A team of Antarctic researchers at the start of the week began its search for one of the most famous lost ships in history—and lost a sub in the process. The search for the shipwreck of Ernest Shackleton's Endurance in the Weddell Sea was called off on Thursday, with the British team looking for it forced to leave the area due to worsening conditions and amid fears they could get trapped, reports Live Science. "Like Shackleton before us, who described the graveyard of Endurance as 'the worst portion of the worst sea in the world,' our well laid plans were overcome by the rapidly moving ice, and what Shackleton called 'the evil conditions of The Weddell Sea,'" says expedition leader Mensun Bound.
The team's SA Agulhas II icebreaker lost all communication with the Autonomous Underwater Vehicle, which the Guardian reports was equipped with cameras capable of taking color photos and sent into waters than can reach nearly 2 miles in depth. The BBC reports it's unclear why: the rough sea-ice conditions (a rep for the US company that facilitated the AUV dive called it "the harshest environment on the planet"), a sub failure, or an undersea collision are all possibilities. The bummer is that it's conceivable the AUV discovered the remnants of the Endurance, which went down in 1915, as the link was lost near the end of its 30-hour dive; but the only way to access its scan data is to physically remove it from the AUV. But the expedition wasn't for naught: The team's primary mission, to study the Larsen C Ice Shelf and the huge iceberg A68, was completed. (Shackleton's survival story is legendary.)