The Minotaur II rocket was carrying a new intercontinental ballistic missile reentry vehicle called the Mk21A, which is being developed jointly by the US Air Force and Lockheed Martin, according to reports earlier this week.
"A Minotaur II+ rocket exploded approximately 11 seconds after launching from Test Pad-01 at 11:01 p.m. PDT [Pacific Daylight Time] Wednesday," the base said in a press release.
An investigative review board is working to determine the cause of the explosion, the release said.
There were no injuries in the explosion and the debris was contained to the immediate vicinity of the launch pad, the release said.