Ketchum returned to the Antarctic again when he served as Deputy Commander, United States Naval Support Force, Antarctica, during Operations Deep Freeze I and II from 1 February 1955 to 22 March 1957.
Ketchum made a return trip to Antarctica when he took command of the U.S. Naval Support Force's operations there as Deputy Commander, participating in the Deep Freeze I and II missions between February 1, 1955, and March 22, 1957.