An unarmed Minuteman III intercontinental ballistic missile was launched early Wednesday from Vandenberg Air Force Base on the central California coast, the Air Force said. The launch was the 136th in a series of Strategic Air Command operational test launches of the weapons system. After a flight of about 30 minutes, the unarmed re-entry vehicles on the missile tracked to their targets in the Kwajalein Missile Range, about 4,200 miles away.