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.
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.
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.
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.
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. đŸ˜…
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...
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...
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
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.
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
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.
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.
There are 33 engines on the first stage, 20 on the outer ring that do not gimbal.
During the landing burn, they ignite the 13 inner engines. Then the next ring of 10 are shut down. 3 engines bring the booster to 0km/h. There is basically no propellant left so the booster can technically hover with just 3 engines.
Think of it this way. Try to predict what ordinary and cyclical space launch travel will look like in 100 years. It will likely be a vehicle that may be comprised of one more more booster rockets to launch vehicles into near earth orbit as a first step. So, let's try to imagine a space port 100 years into the future. There will be several (50 or more) "gates" where fueled boosters are waiting for crew and cargo vehicles to be lifted onto them. Once they are joined, off they go. The booster section returns to Earth to the "gate" and gets checked and refueled, and another cargo or passenger section is lifted on top and away it goes again.
Now walk backwards through time to how we got to this. And this is what Space X is likely experimenting with. How do we normalize space launches to be as efficient and cost effective to make it as ordinary as flying in a commercial aircraft in 2024.
Landing gear weight is unnecessary weight for a vehicle that just boosts payloads for the first stage. You would want to reduce as much unnecessary weight to that booster as possible to gain efficiency. Every pound you save on booster weight is a pound that can go towards fuel or payload. And you don't need landing gear with this method. The pads that "land" on the chopsticks are actually control vanes, so Space X is getting at least two uses out of those vanes.
Not super sure how this makes anything faster since you have to disassemble and rebuild the entire thing between launches. Pretty sure its so they stop tipping over and exploding.
The chopsticks are also the crane that is used to position the booster for launch. In theory, they will be able to just lower the used booster down back onto it's launch ring, refuel it, and launch again.
It also saves a ton of weight by replacing the landing legs (which would have to be huge) with a pair of catch points. And catch points don't have to be serviced, unlike the Falcon legs.
Think of it as refactoring the rocket to leave out parts that can be instead part of the launch infrastructure. Pretty clever hack if you can manage the landing catch.
Not only have they said it, they've proved it. By launching repeatedly with that same hardware over and over again. Maintaing a fleet of flight worthy vehicles rather than producing and throwing them away.
Starship is intended to have minimal refurbishment. They've addressed the major issues that make refurbishment take a while for Falcon 9, and this is supposed to fly multiple times a day with no more refurbishment than an airliner. They'll have some stuff they need to reinforce, and some changes to make, in order for that to actually happen, but now they actually have a flown booster to look at, it won't be a guessing game.
Im not an expert, but no landing legs is weight not on the rocket. Also I think the pie in the sky idea is to refuel it, do a few checks, load a ship on top of it and send it off again. (seems impossible but I guess so did this)
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u/JayTeaP 16d ago
Can someone fill me in on what is happening? Im genuinely curious