magnemoe Posted January 8 Share Posted January 8 2 hours ago, AckSed said: NASA gifts a Phase 1 grant to a new way of cooling I haven't ever considered - bling! https://www.nasa.gov/general/electro-luminescently-cooled-zero-boil-off-propellant-depots/ By using all the normal approaches (vacuum insulation, thermal shields), and then plating the non-sunward side of a fuel depot in LEDs, you just might be able to achieve zero boil-off storage of H2, thanks to a little quirk of physics. Now this is weird, but cool if it works, up to -15 centigrade here so heating is more interesting. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 9 Share Posted January 9 17 hours ago, AckSed said: By using all the normal approaches (vacuum insulation, thermal shields), and then plating the non-sunward side of a fuel depot in LEDs, you just might be able to achieve zero boil-off storage of H2, thanks to a little quirk of physics. So, bye-bye the equilibrium temperature. The object which is radiating more power than receives, and with zero thermal conductivity inside, is the key to the problem. Quote Link to comment Share on other sites More sharing options...
darthgently Posted January 9 Share Posted January 9 So, in an airship or balloon, if the ambient air in the material were replaced with hydrogen or helium, the volume would be more buoyant than either. Wow. Quote Link to comment Share on other sites More sharing options...
AckSed Posted January 9 Share Posted January 9 Funny you should say that. A vacuum can be sustained inside an aerogel pressure vessel, and with a bit of engineering of the materials, scaling up to a dirigible should be theoretically possible: "Approaching air buoyancy in aero/cryogel vacuum vessels" Journal of Materials Science 57, 2022 Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 9 Share Posted January 9 The mission on human remains delivery to the Moon looks failed. https://www.space.com/astrobotic-peregrine-moon-lander-propulsion-failure Quote Link to comment Share on other sites More sharing options...
Codraroll Posted January 9 Share Posted January 9 1 hour ago, AckSed said: Funny you should say that. A vacuum can be sustained inside an aerogel pressure vessel, and with a bit of engineering of the materials, scaling up to a dirigible should be theoretically possible: "Approaching air buoyancy in aero/cryogel vacuum vessels" Journal of Materials Science 57, 2022 Never mind dirigibles. A nano-porous material with closed pores that contain no gas is the holy grail for insulation scientists everywhere. Since most insulation materials are based on stationary gas in pores, the total thermal resistance of the material is limited to that of the gas. So-called vacuum insulation panels overcome that limit by encapsulating the material in a diffusion tight envelope and pumping the gas out. They are extremely effective in theory, but using them in practice is like covering a building in balloons - which they effectively are, only with the pressure on the outside instead of the inside. That means nothing can be cut or punctured, and you can simply forget on-site adjustments. But a material that could sustain its own vacuum ... that would be a revolution worth trillions. Take the length of all the exterior walls in a building, multiply by 20 cm or so. That's the cost savings in building area alone. Quote Link to comment Share on other sites More sharing options...
DDE Posted January 9 Share Posted January 9 2 hours ago, AckSed said: Funny you should say that. A vacuum can be sustained inside an aerogel pressure vessel, and with a bit of engineering of the materials, scaling up to a dirigible should be theoretically possible: "Approaching air buoyancy in aero/cryogel vacuum vessels" Journal of Materials Science 57, 2022 Ah, the fabled rocks that fall upwards. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted January 9 Share Posted January 9 20 minutes ago, Codraroll said: Never mind dirigibles. A nano-porous material with closed pores that contain no gas is the holy grail for insulation scientists everywhere. Since most insulation materials are based on stationary gas in pores, the total thermal resistance of the material is limited to that of the gas. So-called vacuum insulation panels overcome that limit by encapsulating the material in a diffusion tight envelope and pumping the gas out. They are extremely effective in theory, but using them in practice is like covering a building in balloons - which they effectively are, only with the pressure on the outside instead of the inside. That means nothing can be cut or punctured, and you can simply forget on-site adjustments. But a material that could sustain its own vacuum ... that would be a revolution worth trillions. Take the length of all the exterior walls in a building, multiply by 20 cm or so. That's the cost savings in building area alone. Yes, now I guess the main problem here would be that unless you make this foam in vacuum it need to be porous enough for the air to leave, you could then seal the outside but you could not later cut it to size and it could take damage having air leak in putting an nail trough it as an example. Benefit for insulation is that weight is not much of an issue. Quote Link to comment Share on other sites More sharing options...
darthgently Posted January 9 Share Posted January 9 56 minutes ago, Codraroll said: Never mind dirigibles. A nano-porous material with closed pores that contain no gas is the holy grail for insulation scientists everywhere. Since most insulation materials are based on stationary gas in pores, the total thermal resistance of the material is limited to that of the gas. So-called vacuum insulation panels overcome that limit by encapsulating the material in a diffusion tight envelope and pumping the gas out. They are extremely effective in theory, but using them in practice is like covering a building in balloons - which they effectively are, only with the pressure on the outside instead of the inside. That means nothing can be cut or punctured, and you can simply forget on-site adjustments. But a material that could sustain its own vacuum ... that would be a revolution worth trillions. Take the length of all the exterior walls in a building, multiply by 20 cm or so. That's the cost savings in building area alone. Hmm. I know graphene conducts heat extremely well. Not sure how that would interact with the insulative aspects of aerogels in general. It could certainly be the least heat conductive form for graphene, but what would that mean? Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 9 Share Posted January 9 They could try assisting the buoyancy by attracting some Dark Matter (tm) and using its Archimedes force. Then maybe even a cast iron kettlebell would fall up in a pool of the Dark Matter (tm), being less dense than it. Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted January 9 Share Posted January 9 3 hours ago, kerbiloid said: The mission on human remains delivery to the Moon looks failed. https://www.space.com/astrobotic-peregrine-moon-lander-propulsion-failure The Navajo are probably happy about that. Perhaps the Moon spirits were offended… Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 10 Share Posted January 10 10 hours ago, StrandedonEarth said: The Navajo are probably happy about that. Perhaps the Moon spirits were offended… Sailor Moon is not happy about turning the Moon into a cemetery. Quote Link to comment Share on other sites More sharing options...
