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Chang'e 6 lunar sample return mission returns with samples from moon's far side

theguardian.com

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Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#51

Post by vasco »

somenameforme wrote: post #7
scoot wrote: post #3

What are they expecting to be different about samples from the moon's far side to those previously collected?

The 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 sur…

> Well water ice on the Moon was only confirmed in 2018

Thats for surface water, we confirmed a while longer the moon has water underground.

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#52

Post by dotnet00 »

barelyauser wrote: post #47
dotnet00 wrote: post #43

Earlier quoted context omitted.

Weapons 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,…

Don'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.

They definitely combine several sensors to get a proper height reading, but as we've seen with the American and Japanese landers, getting good readings from the sensors, properly accounting for all factors that might affect sensor readings and being able to properly handle sensor disagreements is quite challenging.

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#53

Post by pc86 »

porphyra wrote: post #24
1234554321a wrote: post #18

Earlier quoted context omitted.

[flagged]

Let's not bring sinophobia and geopolitics into a scientific mission to the moon.

No, 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.

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#54

Post by dotnet00 »

gus_massa wrote: post #50
dotnet00 wrote: post #44

Earlier quoted context omitted.

On the Moon you could also use the Moon itself as a heat sink. But yeah, any near-term solutions would use giant radiators.

Solids don't conduct too much heat. I think most of the cooling in a nuclear plant is generated by evaporation of water.

Yes, 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.

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#55

Post by pc86 »

JumpCrisscross wrote: post #34
krisoft wrote: post #5

Earlier quoted context omitted.

> 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 l…

> it is impossible to know this without long term data which is simply not available Generating these data is one of the biggest pay-offs of a lunar colony.

I know data is the plural of datum but seeing "these data" instead of "the data" is always so jarring to me. Almost as jarring as seeming anyone use the word "datum" ever.

Is this one of those generational things like "on accident" vs. "by accident" or regional things like "math" vs. "maths"?

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#56

Post by gus_massa »

ta1243 wrote: post #17
uneoneuno wrote: post #12

Earlier quoted context omitted.

Also 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.

Well 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.

It'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 , 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)

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#57

Post by [deleted] »

JumpCrisscross wrote: post #35
throwaway199956 wrote: post #10

One 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 The other component is the autonomous docking of the return probe in lunar orbit. Soviets have done a lunar sampl…

> the lunar landing of the probe using image processing to guide the final approach Anyone building precision weapons has gotten fairly good at this.

[deleted]

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#58

Post by vlovich123 »

pc86 wrote: post #55
JumpCrisscross wrote: post #34

Earlier quoted context omitted.

> it is impossible to know this without long term data which is simply not available Generating these data is one of the biggest pay-offs of a lunar colony.

I know data is the plural of datum but seeing "these data" instead of "the data" is always so jarring to me. Almost as jarring as seeming anyone use the word "datum" ever. Is this one of those generational things like "on accident" vs. "by accident" or regional things like "math" vs. "maths"?

> The word data can be either singular or plural depending on meaning and context. In general usage, data is treated as singular when used as a mass noun to mean “information” and as plural when used to mean “individual facts.” In scientific and academic writing, data is almost always used as a plural noun. In digital technology, data is usually treated as a singular mass noun to mean “digitally stored information.”

While it’s used interchangeably a lot, it’s also based on whether you have a scientific or CS background. My hunch is that the scientific plural usage will eventually largely die out except in very specific situations after a few generations given that software is eating the world.

[1] https://www.thesaurus.com/e/grammar/data-is-or-data-are/

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#59

Post by JumpCrisscross »

vlovich123 wrote: post #58
pc86 wrote: post #55

Earlier quoted context omitted.

I know data is the plural of datum but seeing "these data" instead of "the data" is always so jarring to me. Almost as jarring as seeming anyone use the word "datum" ever. Is this one of those generational things like "on accident" vs. "by accident" or regional things like "math" vs. "maths"?

> The word data can be either singular or plural depending on meaning and context. In general usage, data is treated as singular when used as a mass noun to mean “information” and as plural when used to mean “individual facts.” In scientific and academic writing, data is almost always used as a plural noun. In digital technology, data is usually treated as a singular mass noun to mean “digitally stored information.”…

Huh, didn’t know about that line. I do tend to refer to scientific data plurally, where each datum is meaningless, and technical data singularly.

Re: Chang'e 6 lunar sample return mission returns with samples from moon's far side

#60

Post by mcculley »

gus_massa wrote: post #50
dotnet00 wrote: post #44

Earlier quoted context omitted.

On the Moon you could also use the Moon itself as a heat sink. But yeah, any near-term solutions would use giant radiators.

Solids don't conduct too much heat. I think most of the cooling in a nuclear plant is generated by evaporation of water.

The nuclear plant nearest to me uses sea water, which is put back into the ocean.
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