The 20-hour
flights of which the latest long-haul airliners are capable might seem very
long to you – but imagine an aircraft able to fly nonstop for five years.
That's exactly
what the U.S. Defense Advanced Research Project Agency (DARPA) has asked aerospace
companies to build, for a new aerial surveillance project that DARPA calls VULTURE.
So serious is
DARPA about demonstrating five-year flight duration that it scheduled an
industry-day event on June 7 so it could discuss the project in detail with
likely bidders.
DARPA wants
VULTURE, which will almost certainly be solar-powered, to be able to carry a
1,000-pound payload. This would include onboard sensors and communications
equipment and would generate 5 kilowatts of electricity to power the aircraft's
systems.
VULTURE stands
for Very-high altitude, Ultra-endurance, Loitering Theater Unmanned
Reconnaissance Element. The word "Unmanned" is key: It'll be a long time before
any people-carrying aircraft will be able to stay aloft for five years.
But the
proposition is much more realistic if you use an unmanned aerial vehicle (UAV).
UAVs have
been around for a long time: the first, the Kettering "Bug",
was developed during World War One.
When Capt.
Ronald Reagan sent a photographer along to Radioplane in 1945 to take pictures
of women assembling the company's OQ-3 remote-control target aircraft, the
photographer snapped some shots of a young woman called Norma Jean Daugherty. The
pictures brought her fame – as Marilyn Monroe.
For
aviation, UAVs represent the wave of the future, particularly for military uses.
Aircraft
that don't have to take into account the limitations imposed by human
physiology can be much more maneuverable than piloted aircraft. And they can
perform dull, long or dangerous missions unsuitable – or physically impossible
– for people.
Because
they are unmanned, UAVs can be designed to suit specific tasks and to offer
performance characteristics piloted aircraft can't match.
They can be
very small or very large. Some proposed UAV projects involve airships, while
many existing programs use aircraft very like the remote-control models sold in
hobby shops. Some UAVs are helicopters – and one test-flown successfully in the
United Kingdom is a tiny flying saucer.
UAVs now
represent very big money. Armed forces throughout the world – including all
four arms of the U.S. military, as well as the Coast Guard – already operate a
huge variety of UAVs. The U.S. Air Force's Predator and Global Hawk UAVs are
famous because of the roles they have played in the Iraq and Afghanistan conflicts.
At least 90
percent of all UAV use today is military. That doesn't mean UAVs can't be used
widely for civilian applications too. In Japan, nearly 2,000 tiny Yamaha
RMAX helicopters, powered by two-stroke motorcycle engines, are used to spray
small rice paddies with pesticide.
UAVs would
be ideal for aerial jobs such as police surveillance, pollution-control
monitoring, fighting forest fires and inspecting pipelines, said Andre Clot,
vice-chairman of United Kingdom-based Unmanned Aerial Vehicle Systems
Association (UAVSA), established to
promote civil use of UAVs.
"If it's
dangerous, dull or dirty, UAVs are not a bad idea," said Clot.
But a major
problem must be solved for UAVs to see wide application in civil aviation. The
world's civil aviation regulators must become satisfied that UAVs can operate safely
and seamlessly within the complex air traffic control and civil airspace
systems established for human-piloted aircraft.
To do so,
UAVs must be able to sense and avoid other aircraft flying nearby and operators
must have reliable communications links with their UAVs to maintain control
over them at all times – and to make sure they know exactly where their UAVs
are.
Safety and
control standards must be completely equivalent to those involving piloted aircraft.
Also, UAVs will need to provide to air traffic controllers and pilots of other
aircraft the same information about their flight plans that manned aircraft
provide.
The key is
for companies to design their UAVs to the same structural standards and with
the same control and communications capabilities as piloted aircraft, said
Clot.
In the UK, aerospace manufacturers now classify their unmanned products as "aircraft" rather than
"UAVs" to engender this thinking.
The
increasing degree to which control of piloted aircraft and their communications
is becoming automated works in favor of the UAV. So does the growing automation
of air traffic management.
Digital
automation techniques for aircraft control and communication are the same for
piloted aircraft as for UAVs. Once all communications and control is digitized,
with each aircraft sending back data to the ground all the time, anything that
goes wrong with one can be fixed very quickly throughout the entire fleet.
"We will
lose a few times, but we will get much better very quickly," said Clot.
"Reliability will jump."
Airliners
already operate largely automatically, particularly when landing in poor
weather. As the automation of aviation accelerates, the idea of flying on a
pilotless airliner may become fact sooner rather than later.
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