The United States Air Force says a test launch of an intercontinental ballistic missile is scheduled to happen on Tuesday. The unarmed Minuteman 3 missile is to be launched from Vandenberg Air Force Base, California, and travel 6,742 kilometres to the Kwajalein Atoll in the Pacific Ocean. It is one in a series of periodic launches to ensure that the ICBM force is reliable. Read also: North Korea continues short-range missile tests The U.S. has 450 nuclear-armed Minuteman 3 missiles ready for combat use, if directed by the president. They are in underground silos around F.E. Warren AFB, Wyoming; Malmstrom AFB, Montana; and Minot AFB, North Dakota. The The last launch of a Minuteman III missile from Vandenberg Air Force Base flew 4,290 nautical miles to a test range in the Marshall Islands back on November 14, 2012.