MaverickSawyer Posted January 28, 2019 Share Posted January 28, 2019 5 hours ago, KSK said: Forget about building a rocket in a clean room. In American America, rocket is clean room. 'Murica! Quote Link to comment Share on other sites More sharing options...
kerbinorbiter Posted January 28, 2019 Share Posted January 28, 2019 Lets just hope it lands Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 28, 2019 Share Posted January 28, 2019 47 minutes ago, tater said: Wonder if I can fly to London via Orlando? Please, wait a little. It's just a flight demonstrator. Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted January 28, 2019 Share Posted January 28, 2019 (edited) 32 minutes ago, kerbiloid said: Please, wait a little. It's just a flight demonstrator. ? I’m pretty sure @tater is referring to being around for the first operational Falcon Heavy mission while on his way from the American SW to his planned London trip. Tater may even want to plan to pass through Orlando both ways, in the event of delays. A pilgrimmage to KSC, preferably capped by a major launch, is at the top of my bucket list 1 hour ago, tater said: Wonder if I can fly to London via Orlando? I’m sure it can be arranged, depending how much you want to spend... Edited January 28, 2019 by StrandedonEarth Quote Link to comment Share on other sites More sharing options...
MinimumSky5 Posted January 28, 2019 Share Posted January 28, 2019 1 hour ago, tater said: Wonder if I can fly to London via Orlando? Definatly, I've flown on that route before. The question is, do you value money or irreplaceable memories more? Quote Link to comment Share on other sites More sharing options...
tater Posted January 28, 2019 Share Posted January 28, 2019 8 minutes ago, MinimumSky5 said: Definatly, I've flown on that route before. The question is, do you value money or irreplaceable memories more? The trick is more logistical than anything else. With highly limited time, and no certainty of a launch, Orlando makes little sense. If I could layover a day, and be reasonably certain of FH, I'd be fine with added cost. Realistically it's not gonna happen. There is a direct SW flight to Orlando every day from ABQ, so at some point I'll either just fly myself, or grab a kid or 2 and do it at the last minute. Quote Link to comment Share on other sites More sharing options...
tater Posted January 28, 2019 Share Posted January 28, 2019 Quote Link to comment Share on other sites More sharing options...
sh1pman Posted January 28, 2019 Share Posted January 28, 2019 3 minutes ago, tater said: Wasn’t there some kind of problem with that static fire? I heard it was shorter than usual. Quote Link to comment Share on other sites More sharing options...
tater Posted January 28, 2019 Share Posted January 28, 2019 (edited) 1 hour ago, sh1pman said: Wasn’t there some kind of problem with that static fire? I heard it was shorter than usual. Nope, they said it was fine. It was inside the normal length range (they vary from test to test depending on issues they might be watching). Edited January 28, 2019 by tater Quote Link to comment Share on other sites More sharing options...
tater Posted January 29, 2019 Share Posted January 29, 2019 Quote Link to comment Share on other sites More sharing options...
Cunjo Carl Posted January 29, 2019 Share Posted January 29, 2019 So, I'm still on the new heat shield. It's interesting from a technical perspective, so I can't really help it! The more I look at methane, the more it looks... completely intractable as a reentry coolant. The problem isn't just that it decomposes when hot, but what it pyrolyzes into at 1000C: Carbon Black (or a relative like graphite or carbon nanotubes). For some reason, I was originally just worried about this happening inside the rocket, but now I think about it even outside in the wind, the decomposition reaction would be a huge issue. Funnily enough, Carbon Black is actually _the_ black body coating of choice in science! They make spray cans of the stuff, and it works really well! However, the whole idea of this steel starship is that it needs to remain a nice white body and reflect away most of the radiant heat. Unfortunately, only a few dozen nm of Carbon is enough to completely change the emissivity of a surface. Carbon black from pyrolysis happily forms directly on many metal (oxide) surfaces and unfortunately typically sticks really really well as a thin film (I learned from a neighboring lab trying to make carbon nanotubes). Unfortunately, once it forms it can be really hard to remove completely. Carbon black is also nigh unkillable from a chemical stand point. I remember trying to remove a very similar coating by soaking it in Caro's acid (an explosively good oxidizer) and it just hung out like nothing was wrong. My boss at the time told me to try soaking it in boiling 'SulphoNitric' (a 200C version of the oxidizer used to make TNT), and that _plus_ scrubbing did the trick. The oxidizing potential of reentry atmosphere probably won't touch it. It also unfortunately doesn't evaporate at pedestrian temperatures at all. Its close cousin, Vitreous Carbon, is actually what we use as a crucible for evaporating _Tungsten_! Perhaps reentry ablation can help keep it from forming too quickly, but I remember Carbon's "sputtering efficiency" being terrible as well, and from a physical standpoint I suspect that means it'll ablate slowly too. I should note that 'thick' films (1s of microns) are typically powdery and the outer layers can be easily wiped away with a cloth, but the inner layers can stick really well. Moral of the story, carbon black (or a relative) grows quickly on surfaces touching 1000C+ methane, which is a huge problem for white-body reentry, and once it grows (that I've experienced) it can't be convinced to move for anything. So.... I have a great new idea for a heat shield I'd like to patent. Simply inject methane through pores machined in a traditional insulating heat shield and the shield will regrow lost thickness with carbon black during reentry! Hey, engineering's all about rolling with the punches right? Nah, I think the water version will wind up being the easy-development choice for SpaceX, but it's sadly 50-80% heavier for the same cooling, will require an extra tank (with a heater), and is actually mildly corrosive to stainless steel in its Deionized form (which we'd need to use). The vapor, hot dry steam, isn't considered corrosive to stainless fortunately. Then again, maybe they have a trick up their sleeve for the methane. I'd be happy to be wrong! Quote Link to comment Share on other sites More sharing options...
