The yellow robot on the side of this ship is about to plunge into the depths of the Pacific Ocean.
Its mission: to recover objects that can be millions of years old.
To collect them, it has to go down.
And down.
Past where sunlight reaches.
Its destination is the ocean floor, more than 4 kilometres below the surface.
This process is at the heart of a global fight between countries and companies over whether to open up a new mining frontier.
These are what the robot is here to collect: polymetallic nodules.
The rock-like lumps, the size of a potato, are filled with critical minerals such as nickel, copper, cobalt and manganese.
Proponents say these are critical for the world to transition from fossil fuels to clean energy and technology.
Nickel and cobalt are used to make batteries for electric cars. Manganese is used in the production of steel.
For decades, the world's been grappling with how to reach these depths, sustainably extract these nodules, and ensure any benefits are shared with developing nations.
But US President Donald Trump doesn't want to wait. He wants America to cash in, fast-tracking the mining of undersea critical minerals with or without any global consensus.
Until now, bringing these nodules to the surface has only been done in testing.
It works like this: The robot motors along the sea floor, vacuuming up the nodules.
They're then sucked up to the ship above, to be taken ashore for processing.
This new frontier is largely in a stretch of the Pacific Ocean, bigger than Queensland and Western Australia combined.
It's called the Clarion-Clipperton Zone (CCZ).
So far, 17 operators have been granted exploration contracts to map and search potential mining areas in the CCZ.
Big business is circling, keen to get in on what proponents say could be a multi-trillion-dollar industry.
These contracts are granted by an obscure UN-affiliated agency, the International Seabed Authority (ISA).
Under international law, it's tasked with regulating the mining of deep-sea resources in international waters, while also ensuring their protection "for the benefit of humankind". It's yet to develop those rules.
In the deep
The dark waters hundreds of metres below the surface are home to some of the world's oldest and strangest creatures.
To reach the nodules you have to descend even further.
Beyond 4 kilometres you enter the abyssal zone. This part of our planet has existed untouched for millions of years.
Marine scientists who've studied the CCZ and the nodules that lie on its sea floor, say there are untold species at these depths that are yet to be discovered or documented.
They want much more research done before mining is allowed.
One environmental concern is the sediment that mining would stir up.
The process creates two plumes of sediment: when the nodules are collected from the sea floor and higher up from the cleaning of the nodules.
Scientists are worried about the impacts on fish and other species if this sediment ends up being swept well beyond the mining zone.
One mining proponent, The Metals Company, says it's spent hundreds of millions of dollars on research that proves the extraction can be done sustainably.
It argues any impact the process does have will be far less damaging than mining on land. It says it's a trade-off the world needs to make.
Some research suggests there's still much to be learned about the nodules themselves and the role they play in the deep-sea ecosystem.
One recent study suggested the nodules lying on the sea floor could be generating oxygen.
It's a stunning hypothesis given light and photosynthesis are usually required to create oxygen.
Mining proponents have dismissed the findings as "flawed", but some scientists say it warrants much more research.
'Gold rush'
The fact so much is still not known about this part of the ocean is the main reason 38 countries are pushing for a moratorium or precautionary pause on deep-sea mining.
Any commercial mining in the vast international waters overseen by the ISA has, until now, not been possible because the agency is still yet to develop regulations.
But while the ISA has 169 countries and the EU as members, the United States is not one of them.
Donald Trump has decided to go it alone.
Trump signed an executive order in April, expediting licence approvals for deep-sea mining in US and international waters. That includes the CCZ, even though it lies far beyond its territorial waters.
The US regulator said the executive order would spark a "gold rush".
The first company to apply for a US permit, The Metals Company, had initially sought approval under the ISA. It's based in Canada but is run by Australian entrepreneur Gerard Barron.
Even though the US is not a party to the UN's Convention on the Law of the Sea, some say any approval would still be a breach of international law.
And that could spark a geopolitical brawl in the rush for this precious treasure at the bottom of the ocean — one Australia could be drawn into as it spreads across the Pacific.
One reason Trump wants to open up seabed mining is China. Beijing dominates the processing and refining of critical minerals and rare earths. The Trump administration regards these products as essential to US national security and economic development.
Some Pacific nations, like the tiny western Pacific state of Palau, want to see Australia support their push for a moratorium or precautionary pause on deep-sea mining.
Palau President Surangel Whipps Jr fears that without proper protections in place, the impacts on the ocean could be irreversible.
"What lies in the deep sea does not belong to any one nation or corporation, but to all of us and future generations."
Credits
Reporting: Mark Willacy, Maddy King and Lara Sonnenschein
3D Modelling: Jack Fisher and Thomas Brettell
Design and graphics: Katia Shatoba, Mark Doman and Patrick Forrest
Editing: Nick Wiggins
Map data of the Clarion-Clipperton Zone was sourced from the International Seabed Authority
Video courtesy of Schmidt Ocean Institute and Geomar
Watch Four Corners'S full investigation, Race to the Bottom, reported by Mark Willacy and produced by Mary Fallon, Monday from 8:30pm on ABC TV and ABC iview.
