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You’re spamming a twice-flagged comment [1][2] that’s already been rebutted [3].
[1] https://news.ycombinator.com/item?id=41828032
Starship Flight 5: Launch and booster catch [video]
211–220 of 1001 posts
Re: Starship Flight 5: Launch and booster catch [video]
#212Video of the catch > Mechazilla has caught the Super Heavy booster! https://x.com/spacex/status/1845442658397049011
10 minutes from 3h25m of this video shows launch and catch.
Historic viewing :)
Re: Starship Flight 5: Launch and booster catch [video]
#213Nothing 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-…
Re: Starship Flight 5: Launch and booster catch [video]
#214[flagged]
Re: Starship Flight 5: Launch and booster catch [video]
#215Anyone knows how the landing is guided? Is it just really precise GPS/altimeter or does it use computer vision?
I'd imagine a combination of inertial and GPS, combined with a Kalman filter. Inertial handles short term estimation; GPS correcting drift in the inertial system. But they could roll in other information sources at the end.
For the centimeterish precision needed to hover into the chopsticks, they also have the opportunity to use signals from the tower area for final alignment. I'm thinking riding a beam like aviation ILS. Just speculating but it would be easy to implement.
Optical/camera alignment is probably out of the question due to fire and smoke.
Re: Starship Flight 5: Launch and booster catch [video]
#216Earlier quoted context omitted.
[flagged]
You’re spamming a twice-flagged comment [1][2] that’s already been rebutted [3]. [1] https://news.ycombinator.com/item?id=41828032 [2] https://news.ycombinator.com/item?id=41828151 [3] https://news.ycombinator.com/item?id=41828048
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Re: Starship Flight 5: Launch and booster catch [video]
#217[stub for offtopicness]
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Re: Starship Flight 5: Launch and booster catch [video]
#218Amazing days ahead of us - if we can avoid blowing ourselves up over pathetic patches of land, we could have the entire solar system under our feet...
Agreed, but I'm concerned that humans being humans, we'll have the entire solar system to blow ourselves over.
In The Expanse (which I highly recommend), they give a new lease on life to that quote attributed to Einstein "I know not with what weapons World War III will be fought with, but World War IV will be fought with sticks and stones" - hurling asteroids towards a planet. I really hope humanity's real future will play out in accordance with some of the more optimistic elements in The Expanse.
Re: Starship Flight 5: Launch and booster catch [video]
#219Nothing 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-…
how much liquid fuel is present when it lands? I assumed all the clouds it was giving off was it dumping fuel to make sure it was empty on landing
Re: Starship Flight 5: Launch and booster catch [video]
#220Earlier quoted context omitted.
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-…
I always thought the liquid sloshing would be one of the hardest to simulate (considering how chaotic fluid mechanics is). Interestingly, I think this caused the 2nd Falcon launch to fail (the LOX sloshing).
It is difficult, but there are modeling approaches that work, such as VoF (https://en.wikipedia.org/wiki/Volume_of_fluid_method). Basically, in addition to velocity, pressure, temperature, etc., you store an additional scalar in each cell of your computational mesh representing the liquid's volume fraction. Then, you solve an additional equation to transport that scalar.