A U.S. Air Force C-17 Globemaster III is unloaded after returning from one of the last Operation Deep Freeze flights of the 2018-2019 Antarctic research season at the Christchurch International Airport, Christchurch, New Zealand, Feb. 21, 2019. The seasons run annually from September 1st to July 31st. Led by Pacific Air Forces, the Joint Task Force-Support Forces Antarctica (JTF-SFA) provides the National Science Foundation-managed U.S. Antarctic Program with logistical support.