Antarctic ship rescue among most tricky The rescue of 52 people from a research ship stuck in sea ice was among the most difficult Antarctic operations for Australian authorities. The stranded passengers were rescued in helicopter transfers to the Australian icebreaker the Aurora Australis on Thursday. The operation took seven hours. The group of scientists, tourists and journalists had been stuck on board the Russian vessel Akademik Shokalskiy since Christmas Eve, after a blizzard pushed sea ice around the ship, freezing it in place. A helicopter from a second rescue vessel, the Chinese icebreaker Xue Long, reached the ship at around 3pm (AEDT) after several attempts were thwarted by severe weather. The group was moved in five flights of up to 12 passengers, with each return journey being about 14 nautical miles. Earlier icebreaking attempts to reach the ship failed because of the thickness of the ice. The Australian Maritime Safety Authority (AMSA) coordinated the rescue. The head of AMSA's emergency response division, John Young, said the rescue was "up there" among the most difficult of Antarctic operations. The movement of the ice and changing weather had introduced a number of "complications," he said. "The difficulty of getting good weather windows, and getting the right ice conditions, really make life very difficult, and in this particular case, the simple fact of having to move 52 people who are not really trained in that environment added complexity," he told reporters on Friday. That's one of the reasons that we're relieved that they're now on their way to Casey [Station], and the ships are left with their professional crews. The Aurora Australis is now making its way through heavy ice and expected to reach open water later on Friday, but won't reach Tasmania until mid-January. The division's supply ship will also stop at Casey Station to complete a resupply operation of the base. Expedition leader Chris Turney took to Twitter to thank rescuers. We've made it to the Aurora Australis safe & sound. Jason Mundy from the Australian Antarctic Division said it was too early to tell what impact the rescue would have on the group's research budget and programs. Under international maritime conventions, the cost of the rescue will be borne by the ships involved. "Like all national programs the Australian Antarctic Division always prepares for the unexpected in Antarctica and our seasonal planning does have space for accommodating the unexpected," he said. We're hopeful that if we can get under way to Casey soon and complete the resupply there, then we should be able to pick up most of the main tasks of the season without too many cancellations or profound impacts.