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China wants to put a solar farm in space by 2025

engadget.com

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Re: China wants to put a solar farm in space by 2025

#31

Post by adrianN »

Shivetya wrote: post #17
AstralStorm wrote: post #10

Earlier quoted context omitted.

1) It is not much more efficient due to transmission losses. (Compared to high voltage DC.) 2) The costs, on top of super expensive solar panels, make this totally pointless economically. Solar panels are hard enough to maintain on Earth. 3) It's a multi gigawatt level microwave gun in space. Want to blast some lightning onto someone? Sure, now you can. Or fry it.

The costs just to put the materials up there makes me wonder the long term viability of just trying to source it from the moon. By the time you are willing to spend the billions required it cannot be much more of step and provides other uses. still I have to agree, how do you even maintain something like this. it would probably lead to a full time presence in space unless robotics become just that good. I just don't…

I'd guess you maintain it by replacing the satellites. We're pretty good at maintaining satellites by replacement.

Re: China wants to put a solar farm in space by 2025

#32

Post by Gravityloss »

AstralStorm wrote: post #13
porpoisely wrote: post #9

Earlier quoted context omitted.

Do they need to? I wonder how feasible it would be to put large computational centers in space and have space solar farms powering these computational centers. So if we want to test complex or long-running programs/models/algos, we can just beam it to the computational centers orbiting earth and wait for the results when it's finished.

How do you cool them in space?

Radiators. Need pretty big ones if the computers want to run cool.

Probably would be better to manufacture most of the stuff on some asteroid or on Mercury and have the computation radiation shielded by a significant mass.

Re: China wants to put a solar farm in space by 2025

#33

Post by audunw »

dexen wrote: post #25

A doomsday weapon in space. As the article mentions, the station will beam the collected energy down to Earth. Whether in visible light, microwave or any other spectral band, it will need two things for everyday operations: - ability to point the beam at an arbitrary point on Earth, to track the collector ground installation, and - ability to focus the beam to proper size The second capability is crucial; if it's fix…

> with little to no countermeasures available.

In the short term, maybe. But it wouldn't take much time to put in place comprehensive defense for such a system.

In a world with ICBMs, a weapon like this is not really something I'd be worried about. It'd be a pretty stupid weapon to use for an initial attack

The only thing I'm worried about is accidents or hacks.. if that's made impossible it should be fine

Re: China wants to put a solar farm in space by 2025

#34

Post by GistNoesis »

I did a quick search on the Energy Returned on Energy Invested calculations. The following site https://dothemath.ucsd.edu/2012/03/space-based-solar-power/ gave an ERoEI of 10:1 for solar panels on earth vs ERoEI of 4.2:1 for solar panels in space. Which would indicate that we would still be better laying solar panel on the ground as long as we got the appropriate empty space.

What did I missed? Have we realized enough progress since 2012 energy-wise, that the threshold has been crossed, or does it only make sense economically due to lower launch prices.

Re: China wants to put a solar farm in space by 2025

#35

Post by fouronnes3 »

fredley wrote: post #30

With regards to climate change and global warming, what about putting this in between the sun and the earth to block some of the energy reaching the planet to allow it to cool?

aka geoengineering. The latest IPCC report is quite critical of it.

Re: China wants to put a solar farm in space by 2025

#36

Post by gotocake »

adrianN wrote: post #29
dexen wrote: post #25

A doomsday weapon in space. As the article mentions, the station will beam the collected energy down to Earth. Whether in visible light, microwave or any other spectral band, it will need two things for everyday operations: - ability to point the beam at an arbitrary point on Earth, to track the collector ground installation, and - ability to focus the beam to proper size The second capability is crucial; if it's fix…

It's a pretty shitty weapon because many countries have the capability to launch a bomb to the satellites and the satellites are way more expensive than the bomb.

Depending on how close it is, you could destroy or at least damage the sattelite without even needing to launch anything. As a weapon, it would be downright silly to threaten a major world power with it. Of course if your goal is just to terrorize countries and groups without a space program, and assuming (big assumption granted) that other countries don’t interfere, then it would be a fairly exotic way of terrifying people. VERY expensive though, and diverting it from power generation to “kill” mode would be even more expensive.

All told, a country that could use this as a weapon doesn’t need to use this as a weapon.

Re: China wants to put a solar farm in space by 2025

#38

Post by rurounijones »

adrianN wrote: post #29
dexen wrote: post #25

A doomsday weapon in space. As the article mentions, the station will beam the collected energy down to Earth. Whether in visible light, microwave or any other spectral band, it will need two things for everyday operations: - ability to point the beam at an arbitrary point on Earth, to track the collector ground installation, and - ability to focus the beam to proper size The second capability is crucial; if it's fix…

It's a pretty shitty weapon because many countries have the capability to launch a bomb to the satellites and the satellites are way more expensive than the bomb.

And this is how we end up with https://en.m.wikipedia.org/wiki/Kessler_syndrome

Re: China wants to put a solar farm in space by 2025

#39

Post by mooreds »

entity345 wrote: post #23
AstralStorm wrote: post #10

Earlier quoted context omitted.

1) It is not much more efficient due to transmission losses. (Compared to high voltage DC.) 2) The costs, on top of super expensive solar panels, make this totally pointless economically. Solar panels are hard enough to maintain on Earth. 3) It's a multi gigawatt level microwave gun in space. Want to blast some lightning onto someone? Sure, now you can. Or fry it.

> Solar panels are hard enough to maintain on Earth. Isn't the main issue that they get dirty, though?

I think they just degrade the same way they do on Earth. This PDF from 2003 talks about a 0.5% yearly degradation, which, if I recall correctly, is similar to ground based pv.

https://www.google.com/url?q=https://ntrs.nasa.gov/archive/n...

Re: China wants to put a solar farm in space by 2025

#40

Post by thinkcontext »

fatjokes wrote: post #19
AstralStorm wrote: post #13

Earlier quoted context omitted.

How do you cool them in space?

Do you need to? Without enough gas in space, how likely is it for something even as powerful as a data center to overheat?

You have gotten it exactly backwards. Vacuum is a great insulator, getting rid of waste heat is a huge problem in space.
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