SpaceX wants to launch one million satellites. Here’s how it could affect the atmosphere and the night sky

Most of humanity has a great tendency to think in the short term, but generally, long-term considerations – air pollution, deforestation and emissions, for example – are not our cup of tea.

This is partly why scientists are so concerned about the recent phenomenon SpaceX proposal To launch a million satellites – data centers – into Earth orbit.

Their concerns range from losing the natural night sky, to losing access to space, to environmental impacts on our atmosphere.

At present, there are roughly 16,000 satellites are orbiting the earthOf which 14,000 are active. SpaceX is responsible for this more than 8,000 Of them.

This number changes weekly as the company deorbits both satellites – where they burn up in our atmosphere. Sends more. On average, the company launches more than two dozen satellites twice a week.

that orbital environment

SpaceX officials have said they would like to see More than 40,000 of these are Starlink satellites In class. Satellites provide Internet connectivity to every part of the world, even the most remote places.

But that’s a lot of stuff in space, and that doesn’t even include the more than 140 million pieces of space debris ranging in size from a millimeter to 10 centimeters. All of these objects pose a threat to astronauts in space, as well as the satellites we depend on for equipment like GPS.

That’s why putting another million satellites into orbit is mind-boggling.

“We saw this transition from thousands of satellites to 10,000 satellites largely through SpaceX. And we were very concerned about maintaining a healthy orbital environment along with it,” said Aaron Boley, co-director of the Outer Space Institute and professor in the Department of Physics and Astronomy at the University of British Columbia.

“It’s completely beyond that. And by almost every metric we can think of, it’s a bad idea in terms of our long-term use and access to space.”

SpaceX has filed its millionth satellite proposal to the US Federal Communications Commission (FCC), citing the need for data centers that will not have an environmental impact on Earth. For example, he said that orbiting data centers would not need to use water for cooling, and noted that the Sun would provide them with nearly constant energy.

Public comments on the plan closed on Friday. At the time of this writing, there were even more 1,000 commentsMost of them asked the FCC not to proceed further.

Another threat to our environment

OK, so what’s the big deal about having so much stuff in space? After all space is big, right?

It’s about the long-term consequences that we think about so badly.

Scientists are concerned as growing evidence shows that rocket launches are affecting our atmosphere by depositing black carbon or soot in the air, which could cause a potential warming effect. increase danger for us ozone layer.

Alois Marais, professor of atmospheric chemistry and air quality at University College London, is working on this Tracking emissions from both launch and reentry. He’s concerned that we’re not discussing the impacts of the thousands of rocket launches required to get those car-sized satellites into space.

“And what are its additional implications?” he asked. “Because it’s actually the mixture of these pollutants that affects the atmosphere.”

The main difference between these pollutants and those produced at ground level by humans is that launches are depositing them directly into the atmosphere.

Recent studies have shown that when satellites reach the end of their lives and burn up upon re-entry, they leave behind metals aluminum and lithium.

Its side effects are not yet known. But this is what worries scientists.

“It’s challenging because we’re doing this type of experiment with the atmosphere when we don’t really know what the outcome will be,” Marais said.

In its FCC filingSpaceX said this would “minimize any atmospheric impacts that would arise from the large number of spacecraft in orbit.” No further details have been provided, however, except that the company says it will move some of the data centers into heliocentric orbit (around the Sun).

That’s good, because a group of astronomers, including John Barrentine, founder of Dark Sky Consulting, has estimated that if every million of SpaceX’s satellites were deorbited, that would mean one satellite would re-enter every three minutes.

access to space

Most people probably don’t think about how often they use satellite communications. But that Instagram post you made? You used a satellite. Are you looking for directions to your friend’s party? You used a satellite. Tapping to pay for that Starbucks latte? You used a satellite.

We use satellites in many ways every day, and the more there are, the more uncertain their use becomes because there is a huge risk of satellites colliding.

Satellites are also threatening how we view space. We already know that satellites are affecting professional observatories both optically and in terms of the electromagnetic radiation they emit. This creates noise, which may interfere with observatories Which depends on the radio frequency.

SpaceX’s FCC filing claims that the satellites will be at altitudes ranging from 500 to 5,000 km. This will affect not only ground-based observatories, but also space-based observatories like Hubble.

For amateurs and casual observers, this means lights that continuously cross our night sky. Look any night and you will surely see a satellite passing by at some point, even over a city. In places with dark skies, it’s even worse, where dozens of sightings can be seen in a single night.

“We’ve got some more detailed simulations that we’re going to include in our FCC comments that suggest that thousands of them could be illuminated at any time, visible in the night sky, which would be bright enough for people to see,” Barrentine said.

The loss of the night sky, which has guided humanity since time immemorial and influenced culture, religion and science, will be immeasurable.

Barrentine also noted that there is a lot they don’t know, as SpaceX hasn’t provided a lot of technical information in its FCC filings.

The company is trying to work with the International Astronomical Union and Center for Dark and Quiet Sky ProtectionIn an effort to reduce the brightness of his satellites, but his proposal to launch one million satellites shocked astronomers.

Barentine said, “I don’t think there was anything covertly involved, but it seems like we abandoned the goodwill we had developed with them over the last several years, then proposed something that at first glance appears to be inconsistent with everything we’ve been talking to them about.”

SpaceX is not the only company proposing to launch large quantities of satellites.

Jonathan McDowell, an astrophysicist and space stability analyst who tracks every launch around the world, estimates that there are proposals from companies and countries (including NASA). China’s two major megaconstellation projects) amounts to 1.7 million satellites.

Now, it’s likely that many of these proposals won’t actually happen, but even half that number would mean a lot of things in the classroom. And it has consequences that affect everyone.

“Even when you go to dark places around Earth, away from your urban or suburban environments, the sky won’t be that dark. And there’s no escaping that,” said Bole, co-director of the Outer Space Institute.

“It really has a global impact. So these launches affect everybody.”