StrandedonEarth Posted February 11, 2019 Share Posted February 11, 2019 Maybe he’s 3D printing them out of stainless steel? I’d say I was joking but that just might be right Quote Link to comment Share on other sites More sharing options...
Xd the great Posted February 11, 2019 Share Posted February 11, 2019 1 minute ago, StrandedonEarth said: Maybe he’s 3D printing them out of stainless steel? I’d say I was joking but that just might be right 3D printing stainless steel? How? How much heat is needed? Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted February 11, 2019 Share Posted February 11, 2019 27 minutes ago, tater said: I simply could not wrap my head around that. Even if Merlins are way cheaper than we imagine (Mueller said they could make one a day, right?), can they possibly be so cheap they don't dominate costs? On the one hand, not having a separate production line for MVacs is definitely savings...but still. Quote Link to comment Share on other sites More sharing options...
RedKraken Posted February 11, 2019 Share Posted February 11, 2019 41 minutes ago, sevenperforce said: 38 engines vs 10? Yep. He has to make back at least 30 million....probably more like 60 million on the engines alone. How much is Falcon 9 to build ....50 million? What is going on? unless raptors cost about the same as merlins...how? elon how? Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted February 11, 2019 Share Posted February 11, 2019 16 minutes ago, Xd the great said: 3D printing stainless steel? How? How much heat is needed? Just use Raptor exhaust as a preheater. (Definitely joking now) Quote Link to comment Share on other sites More sharing options...
tater Posted February 11, 2019 Share Posted February 11, 2019 7 minutes ago, RedKraken said: What is going on? unless raptors cost about the same as merlins...how? elon how? I don't think there's much reason why they should cost more than Merlins, but 38>10, so he'd have to make them like 4X cheaper. Quote Link to comment Share on other sites More sharing options...
DDE Posted February 11, 2019 Share Posted February 11, 2019 3 hours ago, sevenperforce said: Also, Elon says he has a copy of Ignition! on his bedside table. Why am I not surprised? One of us ONE OF US 3 hours ago, StrandedonEarth said: Maybe he’s 3D printing them out of stainless steel? I’d say I was joking but that just might be right Doubtful. Remember that copper brazing escaping with the exhaust? Key word is “brazing”. Wonder if they replicated the Soviet chamber design, which was extremely heavy on copper and vacuum brazing. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted February 11, 2019 Share Posted February 11, 2019 4 hours ago, RedKraken said: Yep. He has to make back at least 30 million....probably more like 60 million on the engines alone. How much is Falcon 9 to build ....50 million? What is going on? unless raptors cost about the same as merlins...how? elon how? Yeah, that does sound implausible. I think he's pushing the boundaries of known economy here. Quote Link to comment Share on other sites More sharing options...
KSK Posted February 11, 2019 Share Posted February 11, 2019 Yep - count me in as one of the ‘yes that does sound implausible’ crowd. Although if it turns out to be even halfway accurate, then their competitors are so badly hosed it’s not even funny. NewSpace Roflstomp. Quote Link to comment Share on other sites More sharing options...
tater Posted February 11, 2019 Share Posted February 11, 2019 11 hours ago, RedKraken said: 268 bar for 20ms (?).....a new high bar. Tweet storm : Some people have suggested the path to build it might be development costs, not cost per vehicle. Quote Link to comment Share on other sites More sharing options...
Xd the great Posted February 11, 2019 Share Posted February 11, 2019 41 minutes ago, tater said: Some people have suggested the path to build it might be development costs, not cost per vehicle. What do you mean Quote Link to comment Share on other sites More sharing options...
wumpus Posted February 11, 2019 Share Posted February 11, 2019 42 minutes ago, tater said: Some people have suggested the path to build it might be development costs, not cost per vehicle. Note the "Falcon 9". Falcon 9 didn't need any new engines (although it more than doubled the power of the existing Merlin engines), while BFR successors require a whole new raptor engine. Falcon 9 (1.0) was thrown together on the cheap (they had to meet the NASA CRS contract), although if you include all the development since then it would add up to much more. Still don't believe any BFR successor could be made cheaper than Merlin by any realistic accounting. Who knows, not using all that carbon might go a long way. Quote Link to comment Share on other sites More sharing options...
