activities by conducting them in remote areas, far
from spies. Now, even ordinary citizens can spot such
activities from space, as happened in 2018, when a
variety of people and organisations, including the
Australian Strategic Policy Institute in Canberra,
used Google Earth and related sources to prove that
“vocational schools” for China’s Uighur Muslims
were actually detention camps, complete with
watchtowers, reinforced walls and razor wire.
But it also means you can peer into your
neighbour’s backyard or see if their car was at
home when the satellite flew over. The images
are good enough that when I try them on my own
neighbourhood, I can see lounge chairs circling
swimming pools in apartment buildings, count the
number of people waiting at a nearby bus stop, and
easily distinguish cars from vans, trucks and buses.
What I can’t do is read licence plates, identify
individual people, or determine
which bus the people at the
bus stop eventually board.
Partly, that’s because even the
best commercially available
satellite images don’t have the
kind of resolution needed to
do this. Whatever you might
see in science fiction movies,
and whatever might become
possible for the military, “we’re not going to have
licence-plate readers in space in the near future”,
Pomfret says.
Furthermore, even the best images are merely
snapshots – isolated in space and time.
That said, it is possible to compare images taken
at separate times. Planet Labs, an Earth-imaging
company based in San Francisco, California, is running
a constellation of satellites dedicated to taking images
of the complete surface of the Earth at least twice a
day at resolutions up to 72 centimetres/per pixel.
Based on that, Planet used images of the Chinese city
of Wuhan, the epicentre of the coronavirus epidemic,
to show that by late January the city had become
“almost bereft of cars and people” in response to
China’s efforts to quarantine the rapidly expanding
virus. “A January 28 image of a bridge across the
Yangtze [River] shows it deserted of vehicles,” the
company said in a 30 January press release – a radical
change from a 12 January image showing a “surge” of
vehicles “flooding” across the same bridge.
But impressive as that is, it’s not the same as
tracking individual people. Nor are satellite images
ever likely to pose much risk to that kind of privacy,
Pomfret says, because even if the technology becomes
available to recognise individual people from space –
or to read licence plates – satellites aren’t likely to be
the easiest way of doing it.number of cars in the parking lots of stores, such as “all
the Wal-Marts in America”, using that to see whether
business is increasing or slumping – information of
value not just to the company, but to investors trying
to decide whether to buy its stock.
All told, says Kevin Pomfret, a former satellite
imagery analyst turned space-law attorney with the
firm of Williams Mullins, in Tysons, Virginia, there
are a “host” of ways in which satellite information can
be used, “which people don’t realise, because they are
behind the scenes”.
I personally first became aware of the power of this
information a few years ago, when I got to wondering
if the course of a local five-kilometre road race was
accurate. (In my spare time, I’m a coach, and one of my
runners had run a time that seemed too fast to be real.)
The race was a simple out-and-back, and I knew
where it started and that the turnaround had been at amailbox, near a farmhouse driveway. I discovered that
the satellite images were good enough that I could not
only find the farmhouse but see the mailbox. Based on
that, I used an internet app which allowed me to overlay
a satellite image and mouse click a routeto measure the
course – and found it to be 300 metres short.
Curious, I tested the app’s measuring abilities
on a college football field and a local track. The track
came up within a half metre of the correct distance:
impressive, because it wasn’t easy to measure
around the curves. But the stunner was the football
field. American football fields are 100 yards long.
I got 100.1 yards – limited mostly by my ability to
position the cursor. I had, I realised, discovered an
incredibly precise measuring tool, which I have since
used many times. But more importantly, it was my
personal introduction to the power of satellite-based
monitoring technologies, and how many potential
uses there are for them.
“[It’s] everything you can imagine,” Johnson says.
“A lot of companies are still trying to imagine what
else we can use imagery for.” Overall, he says, “people
are trying to get a grip on how this changes everything
in our society”.
One change, of course, is that it’s now possible for
anyone to peer at almost anything on the globe.
In some ways that’s a good thing. Not all that long
ago, it was easy for governments to hide clandestineIt’s possible to track the number of cars in the parking
lots of stores, using that to see whether business is
increasing or slumping – information of value not just
to the company, but to investors trying to decide
whether to buy its stock.46 – COSMOS Issue 86
SATELLITE TECHNOLOGY