tater Posted July 21, 2019 Share Posted July 21, 2019 Just now, Ultimate Steve said: Where did this come from? Is it new? Yeah, dearmoon instagram. Also, CRS launch looks unlikely due to weather: Quote Link to comment Share on other sites More sharing options...
tater Posted July 21, 2019 Share Posted July 21, 2019 Quote Link to comment Share on other sites More sharing options...
Cuky Posted July 21, 2019 Share Posted July 21, 2019 I would say that on the right is the vacuum nozzle for Merlin. Both are displayed behind "Falcon 9" sign, and Raptor has nothing to do with F9 Quote Link to comment Share on other sites More sharing options...
NSEP Posted July 21, 2019 Share Posted July 21, 2019 49 minutes ago, Cuky said: I would say that on the right is the vacuum nozzle for Merlin. Both are displayed behind "Falcon 9" sign, and Raptor has nothing to do with F9 The the vacuum nozzle for the Merlin is way larger than the engine on the right. The vacuum nozzle for merlin (2.5m) is around twice the diameter of the sea level nozzle (1.25m) Quote Link to comment Share on other sites More sharing options...
tater Posted July 21, 2019 Share Posted July 21, 2019 1 hour ago, Cuky said: I would say that on the right is the vacuum nozzle for Merlin. Both are displayed behind "Falcon 9" sign, and Raptor has nothing to do with F9 Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted July 22, 2019 Share Posted July 22, 2019 9 hours ago, tater said: I wasn't saying they screw everything up at all, look at Apollo as the on topic example, or many other things. I said that large, government agencies become entities in their own, that often function for reasons that differ from their original raison d'être. In the US, spreading stuff to as many States as possible has a long tradition, going back to the way the Washington Administration sourced the initial 6 Frigates for the nascent USN, though, so it's to be expected. Yes, these are true. But it's also true that similar things happen withing private enterprises. I bet that whoever is in charge of the Falcon line at SpaceX is doing his/her best to make sure that the Falcon budget isn't all going to Starship. Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 1 hour ago, mikegarrison said: Yes, these are true. But it's also true that similar things happen withing private enterprises. I bet that whoever is in charge of the Falcon line at SpaceX is doing his/her best to make sure that the Falcon budget isn't all going to Starship. LOL, yeah, that's certainly true---internal politics at SpaceX, lol. It's inevitable as any organization's size increases, really, but a project like NASA (in the context of the Space Race of the 1960s), leapfrogged straight from nothing to 400k people working on a project, divided into centers all across the nation, which likely accelerated the process, it was an instant, huge corporate entity. Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 BTW, apparently drone shots of the facility in Cocoa, FL show several more sections ready to assemble than are needed to get the FL Orbital Prototype to full height. They are either prepping for another, or they could already be starting on SH. Quote Link to comment Share on other sites More sharing options...
Wjolcz Posted July 22, 2019 Share Posted July 22, 2019 2 hours ago, tater said: BTW, apparently drone shots of the facility in Cocoa, FL show several more sections ready to assemble than are needed to get the FL Orbital Prototype to full height. They are either prepping for another, or they could already be starting on SH. Well, it's meant to be *orbital* prototype so I'd guess the booster is already being built. Unless the Starship is an SSTO? Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 9 minutes ago, Wjolcz said: Well, it's meant to be *orbital* prototype so I'd guess the booster is already being built. Or at least the circular hull sections, yeah. 9 minutes ago, Wjolcz said: Unless the Starship is an SSTO? Starship (the empty version) is an SSTO. For testing this is enough, it only needs to make orbit so that it can reenter at orbital velocities for testing. That's what SSTO Starship is for, nothing more I'd wager. If they can get it to reenter at useful test velocities, they can test it at much reduced cost. Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 Quote Link to comment Share on other sites More sharing options...
