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Starship's Fourth Flight Test [video]

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Re: Starship's Fourth Flight Test [video]

#101
post #99
post #98

Earlier quoted context omitted.

I saw that too. And it must be; it strains reason to think there was some other piece of space junk at exactly the same place and speed.

Of course. I just expected them to fall at the same rate.

They did fall at the same rate, to very high precision. That booster was going like 2000 km/h! The delta is tiny, and likely down to the very low but non-zero aerodynamic accelerations that will differ between objects of different shapes and densities.

Re: Starship's Fourth Flight Test [video]

#102
post #87

Earlier quoted context omitted.

> IFT3 got to orbital altitude, but not orbital velocity I don't think this is correct. "Starship reached orbital velocity!" - https://x.com/elonmusk/status/1768271078999167379 "SpaceX's Starship mega rocket launched from Texas on its third test flight, reaching an altitude of 160 kilometers and achieving orbital velocity [...]" https://x.com/CBCNews/status/1768296197846884741

They turned off the engines early specifically to not reach orbital velocity.

There was an in-orbit relight in the IFT3 flight plan, which failed to happen. IFT4 is somewhat more conservative - just get to orbit (happened), pseudo-land the booster (happened), and get back out of orbit (remains to be seen).

The amount of disinformation that SpaceX and Musk create around failed tests is really annoying and honestly somewhat problematic. It would be nice if SpaceX could just honestly say "this worked and this didn't," but we have to pretend that everything is a miraculous success. After the engine failed on IFT3, the immediate line was "we planned it this way" and then days later "we reached orbital velocity." Launching rockets is impressive enough that you don't have to try to gaslight us all on the way there.

As far as I can tell, my scorecard has IFT1 and IFT3 as failures based on what the flight plans said going in, and IFT2 and (so far) IFT4 as successes.

Edit: I'm suspicious of the fact that they turned off the feed right after cutting the engines and some gas vented. Previous tests have had no problem showing a video feed at this phase.

Re: Starship's Fourth Flight Test [video]

#103
post #100

Earlier quoted context omitted.

None of the past tests has reached orbit (IFT3 got to orbital altitude, but not orbital velocity), so I believe SpaceX is essentially a projection that they will reach orbit this time.

Max q is not orbital speed or height. The max q, or maximum dynamic pressure, condition is the point when an aerospace vehicle's atmospheric flight reaches the maximum difference between the fluid dynamics total pressure and the ambient static pressure. https://en.wikipedia.org/wiki/Max_q

Correct, but the time and velocity when you reach max Q (and the flight plan CSV) indicate something about your path to orbit. I was extrapolating from previous starship tests.

Re: Starship's Fourth Flight Test [video]

#104
post #38
post #37

Earlier quoted context omitted.

It would be better if one could vote for the first and the second stage separately. I believe that the booster has a good chance for a soft splashdown, while the Starship itself will probably explode on reentry.

Why does it keep exploding? Don't they already have the knowledge and tech to achieve this?

Why does your software keep failing during development? Don't you have the knowledge to make it work?

It's the old, non-iterative everything-up-front method to rocket development that's weird. At least as a developer it seems obvious that a more hardware-rich approach with a high iteration rate will lead to a better outcome in the end, _especially_ when you're trying to push hard on the technological boundaries.

Re: Starship's Fourth Flight Test [video]

#105
post #87

Earlier quoted context omitted.

They turned off the engines early specifically to not reach orbital velocity.

There was an in-orbit relight in the IFT3 flight plan, which failed to happen. IFT4 is somewhat more conservative - just get to orbit (happened), pseudo-land the booster (happened), and get back out of orbit (remains to be seen). The amount of disinformation that SpaceX and Musk create around failed tests is really annoying and honestly somewhat problematic. It would be nice if SpaceX could just honestly say "this wo…

I'm always amazed at how wrong people on HN are.

The orbital relight test was not a factor in the fact that Starship was not intended to reach orbital velocity. You may have noticed that the flight plan indicated that Starship was to land somewhere in the Indian ocean and usually reaching orbital velocity vastly increases the difficulty of doing a planned reentry. The flight plans had them turning off the engines before they actually reached orbital velocity

They scrapped the relight test when they realized that they were losing control authority. The relight test was not meant for reaching orbit, it was to prove they COULD relight the engines on Starship while in space.

