Going out on a moonlit night is watching the dark print back. The reflected sunlight from our natural satellite under…
Going out on a moonlit night is watching the dark print back. The reflected sunlight from our natural satellite under an almost full moon is sufficient to glue the night landscape in silver and allow even human eyes to penetrate the gloom. But we can always do it better, right? If a moon is good, it’s probably two even better.
A Chinese scientist thinks it at least. Wu Chunfeng, director of the Tian Fu New Area Science Society, wants to use a satellite as an artificial moon reflecting sunlight back to targeted areas of the earth at night. The reflector would cross a city, providing enough lighting to replace light on the ground with a steady light and potentially saving on electricity costs.
He represents a shining satellite as unfurling in space about 300 miles above the ground and orientates itself towards cities on the ground. It would suffice to light up about 5o square kilometers, according to China Daily and several works in the concert could light up to 4,000 square kilometers. Wu says that the first will be ready to start 2020, and another three years in 2022, although the details of the project remain largely unknown.
The plan may not be all that sounds, but according to satellite experts. Based on the sharp details available, the satellite would probably never work, “said Ryan Russell, Associate Professor of Space Engineering at the University of Texas, Austin.
The biggest lack? A satellite flight that is low enough to deliver so much light would not be able to stay in one place.
“Their requirement of 1
LEO at [300 miles] must be a typo or misspelled spokesman,” Russell said in an email. “The article I read meant that you could float a satellite over a certain city, which of course is not possible.”
Satellites that stand over a fixed point on earth, called a geostationary orbit, are far further away 38,000 miles. At that distance, the reflective surface would have to be massive to provide enough light for people to look back to earth. At a distance of just 300 miles, the moon would whip around the earth for thousands of miles per hour and shine the light in one place in just a fraction of a second.
You can keep an artificial moon in place with rocket guns, says Iain Boyd, Professor of Space Engineering at the University of Michigan, but it would eat fuel, increase costs and demand constant refueling.
A constellation of satellites that circulate the earth would be necessary to keep the lights on all night, weighing reflective tasks to each other as they passed overhead. And even then, fuel is necessary to counteract the small atmospheric dragon, even in low paths above the ground. The international space station revolves around 250 miles and has to be constantly increased back to its orbit as it slows down due to drag.
The cost of starting and firing multiple satellites would likely exceed the savings on electricity, at least for the moment.
It is also the question of whether we want a city light nightlight in the first place. Some cities around the world are already trying to lighten contamination, which makes the nights darker, not brighter. Excessive nightlight abuses the operation of nocturnal animals, blocks the stars and can also interfere with our circadian rhythms and affect health.
If we really need better light solutions, it might be better to focus on more terrestrial alternatives, Russell says.
“It’s a very complicated solution that affects everyone to a simple problem that affects some. It’s easy contamination on steroids, he says.” And they illuminate the entire surface while headlights only shine on the streets that must be lighted. Imagine whole generations of people living in the same neighborhoods that never see the stars at night? “