4 ms·

But I thought they were re-usable?

by neals 4y ago

Ptchd 4y ago
last flight I watched, they only recovered two of the three boosters
castratikron 4y ago
Even more impressive then.
jpgvm 4y ago
They are, they just need a hell of a lot of them to a) finish testing Starship + Super Heavy b) build a giant fleet of both and have replacement engines available for them.
wlesieutre 4y ago
If the super heavy booster lands successfully, yes. If a booster crashes they'll lose 33 engines.
- bell-cot 4y ago
  And to judge by the first few "flights" of Starship, there will probably be a number of crashed Boosters, to iterate over: Inventory->Hardware->Raptor2 -= 33;
- SAI_Peregrinus 4y ago
  IIRC they're planning to "soft land" at least the first one in the ocean. So it's guaranteed to throw 33 away, to avoid the risk of destroying the pad for the first go. If it manages to "land" successfully just above the water, then they'll go for landings back at the pad.
karkisuni 4y ago
Each rocket needs 33 for the booster and 6 for the ship, so thats still about 5 weeks for one, or 10 rockets per year. Will need a lot during development since reusability probably won't work 100% of the time for a while. then their stated goal is having a ton of these things launching for mars, etc.
PaulHoule 4y ago
A starship + booster has almost 40 engines. In a year you could produce enough engines for 9 of them. You can use that many because a mission to the moon might take 10 or so launches including fuel tankers: https://www.teslarati.com/spacex-elon-musk-starship-orbital-refueling-details/ https://www.teslarati.com/spacex-elon-musk-starship-orbital-... (Although I guess you could refly the same tanker a few times) If you were really going to Mars you would need all the Starships you could get, even operations around the Earth and cislunar space could keep a substantial fleet busy if the cost per pound is low enough to encourage new applications. You will also need to replace engines at some rate.
xoa 4y ago
>But I thought they were re-usable? A full stack Starship right now needs 39 engines (33 for Super Heavy, 6 for Starship). SpaceX will definitely lose some to testing (and indeed last I checked they are 100% going to lose all the initial ones, because they're going to do a mock-landing over the ocean before attempting a real landing, so even if it goes perfectly all those are going into the salt water). Once they have SH being recovered, ideally starting launch 2, that will cut the burn rate big time but they'll still probably take a bit to start successfully recovering SS. That's entirely expected and acceptable for MVP and as a worst case for HLS (because Lunar Starship and such aren't coming back to Earth at all, that's Orion's job). SpaceX runs hardware rich, so they will need hundreds just for testing. Long term though they want 1000+ Starships for Mars and other efforts. There will still be expended Starship profiles, and reuse doesn't mean that cadence won't require having more raw vehicles. Fueling orbital depots quickly requires lots of vehicles and trips, and boil off particularly early on means just depending on a few isn't ideal (and that's assuming they have reuse working by then, if they have to just eat the refueling as expended to meet their contract obviously they'll need more). With the current design that's tens of thousands of engines, so at current production they'd be hitting the right numbers in about 22 years which seems in the ballpark of when such an effort might actually get going. At any rate mass production is very important for their plans and how they operate. It's let them iterate very quickly, iron out more kinks, be much more aggressive about testing which in turn feeds back into doing each better, and pushes down the cost per engine dramatically. If you go to the Ars comments first page you'll see pictures comparing Raptor 1 and Raptor 2 and can just visually see the massive simplification (though note it's a little bit unfair because Raptor 1 was much more heavily instrumented, but there is far more stuff removed/improved then just that).
- fosk 4y ago
  > because they're going to do a mock-landing over the ocean before attempting a real landing, so even if it goes perfectly all those are going into the salt water) Are they going to pick them up or let them sink?
  - adgjlsfhk1 4y ago
    They almost certainly will pick them up because they will want to examine every part of it to see how everything held up.
tastyfreeze 4y ago
They are. Rockets using Raptor are still in testing and occasionally explode. Starship uses 6 Raptor engines. The Super Heavy booster uses up to 33 Raptor engines. SpaceX is going to need a lot of Raptors to advance Super Heavy testing where some of them will likely be destroyed.

