CAPE CANAVERAL, FLA. — Ground controllers destroyed a $10 million United States military research rocket when it veered off course after launch from an Air Force pad early Aug. 20.The Aries rocket was carrying a secret cargo for the Strategic Defense Initiative, the anti-missile defense system. Pentagon officials said the cargo was part of a research project called Red Tigress, in which scientists are developing satellite sensors that can distinguish real missile warheads from decoys. Plans for a second launch Aug. 23 were on hold while engineers tried to find out why the $10 million experiment failed, according to an Air Force spokeswoman, Sgt. Ivy Paige. The rocket was manufactured by the Chandler, Ariz., Space Data Division of Orbital Sciences Corporation. One of its Prospector rockets was destroyed after experiencing guidance problems in a commercial launch last June. Air Force officials said no one was injured in the blast, which was triggered by a radio signal from ground controllers shortly after launch. "Range safety personnel destroyed the rocket approximately 23 seconds into flight because it departed from the planned trajectory and violated range safety rules," Sergeant Paige said. The rocket was to have made a nine-minute suborbital flight eastward over the Atlantic Ocean. Instead, it arced southward in the darkness toward the communities of Cape Canaveral and Cocoa Beach. Approval for the second launch would not be given until recovery teams had finished searching the ocean and the Air Force station for debris that could explain what caused the rocket to veer off course, Paige said.