sevenperforce Posted June 9, 2020 Share Posted June 9, 2020 29 minutes ago, RCgothic said: How big is the extended Falcon Heavy fairing? Trying to find some details but coming up empty-handed. Here's the render that SpaceX did themselves: Spoiler Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 9, 2020 Share Posted June 9, 2020 9 minutes ago, sevenperforce said: Here's the render that SpaceX did themselves: Reveal hidden contents I was hoping for some dimensions. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted June 9, 2020 Share Posted June 9, 2020 1 hour ago, mikegarrison said: The current situation really doesn't warrant a huge amount of regulatory oversight because there just isn't enough of it going on. Nobody had to certify the Wright Flyer for airworthiness. But if the commercial space advocates actually do what they want to to, that will change. One-offs and development work will probably still be treated like experimental vehicles (as flight test airplanes are today), but a fleet of rockets? I expect design certification and manufacturing certification and modification certification and all that. This is very true, however at that stage its an success. Current issues is that they try to solve lots of problems at once and fast. They need to get starship hull thickness down. With the thin plates they alredy uses I'm surprised it hold up, yes the raceways help, the methane down pipe is also probably a structural element in a way. Develop procedures for how to operate it, they had two fails because ground handling issues. SN3 collapsed because lack of pressure in LOX tank and SN4 blew up because fail in the quick release system. Note that both of this is also Falcon 9 has to handle. Then they have to jump Starship starhopper style and that did not go flawless with starhopper. Weird they did not used it for more jumps. Is it so different from Starship testing with it has negligible value? they could modify it and add an nose cone and top RCS for more real tests. Then they have flight testing, get up to 20 km and do the flip before landing yes they could do the flip high and have margins to recover and land on the engine from say 5 km, training close to ground operations high up is done all the time in flight training. This includes stuff like dogfights where you set sea level at 3 km height. In short more focus on procedures and test flights, fine tuning easy mass constructions can come later as long as you keep it in mind during development. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted June 9, 2020 Share Posted June 9, 2020 StarLink is literally a cube-sat, fight me. Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 9, 2020 Share Posted June 9, 2020 Pretty! Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 9, 2020 Share Posted June 9, 2020 DM-2 is doing well, mission extension is GO: Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 9, 2020 Share Posted June 9, 2020 1 hour ago, CatastrophicFailure said: StarLink is literally a cube-sat, fight me. Scott points out a few cool features of this video: Quote Link to comment Share on other sites More sharing options...
Spaceception Posted June 10, 2020 Share Posted June 10, 2020 (edited) You know, I was thinking earlier, that if SpaceX had pushed the development path of a reusable second stage, it could've been named Talon And another thing I was thinking for fun - alternative Starship names: Dragonfire = Superheavy. Dragonbreath = Starship. Dragonpuff = Crew/Cargo Dragon (This one is a callback too!) Edited June 10, 2020 by Spaceception Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted June 10, 2020 Share Posted June 10, 2020 3 hours ago, RCgothic said: DM-2 is doing well, mission extension is GO: I think if I had a chance to be off the Earth right now, it would be a good time to say "yes". Quote Link to comment Share on other sites More sharing options...
cubinator Posted June 10, 2020 Share Posted June 10, 2020 26 minutes ago, mikegarrison said: I think if I had a chance to be off the Earth right now, it would be a good time to say "yes". Me too man... Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 10, 2020 Share Posted June 10, 2020 Quote Link to comment Share on other sites More sharing options...
RealKerbal3x Posted June 10, 2020 Share Posted June 10, 2020 1 hour ago, RCgothic said: At timestamp 4:44 in the video above there's a pretty clear view of the piledriver they've installed near the launch pad. I guess they plan to build a more permanent launch pad structure in the future and need to drive piles to support it in the sandy, marshy terrain at the site. Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 10, 2020 Share Posted June 10, 2020 Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 10, 2020 Share Posted June 10, 2020 (edited) Speaking of Raptors, sounds very like a full duration fire! But SN5 rollout is delayed again: And SN7 looks to officially be a test tank! Edited June 10, 2020 by RCgothic Quote Link to comment Share on other sites More sharing options...
