Giant mirrors in space to reflect sunlight at night? No thanks, astronomers say

Imagine this: You’ve worked a long shift, turned off the lights, and lay in bed, when suddenly the sky outside your window shines like it’s daylight.

If the American company has its way, this is what can happen.

mirrored orbital “Considering sending giant mirror into space”sell sunlight after dark,

This is such a plan Cause for concern among astronomers Those who are already concerned about the loss of the night sky due to satellite constellations – hundreds to thousands of satellites from a single company, often provide Internet services – and overall light pollution.

But the California startup says their plan could help solve energy issues as well as provide lighting for disaster rescue plans and other situations.

Astronomers aren’t buying it.

Aaron Boley, an astronomer and associate professor at the University of British Columbia, said there are “fundamental misunderstandings or deliberate misrepresentations” on the company’s website.

“They were talking about reducing light pollution by having this huge light from space. And really it seems like they’re trying to suggest that because it’s natural sunlight, It’s not like pollution,

Company – which filed a request The US Federal Communications Commission is about to launch its first satellite, EARENDIL-1 – which is proposing to use satellites to broadcast reflected sunlight to specific locations such as solar farms after the sun sets.

Reflect Orbital has proposed a few different sizes of satellites, ranging from 10 x 10 metres, 18 x 18 metres, and even 54 x 54 metres.

But even at peak size, some experts say that to provide enough sunlight to a solar farm, thousands of satellites would be needed.

“For example, if you want to see the midday sun, you’ll need a mirror that – from the ground – looks the same size as the sun in the sky,” said Michael Brown, associate professor of astronomy at Monash University in Melbourne, Australia.

“When it’s in orbit it’s several kilometers across. Now, nobody would launch a mirror several kilometers away, so what they do is they launch many smaller mirrors. And Reflect Orbital is talking about a 54-meter-square mirror. And to produce just 20 percent of the afternoon sun, it looks like you need about 3,000, possibly more of these mirrors.”

Reflect Orbital did not respond to requests for comment on this story.

no new concept

The idea of ​​a space mirror is not new, having been first proposed in 1920s. Russia deployed on 4 February 1993 Znamya 2A space mirror with a diameter of 25 metersEventually a bright spot of five kilometers was produced. A few days later, it burned down in Canada.

America and European Space Agency have also made such proposals, although no proposal has come forward yet. Some people say this is because it is not possible.

So why is it still so attractive?

“With the proliferation of objects in orbit, there is a mentality that if you can do something from space, you should do something from space,” Bole said. “And I think that’s the inspiring part of this idea.”

He explained that for the mirrors to work, the satellites would have to be in a polar orbit – like a ring moving from the south to the north poles. This will place satellites directly over Canada.

“It’s another issue like flashing lights when you don’t want it there … so because we have this sun-synchronous design, we’ll have these satellites spread out across Canada as twilight approaches,” he said. “And so Canada needs to be very vocal about this.”

consequences

Reflect Orbital estimates that the light generated by its mirrors will extend for several kilometers.

There are concerns that this could affect not only people who do not want the light, but also wildlife.

John Barrentine, founder of Dark Sky Consulting, said much remains unknown about the technical details of Reflect Orbital. However, he said, information the company has disclosed suggests it may have unintended consequences.

“These objects will appear like very bright stars in the sky, moving slowly, as seen from potentially hundreds of miles or kilometers away from the location on the ground where the light is visible,” he said.

“This is happening at a time when the world is dark. (Animal) biology expects conditions around them to be dark. I’m a little concerned that if you have, let’s say, a migratory bird – which we now know are navigating through the stars at some level – then that could be very disorienting.”

Again, there are implications for observatories, both professional and amateur.

“Reflect Orbital says we’re certainly not going to illuminate your observatories, but if I have bright objects that look like stars in the sky where the beam is reaching the ground, if that’s somewhere close to the observatory, that’s still a problem,” Barentine said.

Monash University’s Brown is also concerned about unintended radio interference from satellites. Recently it was revealed that SpaceX’s Starlink satellites are creating noise in radio observatories,

But there is more that troubles him.

He said, “I’m also more concerned with, strangely enough, I would say in a way, almost from an aesthetic point of view. I like the sky to be like this shared forest.”

“If you go somewhere where it’s nice and dark and look at the night sky and are constantly reminded about technology, I think that’s a bit of a loss.”