That sounds like a shockingly low number even for an expendable engine. Let’s say you have an engine acceptance test, a core stage acceptance test (like the green run), and then launch. That’s 3 of the four uses.If you have to aborted lift-offs or green runs, you’d have to get new engines!You can see why they deleted the green run even for crewed launches. They just don’t have the cycle life in the engines to afford that level of acceptance testing.Just so very short-sighted.
Giving it a different name was likely just part of the internal politics of the time; a way for Musk to clearly distinguish between the initiative he felt was failing, and the one he felt was the way forwards. Once he sorted out the underlying problem there was no need for 2 different engine design tracks, so no need for 2 different names.
Elon did make a statement a week or so ago about the Starship/Super heavy having the thrust of "three Saturn Vs". Maybe he meant with this engine? Even the proposed Raptor 3 thrust doesn't get you to three Saturn Vs. Granted, maybe he didn't mean literally/exactly but it's still interesting he went from two at one point to three.
If the price of Raptor is 1 million $, and we have no indication saying Musk was faking this number, it is already in a good spot (compared to other engines). But I know, he won't stop until they reach the limit.In general I was surprised by the price of modern rocket engines compared to other complex machinery, like jet engines. The engines of the 737 MAX are 14.5 millions each. Sure the plane doesn't have 39 of them. But the price is comparable. Ofcourse there are very big differences, but it isn't a totally out of the blue apples to oranges comparsion. I was initially surprised the prices were so close or maybe I was underestimating jet engine prices.
Quote from: steveleach on 09/19/2023 09:56 pmGiving it a different name was likely just part of the internal politics of the time; a way for Musk to clearly distinguish between the initiative he felt was failing, and the one he felt was the way forwards. Once he sorted out the underlying problem there was no need for 2 different engine design tracks, so no need for 2 different names.I think he is being serious about a new engine.
Didn't the old, long life RS-25 need some pretty heavy refurbishment between launches? Maybe the low restart numbers for the single flight model is mostly from deleting the ability to overhaul it after every launch. Weld things that use to be bolted and such.
Quote from: Alberto-Girardi on 09/20/2023 05:17 pmIf the price of Raptor is 1 million $, and we have no indication saying Musk was faking this number, it is already in a good spot (compared to other engines). But I know, he won't stop until they reach the limit.In general I was surprised by the price of modern rocket engines compared to other complex machinery, like jet engines. The engines of the 737 MAX are 14.5 millions each. Sure the plane doesn't have 39 of them. But the price is comparable. Ofcourse there are very big differences, but it isn't a totally out of the blue apples to oranges comparsion. I was initially surprised the prices were so close or maybe I was underestimating jet engine prices.Jet engines are very complicated. Gas turbines can operate at over 1'600°C, each blade has regenerative and film cooling unlike raptor turbopumps which operate at 600°CThat's why I expect the LEET engine to have film cooling in the turbopumps. They are merging the fuel-rich turbopump with the injector so unless I'm mistaken they could extend the cooling channels from the combustion chamber all the way to the turbopumps.They probably won't be able to reach 1'600°C thought because the pressure is higher than a gas turbine.
Quote from: Sarigolepas on 09/21/2023 03:09 pmQuote from: steveleach on 09/19/2023 09:56 pmGiving it a different name was likely just part of the internal politics of the time; a way for Musk to clearly distinguish between the initiative he felt was failing, and the one he felt was the way forwards. Once he sorted out the underlying problem there was no need for 2 different engine design tracks, so no need for 2 different names.I think he is being serious about a new engine.Since the notional new engine is mentioned by Elon Musk as intended to help mankind become a multiplanetary species, I'm guessing that the Starship/Super Heavy would need to have the first stage modified to use as many as 12 engines with a total of 20 million pounds of thrust and the Starship portion fitted with five engines totaling 6 million pounds of thrust in order to burn enough fuel to reach portions of the solar system beyond Mars.
Quote from: Nomadd on 09/25/2023 06:23 am Didn't the old, long life RS-25 need some pretty heavy refurbishment between launches? Maybe the low restart numbers for the single flight model is mostly from deleting the ability to overhaul it after every launch. Weld things that use to be bolted and such.I recall that the SSME was intended to go some number of flights between work, 4 or 8 flights, something like that.But that after Challenger more is always better so they took them out and serviced them on each flight.I don't know if it was warranted and if they found anything, or if it was a reflexive overreaction that stuck.Seems that after 50+ years that we can do a lot better than the SSME, just on materials and manufacturing alone the RS-25 should be easy to improve on. And not be $100M per engine.
Quote from: hplan on 09/20/2023 05:47 pmQuote from: Alberto-Girardi on 09/20/2023 05:17 pmA note about price.If the price of Raptor is 1 million $, and we have no indication saying Musk was faking this number, it is already in a good spot (compared to other engines). But I know, he won't stop until they reach the limit.In general I was surprised by the price of modern rocket engines compared to other complex machinery, like jet engines. The engines of the 737 MAX are 14.5 millions each. Sure the plane doesn't have 39 of them. But the price is comparable. Ofcourse there are very big differences, but it isn't a totally out of the blue apples to oranges comparsion. I was initially surprised the prices were so close or maybe I was underestimating jet engine prices.The BE4 engine costs about 8 milion, the RD180 25. The Merlin less than 1. The numbers are from EDA.Those numbers are indeed crazy. But they aren't really comparable.Elon always likes to talk about 'marginal cost' -- how much more it costs to make one additional engine. So the $1M figure doesn't include research and development, cost of the factory and equipment to build engines, profit, etc. No doubt if they were selling engines separately, the cost would be much higher.Thanks for the explanation. This is indeed something I didn't consider. Hopefully raptor gets to the state of scaling that the marginal cost and the total ammortized price are nearly the same. IIUC what Elon says is useful if you want to make the design cheaper, but isn't good if you want to know the actual cost. He presumes they will get to the stage were R&D cost won't be vety significant.
