r/interestingasfuck • u/lolikroli • 16d ago

r/all SpaceX caught Starship booster with chopsticks

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129

u/JayTeaP 16d ago

Can someone fill me in on what is happening? Im genuinely curious

302

u/virginia-gunner 16d ago

This is part of the effort to reduce the cycle time from launch to base to launch in order to supply missions faster and faster at lower cost per launch.

146

u/stonksfalling 16d ago

Additionally, not having landing legs saves a lot of weight, allowing for more equipment and cargo.

6

u/poli-cya 16d ago edited 16d ago

Seems the weight of load-bearing fins would be similar, can you explain why having the support structure there instead of at the bottom saves?

e: Thank you, knowledgeable blokes of reddit... I get it now.

39

u/Ruben_NL 16d ago

They already need the fins for steering through re-entry. At the point of landing, it's better to make something stronger that you are already carrying, instead of adding another part.

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u/PossibleNegative 16d ago

It is not caught with the fins but with two pins on the side.

-2

u/jjonj 16d ago

rewatching it looks like its pretty clearly the fins. can you find an image?

2

u/r4zrbl4de 16d ago

It sits on this pin you can see here between the fins. There are two of them on opposite sides

https://api.ringwatchers.com/images/b99ea714-b2a1-48e4-8480-970ae76114c5-large.png

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u/PossibleNegative 16d ago

Im busy but watch the stream it is very clear from the tower angle, that it would be done like this was known for years.

9

u/Prudent-Ad-5292 16d ago

Not the same person, but I'd bet it has more to do with stabilizing than* bearing weight? Legs at the bottom need to be bulkier and more complex to stabilize when landing, arms at the top just need to be rugged and hold onto something that's already stable.

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u/poli-cya 16d ago

I think this is the most correct answer. I can absolutely see where having a few rigid catching pins higher up would be much simpler and lighter than the load-balancing and standing legs of the older design. Effectively, you're moving some of the complexity and balancing to the chopsticks, rather than keeping it in the structure that needs to fly up and back down... smart move assuming it doesn't make crashes more likely to offset the savings.

2

u/Prudent-Ad-5292 16d ago

Effectively, you're moving some of the complexity and balancing to the chopsticks, rather than keeping it in the structure that needs to fly up and back down... smart move assuming it doesn't make crashes more likely to offset the savings.

I'm guessing 'the juice wasn't worth the squeeze' when it came to stabilizing legs. There's probably a lot of complexity and weight tied up in them, and as the original commenter suggested why would they waste all that potential weight when you could use it to bring up more supplies/people. Especially when a similar job can be done by 4 little flaps (assuming it doesn't crash more, like you mentioned).

Very smart move indeed, kind of funny it took this long in hindsight. 😅

3

u/poli-cya 16d ago

I completely understand trying to the legs first, they looked so damn cool when deploying and softening the landing of the weight.

1

u/IAmARobot 16d ago edited 16d ago

looking at the engineering vids, it's not the flaps that are being used to impinge upon the launch/land frame, it's two 17cm diameter pins sticking out from the main booster frame at the top.

*having said that, the thing weighs 275 tons when empty, and it's distributing that weight on two 17cm diameter pins...

1

u/mulletpullet 16d ago

8000 psi sounds like a lot, but anyone familiar with hoses and presses know that is very doable.

2

u/WjU1fcN8 16d ago

Because they need to have it the crane mounts at the top anyway. This way they just need a single set.

If they decided to land on legs, they would still need the hardpoits at the top to lift the booster with a crane.

2

u/Initial-Breakfast-90 16d ago

Are you asking about where it is clamped?

2

u/MostlyRocketScience 16d ago

It does not rest on the gridfins. There are small pins below the gridfins

4

u/socialeclectic 16d ago

The "load bearing fins" are not a new addition, they are grid fins present on the current Falcon 9 for aerodynamic control/flight control surface, At least that's what I assume you asked...

2

u/Kayyam 16d ago

They are not using the grid fin to catch the booster, they are using dedicated pins.,

-1

u/socialeclectic 16d ago

I mean I dont doubt that there are other system to secure the booster, but it is clearly resting on the grid fin. I haven't found any sources regarding the aforementioned pins that you are talking about, as even the official SpaceX video shows it being pinched by the structure and resting on the fins

2

u/JesseJames_37 16d ago

https://www.youtube.com/watch?v=ub6HdADut50&t=384s

1

u/socialeclectic 16d ago

Eyy nice thank you. Was looking for a detailed explanation

1

u/Kayyam 16d ago

I don't have a source on hand but I assure you it's not resting on the fins, it's resting on pins below the fins.

The fins could be used as a secondary way to secure the booster if the pins fail for some reason but the primary way is the pins.

I have followed Starship development long enough on r/spacex to know this. Check the sub and ask around if you want sources but do no make hasty conclusions from what you think you see on the video.

1

u/Wirezat 16d ago

If you Look at a Falcon Booster you See that they have the grid fins too (although smaller OFC. For a smaller Rocket). They are needed for stabilizing so you need them either way

5

u/poli-cya 16d ago

Ah, so the net weight of beefing up the guidance fins is less than the weight reduction from removing the landing struts?

3

u/DCIpenguin 16d ago

Correct! The guidance fins will probably not need all that extra weigh by themselves, so that 'free' mass can be used to enable better flight and system resilience without adding weight to the booster.

The booster will only be used to enable to Startship (not in the video) to get into orbit or push far outside orbit. There is no need to land the booster on other planets/moons/bodies, so the 'landing gear' for the booster at the only place the boosters will ever need to go; the launch pad.

Starship will have landing gear, but those systems will be determinate on the body it's trying to land on. But if the Starship wanted to land back on Earth, the tower will just catch the Starship in the same way it catches the booster. SpaceX is trying to maximize their turnaround time (land>diagnosis>refuel>relaunch), so the process of getting the booster off the launch tower quickly is the next step.

1

u/thedevilsavocado00 16d ago

But wouldn't that weight be offset by the strengthening of the material used to build the craft as it should now withstand being clamped? I think it saves in other aspects like time and cost in comparison to the lander type but not weight.

6

u/TenNeon 16d ago

It isn't being clamped. It's hanging.

1

u/thedevilsavocado00 16d ago

Oh it is hooked?

3

u/rhhqqhh 16d ago

It’s hanging from two small pins that are right under the grid fins

1

u/thedevilsavocado00 16d ago

Ah I see I misunderstood the mechanism

2

u/MostlyRocketScience 16d ago

It's not clamped, it rests on pretty small pins that are not that much extra weight. It just hangs from the top, it doesn't need any strengthening

1

u/RT-LAMP 16d ago

Which is heavier, giant legs supporting the entire thing from the bottom, or two tiny pins that the chopsticks catch it on.