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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]

#811

Post by jve »

Jugurtha wrote: post #797
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'm wondering if they'll be using the vertical equivalent of arresting gear on aircraft carriers[0]. See when fighter jets land on aircraft carriers? There's a cable that decelerates them. That, but for vertical landing. The way these chopsticks are set forces the booster into a dangerous, snake like maneuver (a SnakeX maneuver) at the last second from a vertical setting, to get into the chopsticks. This maneuver is…

SpaceX likes to simplify and not to complexify things. And they demonstrated they can do landing accurately.

Moreover I think Elon discusses the mechazilla arms in one of Tim Dodd interviews. They dont want longer arms, ratger shoeter.

Think about physics involved for longer arms and how much more stress you will putt on the connection points.

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

#812

Post by Jugurtha »

jve wrote: post #811
Jugurtha wrote: post #797

Earlier quoted context omitted.

I'm wondering if they'll be using the vertical equivalent of arresting gear on aircraft carriers[0]. See when fighter jets land on aircraft carriers? There's a cable that decelerates them. That, but for vertical landing. The way these chopsticks are set forces the booster into a dangerous, snake like maneuver (a SnakeX maneuver) at the last second from a vertical setting, to get into the chopsticks. This maneuver is…

SpaceX likes to simplify and not to complexify things. And they demonstrated they can do landing accurately. Moreover I think Elon discusses the mechazilla arms in one of Tim Dodd interviews. They dont want longer arms, ratger shoeter. Think about physics involved for longer arms and how much more stress you will putt on the connection points.

>SpaceX likes to simplify and not to complexify things. And they demonstrated they can do landing accurately.

Yes. Something falling into a web of cables. I'd say it may be simpler than optimally controlling that last SnakeX maneuver to be hugged by a short-armed T-Rex.

>Think about physics involved for longer arms and how much more stress you will putt on the connection points.

That's why I wasn't talking about arms, but cables, as explained by most of the reply.

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

#813

Post by schiffern »

m4rtink wrote: post #640
shellfishgene wrote: post #535

Earlier quoted context omitted.

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.

I seems to remember some article mentioning the Falcon 9 using radar (+ presumably other sensors) & even having a landing site map uploaded (mainly for the return to launch site scenarios) with prioritized exclusion zones in case of a landing failure.

Hans Koenigsmann alluded to mapping during the CRS-16 post-flight press conference.

https://www.youtube.com/watch?v=tVSPCPoc8hs&t=373

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

#814

Post by nine_k »

Yacovlewis wrote: post #571
magicalhippo wrote: post #354

Earlier quoted context omitted.

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

Newton's laws of mechanics are high-school physics IIRC; my son studied them at 8th grade or so. They are really simple; an evening with Wikipedia or 3blue1brown or whatever floats your boat will let you get sufficient understanding, provided you're also comfortable with high-school math.

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

#815

Post by starspangled »

ellipticaldoor wrote: post #747
starspangled wrote: post #46

Earlier quoted context omitted.

That was one of the greatest things I've ever seen.

Can you explain why? I don't understand why this is so important

I certainly can explain it, I'm just not sure I can do it in a way that you could understand. If you yell me what's one of the greatest things you have seen and why, I might be able to better relate.

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

#816

Post by nine_k »

ftio wrote: post #97

What an incredible achievement. Huge congratulations to the team at SpaceX! Still have chills. Anyone know whether the fire toward the bottom of the booster during/after the catch is normal?

I suppose they were venting off and burning some remaining fuel in some conduits.

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

#817

Post by left-struck »

lutorm wrote: post #551
foobarian wrote: post #235

Earlier quoted context omitted.

Even without the catch step, I always feel like their boosters are coming down way too fast way too late, with engines reigniting startlingly close to surface. Never ceases to surprise me.

Every moment your engines are burning at anything less than maximum thrust, you are wasting fuel. You want to relight as late as possible with as high thrust as possible for maximum efficiency. But that it actually works is nuts.

I remember playing KSP, I had used some mod to program a moon lander to do a suicide burn, a maximum thrust burn to land. I did the maths myself and when it actually came to the landing I was 100% certain I had either a bug in my code or did the math wrong because I was coming in way too fast, or so it seamed, but to my surprise the thing slowed down in time! Mind you ksp is way simpler than the real world and the spaceship could handle some… error, the landing was hard but successful

Point is it always seems like you’re coming in too fast

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

#818

Post by jader201 »

DantesKite wrote: post #761
h2odragon wrote: post #732

Earlier quoted context omitted.

good point. we're geeks and do this kind of thing to each other. among normal people it might be rude. she got me a while back with ink solvents. Monks may have been more illuminated making those pretty manuscripts than we appreciated.

If you toss it into Google’s NotebookLM, it’ll probably produce a much more accessible version of the blog that’s succinct and easier to parse in a few minutes.

That’s exactly what I did, and it seemed to do a good job of hitting the main points in about 13 minutes (which is much quicker than how long it would take a slow reader like me read this article).

I’m sure it still didn’t do the article justice, though.

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

#819

Post by 55555 »

asadotzler wrote: post #659
lquist wrote: post #200

What does Starship reusability mean for $/kg to LEO? I know there are longer term targets of $10/kg but that supposes efficiencies that aren’t here yet. Would be helpful to understand before Starship reusability where the state of the art was in terms of $/kg to LEO and where we would be with impending Starship reusability.

Everyone gets this wrong, cost is not price. SpaceX themselves launch Starlinks at about $1,200/kg but they charge customers closer to $12,000/kg. Do the math. Costs coming down are increases in SpaceX profits, not decreases in customer prices.

Over the extremely long term in competitive industries, prices asymptote at ~costs. So it's still a generally useful measure, and in ~all cases, it's at least a directional indicator.

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

#820

Post by aksss »

gadders wrote: post #48

It still blows my mind how the landings are more exciting than the launches.

As in life, when a person is on a road to nowhere, it’s the homecoming that’s sweet. The only thing more exciting than an Earth landing will be a moon or Martian landing. Or the in-orbit fuel consolidation docking, if only because it will be a huge milestone.

https://open.spotify.com/track/7wFmJxJfGCN6DM5913y7pr?si=-Uo...

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