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Tuesday, 23 October 2018

Chinese company to mount Artificial moon

A company in China is planning to launch an artificial moon, to help in lighting up the streets of China.

Last week, Chinese media reported plans

by a private institute to launch an

“artificial moon” over the city of

Chengdu, in Sichuan province, by 2020.

The objective is to provide an alternative

means of street lighting and save on

electricity. Since then, the idea has not

only received wide coverage (including

in The Indian Express, October 19) but

also been viewed with some skepticism.

What is known so far

Information about the project has so far

been incomplete. People’s Daily Online,

the first to report it, said the artificial

moon would be a mirror orbiting

Chengdu at a height of 500 km. It would

reflect the sun’s light at night, and

supplement street lighting in Chengdu,

which has a population of 1.6 million.

People’s Daily Online reported that the

artificial moon’s brightness will be

around eight times that of the moon,

while China Daily reported that the

brightness would be a fifth of a

streetlight’s. The People’s Daily Online

report said the moon would illuminate

an area of diameter between 10-80 km. If

the illuminated area is 50 sq km, an AFP

report said, it would save an estimated

1.2 billion yuan ($170 million) a year in

electricity costs for Chengdu.

If the experiment proves successful, two

more such moons could be sent up by

2022, according to the China Daily report,

which quoted Wu Chunfeng, chairman of

Chengdu Aerospace Science and

Technology Microelectronics System

Research Institute Co Ltd, and head of

Tian Fu New Area Science Society that is

handling the project.

What Chinese media did not clarify is

whether the project has the official

backing of the government. Various other

publications reported that they could not

confirm the project independently with


The challenges

At an altitude as low as 500 km, and

considering a diameter small enough to

be economically viable, accuracy is key.

Missing the angle of reflection by even a

few degrees would miss Chengdu by

miles, a scientist has reportedly said. “If

you want to light up an area with an

error of say 10 km, even if you miss by

one 100th of a degree you’ll have the

light pointing at another place,” BBC

quoted Dr Matteo Ceriotti, a lecturer in

Space Systems Engineering at the

University of Glasgow, as saying.

Again, there must be sufficient glow, but

if this glow covers a large area, it could

potentially affect the daily cycle of

animals and plants, and even affect the

human circadian system — the body

clock. “Many people are in a circadian

fog where our physiology is confused,”

Richard Stevens, a cancer epidemiologist

at the University of Connecticut School of

Medicine, told The New York Times.

Is it possible?

The idea to have a satellite reflect light at

night isn’t new. In 1993, Russia sent up

Znamya 2, a plastic mirror with a

diameter of 65 ft. It managed to reflect a

narrow beam of light, and astronauts on

the then space station Mir reportedly

filmed a patch of light on the surface.

“The two-and-and-half-mile-wide beam

traveled for about eight minutes across

part of the Atlantic Ocean and then

across Europe, including Russia,” The

NYT reported in 1993. For people on the

ground, the light was seen as pulses from

a star-like object.

Six years later, Russia launched Znamya

2.5, which was meant to be a larger

mirror, but it did not deploy properly.

The idea of sending up a giant mirror in

the sky died with it. Until now.

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