Across the otherworldly plains of the Clarion-Clipperton Zone, some 15,000 ft below the surface of the Pacific Ocean, are clustered manganese nodules the size of potatoes. The rare earth metal deposits have grown undisturbed at a rate of about a third of an inch every several million years. Now they are targets for the nascent seabed mining industry.
But plucking them off this dark desert is no easy task. First they need to be found. That's where underwater drones come in. Hovering just feet above the seafloor, the machines can record unprecedented details of a surface less mapped than Mars.
"If you want high-resolution information, you have to put the sensor close to what you're looking at. An AUV [automated underwater vehicle] is the best and most accurate way to do that," said Richard Mills, vice president of marine robotics sales at Kongsberg Maritime. His company's creations can relay images with a resolution of 2x2cm, much better than what's possible with a surface-level ship's sonar.
The most exciting future for drone technology may not be in the sky, delivering packages for Amazon, but underwater helping to discover vast riches. The use of underwater automated vehicles is proving critical in the areas of seabed exploration and mapping. Private companies are developing vehicles with better sensors and more capabilities, while the European Union and university programs around the world are funding similar projects.
In the future, when full-scale seabed mining picks up, deep valleys like the Clarion-Clipperton Zone will likely be the site of tracked vehicles slowly crawling along the ocean's floor sucking up nodules, surrounded by advanced drones feeding real-time data to crews on the surface.
The ocean's floor — where light barely reaches and the temperature is near freezing — holds potentially the largest untapped reserves of rare earth metals. So far, the independent International Seabed Authority has granted dozens of contracts for companies to explore and make environmental reports.
The value of gold alone on the seafloor is estimated to be worth $150 trillion. Meanwhile, the value of nodules — containing manganese, nickel, copper and cobalt — also reaches into the trillions. And then there are deposits formed around thermal vents. With continued demand for rare metals used in today's electronics, from iPhones to solar energy components, it's clear why a number of governments and countries have started a race to the bottom of the ocean.
Mining company DeepGreen Metals has three licensed areas in the Pacific, including two defined resource statements with billions of tonnes in potential metals. "We know the world will be very focused around the environmental impacts. Automated vehicles operating on the ocean floor are the only way," said chairman and CEO Gerard Barron.
Drones will be great for environmental studies of potential mining areas and to follow and observe mining machines, gathering details on dust plumes that can be detrimental to deep-sea creatures, Barron said. There has even been tests for drones to collect small nodules, he said, although currently a seabed-based tracked vehicle is the most common tactic.
"The most efficient way of collecting these nodules from the ocean floor is yet to be agreed upon," Barron said.
Underwater drones have come a long way in over a century of development. The first unmanned, untethered, underwater vehicle was created in 1864 and mostly resembled a torpedo. In the 1950s the University of Washington conducted research with automated underwater vehicles alongside the U.S. Navy. After that, innovation didn't move forward very much until technology allowed for smaller energy sources.
Kongsberg's first AUV, made in the early '90s, is almost unrecognizable to today's model. The vehicle — which looks like a sleek orange torpedo — now takes acoustic, laser and photographic images. Recently, the robot has skimmed the bottom of Arctic waters, mapping manganese nodules in Norway.
Mills predicts new sensor technology to evolve in the future, providing even more detailed images. He also thinks the next generation will have increased in-mission processing capability, including automated object detection that can quantify nodules in real-time.
But the technology may be ahead of the market. Nautilus, the first company to gain deep-sea mining rights, went bankrupt last year after failing to mine Papua New Guinea's waters. The project was opposed fiercely by local conservation groups. So far, there hasn't been a successful large-scale deep-sea mining operation.
The versatile tech has applications in the energy sector, too. Last year the first contract was inked between Norse oil and gas giant Equinor and Italy's Saipem for the use of advanced wireless drone services on a Njord field located off Norway's coast.
Meanwhile, a group of scientists and engineers, supported by the Nippon Foundation of Japan and the General Bathymetric Chart of the Oceans, are attempting to create a mapping of the ocean's floor by 2030. So far, less than 20% has been recorded. The White House announced a plan to survey 4.47 million square miles of seafloor within American borders last year.
"This new status of ocean mapping where we don't want to just map but map and characterize, autonomous underwater vehicles are hugely, critically important component," said Larry Mayer, a professor at the University of New Hampshire and co-head for the Seabed 2030 Arctic and North Pacific Ocean Regional Center. Mayer said underwater drones will be used to look at specific areas in great detail. And for the first time in history, the oceans will seem clear to those on the surface.