High over the Indian Ocean, a giant surveillance drone spots a small suspicious vessel, perhaps an illegal fisher, perhaps a drug or people smuggler.
It swoops down for a closer look, its powerful optics beaming the imagery via satellite to an RAAF operator in a control room thousands of kilometres away in South Australia.
Even individual faces can be recognised.
This will be the Northrop Grumman Triton, an unmanned aircraft the size of a Boeing 737 set to enter service, first with the US Navy and, not that long after, with the Australian Defence Force.
This has been a long time coming. It's not quite there yet, but it's getting closer.
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The US Navy has been conducting trials of three aircraft from its Pax River air station and is set to decide in December whether to buy the first four production aircraft.
US Navy's Commander Jason Rider says the aircraft themselves are flying just fine.
Testing over the past two months relates to performance of the sensor package - the advanced radar and day-night camera that allows Triton to see everything below, whether it's a freighter or a small fishing boat.
"The battle right now is completing the (sensor) integration," he told reporters.
"We are about 20 per cent complete on the test program."
This capability for watching over vast areas of ocean has long interested Australia.
In April 2001, Triton's predecessor, the Global Hawk, flew non-stop from the US to Australia, the first trans-Pacific flight by an unmanned aircraft, a record 13,000km.
Australia made an initial commitment to buy Triton late last year, with final approval for acquisition linked to successful completion of trials for US Navy service.
That will likely be spelled out in the upcoming Defence White Paper, with a decision expected in 2017.
Up to seven will be acquired at a cost of some $3 billion and be based at RAAF Edinburgh in South Australia.
Commander Rider said he was confident Triton would pass its tests for final acceptance.
"What gives me confidence is the fact that ... our systems are not developmental," he said.
"The risk is always in the integration of all the sensors.
"Nothing ever goes incredibly swimmingly. So far we are pretty confident."
Triton had its genesis in a US military research program undertaken the mid 1990s for an aircraft able to conduct high-altitude long-endurance surveillance.
That resulted in the Global Hawk, which has seen service over Iraq and Afghanistan.
Triton is a version especially equipped for maritime surveillance, able to stay aloft for more than 30 hours at an altitude of more than 15,000 metres, far above normal airline routes.
To ensure Triton's suitability for Australia's particular requirements, the government requested some extra research to confirm the aircraft radar's performance against small wooden vessels.
That testing was successful, but the results remain classified.
Although Triton's smaller brethren, such as the Predator and the Reaper, can carry missiles, there are no plans afoot to give Triton any lethal capability.
(Reporter Max Blenkin travelled to the US as a guest of Northrop Grumman)
