What are artificial moon plans of China?

China is planning an artificial moon over the city of Chengdu, in Sichuan province, by 2020. The aim of this initiative is to provide an alternative means of street lighting and save on electricity.

How it is being done?

• The artificial moon would be a mirror orbiting Chengdu at a height of 500 km.
• This moon would reflect the sun’s light at night, and supplement street lighting in Chengdu.
• The artificial moon would illuminate the area of diameter between 10-80 km.
• This lighting by artificial moon is estimated to cause a saving of an estimated 1.2 billion yuan ($170 million) a year in electricity costs for Chengdu.

Challenges being faced:

• The mirror would be placed at an altitude of 500m. Arriving at the small enough diameters would be key. Also if the angle of reflection is missed by even few degrees the illumination would be at miles away.
• The glow may affect the daily cycle of animals and plants, and even affect the human circadian system.

Earlier initiatives:

A similar attempt was made by Russia in 1993 when it had deployed a plastic mirror Znamya 2 with a diameter of 65 ft. It reflected a narrow beam of light and astronauts on the then space station Mir reportedly filmed a patch of light on the surface. Russia launched Znamya 2.5, six years later, which was a larger mirror. But it was not deployed properly and failed.