There’s a mystery under the water in Antarctica. An uncrewed underwater vehicle named Ran went missing while exploring a famous glacier. The valuable piece of equipment didn’t return from a weekend expedition underneath the Thwaites Glacier—a gigantic ice sheet in West Antarctica.
The loss of Ran is a blow to ongoing research into a glacier known as the Doomsday Glacier for how it could contribute to potentially catastrophic sea-level rise if it were to collapse. Thwaites is under threat from warming ocean waters due to climate change. The glacier stores enough water to push sea level up by more than two feet. Sea-level rise contributes to flooding and land loss in coastal communities.
Ran gave scientists a rare view of what was happening underneath the ice shelf as they seek to understand the glacier’s rapid retreat. “Even if you see melting and movements in the ice from satellite data, from Ran we get close-ups of the underside of the ice and information about exactly which mechanisms are behind the melting,” said oceanographer Anna Wahlin in a University of Gothenburg statement on January 31. The Swedish university owns and operates Ran.
Ran is an AUV, an autonomous underwater vehicle. That makes it different from an ROV, which is a remotely operated vehicle. An AUV is given preprogrammed instructions for its explorations while an ROV is operated by humans in real-time. Ran “moves faster than an ROV and can therefore cover longer distances in shorter time,” the university said in an AUV explainer. There are only a handful of research vehicles like Ran in the world.
The AUV was being operated from South Korean research vessel Araon. Ran went missing after having completed successful dives earlier in January. It didn’t reappear at its programmed rendezvous point after its last dive. The ship, along with helicopters and drones, searched for the vehicle. “At this point, Ran‘s batteries are dead,” said Wahlin. “All we know is that something unexpected happened under the ice. We suspect it ran into trouble, and then something prevented it from getting out.”
This is no small vessel. Ran is nearly 25 feet in length and weighs about 4,080 pounds. It was the first craft to venture underneath the Thwaites Glacier in 2019. It gathered data on currents, temperatures and chemical properties from beneath the ice. Researchers also used the vehicle to study the seafloor and track the glacier’s retreat through history.
The AUV’s original purchase price was over $3.6 million. The university hopes to replace Ran with a new AUV to continue its research, but it will need to raise funds to make up the difference between the insurance payout and the cost of current technology.
It’s not easy exploring a glacier. Ran operated in challenging conditions under ice as thick as 1,640 feet. The vehicle’s autonomous nature meant it was out of contact with its host research vessel when it went missing. There may never be answers about what happened during the AUV’s final journey. “Personally, I’m of the opinion that this is a better end than having the AUV aging gathering dust in a garage,” said Wahlin. “At the same time, it is of course a very big loss.”