China's Space Program News Thread

[Anlsvrthng]

Bright night sounds good, but light comes with heat, heat raise temperature which destroy the natural circle of cool/warm of a day, this will destroy the planet.

Street light does it but in much smaller scale, but an artificial moon will do worse, I have to say that whoever comes up with this idea is an idiotic "genius", similar to launching oneself into the space naked. Or like digging a hydraulic dam using a nuclear bomb.

if China manage to use a square km mirror ( unrealistically big) then they can inject the equivalent if on 365 square km the snow melt 1 day earlier.

Or change it by another way, if a farmer make a forest on a corn field then each square km will absorb this magnitude of energy like the net energy of one of the solar mirrors.

 

[taxiya]

You are blowing this way way out of proportion. This will only light up an area of 10 to 80 km. About a size of a city.

So, no, it won't destroy the planet.

then every city on the planet will try to do ONLY that, how many square kilometers will that be, you do the math. Ever heard of the term Urban heat island?

No single act would destroy anything, tens of thousands of it will be able to destroy anything.

 

[Faithlock]

then every city on the planet will try to do ONLY that, how many square kilometers will that be, you do the math. Ever heard of the term Urban heat island?

No single act would destroy anything, tens of thousands of it will be able to destroy anything.

LOL, why are you insisting on blowing this way out of proportion?

Where did you see any other city in the world that would want (or have the resource) to do this?

This is only about one city, the city of Chengdu.

This is not going to change the world. This is just to enrich the city of Chengdu, that is all.

 

[Insignius]

Anyone here read Liu Cixin's "Sun of China"?
Really sounds like it. Maybe long term plan is to use it to reflect and focus sunlight to power solar power farms around the clock, and next step would be weather manipulation to combat droughts. And perhaps in the future (and if necessary), China can weaponize it.

 

[Faithlock]

Anyone here read Liu Cixin's "Sun of China"?
Really sounds like it. Maybe long term plan is to use it to reflect and focus sunlight to power solar power farms around the clock, and next step would be weather manipulation to combat droughts. And perhaps in the future (and if necessary), China can weaponize it.

All had been studied before.

Focus sunlight to redirect to the earth's solar power farms. The economy doesn't work. Way too expansive to get the satellites up there. To make it into a power plant, you need a lot of solar panel (on orbit). Thus, you need BIG satellite. way too expansive to get those big satellite to orbit.

Weather manipulation. The science is not there. Even though it might not be a bad idea to start doing some limited scale experiments.

Weaponize it? That is Ronald Reagan's "Star War". Weapon satellite collect power from sunlight. Convert it to laser to shoot down ICBMs. It was not successful. But I believe the research is still going on.

There are also power beaming. It is on-going research. The satellite collects the power from sunlight. It then converts the energy and "beam" this energy down to earth using radio frequency. They are still doing research on this. But the result of this work had already give rise to the commercial sector, wireless charging of your mobile phone.

 

[taxiya]

LOL, why are you insisting on blowing this way out of proportion?

Where did you see any other city in the world that would want (or have the resource) to do this?

This is only about one city, the city of Chengdu.

This is not going to change the world. This is just to enrich the city of Chengdu, that is all.

Strange way you put it this way. Instead of me blowing it out of proportion, I think you missed forest by only looking at the tree.

Before I put my thoughts forward, I will state that using "Chengdu" in the argument is misleading, it is more appropriate to say some people who come up this idea. Using Chengdu may be offending. That said, I will use "Chengdu" with quotation marks for the sake of avoiding confusion.

1. If no other city in the world want to do it, isn't it something wrong with "Chengdu" thinking it? Or you are saying all human being outside "Chengdu", be it Chinese or Foreigners are all stupid?
2. Does "Chengdu" or any single city has such resources to do so? Does it have the rocket and satellite platform?
   
3. If it benefit "Chengdu", why do you think other cities in the world won't want it too?
4. What makes one city able to launch an satellite this size? It is NEVER a project that a city can do. It is a national one. So in this case, if China is doing it, why would China ONLY doing it for "Chengdu"?
5. What country in this world is going to enrich JUST ONE city using the whole nation's resources? Who in China is going to allow that to happen? Who on earth is going to allow same thing to happen?

 

[Faithlock]

Strange way you put it this way. Instead of me blowing it out of proportion, I think you missed forest by only looking at the tree.

