Interstate 15 hosts over one million road trips from Los Angeles to Las Vegas
every month. Rising over mountains and stretching across broad, open deserts,
“the fifteen” brings weekend travelers from the bustling commercial hub of
Southern California’s west coast to the ever-popular inland entertainment
destination. In light traffic, the drive takes a little over four hours; in
heavy traffic, it can take eight or more; by jet airplane, one hour gate to
Recently, one of our Dove satellites also made the trip, from (directly above)
Los Angeles to (directly above northern) Las Vegas, all while acquiring imagery
along a swath several kilometers wide. It covered the distance in 52
It is well-known that satellites fly in space, high above the atmosphere.
Somewhat less well-appreciated is just how fast they move. Each of our Doves
circles the entire planet about fifteen times per day, collecting gigabytes of data
and monitoring changes all over world.
If you rode aboard a Dove and looked down, this
is what you would see:
52 seconds from Los Angeles to northern Las Vegas, acquired
February 9, 2015, shown actual speed. Image credit: Rob Simmon/Planet Labs
A question I sometimes hear from friends outside the industry is: why one would
choose to collect imagery via satellite instead of, say, drone aircraft? After
all, airplanes are more familiar, and they fly closer to the ground, so they
can see finer details. (The “satellite” imagery one sees of populous areas is
often taken from airplanes, not satellites, for precisely this reason).
In fact, satellites have many advantages over airplanes: safety, privacy,
regulatory, and environmental considerations among them. But as our little
Dove’s “road trip” so clearly demonstrates, the greatest advantage may be
speed. It would take hundreds of aircraft operating simultaneously to match
the area collection rate of a single Dove—and scores more to rotate in
during maintenance and refueling. And our Doves orbit the world non-stop at
this incredible pace for many months before finally burning up harmlessly in
the upper atmosphere.
Drones and aerial reconnaissance planes do have applications, of course.
Airplanes can more easily acquire very high-resolution imagery of concentrated
urban areas or special events. They can fly under high clouds. And one could
hardly ask a satellite to, say, inspect the underside of a bridge. But if the
goal is to learn about the whole world—not just its islands of dense human
habitation—then a flock of Doves may be just the ticket.
For further reading, see Randall Munroe’s colorful discussion of orbital