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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]

#531

Post by Isamu »

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…

I imagine that they will be their own first customer - putting Starlink satellites into orbit while they are gaining confidence in the reliability of the system for external customers.

They have to prove out the landing of the second stage, either with another catch or with landing gear, which they need for the lunar lander anyway.

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

#532

Post by cryptonector »

flaburgan wrote: post #76
treespace8 wrote: post #14

I'm just so happy to see this level of progress. This another big step for opening up space. To think that one day this will be considered normal. 150 Metric tons sent on a fully reusable rocket. Thats like a 747 to space.

So, reusable is supposed to reduce the cost. But the space shuttle was reusable and it has been shutdown because it was too expensive. What is the differences between the two?

The shuttle wasn't fully reusable, just for starters. The boosters were reusable with a lot of refurbishment work. The center tank was expended every time. It was very expensive. Only five shuttles were ever made, which means that no effort was put into automation of production of engines etc., everything was custom, and everything required great care to save the sunk costs.

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

#533

Post by cdash »

pj_mukh wrote: post #392
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.

I know the control algorithms are the mind-blowing part here but, does anyone have any literature about how the Rocket localized itself with respect to the chopstick arms? It must've been some combination of GPS and Radar pings to the arms? And then the onboard IMU to make sure it hits it straight.

Could just be differential/rtk GPS. You can get incredible precision with that.

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

#534

Post by gramie »

When I was visiting the space center in Huntsville, Indiana, I had a chance to talk with one of the volunteers. His name was Brooks Moore (https://www.youtube.com/watch?v=O3hudRA3yL8), and he had been the director of navigation systems for the Apollo (and other) projects.

The first SpaceX barge landing had just taken place, and I asked him what he thought. He got a faraway look in his eyes, and agreed that it had been spectacular. For those guys, it must have seemed like all of their dreams were coming true.

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

#535

Post by shellfishgene »

pj_mukh wrote: post #392
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.

I know the control algorithms are the mind-blowing part here but, does anyone have any literature about how the Rocket localized itself with respect to the chopstick arms? It must've been some combination of GPS and Radar pings to the arms? And then the onboard IMU to make sure it hits it straight.

From the control point of view, isn't this exactly the same as F9 landing on a pad, except the pad is virtual, floating in between the chopsticks and the ground? Or course one difference is that the approach needs to be from the correct direction.

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

#536

Post by faceloss »

ro_bit wrote: post #520

The catch looks amazing, but one thing I don't understand is why SpaceX needs the technology to catch a booster they've already demonstrated the ability to land boosters on barges. Is the arm more cost effective to scale compared to a barge?

[dead]

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

#537

Post by cryptonector »

WalterBright wrote: post #459
credit_guy wrote: post #109

Earlier quoted context omitted.

The main difference is that this is built by a private corporation who can't afford to throw money away, while the Space Shuttle was build by the government, and moreover it had to fulfill a number of conflicting requirements, and commercial profit was not one of them. But on a more technical level. I think the vertical landing is the main difference. Vertical landing was obviously known and done by NASA, this is how…

> and commercial profit was not one of them But it's high cost was the end of it.

Its high cost would (should!) have killed it regardless, but its low reliability was going to be a huge problem too, and arguably it's the lack of reliability that finally killed it.

The high cost should have killed the project before it ever flew, but that's not how governments behave.

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

#538

Post by slashdave »

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.

Yes, indeed. But I will add that the sheer size of the rocket helps in this regard. I think it is rather hard to appreciate the massive scale of the feat by watching videos.

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

#539

Post by slashdave »

credit_guy wrote: post #79
dmix wrote: post #17

Video of the catch > Mechazilla has caught the Super Heavy booster! https://x.com/spacex/status/1845442658397049011

I wonder what will happen when they get to 99% reliability? They clean up and rebuild the Mechazilla every once a hundred catches, on that occasion that one fails?

That, and redundancy. The amount of cash you save allows you to do that.

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

#540

Post by 317070 »

nordsieck wrote: post #526
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…

> 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…

> Just to make sure that it completely submerges quickly.

Why would they want to do that? (genuinly curious).

I reckon there would be a lot of useful data left if they could recover or even just inspect the remains. The remains are one big tank, so it would have floated.

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