Before I put my thoughts forward, I will state that using "Chengdu" in the argument is misleading, it is more appropriate to say some people who come up this idea. Using Chengdu may be offending. That said, I will use "Chengdu" with quotation marks for the sake of avoiding confusion.

1. If no other city in the world want to do it, isn't it something wrong with "Chengdu" thinking it? Or you are saying all human being outside "Chengdu", be it Chinese or Foreigners are all stupid?
2. Does "Chengdu" or any single city has such resources to do so? Does it have the rocket and satellite platform?
   
3. If it benefit "Chengdu", why do you think other cities in the world won't want it too?
4. What makes one city able to launch an satellite this size? It is NEVER a project that a city can do. It is a national one. So in this case, if China is doing it, why would China ONLY doing it for "Chengdu"?
5. What country in this world is going to enrich JUST ONE city using the whole nation's resources? Who in China is going to allow that to happen? Who on earth is going to allow same thing to happen?

You are seeing neither the tree nor the forest.

This project, if successful, will be very controversial. The world community will not allow this project to be expanded to more than a few cities.

Your position is this will increase the temperature (tree) and will destroy the planet (forest). LOL. No and No.

 

[taxiya]

You are seeing neither the tree nor the forest.

This project,(1) if successful, (2)will be very controversial. The world community will not allow this project to be expanded to more than a few cities.

Your position is this will increase the temperature (tree) and will destroy the planet (forest). LOL. No and No.

If you agree that a) it is very controversial and b) the world will not allow it to expand (which are my main points), then what are you arguing about?

If it is controversial, why do you think that ONE city would be able to do so without approval from Beijing?

 

[pipaster]

China to launch a test gravitational wave detecting satellite be end 2019 as a precursor to a three satellite system Tianqin

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[Faithlock]

My final thought on the "China's Artificial Moon" project.

Frankly, I didn't want to write this because I just don't think it is that big of a deal. But based on the consistent questioning from taxiya, I am going to write down what I think about this project.

First of all, all the information I have is on one article. There are virtually zero technical information. That means I have to work backward. What will I do if I am the main designer?

First, the satellite has to have access to sun light at all time, thus it will be on a Sun Synchronous Orbit. Next, you don't want to have the satellite too high up (therefore lose the intensity), thus you want it to be on a Low Earth Orbit. The article said that the orbit will has the altitude of 500km. Thus, a period of about 100 minutes. My rough order of magnitude guess will be that the city of Chengdu will get to see this "Artificial Moon" about 40 or 45 minutes every 100 minutes.

I can see two design approaches.

The first approach is to use a big-ass concave mirror to reflect the sun light directly to the city of Chengdu. This design is conceptually simple. But it has a big challenge. The gimbals to point the mirror to Earth will be of similar design to that of antenna gimbals system for communications satellites. Depends on eventually how big this mirror will be, the gimbals will have to move this big-ass mirror about 160 degree over a period of 45 minutes. I don't think there are any existing antenna gimbals system that have remotely the same kind of requirements (assuming the mirror is very heavy).

There is also the problem of tracking and acquisition of the mirror pointing system. There is no feedback signal to tell the mirror gimbals system how far off it is to the intended target. To compensate it, it will need a separate communication system. But that will increase the complexity of the overall system significantly.

The second approach is to use a diffused laser system. In this approach, the satellite has normal solar panels, except it has a lot of them. The solar panel collects sun's energy and converts it to electricity. The lasers again converts the electricity back to light and target it back to earth. The laser's beamwidth is probably too narrow, thus you would need a diffuser. The diffuser increases the beamwidth of the laser so that the light footprint on earth is between 10-80 km.

Again, this approach will also need to solve the problem of tracking and acquisition. A separate communications system will be needed.

The second approach provides a lot more control over the first approach (you can control the laser beamwidth, intensity, etc.), but is very inefficient (two conversions, one is light to electricity and the second one is electricity back to light).

For the above two approaches, there are significant technical challenges.

For the first approach, I don't know anybody has ever built a antenna gimbals that can move a very heavy antenna (or mirror in this case) with such angular velocity. The result of this work will definitely significantly improve the design of future weather satellite or spy satellite in China.

For the second approach, it is very rare to put lasers in space.The world only has a few programs. And they are usually for space communications systems or weapon systems. Any time you connect laser and space, you are talking about either super high speed communications systems (or super long distance communications systems) or space weapon systems. If China go with this route, it would definitely help China improve future communications and/or weapon systems.

(more to follow)