May 5 (UPI) -- A planned test of a Minuteman III missile was aborted before the missile left Vandenberg Air Force Base, Calif., on Wednesday, the U.S. Air Force said.
The Minuteman III intercontinental ballistic missile, which can be nuclear-armed but was unarmed for the test, was to be launched within a six-hour window beginning at 12:15 a.m. on Wednesday.
The reason for ground abort, defined by the Air Force as prevention of a "crew-ready" aircraft from becoming airborne, was not disclosed in a Wednesday press release.
In the release, officials emphasized that "the Air Force adheres to strict protocols while performing operational test launches, only launching when all safety parameters with the test range and missile are met."
Air Force Global Strike Command is investigating the cause of the abort, and a rescheduled launch is being assessed.
The missile launch was to be the second this year from Vandenberg Air Force Base.
In the first, on Feb. 24, a Minuteman III missile landed 4,200 miles away and on target at the Kwajalein Atoll in the Marshall Islands, and was regarded by the Air Force as a success.
The LGM-30G Minuteman III missile, in use since 1970 and an advanced version of a missile developed in the 1950s, is the only land-based ICBM of the United States military.
It is regarded as one leg, with the Trident submarine-launched ballistic missile and missile-carrying long-range strategic bombers, of the U.S. nuclear triad of platforms.