Racescort666 Posted February 11, 2019 Share Posted February 11, 2019 10 hours ago, Xd the great said: 3D printing stainless steel? How? How much heat is needed? 1-2kW https://www.ge.com/additive/additive-manufacturing/information/direct-metal-laser-melting-technology Quote Link to comment Share on other sites More sharing options...
sh1pman Posted February 11, 2019 Share Posted February 11, 2019 59 minutes ago, tater said: Some people have suggested the path to build it might be development costs, not cost per vehicle. You mean the path as in "development from Falcon 1 all the way to Block 5"? Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted February 11, 2019 Share Posted February 11, 2019 (edited) 11 hours ago, sevenperforce said: Elon says he has a copy of Ignition! on his bedside table. Building rockets for 15 years, and still doesn't read it from memory? 2bad Edited February 11, 2019 by kerbiloid Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted February 11, 2019 Share Posted February 11, 2019 7 hours ago, DDE said: Remember that copper brazing escaping with the exhaust? Key word is “brazing”. Wonder if they replicated the Soviet chamber design, which was extremely heavy on copper and vacuum brazing. Well to be fair that was my guess. I mean I think I was right, but still. Quote Link to comment Share on other sites More sharing options...
tater Posted February 11, 2019 Share Posted February 11, 2019 54 minutes ago, Xd the great said: What do you mean 35 minutes ago, sh1pman said: You mean the path as in "development from Falcon 1 all the way to Block 5"? Yes, or just to operational F9. He might mean there is a path to developing BFR that won't cost 5-10 B$. Quote Link to comment Share on other sites More sharing options...
DDE Posted February 11, 2019 Share Posted February 11, 2019 3 hours ago, sevenperforce said: Well to be fair that was my guess. It was also Musk’s guess. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted February 11, 2019 Share Posted February 11, 2019 1 hour ago, DDE said: It was also Musk’s guess. AFAIK Elon initially guessed the green flash was "a bit of copper from the chamber" and then eventually confirmed it was "because we vaporized some copper" but brazing was my own speculation. Quote Link to comment Share on other sites More sharing options...
MaverickSawyer Posted February 11, 2019 Share Posted February 11, 2019 Could be that they made part of the combustion chamber out of copper. After all, it's a darn fine thermal conductor. Quote Link to comment Share on other sites More sharing options...
tater Posted February 11, 2019 Share Posted February 11, 2019 The more I think of it, the more I am convinced he must mean the dev cost. The figure I keep seeing for F9 is 380 M$. NASA cost-estimation software first caled their estimated dev cost 4 B$, then they included new assumptions with commercial partners (after SpaceX), and it dropped to 1.7 B$ (so still 4X higher than it actually cost). I think if you add in the subsequent dev costs at SpaceX for Merlin improvements, F9 non-propulsion block changes, booster landing, etc, that's gotta add some hundreds of millions at the very least. That starts putting the F9 dev costs up to block 5 (maybe they include fixing the blown up pad in there as well) in the 0.5 - 1 B$ range. This is still 5 - 10 X cheaper than the numbers we have heard for BFR dev cost from both Musk and Shotwell. If they can get BFR dev costs down to on the order of a billion or less, this is huge (and the spacecraft will still cost 100s of millions for each one). Quote Link to comment Share on other sites More sharing options...
zolotiyeruki Posted February 11, 2019 Share Posted February 11, 2019 If you parse the tweet carefully, the question referred specifically to the engines, but Musk may be referring to the cost of the entire stack. In that case, you have to consider the cost savings of SS tanks and structure vs CFC (how much is that?), and that there's no disposable fairing ($5m?). Quote Link to comment Share on other sites More sharing options...
tater Posted February 11, 2019 Share Posted February 11, 2019 13 minutes ago, zolotiyeruki said: If you parse the tweet carefully, the question referred specifically to the engines, but Musk may be referring to the cost of the entire stack. In that case, you have to consider the cost savings of SS tanks and structure vs CFC (how much is that?), and that there's no disposable fairing ($5m?). Very true, I didn't look at it that way. So he could be talking about total cost of making engines for F9 in a given time frame vs the total cost for making the required number of Raptors in the same time frame. Even with reuse, if they launch 20 F9s, they need 20 MVacs. Assuming even with reuse some engines get replaced, or that they need to make a small number of boosters per year, they might need another... call it 18 M1Ds. That's 38 engines. If a single Starship/Super Heavy could replace those 20 F9 launches, it's break even. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted February 11, 2019 Share Posted February 11, 2019 40 minutes ago, tater said: So he could be talking about total cost of making engines for F9 in a given time frame vs the total cost for making the required number of Raptors in the same time frame. Even with reuse, if they launch 20 F9s, they need 20 MVacs. Assuming even with reuse some engines get replaced, or that they need to make a small number of boosters per year, they might need another... call it 18 M1Ds. That's 38 engines. If a single Starship/Super Heavy could replace those 20 F9 launches, it's break even. But he said “build”, any sane person would parse that as “the cost of making the entire rocket from ground up, incl. engines”. I don’t know how 38 Raptors + SS hull can be cheaper than 10 M1D + aluminum hull, but it seems that’s what he meant. Quote Link to comment Share on other sites More sharing options...
tater Posted February 11, 2019 Share Posted February 11, 2019 31 minutes ago, sh1pman said: But he said “build”, any sane person would parse that as “the cost of making the entire rocket from ground up, incl. engines”. I don’t know how 38 Raptors + SS hull can be cheaper than 10 M1D + aluminum hull, but it seems that’s what he meant. Yeah, that's why I have to assume "build" means to build it the first time, ie: dev cost. Quote Link to comment Share on other sites More sharing options...
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