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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

#101

Post by Dalewyn »

darkwater wrote: post #68
pc86 wrote: post #53

Earlier quoted context omitted.

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.

So if it's "us" it's good, and if it's "them", it's bad?

At the end of the day? Yes. No, the world ain't fair.

Whoever makes a permanent presence on the Moon first gets to decide what everyone else can do there.

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

#102

Post by Quasimarion »

scoot wrote: post #3

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

Checkout this paper:

https://www.sciencedirect.com/science/article/pii/S254243512...

Takeaway: The samples indeed are very different.

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

#104

Post by elzbardico »

photochemsyn wrote: post #14
JumpCrisscross wrote: post #4

Earlier quoted context omitted.

> nuclear power plans by Russia not so much Why? Any lunar base without nuclear power plans is not a serious effort.

Solar 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 the…

You'll need a massive amount of batteries for solar night. People severely over-estimate battery storage.

Even on earth, giant grid-scale storage system are not able to supply all the power for region they serve alone for more than some 4 or 6 hours. In the moon, they would have to supply power for some two weeks.

Battery storage is not a real solution on earth, it is even less plausible in the moon.

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

#105

Post by somenameforme »

JumpCrisscross wrote: post #32
somenameforme wrote: post #30

Earlier quoted context omitted.

The 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.

> 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.

I 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_ge...

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

#106

Post by orbital-decay »

mturmon wrote: post #89
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…

Here's an article on DIMES, the system JPL developed in the early 2000s to address the problem of estimating horizontal velocity for the Mars landers: https://robotics.jpl.nasa.gov/media/documents/DIMES-ai-space... Martian winds make this more important there than on the Moon. The DIMES system integrates radar, visual images, and IMUs. They did not have a dedicated Doppler radar for horizontal velocity, for technical…

ALHAT/LVS problem seems to be the overly broad requirements, it's overengineered (hence the modularization in LVS) which led to long delays during the development. For comparison, Chang'e 3 TRN solution was dead simple, it was roughly speaking a webcam combined with the specific lighting angle during the landing. Then they iterated on it in subsequent missions, creating a decent system that was less dumb and restrictive than the original.

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

#107

Post by somenameforme »

floxy wrote: post #82
itishappy wrote: post #42

Earlier quoted context omitted.

> And this, so far as I know, is a completely unexplored question. To date, no mammals have given birth in space. We sent pregnant mice and had them return to Earth to give birth, and we've sent mouse zygotes and grown them in space, but no birth!

Mice in space: https://www.youtube.com/watch?v=q7lgj3aZ8dU

That video is awesome. This [1] seems to be a pertinent paper. One thing I don't understand is why we intentionally limit the experiments. Having male + female and then running the experiment through generations seems like it would be vastly more informative. For instance that 'race tracking' behavior around the cage, only seemed to emerge in young mice. What sort of new behaviors, adaptions, etc will emerge in the first generation born entirely in low g?

Or perhaps even the 2nd generation could be even more telling. Why not simply run the experiment until they all die off, or go full Malthus? Another interesting idea would be to create a faux terrarium type enclosure instead of a plain cage. Would the mice exhibit a bias towards the "ground"? And also it's kind of odd that none of the studies thought to include a lens wiper for their cameras after the first one demonstrated the problem. In 0g, various 'matter' ends up getting stuck on the camera lens, increasingly trending towards 0 visibility.

[1] - https://www.nature.com/articles/s41598-019-40789-y

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

#108

Post by jimbobthrowawy »

pavel_lishin wrote: post #88
standardUser wrote: post #80

Do 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.

Yep, the latest NASA lander is dropping samples in containers meant to be picked up by a later mission: https://www.nasa.gov/news-release/nasa-sets-path-to-return-m...

There's also a sample container inside the rover intended to be sent back. The cached samples exist so that more can be taken, and so it's still possible to get samples if the sample container in the rover fails to open for some reason.

The initial plan for retrieval involved Roscosmos and ESA, but that's been called off for now. So they need some new plans. My favourite part of their initial sample return plan was the decision to not use a parachute to land it on earth, since they couldn't be sure one wouldn't fail.

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

#109

Post by SaulGoogman »

scoot wrote: post #3

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

I just learned it on the radio on my way to work this morning.

The last sample reveals something about the surface of the moon.

The sample this time is from a big, deep hole created by a heavy hit which penetrated into the core of the moon, thus reveals the internals of the moon.

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

#110

Post by SaulGoogman »

HenryBemis wrote: post #40
scoot wrote: post #3

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

I was thinking about "what have they found there?". I remember reading that the Central Bank of China was feversly buying Gold, and a few weeks ago they stopped all buying. Then this came to focus, and it made me think... did they find 100 tons of Gold up there, and they know that if they start bringing this in (on Earth) they price will plummet, and expect a massive sell-off in the next few weeks??? But then I do re…

In that case, this destination should be Venus, 'cos it's Chinese name is Gold Planet, if translated back to English literally.
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