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Chang'e 6 lunar sample return mission returns with samples from moon's far side
- PM_me_your_math 2y ago[dead]
- ck2 2y agoThe international moon base plan is fascinating. https://en.wikipedia.org/wiki/International_Lunar_Research_Station https://en.wikipedia.org/wiki/International_Lunar_Research_S... (nuclear power plans by Russia not so much) Is there enough gravity on the moon to prevent the long-term health problems from the space station like bone, muscle and vision loss?
- JumpCrisscross 2y ago> nuclear power plans by Russia not so much Why? Any lunar base without nuclear power plans is not a serious effort.
- consumer451 2y agoI often wondered, how do you deal with all the waste heat from a fission power reactor, in a vacuum? Giant radiators? edit: fixed typo, derp. fusion=fission
- creer 2y agoPerhaps? Any reason that sounds silly to you?
- consumer451 2y agoNo, and this is not some attack on nuclear power. I am just curious. On earth, nuclear power plants use lots of water and cooling towers. How does that work in a place with no spare water? I also meant to write fission in my original question, not fusion.
- creer 2y agoMostly cooling towers are not likely to work in a place with no atmosphere. Radiators though, are constantly used in spacecraft, and seem to work well. Low gravity, no motion might let the thing be mostly the radiator, with not much support structure. Except it might need to be in shade, in the shadow of a building? hill? solar panels?
- squarefoot 2y ago> How does that work in a place with no spare water? I wonder if recycling human liquid waste through evaporation could be of some use for that purpose.
- rplnt 2y agoIt would likely be a thermal reactor, I guess? So no waste heat, since the little heat it gives is used to generate electricity.
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- eternauta3k 2y agoThermal power plants don't use up the heat. They make energy through its transfer (like a dam with water).
- ianburrell 2y agoMost nuclear reactors are thermal power plants and they all need to dump waste heat. Thermal power plants convert heat into electricity with turbines and are limited by dumping the waste heat. Are you thinking of radioisotope generators? Those aren't reactors. They use thermocouples and need to get rid of the waste heat. The Voyager RTGs have radiator fins.
- rplnt 2y agoYeah, that's what I meant, sorry about the incorrect naming.
- JumpCrisscross 2y ago> Giant radiators? Yup, that's the thing on top [1]. [1] https://www.nasa.gov/tdm/fission-surface-power/ https://www.nasa.gov/tdm/fission-surface-power/
- consumer451 2y agoThanks, I have seen a lot of pages on nasa.gov, but not that one. Neato!
- bongodongobob 2y agoHeat is what you use to make steam and drive the turbines with. I don't understand your question.
- dotnet00 2y agoOn the Moon you could also use the Moon itself as a heat sink. But yeah, any near-term solutions would use giant radiators.
- gus_massa 2y agoSolids don't conduct too much heat. I think most of the cooling in a nuclear plant is generated by evaporation of water.
- dotnet00 2y agoYes, what I mean is that theoretically you could do something like have a very very wide base to passively dump heat into the ground (since we're still only looking at kW scale reactors in space), or actively cycle large amounts of regolith through the cooling loop (say, via a heat exchanger from a closed water loop) and dump it out. Depending on how much heat the system can handle, you could maybe even extract stuff boiling off from the regolith.
- mcculley 2y agoThe nuclear plant nearest to me uses sea water, which is put back into the ocean.
- gus_massa 2y agoInteresting. I had to look for more details. I found this link https://nuclear.duke-energy.com/2013/11/13/why-don-t-all-nuclear-plants-have-cooling-towers https://nuclear.duke-energy.com/2013/11/13/why-don-t-all-nuc... Oversimplifiying: All new plnats have cooling towers, so the water they return to the environment is not too hot.
- SaulGoogman 2y agomaybe not so hot indeed due to the scarce air that's why it's so cold at night on the moon. Only turn on the reactor at night to generation and use capacitors at day?
