Live coverage: SpaceX countdown at Vandenberg aborted at T-minus 3 seconds

SpaceX aborted a countdown at Vandenberg Space Force Base in California at T-minus 3 seconds Thursday, delaying the launch of a Falcon 9 rocket with the first set of 10 missile tracking and data relay satellites for the U.S. military’s Space Development Agency. The next launch opportunity is Friday at 7:29 a.m. PDT (10:29 a.m. EDT; 1429 UTC), assuming SpaceX resolves the issue that caused the rare countdown abort.