SCOTIA, N.Y. — An annual mission to the South Pole that involves hundreds of members of a New York Air National Guard unit is now underway.

Some 500 airmen of the 109th Airlift Wing will take part in Operation Deep Freeze, which started last week. It’s the Schenectady County-based unit’s 31st season of conducting missions at McMurdo Station in Antarctica.

The 109th uses its six LC-130 Hercules cargo planes based at Stratton Air National Guard Base to provide logistical support to the National Science Foundation-managed U.S. Antarctic Program.

By the time the deployment wraps up next year, the unit will have flown about 1,800 flying hours while conducting more than 200 missions.

The 109th is the only unit in the U.S. military that operates ski-equipped aircraft capable of landing on snow and ice.