- meepmorp 2y agoYou can't really turn fission reactors on and off, they're always producing decay heat even if not being used for power generation. But why not radiate the excess heat into the crust of the moon with a subsurface loop, kind of like a ground source heat pump.
- hoseja 2y agoThe day is 28 times longer than on Earth. You'd need very big capacitors.
- photochemsyn 2y agoSolar PV linked to battery storage is the obvious energy source for a moonbase. All reactors require coolant circulation and water is going to be among the most valuable commodities on the moon, not something you want to circulate through a reactor (where you inevitably get tritium formation, making the water unsuitable for other uses). Maybe you could use helium or liquid sodium metal as the primary coolant, but then you still need to generate electricty via secondary water coolant loop that runs a steam-powered turbine. Really not plausible on the moon.
- porphyra 2y agoYou'll need an insane amount of battery storage, since the moon only rotates once per month and you'll need to power through a long period of no sunlight.
- Lord-Jobo 2y agoOr just very long power lines and multiple solar stations, it's not like the moon is impossible large. But that would be harder than a singular location using nuclear fuel, it's true.
- dotnet00 2y agoOr alternatively, for polar bases, very tall panels, which would be able to be in permanent sunlight.
- JumpCrisscross 2y ago> very tall panels, which would be able to be in permanent sunlight Or normal panels on the rim of Shackleton [1]. (You'd still want to bootstrap with fission.) [1] https://en.wikipedia.org/wiki/Shackleton_(crater)#Potential_uses https://en.wikipedia.org/wiki/Shackleton_(crater)#Potential_...
- photochemsyn 2y agoA belt of solar panels encircling the moon would solve that problem though perhaps a bit ambitious at present.
- somenameforme 2y agoThe moon is fairly unique (relative to Earth) in that the exact same spot will go from -200C to +100C on a two week cycle (day and night). It seems "obvious" that there must be some clever way to exploit this to generate energy in a simple and novel fashion.
- JumpCrisscross 2y ago> seems "obvious" that there must be some clever way to exploit this to generate energy in a simple and novel fashion Sure, once you have two-week power-storage infrastructure. (And the scale to harvest a useful amount of energy once a month on average.) In the meantime, i.e. our lifetimes, you have countries that can build space nuclear reactors and countries being performative.
- somenameforme 2y agoI see a couple of issues here. The first is that creating, maintaining, and operating a nuclear facility on the Moon would almost certainly be far more challenging than "just" maintaining a couple of weeks of power storage. But that kind of implicitly leads into the other issue. That is that you only really need the scale of power that nuclear can offer once you've already substantially industrialized the Moon. For some simple habs and research areas, even something as small/simple as a radioisotype generator [1] would be more than fine. Beyond all this, I meant novel when I said novel. The regular extremes of heat and cold offer all sorts of interesting ideas. You've got room for predictable and endless convection on basically an arbitrarily large scale there. There is certainly going to be some clever way to exploit this in a novel fashion. [1] - https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...
- itishappy 2y agoGood news! Thermal cycles are caused by the sun, and we can harvest sunlight directly! Storage is an issue...
- pie420 2y ago
- krisoft 2y ago> Is there enough gravity on the moon to prevent the long-term health problems from the space station like bone, muscle and vision loss? Nobody knows. You might think scientist can science up answers to any question but it is impossible to know this without long term data which is simply not available. There were some experiments done in parabolic flights [2] but those only last for a very short time. There is this literature review [2]. They are not optimistic: "It can be anticipated that partial gravity environments as present on the Moon or on Mars are not sufficient to preserve all physiological systems to a 1 g standard if not addressed through adequate countermeasures." Which is space speak for "you will need to go to the gym on the moon". But they are willing to admit how little there is to know for certain: "The methodological quality of the vast majority of the available/included studies is too low to generate a compeling evidence." 1: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10411353/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10411353/ 2: https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00583/full https://www.frontiersin.org/journals/physiology/articles/10....