DDE Posted January 29, 2019 Share Posted January 29, 2019 (edited) @Cunjo Carl Tomorrow’s Elon Musk: “New architecture. We’re painting it black. We’re also painting all the Teslas black.” The Media, likely: “Is Elon Musk hinting at release of an updated version of The International Jew, The World’s Foremost Problem?” Edited January 29, 2019 by DDE Made headline more clickbaity Quote Link to comment Share on other sites More sharing options...
Reactordrone Posted January 29, 2019 Share Posted January 29, 2019 47 minutes ago, DDE said: @Cunjo Carl Tomorrow’s Elon Musk: “New architecture. We’re painting it black. We’re also painting all the Teslas black.” The Media, likely: “Is Elon Musk hinting at release of an updated version of The International Jew, The World’s Foremost Problem?” Given what he's responding to I'll assume that means he thinks powerful people own the press. Quote Link to comment Share on other sites More sharing options...
DDE Posted January 29, 2019 Share Posted January 29, 2019 1 minute ago, Reactordrone said: Given what he's responding to I'll assume that means he thinks powerful people own the press. Correct. But the press (in the form of the elite blue checkmark Twitterati) responded by spinning it into antisemitism (to be frank, the actual antisemites did their best to help), which is what I’m parodying using references to “You can have the Ford T in any colour, so long as it’s black” and Henry Ford’s actual political views, in a bout of grotesque humour. But I’m serious about Starship being carbon black. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 29, 2019 Share Posted January 29, 2019 Spoiler They want to rent a press to make the flat sheets of steel, but somebody owns it and doesn't want to lease? Quote Link to comment Share on other sites More sharing options...
Xd the great Posted January 29, 2019 Share Posted January 29, 2019 If the carbon soot collects on the starship, is it a good ablative heatshield? Quote Link to comment Share on other sites More sharing options...
DDE Posted January 29, 2019 Share Posted January 29, 2019 1 hour ago, Xd the great said: If the carbon soot collects on the starship, is it a good ablative heatshield? Ablative, no. It’s crazy resistant to heat, almost as good as RCC; you’d usually go for heat soak/radiative TPS with it. Quote Link to comment Share on other sites More sharing options...
Piscator Posted January 29, 2019 Share Posted January 29, 2019 I wouldn't just worry about the carbon, but about the hydrogen as well. Hot hydrogen is know to have some unwelcome effects on the material properties of several alloys. 300 series steel appears to be resonably resistant against hydrogen - at least at low temperatures - but with the intended reuse rates there might be something to watch out for. Water as a coolant might be quite sensible since it could double as radiation shielding in the final, interplanetary versions of the vehicle. Quote Link to comment Share on other sites More sharing options...
DDE Posted January 29, 2019 Share Posted January 29, 2019 44 minutes ago, Piscator said: Water as a coolant might be quite sensible since it could double as radiation shielding in the final, interplanetary versions of the vehicle. It wouldn’t pull triple duty like methane would - because the design already relies on the propellant for almost all of its radiation shielding. Quote Link to comment Share on other sites More sharing options...
Xd the great Posted January 29, 2019 Share Posted January 29, 2019 19 minutes ago, DDE said: It wouldn’t pull triple duty like methane would - because the design already relies on the propellant for almost all of its radiation shielding. But you could dump all the water for life support, because who is gonna drink during reentry? Quote Link to comment Share on other sites More sharing options...
DDE Posted January 29, 2019 Share Posted January 29, 2019 2 minutes ago, Xd the great said: But you could dump all the water for life support, because who is gonna drink during reentry? True, here the big question would be whether the onboard supply would be sufficient. But I’m not sure you want to deal with superhot steam. Quote Link to comment Share on other sites More sharing options...
Xd the great Posted January 29, 2019 Share Posted January 29, 2019 22 minutes ago, DDE said: True, here the big question would be whether the onboard supply would be sufficient. But I’m not sure you want to deal with superhot steam. Im not sure whether superheated steam or dissociated methane is worse. Quote Link to comment Share on other sites More sharing options...
tater Posted January 29, 2019 Share Posted January 29, 2019 Quote Link to comment Share on other sites More sharing options...
Xd the great Posted January 29, 2019 Share Posted January 29, 2019 21 minutes ago, tater said: MOAR STRUTS to prevent stuff from failing. Quote Link to comment Share on other sites More sharing options...
tater Posted January 29, 2019 Share Posted January 29, 2019 Quote Link to comment Share on other sites More sharing options...
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