WASHINGTON — A SpaceX Falcon 9 rocket lifted off Sept. 2 at 7:25 a.m. Pacific from Launch Complex 4 East at Vandenberg Space Force Base, California, carrying 13 U.S. military satellites.
The mission to low Earth orbit was the second launch of the Space Development Agency’s Tranche 0 mesh network of military communications and missile tracking satellites. The primary 10 satellites of Tranche 0 launched April 2.
SDA is a U.S. Space Force organization constructing an area data network — called the Proliferated Warfighter Space Architecture — that features a transport layer and a missile-tracking sensor layer. The agency goals to deploy an online in space that may move data from satellite to satellite, and pass information to military systems on the bottom, at sea and in flight.
This was SpaceX’s third try to launch the Tranche 0 mission. The launch had been scheduled for Aug. 31 but was called off in the course of the pre-launch countdown resulting from a first-stage engine issue on the Falcon 9. A second attempt Sept. 1 was scrubbed minutes before the scheduled liftoff when an issue was discovered with a valve on the bottom support equipment that needed additional troubleshooting.
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After separating from the second stage about two and a half minutes into the flight, the booster performed three engine burns and returned to Landing Zone 4 at Vandenberg about eight minutes after liftoff. As is customary with military launches, SpaceX didn’t provide views of the second stage or payload updates after booster separation.
The 13 spacecraft of the Tranche 0 constellation launched on Saturday included 11 communications satellites — 10 made by Lockheed Martin and one made by York Space — and two missile-tracking sensor satellites made by SpaceX.
Each Tranche 0 launches were performed by SpaceX under a December 2020 $150 million contract.
This was SpaceX’s 61st launch thus far this yr and 260th overall. The primary-stage booster for this mission accomplished its thirteenth flight. SpaceX thus far has recovered 222 first stages.