A SpaceX Falcon 9 rocket launched 13 Tranche 0 demonstration satellites for the U.S. military’s Space Development Agency. The launch is the second of two Falcon 9 missions to carry SDA demonstration spacecraft for a future constellation of military missile tracking and data relay satellites. The Falcon 9’s first stage booster returned to Landing Zone 4 at Vandenberg. Delayed from June. Launched delayed from Aug. 31 due to an engine issue on the Falcon 9 rocket and delayed from Sept. 1.