- somenameforme 2y agoAnother, perhaps even more interesting question, is also how the first generation who are born in low g will evolve and adapt. And this, so far as I know, is a completely unexplored question. Mammal experiments might be interesting, but at some point you simply have to do it with humans, not only because of our fairly long gestation period, but also because of how absurdly undeveloped we are even once when born. There's every reason to think a human baby may develop differently than other mammals which do far more development within the womb.
- pelagicAustral 2y agoI do not know for a fact, but I wouldn't think there is a single chance in hell that living in an environment with 1/6th of the gravity we've got on earth would not cause long term effects in your health, specially to the bones and muscle.
- lawlessone 2y agoProbably fine .. as long as you don't come home.
- uneoneuno 2y agoAlso changes eye shape over time, causing vision issues, etc.. Longer you're up there the more starts to go wrong. We were built to fight off gravity. I think its worth considering that it may be fundamentally impossible for humans to reproduce/gestate babies/live entire lifetimes/generations in low gravity conditions.
- ta1243 2y agoWell there's a world of difference between micro-gravity (where there have been problems with nice) and low gravity like on the moon (where there's been no experiments) If you did have viable babies in low (not zero) gravity situations though, would you in fact be starting a new species.
- gus_massa 2y agoIt's not clear when a new specie is different from the previous one, but you probably need: * Like 100.000 years, probably more. (From the split of us from chimps 5.000.000 I counted like 30 species in https://en.wikipedia.org/wiki/Human_evolution https://en.wikipedia.org/wiki/Human_evolution , but the number depends a lot on who count them.) * Isolate the populations so they can't interbreed (first because they can't meet and later becuse the dna is incompatible)
- dekhn 2y agoI assume that any large scale colonization of space will involve deeply modified germline humans: reduced oxygen requirements, greater tolerance to radiation, fewer rigid bones, tolerance to many forms of low gravity, loss of ability to live on the surface of a high G planet. And I guess an increased tolerance to boredom given how long it takes to get anywhere when minimizing energy expenditure.
- numpad0 2y agoRadiation is going to be a bigger problem, which calls for a deep underground base, which I'm suspecting it coincidentally also enable centrifugal artificial gravity
- scoot 2y agoWhat are they expecting to be different about samples from the moon's far side to those previously collected?
- somenameforme 2y agoThe reason you seek to explore what you don't know is because you don't know what you don't know. In general I don't think people really appreciate how ridiculously little we know about everything outside of our planet. Like for instance it was only in 2013 (!!!) that it was discovered that Mars' soil is relatively 'moist', about 2% water by mass. And that's just the topsoil layer - it's suggestive that below the surface it could well be even more moist. But the Moon's much closer, so we must know more, right? Well water ice on the Moon was only confirmed in 2018!! [1] So actually starting to get surface samples, and explore more of the Moon, ideally with a rapid return to humans on it is so exciting because who knows what we'll find out next? The unknown is precisely what makes exploring the unknown so enticing, rewarding, and fun! [1] - https://www.space.com/41554-water-ice-moon-surface-confirmed.html https://www.space.com/41554-water-ice-moon-surface-confirmed...
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- porphyra 2y agoLet's not bring sinophobia and geopolitics into a scientific mission to the moon.
- pc86 2y agoNo, but can we bring realism into it? The explorers may be exploring for the sake of it, but the people paying for it definitely aren't. Many - perhaps even most - of the people at NASA would have probably done the job for free if they were able, but the people allocating NASA's budget in the 50s and 60s were doing so for geopolitical reasons first and foremost.
