Passengers on board a research ship that has been trapped in Antarctic ice for more than a week are expected to be rescued by helicopter on Thursday after three icebreakers failed to reach the paralyzed vessel, officials said.

The Australian Maritime Safety Authority’s (AMSA) Rescue Coordination Centre, which is handling the operation, said early Thursday that weather conditions had improved in the area since Wednesday and rescue flights were likely to commence shortly.

“Wind in the area is now down to 10 knots (19 kmh) and visibility has improved. Weather conditions are expected to remain favorable over the next 36 hours,” the center said in a statement.

The 74 scientists, tourists and crew on the Russian ship MV Akademik Shokalskiy, which has been stuck since Xmas Eve, had been hoping the Australian icebreaker Aurora Australis would be able to crack through the thick ice and allow them to continue on their way. The Aurora came within 20 kilometers (12 miles) of the ship Monday, but fierce winds and snow forced it to retreat to open water.

The helicopter on board the Chinese-flagged vessel Snow Dragon will be used to rescue 52 scientists and tourists, a dozen at a time, over five hours. All 22 crew members are expected to stay with their icebound vessel, which is not in danger.

The center said the passengers will be flown 11 kilometers (7 miles) to the Chinese ship, from where they will be transported 4 kilometers (2 miles) by barge to the Australian icebreaker.

The Snow Dragon, which is waiting with the Aurora at the edge of the ice pack, was also unable to crack through the ice, as was France’s L’Astrolabe.

The Akademik Shokalskiy, which left New Zealand on Nov. 28, got stuck Xmas Eve after a blizzard pushed the sea ice around the ship, freezing it in place about 2,700 kilometers (1,700 miles) south of Hobart, Tasmania. The ship isn’t in danger of sinking and has weeks’ worth of supplies on board, but it cannot move.

The scientific team on board had been recreating Australian explorer Douglas Mawson’s 1911 to 1913 voyage to Antarctica. Expedition leader Chris Turney had hoped to continue the trip if an icebreaker managed to free the ship.

(AP)