I'm outside at my rural Saskatchewan farm, chatting with my neighbors who
I've invited over to appreciate the night sky through my telescope. After
exclamations and open-mouthed wonder over Saturn's rings, and light that has
been traveling through space for more than two million years to reach our
eyes from the Andromeda Galaxy, our conversation inevitably turns to the
pandemic, our work-from-home arrangements and complaints about rural
internet. My neighbor casually mentions they've just switched to using
Starlink for their internet provider.
I glance up and notice a bright satellite moving across the sky, almost
certainly a Starlink, since they now make up almost half of the nearly 4,000
operational satellites and they're extremely bright. I take a deep breath
and carefully consider how to discuss the substantial cost that we're all
going to have to pay for Starlink internet.
I don't blame my neighbors for switching. Here, as in many rural parts of
North America, there aren't great internet options, and with many people
working and taking classes from home during the pandemic, anything that
makes life easier is immediately accepted.
But I know exactly how high this cost could be. My paper, forthcoming in The
Astronomical Journal, has predictions for what the night sky will look like
if satellite companies follow through on their current plans. I also know
that because of the geometry of sunlight and the orbits that have been
chosen, 50 degrees north, where I live, will be the most severely affected
part of the world.
With no regulation, I know that in the near future, one out of every 15
points you can see in the sky will actually be relentlessly crawling
satellites, not stars. This will be devastating to research astronomy, and
will completely change the night sky worldwide.
The future is too, too bright
In order to find out how badly the night sky is going to be affected by
sunlight reflected from planned satellite megaconstellations, we built an
open-source computer model to predict satellite brightnesses as seen from
different places on Earth, at different times of night, in different
seasons. We also built a simple web app based on this simulation.
Our model uses 65,000 satellites on the orbits filed by four
megaconstellation companies: SpaceX Starlink and Amazon Kuiper (United
States), OneWeb (United Kingdom) and StarNet/GW (China). We calibrated our
simulation to match telescope measurements of Starlink satellites, since
they are by far the most numerous.
Starlink has so far made some strides toward dimming their satellites since
their first launch, but most are still visible to the naked eye.
Our simulations show that from everywhere in the world, in every season,
there will be dozens to hundreds of satellites visible for at least an hour
before sunrise and after sunset. Right now, it's relatively easy to escape
urban light pollution for dark skies while camping or visiting your cabin,
but our simulations show that you can't escape this new satellite light
pollution anywhere on Earth, even at the North Pole.
The most severely affected locations on Earth will be 50 degrees north and
south, near cities like London, Amsterdam, Berlin, Prague, Kiev, Vancouver,
Calgary and my own home. On the summer solstice, from these latitudes, there
will be close to 200 satellites visible to the naked eye all night long.
I study orbital dynamics of the Kuiper Belt, a belt of small bodies beyond
Neptune. My research relies on long time-exposure, wide-field imaging to
discover and track these small bodies to learn about the history of our
Solar System.
The telescope observations that are key to learning about our universe are
about to get much, much harder because of unregulated development of space.
Astronomers are creating some mitigation strategies, but they will require
time and effort that should be paid for by megaconstellation companies.
Unknown environmental costs
Starlink internet might appear cheaper than other rural options, but this is
because many costs are offloaded. One immediate cost is atmospheric
pollution from the hundreds of rocket launches required to build and
maintain this system.
Every satellite deployment dumps spent rocket bodies and other debris into
already-crowded low Earth orbit, increasing collision risks. Some of this
space junk will eventually fall back to Earth, and those parts of the globe
with the highest overhead satellite densities will also be the most likely
to be literally impacted.
Starlink plans to replace each of the 42,000 satellites after five years of
operation, which will require de-orbiting an average 25 satellites per day,
about six tons of material. The mass of these satellites won't go away—it
will be deposited in the upper atmosphere. Because satellites comprise
mostly aluminum alloys, they may form alumina particles as they vaporize in
the upper atmosphere, potentially destroying ozone and causing global
temperature changes.
This has not yet been studied in-depth because low Earth orbit is not
currently subject to any environmental regulations.
Regulating the sky
Currently, low Earth orbit, where all of these satellites are planned to
operate, is almost completely unregulated. There are no rules about light
pollution, atmospheric pollution from launches, atmospheric pollution from
re-entry, or collisions between satellites.
These megaconstellations might not even be financially viable over the long
term, and internet speeds may slow to a crawl when many users connect at the
same time or when it rains.
But companies are launching satellites right now at a frenetic pace, and the
damage they do to the night sky, the atmosphere and the safety of low Earth
orbit will not be undone even if the operators go bankrupt.
There's no doubt that rural and remote internet users in many places have
been left behind by internet infrastructure development. But there are many
other options for internet delivery that will not result in such extreme
costs.
We can't accept the global loss of access to the night sky, which we've been
able to see and connect with for as long as we've been human.
With co-operation instead of competition between satellite companies, we
could have many fewer in orbit. By changing the design of satellites, they
could be made much fainter, having less of an impact on the night sky. We
shouldn't have to make a choice between astronomy and the internet.
But without regulations requiring these changes, or strong pressure from
consumers indicating the importance of the night sky, our view of the stars
will soon be changed forever.
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