Operation Catchpole is launched as American troops devastate the Japanese defenders of Eniwetok and take control of the atoll in the northwestern part of the Marshall Islands. The loss for the Japanese was significant: only 64 of the 2,677 defenders who met the Marine and Army force survived the fighting. The Americans lost only 195. The position on Eniwetok gave U.S. forces a base of operations to finally capture the entirety of the Marianas. Eniwetok was also useful to the United States after the war–in 1952 it became the testing ground for the first hydrogen bomb.