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The catch looks amazing, but one thing I don't understand is why SpaceX needs the technology to catch a booster they've already demonstrated the ability to land
by ro_bit 2y ago
The catch looks amazing, but one thing I don't understand is why SpaceX needs the technology to catch a booster they've already demonstrated the ability to land boosters on barges. Is the arm more cost effective to scale compared to a barge?
- mlyle 2y agoThe argument is that you don't need to spend the vehicle mass on legs, so you get performance. On the other hand, I imagine you could wipe out any benefits to $/mass launched pretty quickly by blowing up the tower.
- msk-lywenn 2y agoMaybe the goal is to refill and relaunch immediately?
- slashdave 2y agoThis. You can lower the rocket back on the launch base, refill, and launch again within hours.
- cubefox 2y agoAfter checking if everything is okay with the vehicle. And of course the government agencies must determine that frequent sonic booms (there is one per booster landing) are acceptable for the public.
- valine 2y agoThe landing legs are heavy. SpaceX would rather have more payload than carry legs to space on every launch. Also landing on the launch pad means you don’t have to transport the rocket. Just have the arms set it down and you’re ready to launch again.
- _djo_ 2y agoThis booster is much, much larger than the Falcon 9 first stages that land on barges. It's ~70 metres high, versus ~40 metres for the Falcon 9 first stage, and weighs about 275 000 kg compared to the ~20 000 kg of the Falcon 9 first stage. In short, it would require such huge and heavy landing legs and landing barges that it probably wouldn't be feasible.
- mock-possum 2y agoHoly shit I didn’t realize it’s an order of magnitude heavier
- db48x 2y agohttps://www.reddit.com/r/space/comments/exvu55/size_comparison/ https://www.reddit.com/r/space/comments/exvu55/size_comparis... https://www.visualcapitalist.com/comparing-the-size-of-the-worlds-rockets-past-and-present/ https://www.visualcapitalist.com/comparing-the-size-of-the-w...
- stetrain 2y agoFYI that first link is showing a previous, larger, concept iteration of Starship (then known as ITS) which would have had a 12m diameter, versus the 9m version that SpaceX ended up building. The second link seems to show a version of Starship that's relatively up-to-date.
- db48x 2y agoYup. Someone should make a new graphic.
- migueloller 2y agoThe square-cube law strikes again! https://en.m.wikipedia.org/wiki/Square%E2%80%93cube_law https://en.m.wikipedia.org/wiki/Square%E2%80%93cube_law
- faceloss 2y ago[dead]
- cryptonector 2y agoWeight. Legs weigh a lot. That's dead weight for a launch system, and it serves only to reduce payload to orbit. For Falcon 9 that's not that big a deal because they're NOT trying to reuse the second stage. Whereas with Starship they need more fuel to recover the ship, and that means they need to save weight elsewhere to avoid losing too much payload to orbit.
- iamcreasy 2y agoSpaceX is also not very happy with the pair of forward flaps and 10 ton thermal protection needed as control surface and re-entry.
- db48x 2y agoIt takes time for the barges to return the booster to the launch pad. They want to be able to launch Starship, have the booster land back at the launch pad, have the arms set it back down on the ground, and recycle the booster for another launch in just a few hours. Then the arms can be used to stack the booster and the next payload on the launch platform.