Brag Fall 2021

By Samantha Lawler
Assistant Professor, Astronomy
MEGACONSTELLATIONS
BLOCKING OUT THE STARS
Dr. Samantha Lawler has become a champion for
stargazers by speaking out about megaconstellations.
For as long as we’ve been human, the
stars have been a constant source of
wonder and knowledge. Countless
human civilizations have traditional
knowledge that is intimately tied to
stargazing: telling us when to plant crops,
when to hunt certain foods, when to expect
seasonal changes.
The night sky is changing. For the past
century, we stargazers have had to contend
with increasing urban light pollution, forcing
us to travel farther and farther from cities and
towns to see the stars as we’ve seen them for
thousands of years. But now a new source
of light pollution threatens the night sky
worldwide.
Several private companies are currently
launching satellites at a frenetic pace:
we have entered the era of satellite
megaconstellations. There are now
approximately 4,000 operational satellites in
orbit. Almost half of them were launched by
American company SpaceX for their Starlink
megaconstellation in the past 2 years, and
they have provisional permission from the
US government to launch 40,000 additional
satellites, a stunningly huge number.
These satellite megaconstellations are
primarily to provide global internet, a
welcome service for many in rural and
remote locations who have long been left
behind by infrastructure developments. But
the cost to the world will be much higher than
most people are aware of, whether or not
they are able to access the services provided.
These satellites are a problem for stargazing
and research astronomy because they reflect
sunlight. I became aware of this problem
when I moved to my farm near Edenwold,
Saskatchewan in 2019, and suddenly had
access to the Milky Way out my back door
for the first time in my life. I noticed the
increase in satellites, and wondered how
bad it would get. I’ve just written a research
paper, currently in press for The Astronomical
Journal, to answer that question.
In this work, I led an all-Canadian team
comprised of myself, Dr. Aaron Boley at
UBC and Dr. Hanno Rein at the University of
Toronto. We built a computer model (see
insert) to predict satellite brightnesses at
different places on Earth at different times
of night in different times of year. Our model
uses 65,000 satellites on the orbits filed by four
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