In a purge directed at the noble workers who maintain street lights, an institute in Chengdu proposes to shine some sunlight on the city’s streets at night. They reckon that sending up a satellite to an altitude of 500 km to illuminate a circle with a radius of about 80 km with a mirror reflecting sunlight would be cheaper than maintaining the city’s lighting system. Do the numbers add up? Financially, yes — because sunlight is free, the high cost of a launch would be offset over time. But in terms of space science, perhaps the Chinese government was wise not to claim oversight of this project. To remain over Chengdu, a geostationary satellite would have to be about 35,000 km up.
At that distance, angular control matters. If the mirror is a tiny fraction off true, it would illuminate Chongquing instead of Chengdu. And even if it stayed true, the kind of granular control claimed by the project’s promoters may not be possible. They have said that they would be able to control the degree of sunlight falling at night by changing the angle of the mirror. However, the degree of mechanical accuracy required may not be feasible, in which case Chengdu would be lit up all night. That might reduce the crime rate, but would play havoc on the circadian rhythms of citizens. The effects are predictable only to the extent that they are unpleasant.
But look on the bright side: The Chinese propose to turn night into day. That’s a god-like ambition, even if it’s happening in a god-purged country. It is Promethean with Chinese characteristics. It is a modern instance of a very old dream — to control nature and its elements, and to bend them to the human will. Now, if that mirror would just hold still.