LIEUTENANT Uchatius could not have expected it at the time but his novel attack on Venice in August 1849 has become an important date in the history of modern aviation.
The Austrian officer launched 200 ''balloon bombs'' controlled by lengths of copper wire and timed fuses. He may well have been the father of a new weapon: the military drone. More than 160 years later, technology is driving military and civilian uses of unmanned aerial vehicles (UAVs) into remarkable areas. On the smallest scale, moths have had been implanted with electrodes to control their movements. On the grandest, UAVs could be flying in civilian airspace by the end of this decade, some experts believe. This potential is one of the reasons why the UAV sector is the most dynamic of the aviation industry. It is worth an estimated $US6 billion ($5.7 billion) a year, according to US market analyst the Teal Group. And that figure is expected to double within 10 years.
This potential has been accompanied by fears among scientific critics and human rights groups that downgrading the ''man in the loop'' means devolving life-and-death decisions to airborne robots.
Those anxieties are unlikely to be allayed as arms manufacturers and start-up firms jostle for position in a competitive field.
A crucial piece of technology to take drones to the next level is a robust ''sense and avoid'' system, allowing unmanned planes to fly safely in busy airspace. Arms maker BAE Systems is confident this development is within reach and that craft will be able to manoeuvre safely in civilian airspace by 2020.
The engineering director (systems and strategy) at BAE, Lambert Dopping-Hepenstal, says a collaboration between aerospace firms and the British government is looking at all the issues needed to persuade air traffic regulators that civilian drones were safe.
''They have to behave correctly even if they lose communications links to the ground. They must be able to behave as safely as a human pilot,'' he says. ''It's about long endurance activities like search and rescue. You can put them into places where you couldn't put a human - for example, an ash cloud. In Fukushima, after the Japanese earthquakes, they used a small UAV to assess damage and radiation. And there's no night flying in fighting forest fires.'' A drone could carry on dousing flames overnight.
Britain's Civil Aviation Authority says 120 companies and other groups have been given approval to fly UAVs in Britain. Five police forces are said to be among them.
Drones can now only be flown within ''line of sight'' of the operator, but even with these restrictions companies can see the potential.
The Unmanned Aerial Vehicle Systems Association's Andre Clot says: ''This is not an aerospace market any more. It is an information and technology market. We are seeing lots of small, nifty, flexible companies coming up with solutions, and they offer much lower prices than the bigger manufacturers.''
Drone technology is rapidly spreading around the globe and the military is still driving innovation. Israel has long been a leading developer. It sells the vehicles to US and European armies. Working with US manufacturer Northrop Grumman, Israel Aerospace Industries (IAI) had a contract to fly them over Iraq.
Britain's Watchkeeper drone, a military ''target acquisition'' spotter, is based on an Israeli prototype. An IAI spokesman said the firm had sold $1 billion worth of drones ''over the past few years''.
Some drones are so small they are intended to resemble insects. The US Defence Advanced Research Projects Agency (DARPA)has commissioned a drone the size of a hummingbird, equipped with a camera, from AerEnvironment.
A Dutch firm, Green X, builds drones that fly by flapping wings and are disguised as falcons or hawks. They have been flown low around Schiphol airport to scare away geese.
Bio-inspired technology has been a source for one of the more improbable strands of drone research. DARPA has implanted electrodes into the pupae of tobacco hawkmoths to learn how to control animals remotely, exploiting their flights.
The British Ministry of Defence's science and technology laboratory recently produced a briefing on research ''to stimulate new lines of thought''. The review carries reference to a US patent on an ''animal sensor network''. The US study, it said, aimed to develop a ''method for the remote guidance and training of free-roaming animal sensor networks''.
It noted: ''Electrodes implanted into the nervous systems of animals are used to provide clues and rewards by stimulating specific regions of the brain to induce desired behaviours, such as the direction and speed of movement.
''Each animal carries a backpack containing wireless networking equipment, sensors, and data storage and processing equipment.'' Animals, it suggests, could be trained in odour detection.
A call by the ministry for research proposals last September asked for projects involving a micro unmanned aircraft system (weighing less than 2 kilograms) and nano UAS (60 grams or less), which would ''operate inside buildings and within deep urban canyons'' and ''confined spaces''.
The ministry was also interested in ''bio-inspired technology'' for small systems and aircraft that could detect chemical, biological and radiation hazards, and be used in ''crowd monitoring''. Another use would be for miniature drones that could ''perch and stare on the edge of buildings, on window ledges, [or] on telegraph wires''.
One big weakness of these drones is their reliance on radio signals. The Defence Science and Technology Laboratory is eager to improve anti-jamming technology to prevent unmanned aircraft being disabled mid-flight or even hijacked.
Drone makers often focus on civilian uses of the technology to try to stop it being demonised.
The Association for Unmanned Vehicle Systems International issued a code of conduct, noting that: ''Whether it is aiding search and rescue efforts, navigating through airspace too hazardous for manned vehicles, or furthering scientific research, UAS are capable of saving time, saving money and, most importantly, saving lives.''
While drones are best known for attacks on al-Qaeda in Pakistan, Afghanistan and Yemen, they are already being used for police surveillance, monitoring fires and inspecting wind turbines, crops, high buildings and power lines. Once they can fly in mixed airspace, their roles will proliferate.
Guardian News & Media