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Chinese City 'Plans To Launch Artificial Moon To Replace Streetlights' (theguardian.com)
The south-western Chinese city of Chengdu is planning to launch an illumination satellite in 2020 that is "designed to complement the moon at night," though it would be eight times as bright. "The 'dusk-like glow' of the satellite would be able to light an area with a diameter of 10-80km, while the precise illumination range could be controlled within tens of meters -- enabling it to replace streetlights," reports The Guardian. From the report: The vision was shared by Wu Chunfeng, the chairman of the private space contractor Chengdu Aerospace Science and Technology Microelectronics System Research Institute Co (Casc), at a national mass innovation and entrepreneurship event held in Chengdu last week. Wu reportedly said testing had begun on the satellite years ago and the technology had now evolved enough to allow for launch in 2020. It is not clear whether the plan has the backing of the city of Chengdu or the Chinese government, though Casc is the main contractor for the Chinese space program.
The People's Daily was quick to reassure those concerned about the fake moon's impact on night-time wildlife. It cited Kang Weimin, director of the Institute of Optics, School of Aerospace, Harbin Institute of Technology, who "explained that the light of the satellite is similar to a dusk-like glow, so it should not affect animals' routines."
The People's Daily was quick to reassure those concerned about the fake moon's impact on night-time wildlife. It cited Kang Weimin, director of the Institute of Optics, School of Aerospace, Harbin Institute of Technology, who "explained that the light of the satellite is similar to a dusk-like glow, so it should not affect animals' routines."
They plan on using mirrors, and I assume a geo orbit that doesn't get eclipsed by the Earth.
Even if they did get it up there, I doubt it would last long.
Hubble has had all its gyros replaced already and the replacements are failing again.
This is something that needs precise control, every night, continuously. It doesn't have to just point itself somewhere and stay still for a long period of time, it needs to constantly move the mirror to keep the desired spot illuminated as it orbits. That's going to require the gyros and reaction wheels to be on 24/7.
How do you get a mirror that big into geostationary orbit?
Easy. Ask the Russians. They experiomented with this sort of thing in the 1990s.
The mirror deployed successfully, and, when illuminated, produced a 5 km wide bright spot, which traversed Europe from southern France to western Russia at a speed of 8 km/s.[1] The bright spot had a luminosity equivalent to approximately that of a full moon.
https://en.wikipedia.org/wiki/...
Regarding focusing: even with a perfectly shaped mirror, you can't circumvent the fact that the sun is not a point source. Sun diameter D=1.4e+9 m, sun distance L=1.5e+11 m, geostationary orbit distance R=3.6e+7 m. The spot at the earth surface will have a minimum diameter D R/L=340 km, for ideal optics. The claimed diameter of 10 to 80 km is physically impossible from geostationary orbit. They would need to use low-earth orbit, about 1000 km altitude, which would require multiple satellites to illuminate a single town throughout the night.
By the way, the difference between an ideal focusing mirror and a flat mirror is negligible for illumination purposes. For a 200 m diameter mirror, it would add another 0.2 km to the spot size if it's flat rather than paraboloid.
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Or the way many Americans think that all of Mexico is like Tijuana. Or the way many Americans think that Asian = oriental. Or the way many Americans think that there aren't any other free countries in the world (heaven forbid if you should point out some countries that enjoy more freedom than the USA).
In general, Americans are ignorant, uncultured and untravelled rubes.
It says southwestern city not all cities have the smog issue but then you are likely American and geography is your greatest enemy.
I've spent time in Chengdu. Seen the pandas, climbed the scared mountain. Not much of a view any more.
Most of the populated regions of China have terrible air .
You may be thinking of Kunming, further south in Yunnan, which is now the only major city in China with breathable air and blue sky.
And don't call me a Meiguoren.
Come now, as a fellow American, I have to call you out. Our culture is is immature, nieve, rough, stobborn unnecessarily pigheaded, and ultimately hypocritical. Because we are a child nation with guns and a thirst for blood, compared to the rest of the world. It's hardly fair to scapegoat all of Humanity for the limitations of Americans