A new and innovative project to replace street lights in the city of Chengdu, China is underway. Scientists from the Tian Fu New Area Science Society, the organisation responsible for the project, are testing a satellite to act as an artificial moon reflecting sunlight back to Earth. The first ‘moon’ is planned to be launched by 2020 with three more to follow by 2022 based on the pilot’s success. By lighting up a total area of 50 miles across, $173 million USD is expected to be saved annually.
Its expected brightness will be eight times that of the original moon at an orbit of 500km however it still wouldn’t light up the entire night sky. Instead, the overall brightness is believed to be “around one-fifth of normal streetlights” according to Wu Chunfeng, Chief of the Tian Fu New Area Science Society. One benefit is that it will be able to assist rescue efforts in disaster zones during blackouts.
However, further testing and development needs to be conducted as its effects on nature are still unknown. Nature often increases its activity in reaction to light stimuli. For instance, hundreds of coral species in the Great Barrier Reef release eggs and sperm in an annual spawning event linked to the brightness of moonlight. Albatrosses fly more frequently and for longer periods of time under a full moon perhaps due to greater vision. Thus, additional moons could result in unforeseen consequences that affect ecosystems, how they work and their biological clocks. Wu has stated that testing will be conducted in an uninhabited desert to determine whether any detrimental effects will occur as a result.
Still, there remains some unanswered details about the satellite including its exact height, size and light intensity. Furthermore, if the satellite is to only cover the city of Chengdu, it must orbit the earth at a distance of 36000km to revolve at the same speed and direction thus appearing stationary. This is in contradiction to reports of a 500km orbit.