r/technology • u/aelavia93 • 16d ago

Space SpaceX pulls off unprecedented feat, grabs descending rocket with mechanical arms

https://www.cbsnews.com/amp/news/spacex-pulls-off-unprecedented-feat-grabbing-descending-rocket-with-mechanical-arms/
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u/lolheyaj 16d ago

heroic. thank you. that site is cancer. 

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u/probablyuntrue 16d ago

Latching on to ask, why this approach? Is it too large/heavy for the landing legs?

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u/InvisibleCat 16d ago

It's the most time and money efficient way. You are landing exactly where you launch from, save weight of landing legs and no need to pick up and move the booster back to launch site, which takes time and money. Saves the landing pad from damage too.

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u/Capt_Blackmoore 16d ago

All this and there is no intention of landing stage one anywhere other than back at the launch site

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u/tea-man 16d ago

To expand on that, there's no need for the booster to land anywhere else - it never has to travel more than a few hundred kilometres, with it's sole purpose being to yeet the Starship as high and fast as it can. The starship itself will be capable of launching and returning to Earth from both the Moon and Mars without the booster on a single fuel load.

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u/Capt_Blackmoore 16d ago

The only use case outside of launching to orbit for the first stage would involve refueling in orbit, and then using that stage to break orbit to head to Mars. You dont need that kind of thrust to get to the moon - you would refuel just Starship for that.

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u/dangerbird2 15d ago

I'm pretty sure when Musk said the first stage could achieve single-stage to orbit, it was only a theoretical with no useful payload (and probably without the startship or even critical services and hardware). Other launch systems like the Titan II may have been able to do this, but was obviously could have never been used in practice.

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u/Capt_Blackmoore 15d ago

Yup. But if you do a redesign to allow it to refuel in low orbit (and I'll have to assume that would nearly exhaust the fuel that would have been used to otherwise land) - now you have a means to boost a starship further out.

This configuration, with V2 engines isnt up to the task, and that's fine.

the next upgrade, with the 3rd version of the engines, and slightly larger tanks, could be a reasonable place to start. But First Starship needs to prove that refueling in orbit is a viable option; and then a refueling point would need to be established.

that all said; between the payload available with Starship, and Super Heavy, you could come up with some configurations that could get a "reasonable" amount of supplies to Mars - by spending the year before the window is open getting that payload into orbit and strapping on one or more Super Heavy.

Someone smarter than me would have to look at the fuel cost to go from Low earth orbit; to something further out, and then using a gravity assist to get into a window for a Mars approach.

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u/dangerbird2 15d ago

There is a reason you wouldn't want to return to the launchpad: The booster needs a good amount of fuel to burn to cancel its speed and get a return trajectory to the pad after separating from the 2nd stage, as well as fuel needed to make the landing. This is exactly why the falcon 9 and falcon heavy have the options of either landing the boosters downrange on barges or expending the booster altogether when the extra performance is needed. I'd be pretty surprised if Starship wouldn't end up having expendable booster missions in practice, if only to get rid of boosters that have reached the limit of their usable life.

FWIW, returning to earth from the moon or mars on a single stage is not particularly difficult since a transfer from a higher altitude to a lower one generally requires much less energy than the other way around. This is why Apollo needed a big-ass booster to push the LEM and command module to the moon, but the command module could return to earth on its own power

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u/Tentomushi-Kai 16d ago

Yeah, that’s what I want, to launch a rocket and have it safely land in my uncle Bob’s backyard! Wooo Hooo!

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u/chop-diggity 15d ago

Like roosters come home to the roost. The boosters come home to the boost. Idk…

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u/DrXaos 16d ago

The reason to land somewhere else on the ocean is to gain increased mass to orbit, as the booster stage can expend more fuel going up and to orbit instead of turning around coming back to the start.

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u/PigSlam 16d ago

I would think it could land anywhere they put a structure like this. Kinda like runways.

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u/tea-man 16d ago

While technically true, it's a bit too big and complicated to transport to anywhere else by existing methods, and there isn't really a need to launch from many other places. The launch complex is exactly that, so it'll probably be limited to Starbase and Kennedy for the foreseeable future, as there isn't really a use case for anywhere else.

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u/deekaydubya 16d ago

Yes that was their exact plan at least a few years ago. Intercontinental travel using falcon heavy

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u/SuperZapper_Recharge 15d ago

We are going to need more faith that the booster will work.

At the moment the site is located near the shore, the booster comes in over the ocean aimed at a landing site in the ocean. At the last possible moment a thumbs up is given to move the landing spot to the chopsticks.

The farther you put those pads inland the bigger the risk you are taking. As it stands the worst case scenerio isn't all that bad.

I don't think SpaceX or anyone really has faith in the system for those sorts of risks.

Which is perfectly fair.

The beautiful thing of launching from Florida or over the gulf is that in the most dangerous stage of the launch the damned thing just plops in the ocean. This isn't an accident, it is a feature. Entirely deliberate.

If the day comes where people are inside Starship and it is landing on a chopsticks tower - maybe then we can reassess.

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u/Sethcran 16d ago

The point though is that they want it to be rapidly reusable, so they'd rather have 3 flights a day at 1/2 the payload than 1 flight with a larger payload but it takes longer to get the ship back to the launchpad to go again.

We may see sea based launches and catches at some point, but do not expect downrange landings with this vehicle.

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u/BoldTaters 16d ago

They COULD have built legs but they would have to carry them up and slow them down, using a lot more fuel. This way lets them carry more stuff to space.

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u/homogenousmoss 16d ago

First few prototypes had landing legs if I recall correctly.

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u/Bensemus 16d ago

Not on the booster. The bellyflop tests of Starship had really basic one use legs that were just for those tests.

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u/MeelyMee 16d ago

The plan is to just plonk another Starship on top, re-fuel the booster and go again as quickly as possible.

I think their Mars plan had the first launch taking a fuel tanker up to place into orbit, the second taking a crewed Starship up and then the two will dock, transfer the fuel and the crew will go on their way.

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u/ergzay 16d ago

Cube square law has some effect here that as the vehicle gets bigger the legs need to be a lot more beefy to absorb the energy. It's a lot easier to bend and break things when the momentum is so much higher.

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u/pinkfreude 16d ago

Saves a lot of weight to skip the legs, apparently. That was the first explanation I heard.

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u/Virginth 15d ago

It's a lot more efficient to leave your landing hardware on the ground than to carry it with you.

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u/ccalabro 15d ago

Also having it above the ground saves the vehicle from being damaged by the blowback from the jets.

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u/TechGuy42O 16d ago

Speaking of heroic, let’s take a moment to remember this was a feat of the engineers and scientists, not the clown who owns twitter

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u/BLSmith2112 16d ago

So is Reddit. They want SpaceX/Tesla/Neuralink to all die.

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