Quote from: Alberto-Girardi on 09/20/2023 05:17 pmA note about price.If the price of Raptor is 1 million $, and we have no indication saying Musk was faking this number, it is already in a good spot (compared to other engines). But I know, he won't stop until they reach the limit.In general I was surprised by the price of modern rocket engines compared to other complex machinery, like jet engines. The engines of the 737 MAX are 14.5 millions each. Sure the plane doesn't have 39 of them. But the price is comparable. Ofcourse there are very big differences, but it isn't a totally out of the blue apples to oranges comparsion. I was initially surprised the prices were so close or maybe I was underestimating jet engine prices.The BE4 engine costs about 8 milion, the RD180 25. The Merlin less than 1. The numbers are from EDA.Those numbers are indeed crazy. But they aren't really comparable.Elon always likes to talk about 'marginal cost' -- how much more it costs to make one additional engine. So the $1M figure doesn't include research and development, cost of the factory and equipment to build engines, profit, etc. No doubt if they were selling engines separately, the cost would be much higher.
A note about price.If the price of Raptor is 1 million $, and we have no indication saying Musk was faking this number, it is already in a good spot (compared to other engines). But I know, he won't stop until they reach the limit.In general I was surprised by the price of modern rocket engines compared to other complex machinery, like jet engines. The engines of the 737 MAX are 14.5 millions each. Sure the plane doesn't have 39 of them. But the price is comparable. Ofcourse there are very big differences, but it isn't a totally out of the blue apples to oranges comparsion. I was initially surprised the prices were so close or maybe I was underestimating jet engine prices.The BE4 engine costs about 8 milion, the RD180 25. The Merlin less than 1. The numbers are from EDA.
Quote from: Vahe231991 on 09/25/2023 04:14 pmQuote from: Sarigolepas on 09/21/2023 03:09 pmQuote from: steveleach on 09/19/2023 09:56 pmGiving it a different name was likely just part of the internal politics of the time; a way for Musk to clearly distinguish between the initiative he felt was failing, and the one he felt was the way forwards. Once he sorted out the underlying problem there was no need for 2 different engine design tracks, so no need for 2 different names.I think he is being serious about a new engine.Since the notional new engine is mentioned by Elon Musk as intended to help mankind become a multiplanetary species, I'm guessing that the Starship/Super Heavy would need to have the first stage modified to use as many as 12 engines with a total of 20 million pounds of thrust and the Starship portion fitted with five engines totaling 6 million pounds of thrust in order to burn enough fuel to reach portions of the solar system beyond Mars.An F-1B thrust class next gen. engine would be perfect for a much larger next gen Starship system in the far future having the same engine counts for booster (33 engines) and ship (6 engines) as the current Starship system has.
Quote from: DJPledger on 09/25/2023 06:24 pmQuote from: Vahe231991 on 09/25/2023 04:14 pmQuote from: Sarigolepas on 09/21/2023 03:09 pmQuote from: steveleach on 09/19/2023 09:56 pmGiving it a different name was likely just part of the internal politics of the time; a way for Musk to clearly distinguish between the initiative he felt was failing, and the one he felt was the way forwards. Once he sorted out the underlying problem there was no need for 2 different engine design tracks, so no need for 2 different names.I think he is being serious about a new engine.Since the notional new engine is mentioned by Elon Musk as intended to help mankind become a multiplanetary species, I'm guessing that the Starship/Super Heavy would need to have the first stage modified to use as many as 12 engines with a total of 20 million pounds of thrust and the Starship portion fitted with five engines totaling 6 million pounds of thrust in order to burn enough fuel to reach portions of the solar system beyond Mars.An F-1B thrust class next gen. engine would be perfect for a much larger next gen Starship system in the far future having the same engine counts for booster (33 engines) and ship (6 engines) as the current Starship system has.Opinion:I'd think they'd want to design a new engine to fit the current package, otherwise the thrust structures and plumbing would have to radically change. That's maybe 20-25% towards a new design. OTOH, maybe a new design is a development branch they're looking at.
Quote from: OTV Booster on 09/27/2023 05:19 pmQuote from: DJPledger on 09/25/2023 06:24 pmQuote from: Vahe231991 on 09/25/2023 04:14 pmQuote from: Sarigolepas on 09/21/2023 03:09 pmQuote from: steveleach on 09/19/2023 09:56 pmGiving it a different name was likely just part of the internal politics of the time; a way for Musk to clearly distinguish between the initiative he felt was failing, and the one he felt was the way forwards. Once he sorted out the underlying problem there was no need for 2 different engine design tracks, so no need for 2 different names.I think he is being serious about a new engine.Since the notional new engine is mentioned by Elon Musk as intended to help mankind become a multiplanetary species, I'm guessing that the Starship/Super Heavy would need to have the first stage modified to use as many as 12 engines with a total of 20 million pounds of thrust and the Starship portion fitted with five engines totaling 6 million pounds of thrust in order to burn enough fuel to reach portions of the solar system beyond Mars.An F-1B thrust class next gen. engine would be perfect for a much larger next gen Starship system in the far future having the same engine counts for booster (33 engines) and ship (6 engines) as the current Starship system has.Opinion:I'd think they'd want to design a new engine to fit the current package, otherwise the thrust structures and plumbing would have to radically change. That's maybe 20-25% towards a new design. OTOH, maybe a new design is a development branch they're looking at.I think people are reading way too much into something that happened a couple of years ago, and that everyone involved has probably moved on from now.