But I thought they were re-usable?

by neals 4y ago

But I thought they were re-usable?

Ptchd 4y ago

last flight I watched, they only recovered two of the three boosters

castratikron 4y ago

Even more impressive then.

jpgvm 4y ago

They are, they just need a hell of a lot of them to a) finish testing Starship + Super Heavy b) build a giant fleet of both and have replacement engines available for them.

wlesieutre 4y ago

If the super heavy booster lands successfully, yes. If a booster crashes they'll lose 33 engines.

bell-cot 4y ago
And to judge by the first few "flights" of Starship, there will probably be a number of crashed Boosters, to iterate over: Inventory->Hardware->Raptor2 -= 33;
SAI_Peregrinus 4y ago
IIRC they're planning to "soft land" at least the first one in the ocean. So it's guaranteed to throw 33 away, to avoid the risk of destroying the pad for the first go. If it manages to "land" successfully just above the water, then they'll go for landings back at the pad.

karkisuni 4y ago

Each rocket needs 33 for the booster and 6 for the ship, so thats still about 5 weeks for one, or 10 rockets per year. Will need a lot during development since reusability probably won't work 100% of the time for a while. then their stated goal is having a ton of these things launching for mars, etc.

PaulHoule 4y ago

A starship + booster has almost 40 engines. In a year you could produce enough engines for 9 of them. You can use that many because a mission to the moon might take 10 or so launches including fuel tankers: https://www.teslarati.com/spacex-elon-musk-starship-orbital-refueling-details/ https://www.teslarati.com/spacex-elon-musk-starship-orbital-... (Although I guess you could refly the same tanker a few times) If you were really going to Mars you would need all the Starships you could get, even operations around the Earth and cislunar space could keep a substantial fleet busy if the cost per pound is low enough to encourage new applications. You will also need to replace engines at some rate.

xoa 4y ago

>But I thought they were re-usable? A full stack Starship right now needs 39 engines (33 for Super Heavy, 6 for Starship). SpaceX will definitely lose some to testing (and indeed last I checked they are 100% going to lose all the initial ones, because they're going to do a mock-landing over the ocean before attempting a real landing, so even if it goes perfectly all those are going into the salt water). Once they have SH being recovered, ideally starting launch 2, that will cut the burn rate big time but they'll still probably take a bit to start successfully recovering SS. That's entirely expected and acceptable for MVP and as a worst case for HLS (because Lunar Starship and such aren't coming back to Earth at all, that's Orion's job). SpaceX runs hardware rich, so they will need hundreds just for testing. Long term though they want 1000+ Starships for Mars and other efforts. There will still be expended Starship profiles, and reuse doesn't mean that cadence won't require having more raw vehicles. Fueling orbital depots quickly requires lots of vehicles and trips, and boil off particularly early on means just depending on a few isn't ideal (and that's assuming they have reuse working by then, if they have to just eat the refueling as expended to meet their contract obviously they'll need more). With the current design that's tens of thousands of engines, so at current production they'd be hitting the right numbers in about 22 years which seems in the ballpark of when such an effort might actually get going. At any rate mass production is very important for their plans and how they operate. It's let them iterate very quickly, iron out more kinks, be much more aggressive about testing which in turn feeds back into doing each better, and pushes down the cost per engine dramatically. If you go to the Ars comments first page you'll see pictures comparing Raptor 1 and Raptor 2 and can just visually see the massive simplification (though note it's a little bit unfair because Raptor 1 was much more heavily instrumented, but there is far more stuff removed/improved then just that).

fosk 4y ago
> because they're going to do a mock-landing over the ocean before attempting a real landing, so even if it goes perfectly all those are going into the salt water) Are they going to pick them up or let them sink?
- adgjlsfhk1 4y ago
  They almost certainly will pick them up because they will want to examine every part of it to see how everything held up.

tastyfreeze 4y ago

They are. Rockets using Raptor are still in testing and occasionally explode. Starship uses 6 Raptor engines. The Super Heavy booster uses up to 33 Raptor engines. SpaceX is going to need a lot of Raptors to advance Super Heavy testing where some of them will likely be destroyed.