In January 1915, polar explorer Ernest Shackleton’s ship, Endurance, became icebound in the Antarctic. What happened next would become legend: Shackleton and his crew watched their ship slowly sink, survived a year and a half stranded on the ice, and eventually secured their own rescue with an 800-mile journey in an open lifeboat. Every member of the 28-man team survived.
Now, 106 years later, the wreck has been found, in remarkable condition, at a depth of nearly 10,000 feet in the Weddell Sea. An expedition team from the Falklands Maritime Heritage Trust led by polar geographer John Shears located the wreck using an underwater autonomous vehicle on March 5, after a month at sea. They announced the discovery to the world four days later.
The mission to locate Endurance had other goals—ones that focused on environmental dynamics and scientific research that Shackleton and his men likely could have never envisioned a century ago. The crew spent nearly six weeks off the coast of Antarctica aboard the South African icebreaking polar research vessel Agulhas II, during which time scientists and researchers conducted studies on a wide range of topics, including maritime navigation and how the changing climate has affected ice levels around Antarctica.
“A lot of these snow and ice properties we measure here are needed to learn about the structure of the ice and snow in the Weddell Sea,” says Lasse Rabenstein, the expedition’s chief scientist. “It’s a complicated and special one, more complicated than other parts of the Antarctic or Arctic.”
Researchers often evaluate ice thickness in specific areas of Antarctica via satellite imagery, but as Rabenstein told Outside, at some point scientists need to study the ice and water on-site.
That’s not all the researchers aboard the vessel studied. Rabenstein, a geophysicist, recently founded his own company, called Drift and Noise, which specializes in navigating frozen seas. At a 24-hour ice information desk aboard the ship, Rabenstein and his crew kept up-to-date satellite images and ice drift forecasts for the crew and the subsea team to help them navigate through the dark and in whiteout conditions. The information they provided helped in the search for the lost ship. It also furthered Rabenstein’s research around navigation in ice.
“With my company, we are writing navigation software for research ships in the ice. I learned a lot about what else is needed in a software to navigate safely, so for me that was the most important goal: to apply our own tools and learn how we can improve them,” Rabenstein says.
Meanwhile, engineering scientists used sensors to learn more about how the Agulhas II reacted to pressure from the ice to optimize future polar vessels for safety and stability, Rabenstein explained. Representatives from the South African weather service deployed weather balloons and scanned the water column, collecting data that was shared with a global research community.
In total, the expedition team was composed of 63 people with various backgrounds and areas of expertise: engineers, geophysicists, doctors, statisticians, scientists, polar field guides, oceanographers, and beyond.
For a group of individuals whose highly specialized work often takes them to far-flung places, the opportunity to be a part of the legendary explorer’s story was significant. Nico Vincent, manager of the subsea team, said that even if the team had failed to locate Endurance, the expedition would have provided worthwhile outcomes.
“Secondary objectives have been successfully achieved too: ice science, weather forecast, marine engineering research, education for kids, and media support,” Vincent says.
Of course, locating Endurance was the team’s primary task, Vincent stressed, and all 63 members of the expedition contributed in some way to the search for the lost ship.
The Agulhas II was outfitted with two helicopters, all the materials to install an ice camp, and loads of scientific research equipment, including two underwater autonomous vehicles (AUV) that did the heavy lifting of hunting for the wreck.
While many have dreamed of finding Endurance, this is only the second expedition mounted to try finding the wreck. In 2019, a crew consisting of many of the same individuals set out in an icebreaker equipped with an AUV to scan the seafloor, but the expedition lost the vehicle in the drifting ice. This time around, the group also brought a robust team of sea ice physicists and researchers to help the AUV navigate through the ice.
“The Weddell Sea is probably the most difficult ocean to travel on worldwide,” Rabenstein says. “The goal was to assist the ship as much as possible with information so that we can smoothly and smartly travel through the ice.”
The subsea team operated about 30 dives with the primary AUV before locating the wreck, watching from a computer screen as the AUV scanned the ocean floor for four to eight hours at a time. Vincent ensured they were prepared for any eventuality: they brought 50 tons of equipment with them, including three winches, more than 40 miles of fiber optic tether for the AUV, homemade ice drill augers able to drill ice up to 16 feet deep, and more. The staff tested the equipment for six months before the expedition.
Vincent explained that operating an AUV under these conditions is extremely challenging, requiring high-tech equipment and a strong, experienced team. “To make it under drifting ice is harder than landing on the moon in 1969,” he says.
For many members of the expedition team, this was a unique mission. “I never had an expedition where we had really a search-and-find target,” Rabenstein says. “Either we succeed completely by finding the wreck or we fail. Usually when you do scientific operations, there’s a goal, but it’s more open—not a fail-or-succeed goal.”
After locating the wreck, the crew paid a visit to Shackleton’s grave in Grytviken, South Georgia, to pay their respects.
The explorer died of a suspected heart attack in 1922 while pursuing another Antarctic expedition.
“Shackleton is probably more important for me than for the average person in society,” Rabenstein says. “He never gave up, but he also did not push it to the limit—all of his people he took on his expeditions, all of them survived. Other polar explorers were not so successful at that. He was a real hero if you look at how he dealt with failure.”
The S.A. Agulhas II is projected to make landfall March 19.