A drone as seen in the movie Prometheus (Alamy)
When Hollywood director Ridley Scott filmed astronauts looking for aliens in his 2012 movie Prometheus, little did he know that it would one day inspire a Network Rail drone project. But, bizarrely, that's exactly what has happened. Network Rail, which owns and maintains most of the railway infrastructure in Britain - from vast stretches of track to thousands of bridges, tunnels and level crossings - has long sought cheaper and easier ways of surveying the many underground caves and abandoned mines dotted around its property.
Engineers must account for "shallow" subterranean voids when doing building work or moving heavy machinery, because the caverns might collapse and cause the ground above to shift. There are more than 5,000 of these shallow voids in Britain.
At an innovation workshop in 2018, Network Rail's principal mining engineer Neal Rushton found himself seated at a table with electronics experts and robot researchers. He sketched a simple drawing of the sort of device he was looking for - something that could travel down a 15cm borehole, enter an underground cave and map its interior.
Existing methods of mapping these areas are slow and sometimes hazardous. Surveyors either drill multiple boreholes into the ground, through which they poke sensors at the end of long sticks in order to scan the space below; or technicians enter the mine shafts and caverns themselves to collect the data by hand. Dangerous gases, cave-ins and even explosions are all possible causes of harm to such workers.
Robotics engineer Simon Watson came up
with a folding design for the drone
When Simon Watson, a robotics engineer at the University of Manchester, saw Mr Rushton's drawing, he immediately piped up: "Eh, I've watched a film about that," he said. "It's Prometheus."
In a well-known scene in the science-fiction blockbuster, four spherical drones whizz off into a creepy, unexplored alien structure, scanning it with lasers as they go in order to build up a 3D model of the environment. It's a tantalising moment in which the human space travellers realise the enormous scale of the outlandish place they have stumbled upon.
Mr Rushton knew the film and so instantly recognised Mr Watson's analogy, which got everyone at the table talking. "A tool like that would be invaluable," says Mr Rushton today. "Not just for us but for hundreds of applications around the world."
This is how the "Prometheus" drone project got its name and, although the caverns Network Rail hopes to explore with the device will be smaller than the alien tunnels in the film, the technological principles are almost exactly the same.