An autonomous underwater vehicle developed by the UK’s National Oceanography Center will begin a 30-day expedition off the coast of Donegal, Ireland next week.
The device, known as Autosub Long Range (ALR), is tasked with helping researchers understand the water exchange between shallow coastal waters and deep ocean trenches.
Once launched from the Donegal coast, the device, which can be remotely operated from a mission base in Southampton, will set off for an underwater shelf, track the continental slope down to 1500 metres (nearly 5,000 feet), and begin its data-gathering mission. Simultaneously, a school of smaller remotely-operated AUVs will map the upper water column.
At predetermined intervals, the robo-sub will come to the surface and transfer data back to the research team via iridium satellite data link. Once the mission is complete, ALR will return to the shore for recovery.
Fitted with oceanographic sensors and satellite communications, ALR has a range of 6000km (3728 miles), an endurance of six months and a depth rating of 6000m (19,685 feet). Those capabilities are achieved, at least in part, by a design which sees the robo-sub operate with relatively slow, power-saving propulsion speed (surface 3.8 mph; sub-surface 0.89 mph).
Mine rare earths and precious metals on the ocean floor
ALR’s sensors include dual 600 kHz Acoustic Doppler Current Profilers used to measure measure the water velocities above and below the submarine to a range of 50 meters (164 feet). A microstructure turbulence probe is used to measure small scale turbulence in the undisturbed water in front of the AUV.
Meanwhile, a fluorometer provides information on the turbidity of the water and a conductivity, temperature and pressure (CTP) sensor is used to calculate water salinity and to identify different water masses.
The forthcoming expedition off the Irish coast is purely for scientific research, but UK?s National Oceanography Center also develops autonomous underwater vehicles for commercial use, of which there are many.
For example, there is growing global interest in the use of AUVs for detecting valuable deposits of minerals and precious metals on the seafloor.
AUVs provide a cheap and effective way for governments and companies to survey vast tracts of ocean without the expense of time-consuming manned operations.
Ocean mining has the potential to become a very lucrative sector of the mining industry. Japan, for example, is estimated to have underwater ocean resources ?including precious metals– worth more than $2.3 trillion.
The country’s government state-backed Japan Oil, Gas, and Metals National Corp. has plans to deploy remote-controlled robots at depths of up to 2,000 meters to mine rare earths and precious metals on the ocean floor.
If fitted with different sensors, simpler AUVs like that being tested off the coast of Ireland next week could not only be used for initial prospecting and mapping, but could also be used to monitor the environmental impact of ocean mining projects.