Just stop being wrong.

Re: Starship's Fourth Flight Test [video]

#106

Earlier quoted context omitted.

> IFT3 got to orbital altitude, but not orbital velocity I don't think this is correct. "Starship reached orbital velocity!" - https://x.com/elonmusk/status/1768271078999167379 "SpaceX's Starship mega rocket launched from Texas on its third test flight, reaching an altitude of 160 kilometers and achieving orbital velocity [...]" https://x.com/CBCNews/status/1768296197846884741

If you look at the readings on the screen and do some basic physics instead of relying on the press releases of a biased party, you will realize that they were short of orbital velocity. At that altitude, orbital velocity is 27000 km/h, and IFT3 got to 21000-22000 km/h. As we're speaking, IFT4 has reached orbit.

> IFT3 got to 21000-22000 km/h

This is incorrect. It got to approximately the same velocity as this launch.

> If you look at the readings on the screen

Uhh.... OK.... https://youtu.be/W1WfCVZFZPo?si=XrVOUvsjxAHsvrLU&t=576

> instead of relying on the press releases of a biased party

Elon Musk... ok, he's a biased party. But I also quoted CBC News. Are you suggesting that they're biased or simply not terribly thorough?

Re: Starship's Fourth Flight Test [video]

#107

Earlier quoted context omitted.

If you look at the readings on the screen and do some basic physics instead of relying on the press releases of a biased party, you will realize that they were short of orbital velocity. At that altitude, orbital velocity is 27000 km/h, and IFT3 got to 21000-22000 km/h. As we're speaking, IFT4 has reached orbit.

> IFT3 got to 21000-22000 km/h This is incorrect. It got to approximately the same velocity as this launch. > If you look at the readings on the screen Uhh.... OK.... https://youtu.be/W1WfCVZFZPo?si=XrVOUvsjxAHsvrLU&t=576 > instead of relying on the press releases of a biased party Elon Musk... ok, he's a biased party. But I also quoted CBC News. Are you suggesting that they're biased or simply not terribly thorough?

CNBC parrots what SpaceX's press release says, and they have no other sources (see what they do with other corporations). And yes, they got closer than I thought, but still short for 170 km. 150 km has a higher orbital velocity.

Edit: 28000 km/h at 150 km.

Re: Starship's Fourth Flight Test [video]

#108

hello this ship be visible without any additional help? crossing in the sky on its test path?

I was wondering this too. The length is about half of ISS, and the altitude is about half or lower, so it seems plausible that it could be quite visible from some places.

I wonder if the proposed flight path for these tests is published anywhere?

Re: Starship's Fourth Flight Test [video]

#109

This will be crammed into my Twitter feed relentlessly. Unlike today's successful Boeing launch, which wasn't in the feed or any trending topics whatsoever. Twitter is only a news source for topics with benefits.

Boeing launch was yesterday. Every space account on X was talking about it. The ULA, Boeing, and NASA accounts were all posting about it. Elon retweeted the livestream and wished them luck : https://x.com/elonmusk/status/1798338630471364871 He also congratulated them and retweeted a follow up post from Nasa Kennedy Space center.

[deleted]

Re: Starship's Fourth Flight Test [video]

#110

The stream has ended now. I'm editing the comment to provide guidance for the next time that someone wants to watch a SpaceX stream via VLC: Get the URL by going to the Twitter feed (e.g. via spacex.com/launches if you don't want to search for it) and extract the appropriate URL using the network traffic developer tools of your browser. It might be hosted on pscp.tv , the domain of the old Periscope live video stream…

V4 demonstrating steady confident progress. The hard bit coming up in 25 minutes. Going forward getting to this point in the flight plan is now basically table stakes. What a marked difference from V1. Love to see it.

I don't understand one stuff, did the booster land on a drone ship or it just crashed into water ?

At the end of the video feed for the booster, it looks like there is a huge fire and everything is destroyed, but the crowd is cheering

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