The U.S. Coast Guard Cutter Polar Star departed the Antarctic region last week after 65 days south of the Antarctic Circle as part of of Operation Deep Freeze 2025.

The annual event is led by the U.S. Antarctic Program in conjunction with the Department of Defense to support the U.S. National Science Foundation. The operation coordinates strategic airlift, tactical deep field support, aeromedical evacuation, search and rescue, sealift, bulk fuel supply, port cargo handling and transportation. Polar Star’s crew performed icebreaking duties in McMurdo Sound, clearing routes to ensure safe passage for cargo vessels for McMurdo Station and New Zealand’s Scott Base.

“The surface ice conditions in McMurdo Sound were abnormally light this year, a welcome change of pace from the extreme conditions experienced last year,” Capt Jeff Rasnake, Polar Star’s commanding officer, said in a service news release issued Thursday. The Polar Star left McMurdo Sound on Tuesday. “Operation Deep Freeze presented a number of challenges, beyond those inherent in maintaining and operating a 49-year-old ship. We benefited tremendously from a great deployment plan which allowed us to take advantage of favorable conditions and use the elements to stay ahead of events without pressing the cutter or crew excessively. That up-front planning made a big difference.”

Polar Star also conducted a crew exchange with the New Zealand Defense Force ship Aotearoa. 

“Operation Deep Freeze works closely with other Antarctic programs to include those of New Zealand and Australia, as well as their respective defense forces,” said Lt. Cmdr. Rachel Rand, Polar Star’s operations officer. “The ability to collaborate with others to achieve mission success and ensure the United States’ vital interests in the Polar regions makes this assignment so unique.”

The crew has traveled nearly 16,000 miles since departing its Seattle homeport in November with stops in Honolulu, Sydney and McMurdo Station. 

The Polar Star is the United States’ only heavy icebreaker. The 399-foot heavy polar icebreaker commissioned in 1976, weighing 13,500 tons. It is 84-feet wide with a 34-foot draft. The cutter’s six diesel and three gas turbine engines produce up to 75,000 horsepower, according to the Coast Guard.

During the operation, a civilian logistics specialist suffered a myocardial infarction Feb. 13, and an LC-130 Hercules “ski-bird” flew patient from Antarctica to New Zealand for medical treatment.

The partnership between the National Science Foundation and the military was key to ensuring rapid medical care and evacuation of the patient, Maj. Thomas Powell, McMurdo Station flight surgeon, said in a news release about the incident.

previous coverage

• Ski-bird medevacs contractor from Deep Freeze