make sure the fiery end of the rocket points to the ground before start of maneuvering.

I do remember the Shuttle pitch and roll real early, though I thought that was to point the antennas (K-band was it?) at the receivers.

The roll is to change the orbital inclination, the pitch is to set ascent trajectory.

Re: Starship's Third Flight Test [video]

#410

Post by satiric » Sun, Mar 17, 2024, 7:21 PM UTC

DarmokJalad1701 wrote: post #386

pclmulqdq wrote: post #376

Earlier quoted context omitted.

Starship today can't launch anything. Saying that it can launch the ISS in 3 launches is what Elon Musk says it can do. I don't trust Elon Musk's word for things until I see what someone does with those words. Generally, he is off by a factor of 10-100 on his promises.

> Starship today can't launch anything Why not? With the capability demonstrated today, they can just as easily tweak the ascent profile to end up in a stable orbit outside the atmosphere. Their trajectory was suborbital on this flight on purpose.

Well, for one, the payload doors don't work.