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 went back to Antarctica again while serving as Deputy Commander for the U.S. naval operation in Antarctica during Operations Deep Freeze I and II from February 1, 1955, to March 22, 1957.