DDE Posted January 10 Share Posted January 10 12 hours ago, StrandedonEarth said: The Navajo are probably happy about that. Perhaps the Moon spirits were offended… Well, they definitely weren't alone. There was a certain thing that's not known for stability: Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 10 Share Posted January 10 Btw, as the lunar seas have craters, and they are ring-shaped like atolls, why not rename the in-sea craters into atolls, declare them off-shore zones, and set a tax-free mode there to attract investment into the lunar infrastructure? Just imagine the laundry perspectives. The Moon would become a spa in a decade. Quote Link to comment Share on other sites More sharing options...
AckSed Posted January 13 Share Posted January 13 Autophagous (self-consuming) rockets are somewhat interesting to military planners, as there's none of the mass penalty of a casing to contain the pressure. They just need a bit more work: Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 13 Author Share Posted January 13 Giant ring of galaxies https://www.google.com/amp/s/amp.theguardian.com/science/2024/jan/11/newly-discovered-cosmic-megastructure-challenges-theories-of-the-universe Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 14 Share Posted January 14 Spoiler Quote Link to comment Share on other sites More sharing options...
DDE Posted January 14 Share Posted January 14 On 1/13/2024 at 10:23 PM, AckSed said: Autophagous (self-consuming) rockets are somewhat interesting to military planners, as there's none of the mass penalty of a casing to contain the pressure. They just need a bit more work: Given how many rocket failure modes seem to come with pulsations of thrust, I hereby propose a new theory. Every rocket wishes it were the Orion Drive. Quote Link to comment Share on other sites More sharing options...
AckSed Posted January 18 Share Posted January 18 CalTech's space-based solar power experiments satellite concludes its mission: https://www.caltech.edu/about/news/space-solar-power-project-ends-first-in-space-mission-with-successes-and-lessons Short version: the deployable ultralight structure had some new glitches that needed some figuring out so it could deploy, the wireless power transfer degraded a bit and non-space-rated gallium arsenide solar cells are surprisingly consistent. It's all good data. Side note: I prick my ears up every time I hear about Momentus' MET water thrusters on their tugs, as it's a key technology for the Spacecoach water-fuelled low-cost spacecraft concept. Quote Link to comment Share on other sites More sharing options...
insert_name Posted January 18 Share Posted January 18 seems like water on mars is more widespread than previously thought, with large amounts of water ice on the equator https://www.space.com/mars-water-ice-equator-frozen-ocean Quote Link to comment Share on other sites More sharing options...
AckSed Posted January 18 Share Posted January 18 Looks like Starship will need to pack some heavy-duty mining equipment... but we knew that. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 21 Share Posted January 21 Just to not bother somebodyself with inventing Y, Z, and ZZ infections. https://www.theguardian.com/society/2024/jan/21/arctic-zombie-viruses-in-siberia-could-spark-terrifying-new-pandemic-scientists-warn In any unclear situation, say "it came from Siberian swamps". Quote Link to comment Share on other sites More sharing options...
DDE Posted January 21 Share Posted January 21 1 hour ago, kerbiloid said: In any unclear situation political mudslinging can ensue: Quote Threat of outbreak from microbes trapped in permafrost for millennia raised by increased Siberian shipping activity Gee, I wonder how demands for international environmental regulation over the Arctic would turn out these days. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted January 21 Share Posted January 21 On 1/18/2024 at 10:07 PM, AckSed said: Looks like Starship will need to pack some heavy-duty mining equipment... but we knew that. Yes most assumed permafrost was common on Mars but you need to know your landing location has it. Easiest way to get it is to drill down then use hot water to melt the ice so you get more water out. Drill rigs drilling water wells or for underground heat pumps should work unless many hundreds of meter down. Its an 3-4 axes truck, yes you need to make it work unmanned in the start but not something I class as heavy in mining. For space its very heavy. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 22 Share Posted January 22 On 1/19/2024 at 12:07 AM, AckSed said: Looks like Starship will need to pack some heavy-duty mining equipment... but we knew that. Several (6? 8?) years ago, in the possible lunar base discussion, I had suggested that the lunar modules should be buried into trenches, so the first thing to deliver is a heavy bulldozer to dig out these trenches and then cover them with ground. They were laughing and suggesting to ram the bulldozer into the lunar surface at several km/s speed, so the trench will appear without digging, *** Several years later I was suggesting a sandbag fortress to reinforce the pioneer lunar outposts. Nobody took this seriously. Well, well... *** P.S. Btw, my next suggestion on the deuterium fusion plant and superheavy launchpad complex is still on the table. Spoiler P.P.S. Btw the Project Horizon base was beginning from the several lunar tractors delivery. Quote Link to comment Share on other sites More sharing options...
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