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Starship Flight 5: Launch and booster catch [video]

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Re: Starship Flight 5: Launch and booster catch [video]

#571

Post by Yacovlewis »

magicalhippo wrote: post #354
drexlspivey wrote: post #230

Earlier quoted context omitted.

The booster was falling at 4500 Km/h 30 seconds before the catch with 2-3% fuel left. How is that amount of fuel remotely enough to stop the downward momentum?

First off, the booster was going about 1250 km/h when it started its landing burn, it relied purely on drag to get it slowed down to that speed. Going by the telemetry of the seconds before the landing burn and noting the speed vs time, it seems drag was around 40 m/s^2 when it was going at around 3000 km/h. Since drag depends on velocity squared though, it had reduced to just above 10 m/s^2 just before the engines l…

What kind of work do you do that you're able to understand this stuff? Genuinely curious. I'm way beyond my depth trying to follow

Re: Starship Flight 5: Launch and booster catch [video]

#572

Post by georgeburdell »

hnpolicestate wrote: post #513

This is why Musk is silly when he claims fear over what certain possible gov administrations would do to him if elected. He's allowed to believe whatever he wants. He's too valuable to the United States. Imagine what a BRICS country would pay for his talent? Worth his weight in gold wrapped platinum.

It’s justified. https://www.latimes.com/california/story/2024-10-11/la-me-sp...

Re: Starship Flight 5: Launch and booster catch [video]

#573

Post by gcanyon »

dtquad wrote: post #183
ghc wrote: post #23

Nothing could have prepared me for how that catch looked. I was sure the rocket was careening into the tower at the last second before it straightened out. The control algorithms must be incredible for the landing system to work within those small tolerances.

MIMO and nonlinear control theories are probably some of the hardest topics in all of engineering. SpaceX control system also has to compensate for the fuel moving inside their rockets so the control algorithms probably involve some kind of fast numerical fluid simulation. Another interesting thing SpaceX is doing is to use consumer-grade chips in triple redundancy configurations instead of using $100,000+ radiation-…

> control system also has to compensate for the fuel moving inside their rockets

My stepfather worked as a programmer on the Apollo program, and the thing he always talked about as his biggest accomplishment was working on the "slosh problem" -- so yeah, props to the SpaceX team for managing that landing. And props to my stepdad for managing it on hardware that was... a billion times less capable? :-)

Re: Starship Flight 5: Launch and booster catch [video]

#575

Post by gcanyon »

stetrain wrote: post #423
ghc wrote: post #23

Nothing could have prepared me for how that catch looked. I was sure the rocket was careening into the tower at the last second before it straightened out. The control algorithms must be incredible for the landing system to work within those small tolerances.

Here’s a video from a farther vantage point that gives a better perspective on the landing process: https://x.com/shaunmmaguire/status/1845444890764644694

That's amazing footage, and you're right about the perspective: from the official feed the distances seem compressed compared to what we see in this footage.

Re: Starship Flight 5: Launch and booster catch [video]

#576

Post by cryptonector »

HarHarVeryFunny wrote: post #143
teractiveodular wrote: post #19

It's difficult to overstate how important the milestone of catching the booster is. Now we have a reusable rocket an order of magnitude larger than anything we've had before, and the cost of kg to orbit just nosedived.

I'm not sure how critical "catching" the booster is to reusability, but it does save weight by not needing legs for landing, and perhaps the booster suffers less stress this way? Note that the booster is not really being "caught" although this is the word it seems we're stuck with. It's really more like landing on the arms, since it throttles to a hover at that point.

> but it does save weight by not needing legs for landing

That was the exact reason they went this way.

Re: Starship Flight 5: Launch and booster catch [video]

#577

Post by cryptonector »

WalterBright wrote: post #487
ptek wrote: post #52

Very inspiring, glad I woke up to watch it. Congratulations to the SpaceX team. This is what competition looks like. It’s funny how last decade SpaceX had to sue the government to get more launches.

California officials reject more SpaceX launches, with some citing Musk's X posts https://twitter.com/shellenberger/status/1845131546501734440...

That's madness. And unconstitutional.

Re: Starship Flight 5: Launch and booster catch [video]

#578

Post by asdf123qweasd »

creer wrote: post #554
ChuckMcM wrote: post #516

Pretty impressive. The engineering team at SpaceX is really something. Some thoughts; The 'chopsticks catch' was amazing to watch. Seems like it adds a lot of risk and clearly the booster needs additional fire suppression systems :-) perhaps the tower could mount something that sprays the booster like the barges have for the F9 boosters. The heatshield held out for a much longer time, the asymmetric heating on the fl…

They showed 4 streams at once during some of the reentry. One view of each control surface. They may have had still more views but just that 4 was a first.

Imagine, linking that video into a 360° virtual cockpit As if you were inside a booster made from glass.

Re: Starship Flight 5: Launch and booster catch [video]

#579

Post by lutorm »

goodgrief99 wrote: post #330

Why don't they mount moving video cameras? I mean, the second part of the fly is pretty boring. They shows us a view from 2 static cameras. Is it so difficult to make one camera moving? With 360 degrees view. Show us the shape of the earth the full circle, show us the moon. Is it so hard?

The primary purpose of having those cameras is to gather test data, not provide entertainment.

Re: Starship Flight 5: Launch and booster catch [video]

#580

Post by ls612 »

iknowstuff wrote: post #555
nordsieck wrote: post #526

Earlier quoted context omitted.

> The detonation at the end was pretty spectacular too, but I suspect that structurally the tanks failed as the rocket hit the water vs anything that was an engineering failure. It's possible that SpaceX programed the AFTS to trigger some time after the rocket touched down in the water. Just to make sure that it completely submerges quickly. > I can easily imagine that flight 6 will be nominal end to end without any…

correct me if I’m wrong but I don’t think the second stage is meant to be caught. It will have legs to land on Earth/Mars without any landing infrastructure.

It is expected to land astronauts on the Moon as well this decade, which will certainly require legs.
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