Guest Posted July 22, 2019 Share Posted July 22, 2019 2 hours ago, tater said: Starship (the empty version) is an SSTO. I’ve seen Elon mention this (which is amazing) but at the same time how much DV does it cost to get into a minimal orbit? Starship supposedly has 6.9k m/s, but does that even get you a circularised orbit outside the atmosphere? Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 2 minutes ago, Dale Christopher said: I’ve seen Elon mention this (which is amazing) but at the same time how much DV does it cost to get into a minimal orbit? Starship supposedly has 6.9k m/s, but does that even get you a circularised orbit outside the atmosphere? That's with 100-125 tons of payload, I think. Quick check, if we call SS prototype 100 tonnes with reserve props for landing included, and we weight the Isp for SL vs Vac (I'm assuming 2km/s dv at SL, the rest at Vac) to 369s (330 @SL, 380 Vac), then SS has almost 9400 m/s of dv. The dry mass is assumed 75 tonnes for this, obviously. If you shave off a few tons of mass at the pad, >9500 is possible. Dunno what the effect of superchilling props might be, but that's certainly possible for this use case. Again, the only point is to get the thing to where they can do proper reentry testing. Quote Link to comment Share on other sites More sharing options...
Guest Posted July 22, 2019 Share Posted July 22, 2019 I wonder if Starship is intended to keep its fuel refrigerated or if they are planning on keeping it at a substantially higher temp for long term storage. It has to hold it for months to get to Mars after all. I wonder how this effects the DV numbers for a Starship fuelled in orbit compared to one fuelled on the pad. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted July 22, 2019 Share Posted July 22, 2019 39 minutes ago, Dale Christopher said: I’ve seen Elon mention this (which is amazing) but at the same time how much DV does it cost to get into a minimal orbit? Starship supposedly has 6.9k m/s, but does that even get you a circularised orbit outside the atmosphere? More of an issue starship only has 3 surface engines so it can not lift off with full fuel load. Think they plan on using the vacuum engines at surface in an abort, this will ruin the engines but might give enough TWR to get away? Now they could replace the vacuum engines with surface ones placed lower to manage higher lift off weight. Still not an SSTO but you could practice an higher speed reentry. Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted July 22, 2019 Share Posted July 22, 2019 Last I recall from an Elon tweet a month or three ago, the VacRap was put on the back burner to focus on getting the SeaLRap flight-ready for testing StarShip and then SH. VacRap dev will continue when it is needed. They’ll take the ISP hit in the meantime to speed development towards flight testing. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted July 22, 2019 Share Posted July 22, 2019 A 75t dry 1100t full Starship with 380s RVacs has a dV of around 10km/s. Just enough to orbit and land. I don’t think the prototypes can pull this off, not without the booster. Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 7 minutes ago, sh1pman said: A 75t dry 1100t full Starship with 380s RVacs has a dV of around 10km/s. Just enough to orbit and land. I don’t think the prototypes can pull this off, not without the booster. Yeah, the wiki page needs to be rewritten. They list SL and Vac Isp, bit for "Raptor," they should in fact list the 2 engines separately. That said, if the Isp is 330 at SL, it's certainly higher in vacuum. If the diff between SL and vac cof SL Raptor is the same as Merlin 1D, that makes vac Isp around 363. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted July 22, 2019 Share Posted July 22, 2019 2 minutes ago, tater said: If the diff between SL and vac cof SL Raptor is the same as Merlin 1D, that makes vac Isp around 363. Which brings us to ~9.5km/s dV (most of the orbital velocity will be gained at near vacuum Isp), that’s assuming the prototypes dry mass is 75t, and I doubt it is this low. Maybe it can reach orbit but not land afterwards. If I were them, I’d build and test the booster first, then go for orbital and reentry tests. Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted July 22, 2019 Share Posted July 22, 2019 (edited) No problem if they are a little low on delta-v. Just revert to VAB and add moar boosters.... Edited July 22, 2019 by mikegarrison Quote Link to comment Share on other sites More sharing options...
Silavite Posted July 22, 2019 Share Posted July 22, 2019 If Starship alone is short of dV to orbit, it may still be able to fly a mission similar to the Shuttle's abort once around profile. Quote Link to comment Share on other sites More sharing options...
tater Posted July 22, 2019 Share Posted July 22, 2019 Quote Link to comment Share on other sites More sharing options...
Guest Posted July 22, 2019 Share Posted July 22, 2019 (edited) @Silavite Starship shouldn’t really be flying SSTO missions, It’s just a capability I’ve heard Elon mention due to its DV. There’s very little reason for it outside of some test. The suborbital intercontinental hops might be a possibility without the super heavy booster but the graphics I’ve seen so far have them launched with the booster. Eventually I’d like to play around in Real Solar System to attempt to get a better idea of what’s exactly possible/likely. Edited July 22, 2019 by Guest Quote Link to comment Share on other sites More sharing options...
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