Somewhere between Australia and South America, the NOAA research vessel Rainier is currently trying to map over 8,000 square nautical miles of Pacific seafloor in search of critical minerals. Because nothing says "let's explore the ocean" like sending a couple of neon submersibles nearly 6,000 meters down to hop along the bottom like robotic kangaroos.
The submersibles, built by Orpheus Ocean (spun off from Woods Hole Oceanographic Institution in 2024), are designed for the deep sea's squelchy substrate, which teems with microbes, worms, snails, and egg-size metal nodules containing copper, cobalt, nickel, and manganese. You know, the stuff your smartphone screams for.
Orpheus's philosophy: "deep for cheap." Each vehicle costs a couple hundred thousand dollars to build, versus the usual $5 million to $10 million. And unlike most autonomous ocean vehicles, they can push into the seafloor and capture sediment cores - and the creatures within. It's like a Roomba that also takes soil samples and has a dark sense of humor about pressure.
Engineers have been tinkering with these designs for years at WHOI, NOAA, and NASA. The prototype vehicles were rated to dive 11,000 meters - the deepest part of the Mariana Trench. They've completed two commercial deployments, but this expedition is their biggest test: operating over large ranges for multiple weeks with multiple instruments. Using Rainier as home base, they'll swim out 10 kilometers at a time, taking one high-resolution image per second and up to eight physical samples from the seafloor apiece.
If all goes well, this could help establish the vehicles as a tool for government agencies, scientists, and companies hoping to probe the vastly understudied deep sea. Currently, scientists must wait for limited time on expensive government-owned submersibles. "A lot of this region that we're surveying … has really never been explored in any kind of detail," says Orpheus cofounder Jake Russell. "Anything we see is going to be new to NOAA and new to science."
The Orpheus subs are autonomous underwater vehicles (AUVs) that operate on preprogrammed commands and live decision-making, untethered to a ship. But unlike traditional gliding AUVs, these are short and stout with little legs - better for soft landings and sucking out sediment cores. When they land, they lift off, thrust a few feet, and settle again in a hopping fashion. Think pogo stick, but for science.
Their bodies are mostly syntactic foam (the same stuff that carried James Cameron to the Mariana Trench in 2012 - he donated leftover material for earlier Orpheus prototypes), with electronics encased in thick glass spheres. At under two meters long and under 600 pounds, Russell says they're the smallest - and least expensive - ocean vehicles capable of descending to 6,000 meters. They're designed to populate future fleets of robotic explorers.
"Anytime you do things in the deep ocean, you always run this risk, when you put something over the side [of a ship], that it might not come back," says Caltech geobiologist Victoria Orphan, who worked with an Orpheus vehicle on a science campaign in spring 2024 to study deep-sea methane seeps off Alaska's Aleutian Islands. Losing a vehicle from existing fleets (operated by NOAA, WHOI, and MBARI) can be disastrous, given scientists already compete for limited time.
During that expedition, frigid temperatures and steep topography added challenges, taking the full three weeks for the sub to get high-resolution photographs. But Orphan remains excited: "There's a lot of real, unknown science right at that interface between the sediment and the ocean surface."
Russell envisions pairing the vehicles with payloads that sense chemical seeps, sediment plumes, DNA from ocean life-forms, or the magnetic tug of buried cables. The vehicles are "the best of both worlds," says deep-sea ecologist Andrew Sweetman of the Scottish Association for Marine Science. They roam large areas like an AUV but carry out precise sampling like a remotely operated vehicle (ROV). Their small size means they don't require a large research vessel - potentially democratizing deep-sea science for smaller or poorer countries.
But cheaper ocean vehicles have also caught the eye of companies. Russell says inquiries come weekly from deep-sea mining, defense, offshore wind, telecom, and oil and gas businesses. He notes Orpheus is merely a "service provider," collecting data but not making decisions about seafloor use, and that better data "raises the bars" for regulators. However, many scientists are uneasy about the growing push for seabed mining, especially after an executive order from President Donald Trump mandated rapid mineral exploration and processing, and the administration announced a new Marine Minerals Administration.
"I think the push for deep-sea mining is happening way too fast," says Sweetman. Deep-sea communities are "probably the most stable environment on our planet," adds Orphan. "The organisms that live there are really not adapted to a lot of disturbance, and it takes a really, really long time for them to recover, if at all."
One proposed mining method involves a giant bulldozer-like machine trawling the seafloor and sucking up material, leaving scar marks and sediment plumes. Brett Hobson, an ocean engineer at MBARI, says Orpheus-like technology might enable companies to "take samples in a more surgical way, instead of just grossly scooping everything up." But Orpheus won't be the only option - companies and agencies in Norway, France, Japan, China, and the UK are developing similar vehicles. "What we really need [as] a society is just more of these systems out there," says Hobson.
As Orpheus's neon vehicles plunge into the Pacific over the next few weeks, their readiness for future scientific and resource surveys should become clearer. Each dive yields "just the smallest of postage stamps of our planet," says Orphan. "There's still so much to learn."