54 Australian Geographicin the heat, Gosse Bluff
looks like a mountain
range drifting above an
endless plain. Its position in
the landscape and incongruous shape draw me closer.
The nearer I get, the more intriguing it becomes, as
its walls rear up like the ramparts of an ancient city.
The illusion becomes complete as I follow the track
through a gap to the inside of a fortress, its walls
glowing in the late afternoon light.
To gain a better look, I launch my UAV (‘unmanned
aerial vehicle’ or drone) into the sky and slowly rotate
its camera to take a panorama of this crater. The
awesome scale becomes clear and I think about the
impact that created it. Tnorala (Gosse Bluff) is about
180km west of Alice Springs in the Northern Territory.
It was born 142 million years ago when an object
from space, probably a comet, plunged into the Earth,
creating a perimeter of fractured rock 20km across.
Much of it has since eroded away, leaving just the
5km-wide crater seen today.
Photographing this landscape with a UAV provides
a dramatic result. Unlike a helicopter, it remains below
120m, which gives an aerial perspective while retain-
ing a terrestrial connection. The drone has a gimbalthat rotates 3600, creating a unique perspective and
the opportunity for unusual panoramas. In Australia’s
Red Centre, a UAV can be flown into canyons and
gorges and made to hover below mountain peaks.
While flying I had visits from eagles, falcons and kes-
trels that would check out the drone as it hovered,
and then, curiosity appeased, soar up into the sky.
Using a UAV in the outback, however, comes with
its own particular challenges. Willy-willies are frequent
and come with little warning, throwing up fine par-
ticles that clog delicate motors. Then there’s the heat.
Even in October, temperatures can be intense.
Batteries heat up during flight and must be cooled
before recharging. When the external temperature
climbs above 400C, chargers, iPads and sensitive
electronic gear shut down. Recharging is another
challenge. My 4WD is fitted with special batteries that
are charged using the engine and solar roof panels.
These in turn charge a pair of UAV batteries, which
provide 15 minutes of flight time. Also to be charged
are batteries for a smaller UAV for shooting video,
transmitters, monitors and iPads, which run apps to
control the drones. Because most images are taken at
first and last light, charging goes on through the night
to ensure everything is ready for the next dawn.FROM A
DISTANCE,
Hovering in the heat, the drone captures an eagle’s-
eye view from the centre of Tnorala (Gosse Bluff). With
landing gear raised, the camera takes a series of images
that reveal the steep walls of the impact crater.