- throwaway199956 2y agoOne thing they seems to have got working fairly reliably is the lunar landing of the probe using image processing to guide the final approach and touch down. It seems to have worked well in this and the previous mission, there are videos on youtube of that. https://youtu.be/wUju9-cckKA?si=nZFOCga10mnCA_vs https://youtu.be/wUju9-cckKA?si=nZFOCga10mnCA_vs The other component is the autonomous docking of the return probe in lunar orbit. Soviets have done a lunar sample return, but they had a probe that would lift off directly into a earth return trajectory, but that seems to have limited both the liftoff mass and the possible zones in moon from which it can lift off. This seems a much more complex mission than that. Also some animated videos of the misson show a skip re-entry back to earth, don't know if it is the case during this particular flight.
- JumpCrisscross 2y ago> the lunar landing of the probe using image processing to guide the final approach Anyone building precision weapons has gotten fairly good at this.
- dotnet00 2y agoWeapons guidance systems get to be simpler in many ways. If you've seen some of the Lunar or Martian landing videos, you'll notice that it's very hard to tell the scale. Especially on the Moon, the lack of atmosphere to disturb the surface makes it fractal-like, which probably really messes with the CV algorithm. It'd work fine when high up, but as you approach for landing, it would probably struggle, especially for, say, estimating how far away the surface is.
- barelyauser 2y agoDon't they use radar altimeters to get altitude? You don't need to rely only on image processing. You can even pull off stereo using a single camera since you are moving and know the altitude at every point.
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- omneity 2y agoI sincerely hope there's no moonseed in it. https://en.wikipedia.org/wiki/Moonseed_(novel) https://en.wikipedia.org/wiki/Moonseed_(novel)
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- jiehong 2y agoThey only linked to other articles of the guardians but not to the official announcement. Official announcement by the CNSA: https://www.cnsa.gov.cn/n6758823/n6758838/c10565180/content.html https://www.cnsa.gov.cn/n6758823/n6758838/c10565180/content.... Congratulations for such an achievement!
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- standardUser 2y agoDo either China or the US have plans to attempt a Mars sample return? Does China have the rocket power to attempt such a mission? The US seems focused solely on the return moon missions, with any Mars mission presumably behind at least 5 more major Artemis missions that are scheduled through 2031.
- dotnet00 2y agoChina as far I'm aware doesn't have any solid plans on the books yet. NASA has been working on planning out a Mars sample return for a few years now, part of the Perseverance rover's job is to collect samples, store them in canisters, and drop them for future retrieval. This ensures that the samples have a much lower risk of having been contaminated, if, say, they end up being retrieved by a crewed mission. The issue has been that previous proposals have all been too complex and too expensive, eg, a second rover that has to retrieve the samples and then place them on a lander which has a rocket on-board, the rocket then launches back into orbit, where an orbiter picks up it up and brings it home. They've recently started soliciting other ideas for a way it might be done from private industry. The most promising in my opinion being to use a Starship, so they would be able to send a large enough return rocket to not need an orbital rendezvous, significantly simplifying things. I doubt they're seriously proposing a crewed Starship sample retrieval just yet. Another neat proposal I've heard is to build on the success of the Ingenuity helicopter to have a bunch of similar helicopters go around picking up the samples instead of a rover.
- standardUser 2y agoExcellent info, thank you. If you or anyone else have favorite news sources for keeping up on space programs, please share. I tend to get most of my space news from HN.
- dotnet00 2y agoI usually just pick it up from X, following a couple of good, space focused journalists helps push most space news up to me. Adding to the Mars Sample Return thing, apparently China just recently announced their intention to do it ~2030.
- lucubratory 2y agoSuper impressive. A return mission from the far side is very technically difficult, and pulling it off paves the way for a staffed lunar lander on the far side.
- hoseja 2y agoHow is it more difficult than return from the near side, besides the need for a relay?
- lucubratory 2y agoHaving to route all of your communications through a relay, having to explicitly build out backups to your backups for comms rather than being able to look up with your instruments, a longer delay requiring more autonomy on the lunar surface, more radiation, more micrometeorite impacts, rougher terrain, other things.
- anjel 2y agoNow let's see China accomplish the same with all-analog circuitry
- __m 2y agoAnd nazi scientists