Silavite Posted June 10, 2020 Share Posted June 10, 2020 1 hour ago, RCgothic said: What does he mean by, "cryo strength bump of CH4"? Is he referring to the increase in strength of stainless steel at the cryogenic temperatures of liquid CH4? Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted June 10, 2020 Share Posted June 10, 2020 37 minutes ago, Silavite said: What does he mean by, "cryo strength bump of CH4"? Is he referring to the increase in strength of stainless steel at the cryogenic temperatures of liquid CH4? Yes Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 10, 2020 Share Posted June 10, 2020 (edited) We're up to #30 for Raptors: Edited June 10, 2020 by RCgothic Quote Link to comment Share on other sites More sharing options...
tater Posted June 10, 2020 Share Posted June 10, 2020 Quote Link to comment Share on other sites More sharing options...
tater Posted June 11, 2020 Share Posted June 11, 2020 Quote Link to comment Share on other sites More sharing options...
Shpaget Posted June 11, 2020 Share Posted June 11, 2020 11 hours ago, RCgothic said: ~80 extra ISP is huge, but CH4 is only about half as dense as RP1 (even near freezing point). How does that factor in? Quote Link to comment Share on other sites More sharing options...
Silavite Posted June 11, 2020 Share Posted June 11, 2020 (edited) 33 minutes ago, Shpaget said: ~80 extra ISP is huge, but CH4 is only about half as dense as RP1 (even near freezing point). How does that factor in? That's comparing SL ISP of a kerolox engine to vacuum ISP of a methalox engine. Visiting Wikipedia gives me a sea level ISP of 311 s for the RD-180 and a vacuum ISP of 359 s for the RD-0124. The numbers for Raptor are 330 s at sea level and 380 s in vacuum (for the sea level and vacuum engine types, respectively). Raptor's ISP numbers are still impressive, but it's not quite an 80 second improvement. It's also worth noting that Raptor is expected to have a better TWR than both of these engines. Edited June 11, 2020 by Silavite Quote Link to comment Share on other sites More sharing options...
Jacke Posted June 11, 2020 Share Posted June 11, 2020 54 minutes ago, Shpaget said: ~80 extra ISP is huge, but CH4 is only about half as dense as RP1 (even near freezing point). How does that factor in? Rocketry rule of thumb: launch vehicles cost in proportion rougly to their volume. Of course, that's only about one of five costs (payload, bus, launch vehicle, integration, ground support) for a payload. So some increase in cost, but not likely a lot. Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 11, 2020 Share Posted June 11, 2020 (edited) 1 hour ago, Shpaget said: ~80 extra ISP is huge, but CH4 is only about half as dense as RP1 (even near freezing point). How does that factor in? What Elon is saying is that the following tank mass factors roughly balance for a given mass of propellant: CH4 is less dense compared to RP1 and so the CH4 tanks have to be bigger and weigh more. A higher proportion of the propellant is LOX, which is more dense and so the larger CH4 tank is a smaller proportion of the tanks as a whole (so the extra mass is not as much as you might think). No insulation is required on the common intertank bulkhead because CH4 remains liquid closer to LOX temperatures, unlike RP1. This saves mass. The tank is colder filled with CH4 than with RP1, and this actually boosts the material strength of the tank. So the tank can be made thinner, saving mass. The four factors roughly balance. This means we could build an upper stage with similar tank mass fraction to F9US, except with 22s more ISP and twice as much thrust. The F9US is already a beast of a stage! It can give 8km/s to a 7.3t payload! For reference Centaur, the benchmark HYDROLOX stage, can't even give 7km/s to half as much payload (Centaur weighs half as much as F9US dry). A hypothetical single-Raptor powered upper stage with a similar tank fraction and TWR to F9US as Elon has just suggested is possible, would give 9km/s to 12.5 tonnes! Space X really is leaving the rest of the industry for dead in upper stage technology. Edited June 11, 2020 by RCgothic Quote Link to comment Share on other sites More sharing options...
Scotius Posted June 11, 2020 Share Posted June 11, 2020 Regular Raptor or vacuum optimized Raptor (VacRaptor?)? Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 11, 2020 Share Posted June 11, 2020 17 minutes ago, Scotius said: Regular Raptor or vacuum optimized Raptor (VacRaptor?)? RVac, ~380s. Quote Link to comment Share on other sites More sharing options...
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