Australian Maritime Safety Authority, via European Pressphoto Agency

The view from the Akademik Shokalskiy, stuck in pack ice near Cape de la Motte, Antarctica. An Australian icebreaker was in sight early Monday.

An Australian icebreaker worked its way slowly through thick ice off Antarctica early Monday in the latest attempt to rescue about 70 people aboard a stranded research ship.

The ship, the 233-foot Akademik Shokalskiy, became stuck in the ice last Tuesday when strong winds pushed loose pack ice up against it near Cape de la Motte, about 1,700 miles south of Hobart, Tasmania. It is carrying the Australasian Antarctic Expedition, scientists and tourists who are studying changes to the environment of East Antarctica in the century since the region was first explored.

By early Monday, the icebreaker, the Aurora Australis, was about 20 miles from the Shokalskiy, Chris Turney, a leader of the expedition, said in a phone interview from the ship. "We've been in contact with them and we can see them," he said.

The Australis is the second icebreaker to try to reach the ship as part of the rescue operation, which is being coordinated by the Australian Maritime Safety Authority. A Chinese vessel, the Xue Long, had tried early Saturday but was stalled by the thick ice.

Dr. Turney, who is a professor of climate change at the University of New South Wales, said that if the Australian ship was unable to clear a path to free the Shokalskiy, the Xue Long, which has remained in the area, had a helicopter that could be used to ferry people to the Australis. The Australis would take them to Casey Station, a base operated by the Australian Antarctic Division, and from there they would take other ships home.

"We've warned everyone on board that that's a possibility," Dr. Turney said. All on board are well and morale is good, he said.

The expedition, with a multidisciplinary team of about 25 professors and graduate students and 20 tourists, set sail from Bluff, New Zealand, on Dec. 8 on what was to be a monthlong voyage. The expedition is retracing some of the travels, and replicating some of the studies, of the Australian geologist Douglas Mawson, who first explored East Antarctica from 1911-14.

The ship anchored at the edge of pack ice on Dec. 18, and Dr. Turney and others spent a day journeying about 45 miles across the ice to Mawson's hut. The ship then headed east through open water. But as it began heading north, it "ran afoul of very strong winds" that pushed the loose ice in its way. "It pegged us in," he said, and the frozen expanse quickly grew as more ice piled up. "At first we were just two nautical miles from getting to open water, and now it's 20," he said.

Even though it is summer in the Antarctic, waiting for the ice to break up on its own is not an option, Dr. Turney said, because of the risk that the ship could drift along with the ice and collide with one of several icebergs in the area, which are drifting independently of the pack ice.

Since the ship became stuck, Dr. Turney and others have been a regular presence on Twitter and other social media sites. Some have made short videos describing their experiences.

Dr. Turney said that some of the people aboard had gone onto the ice to study birds and make other scientific observations, and that others had occupied themselves on board with ad-hoc classes in subjects like knot tying. And a steady diet of films has been available to help pass the time, he said.

"At first, people were starting to watch disaster movies," Dr. Turney added. "But I had to stop that." Now it is mostly comedies, although episodes of the hit series "Breaking Bad" have been popular, too.