When Lauchie Scott was a teenager growing up in rural Nova Scotia, a satellite was something you might expect to see crossing the night sky once or twice an hour.
Fast forward about three decades to a summer vacation he recently spent under similarly dark skies when he found himself counting satellites at the rate of one per minute.
“That was with my naked eye,” said Dr. Scott, a scientist and aerospace engineer with Canada’s Department of National Defence. “It’s actually pretty profound that without needing any equipment I can visually notice the change over the span of my life.”
The change marks the rise of satellite mega-constellations – including Elon Musk’s Starlink – which rely on hundreds to thousands of individual spacecraft flying just above the planet’s outer atmosphere where they can provide clients with uninterrupted mobile communications around the globe.
It has transformed Dr. Scott’s research specialty, known as space domain awareness, a field that is concerned with tracking all of the objects orbiting overhead and understanding what potential hazards they may pose.
Now, in collaboration with astronomers at Western University in London, Ont., Dr. Scott has a prototype camera system that can be reproduced and deployed to monitor satellites in the night skies across Canada.
“On some nights, we’ve had dozens of satellites visible at a given instant and we’ve had more than one thousand separate satellites tracked in a given night from just one location,” said Peter Brown, a professor with the university’s Institute for Earth and Space Exploration.
An expert in meteors and their origins, Dr. Brown has long been involved in developing inexpensive ways of recording the incoming bits of rock and dust that wander the solar system and regularly plummet through Earth’s atmosphere.
But it was a query from Dr. Scott two years ago that eventually led to his working on how to repurpose the technology for tracking the growing population of Earth-orbiting satellites.
The need is pressing. Not only are there more satellites than ever – more than 8,000 at latest count, with tens of thousands more heading for the launch pad – many have electric thrust systems that allow them to adjust their orbits autonomously.
“They’re actually very difficult to track because they don’t behave like an object naturally would in orbit,” Dr. Scott said. “Those thrusters turn on and off whenever the computer on board decides.”
Then there are all the assorted and inactive pieces of human-made space debris that are too small to track and may number in the millions – each moving with an average orbital velocity of 28,000 kilometres an hour. Together it points to the prospect of collisions and the risk of a chain reaction as more debris creates more hazards.
Over the years, Dr. Scott has been involved in ways to better assess the issue using space-based tools. He has participated in Sapphire, Canada’s first military satellite, which contributes data to the U.S.-operated Space Surveillance Network. This year, he was named the principal investigator for Redwing, an upcoming Canadian microsatellite that will monitor objects in space from orbit and is slated for launch in late 2026.
But the collaboration with Western, which got under way earlier this year, represents a chance to gather satellite information from stations on the ground, though it is limited to operating at night and in clear weather when satellites can be observed.
The project involves clusters of eight cameras with overlapping fields of view that together cover most of the sky without the need for moving parts. Thanks to a revolution in digital imaging electronics, such cameras have become increasingly sensitive and affordable.
The cameras record the sky at the rate of 20 frames per second and can detect objects that are several times fainter than the limit of what can be seen with the human eye. That’s good enough to spot satellites as small as 40 centimetres across in low Earth orbit.
The other end of the system is computer software that can rapidly analyze the data and provide useful information on everything the cameras can see. In addition to tracking objects, it can also see changes in brightness that could signal a satellite tumbling out of control. It can also provide data to those who are looking to predict and prevent potential collisions.
“The goal is to basically turn that into a regular kind of product where we can monitor things in low Earth orbit over Canada in an active way,” Dr. Brown said.
He said his team at Western aims to make the data freely accessible to aid the space community. Such efforts are commensurate with Canada’s membership on the UN Committee on the Peaceful Uses of Outer Space, among other organizations.
Michael Byers, a policy expert at the University of British Columbia who has studied the potential risks of satellite mega-constellations, said other countries are also trying to address the issue. However, he added, the sheer number of satellites that are projected over the next decades will have consequences that are difficult to fully assess.
“This realm of what’s called new space has completely outpaced the ability of governments to keep up,” he said.
Dr. Scott said the next step for the tracking system developed by Western is to add more observing posts across the country, in part to get around the limitation of poor weather in any one location.
“We ought to be able to mitigate cloudy skies in order to take advantage of these cameras,” he said. “And they’re so low cost that it allows us to do that.”